Why use differential circuits in RF signal chain applications? What are its advantages?

“When it comes to communication systems, differential circuits always offer better performance than single-ended circuits—they have higher linearity, immunity to common-mode interference signals, and more. Today we will talk about the 4 major advantages of differential circuits in RF signal chain applications~

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When it comes to communication systems, differential circuits always offer better performance than single-ended circuits—they have higher linearity, immunity to common-mode interference signals, and more. Today we will talk about the 4 major advantages of differential circuits in RF signal chain applications~

1. Using differential circuits can achieve higher signal amplitudes than using single-ended circuits

Differential signals provide twice the amplitude of single-ended signals at the same supply voltage, and it also provides better linearity and SNR performance.

Figure 1. Differential Output Amplitude

2. Differential circuits have good immunity to external EMI and crosstalk from nearby signals

This is because the received wanted signal voltage is doubled, the effect of noise on tightly coupled traces is theoretically the same, they cancel each other out.

3. Differential signals tend to generate lower EMI as well

This is because changes in signal level (dV/dt or dI/dt) create opposing magnetic fields, which again cancel each other out.

4. Differential signal can suppress even order harmonics

The following shows an example of continuous wave (CW) passing through a gain block.

When using a single-ended amplifier, as shown in Figure 2, the output can be expressed as Equation 1 and Equation 2.

Figure 2. Single-ended amplifier

When using a differential amplifier, the input and output are shown in Figure 3, expressed as Equation 3, Equation 4, Equation 5, and Equation 6.

Figure 3. Differential Amplifier

Ideally, the output does not have any even-order harmonics, making differential circuits a better choice for communication systems.

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During the Spring Festival, the TV is turned on for 7 hours every day.

Every Journal Reporter: Peng Fei Every Journal Editor: Song Sijin

With the resumption of work and production in various places, we bid farewell to the longest Spring Festival holiday in history. What are you doing at home this holiday season?

Today (February 26) morning, at the Hisense Internet TV Big Data Online Communication Conference, Xu Xiaorong, Deputy General Manager of Hisense Juhaohao, told the “Daily Economic News” reporter that from the point of view of the boot time, watching TV has become a popular choice for many people. Home preferred.

The Internet TV big data released by Hisense shows that from January 20th to February 18th, the average daily life of Hisense Internet TV households reached 24.9 million, far exceeding the traditional peak daily life on New Year’s Eve.

Interestingly, under the wave of Internetization of TV, its ability to compete with mobile phones for audiences has also emerged during this special Spring Festival. Xu Xiaorong said that the conversion rate of new Internet TV users has been significantly improved.

A tie with the mobile phone in the Spring Festival

In Xu Xiaorong’s impression, according to the laws of previous years, New Year’s Eve will generally reach the peak of ratings. Judging from the data, on New Year’s Eve, Hisense Internet TV cloud platform Juhaohao has more than 22 million active households, a year-on-year increase of 60%.

However, the climax of New Year’s Eve was broken this year during the longest Chinese New Year holiday in history.

Judging from the data of Hisense Internet TV sets, during the 30 days from January 20 to February 18, the average daily boot time of Hisense Internet TV was 412 minutes, an increase of 25.76% from the previous cycle, and the average daily number of active households It reached 24.9 million, an increase of 13.2% from the previous cycle.

This data is based on real-time monitoring of the world’s largest Internet TV cloud platform. Data shows that as of December 31, 2019, Hisense Internet TV services operated by Juhaohao reached 51.27 million households worldwide, including 39.01 million domestic households and 12.26 million overseas households, providing scenario-based AI services for about 150 million consumers. In 2020, the number of households served by Juhaohao will exceed 65 million.

“The days after New Year’s Eve far exceed the data on New Year’s Eve, which shows that watching TV has become the first choice for many people to stay at home, and it is equal to the average daily use of mobile phones by the public.” Xu Xiaorong said.

According to the statistics of the program viewing big data system (CVB) of the State Administration of Radio, Film and Television, from January 25 to February 9, the average daily viewing users of cable TV and IPTV nationwide increased by 23.5% compared with last December, and the total viewing time increased by 41.7%. The average daily viewing time in front of the TV is nearly 7 hours.

According to the “2020 Chinese Smart TV User Spring Festival Insight Report” released by Aowei Interactive Entertainment, the smart TV boot rate during the Spring Festival this year reached 45.0%, an overall increase of 11.1% compared to usual. In addition to the obvious increase in the boot rate, the smart TV during the Spring Festival this year was 6.62 hours.

“The 412 minutes of Hisense Gathering is 6.87 hours when converted into hours.” Xu Xiaorong said that in the field of smart TVs, it exceeds the industry average and is close to the length of cable TV.

Large-screen education, medical film and television dramas become “just need”

If a tie between TV and mobile phone is a manifestation of data, the unique large screen of Internet TV has become a key part of the outcome of the two sides.

“The big screen education represented by Juhaohao Education will play a greater role in the big industry of online education.” Xu Xiaorong said when referring to online education, everyone has seen that in response to this postponement of the school, the education department, Schools, parents, teachers are looking for alternatives.

Since the postponement of the start of the school year, the education department, schools and other parties have been looking for alternative ways. Their trajectory has roughly gone through: the school called on parents to download various mobile apps, the local education department recorded the curriculum and standardized teaching content, and the Ministry of Education designated China Education TV to record “Ibid.” One Class” to standardize the uneven teaching content in different places.

“With the announcement of the postponement of the start of school all over the country, the live and on-demand courses of Juhao Education have also attracted much attention.” In Xu Xiaorong’s view, “big screen education” plays a unique role in special times. According to the Hisense AI TV Big Data Center, during the Spring Festival holiday, Juhaohao Education's average daily on-demand time increased by 30% month-on-month, and active families increased by 134% compared with last year's winter vacation. At the peak, more than 2.45 million households learned online through large TV screens every day.

Compared with the popularity of children’s online education, adults’ attention to TV also has a clear tendency this Spring Festival.

According to the information from Jujiao, during the Spring Festival, the content that attracts more attention includes news information, TV series and movies related to the epidemic. For example, as of February 18, the number of on-demand episodes of the “War Epidemic” channel has reached 760 million. The number of on-demand episodes of “Emergency Doctor” produced in 2017 has been increasing, ranking 10th among many popular dramas; Korean movies in 2013 The on-demand volume of “Influenza” increased by 49 times month-on-month.

As for the reason, Xu Xiaorong told the reporter of “Daily Economic News” that the plot of rescuing infectious diseases in the TV series is the reason for its resurgence, and the on-demand volume of other medical works has also increased significantly.

daily economic news

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Mi 10 Pro: “100-megapixel” camera! Is it really better than Huawei Leica lens?

The Xiaomi Mi 10 series came with “100 million pixels” as expected. I remember that more than three months ago, Xiaomi launched a water-testing product, the Xiaomi CC9 Pro, which was also the first model to mass-produce a 100-megapixel camera. It scored 121 points in the DxOMark camera evaluation, which was tied for the first place in the world with Huawei Mate 30 Pro.

It’s like getting first place every time in an exam, but as a result, a so-called “underachiever” is tied for first place with himself. This kind of thing is unacceptable to anyone! Later, Huawei may have seen that Xiaomi has gradually caught up with itself, so it sent the Huawei Mate 30 Pro to the test again, euphemistically called “retest”, but this time the test is the 5G version.

Sure enough, the organization DxOMark is also a very chicken thief, scoring 123 points for Huawei Mate 30 Pro 5G, which is two points higher than CC9 Pro. The new Xiaomi Mi 10 released this time, the high-end version of the Xiaomi Mi 10 Pro officially topped the DxOMark list with a score of 124 points, realizing Lei Jun’s vision that “Xiaomi mobile phone cameras will overwhelm Huawei”.

Although the rating of Xiaomi Mi 10 Pro surpassed that of Huawei Mate 30 Pro 5G this time, it still leaves many questions for many people. Is the “100-megapixel” camera on this phone better than Huawei’s Leica lens? For this question, I believe that many people focus on the word “Leica”.

We often see the “LEICA” LOGO on Huawei Mate series and P series products, and this feature started from Huawei P9, which means it has a history of 4 years, but the lens used by Huawei is only “Leica certified” “Instead of being produced by Leica, there may be many people who think that Huawei’s mobile phone lenses are produced by Leica!

As for why Huawei is equipped with Leica-certified lenses, this is similar to the “Porsche Design” used by Huawei. Porsche Design is not a Porsche car. PORSCHE” is a company that designs auto parts for cars.

Huawei uses “Porsche Design” to confuse the concept, making consumers mistakenly think that it is a joint model of Porsche cars, which looks very high-end. The same is true for this Leica certification. We know that Leica cameras in the past were very expensive, often costing tens of thousands of dollars. Huawei’s use of Leica-certified lenses is undoubtedly a gold medal for the product, just like a mobile phone designed by Porsche.

Therefore, when we understand Huawei’s “Leica lens”, there is no need to over-understand how much this lens is related to Leica. In fact, it is the same as the Leica-certified lens used by Panasonic cameras. In theory, the Leica team has cooperated with the Huawei camera team. , As for the sensor provided by Sony, software optimization is also the result of the strength of the team.

Let’s take a look at Xiaomi again. Maybe the brand advantage of the Leica-certified lens equipped by Huawei will be better than that of the Xiaomi Mi 10 Pro, but this is only in terms of lenses, not to mention that it is not necessarily good, because the Xiaomi Mi 10 Pro is equipped with an 8P lens, which can Greatly increase the amount of light condensing. As I said above, this is just a competition of lenses, that is, a competition of convex lenses.

Also affecting the overall imaging results are sensor and software optimizations. The main camera sensor equipped with the Xiaomi Mi 10 Pro is the highest in history, with a 108-megapixel, 1/1.33-inch image sensor, an equivalent focal length of 25mm, an f/1.69 aperture lens, and a lot of optical image stabilization.

In contrast, Huawei Mate 30 Pro 5G has no advantage. The main camera is 40 million pixels, 1/1.7-inch image sensor, f/1.6 aperture lens, equivalent focal length of 27 mm, and optical image stabilization. From the perspective of the entire parameter, Xiaomi’s “100-megapixel” camera does surpass the main camera of Huawei Mate 30 Pro 5G.

On other cameras, we can also briefly understand that Xiaomi Mi 10 Pro is also equipped with a 12-megapixel, 1/2.6-inch image sensor, a 50mm equivalent focal length, a portrait lens with f/2 aperture; 8-megapixel, 1/4.4 20-megapixel, 1/2.8-inch image sensor, 16mm-equivalent focal length, f/2.2 aperture ultra-wide-angle lens.

Huawei Mate 30 Pro 5G is equipped with a 40-megapixel 1/1.54-inch sensor, f/1.8 lens, and an ultra-wide-angle cine lens with an equivalent focal length of 18 mm; an 8-megapixel, 1/4-inch sensor, f/2.4 lens, equivalent 80mm focal length, telephoto lens that supports optical image stabilization; ToF 3D depth-sensing camera.

Huawei’s ultra-wide-angle movie lens may have more advantages in terms of parameters, but with its powerful 100-megapixel capability, the Xiaomi Mi 10 Pro scored 104 points in DxOMark for video, surpassing the Huawei Mate 30 Pro 5G. As for zoom, the former supports up to 50x digital zoom, the latter 30x.

It is worth mentioning that the Xiaomi Mi 10 Pro also has a 50mm-equivalent, 1200-pixel portrait lens. I personally prefer this camera combination of the Xiaomi Mi 10 Pro. I think it is better than the rear quad camera of the Huawei Mate 30 Pro 5G. more practical. What do you think about this? Welcome to leave a message in the comment area and tell us your opinion!

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After completing the design of the power module, how to measure it?

“The step-down power supply chip is an indispensable core component in the design of Electronic products. The power supply module composed of the power supply chip provides various power supplies used by electronic products. For automotive products, the voltage of the car battery will vary between 9V-16V. In this case, the power module needs to adapt to the changing conditions of the battery voltage and load. How to test the power supply is very important. Many companies The test of the power module of the electronic products of the company is based on the reference circuit and layout example given by the Datasheet, and the ripple of the output voltage is simply tested, and the power efficiency is over.

“

1 Overview

The step-down power supply chip is an indispensable core component in the design of electronic products. The power supply module composed of the power supply chip provides various power supplies used by electronic products. For automotive products, the voltage of the car battery will vary between 9V-16V. In this case, the power module needs to adapt to the changing conditions of the battery voltage and load. How to test the power supply is very important. Many companies The test of the power module of the electronic products of the company is based on the reference circuit and layout example given by the Datasheet, and the ripple of the output voltage is simply tested, and the power efficiency is over. It is believed that all parameters of the power mode Datasheet have been marked, and there is nothing to measure, and no parameters can be changed. The actual buck circuit has many parameters that need to be tested. The picture below is a TI buck power chip LM60440, which meets the on-board requirements of AECQ-100.

In the Datasheet of LM60440, parameters such as efficiency curve graph, start-up timing graph, load transient response graph, ripple voltage graph and EMC test graph are provided. These test data are based on the EVM board test of LM60440. Tested in good condition. The actual electronic products should be tested according to specific customer requirements and system requirements. The LM60440 was used in a product we developed to step down to obtain an output voltage of 3V3. After completing the design of the schematic diagram, after getting the Demo sample by playing Allegro, the test of the power module is mainly completed from the following seven dimensions:

1. Input voltage performance test, including cold start test, enable voltage threshold test;
2. Output voltage performance test, including output voltage ripple test, load transient test, loop stability test;
3. Timing test: boot sequence, shutdown sequence;
4. Protection function test: overvoltage protection, overcurrent protection, short circuit protection, overtemperature protection;
5. Efficiency test;
6. PWM switching frequency test;
7. Withstand voltage test of key components, mainly including MOSFET, DIODE, Inductor, input capacitor, and output voltage;

Completing the above seven tests can basically reflect the performance of the power module. The following will make a comparative analysis of the measured data of the seven aspects in the test and the data in the Datasheet for discussion, and see how many test contents other friends have in the power supply design.

2. Analysis of test cases

2.1 Input voltage performance test

2.1.1 Cold start test

The cold engine start test is generally called the cold-trank test. This is because when the engine starts, a large current of the battery is required to work, resulting in a rapid drop in the battery voltage. There are corresponding test specifications for such working conditions, such as ISO 7637-2 (test pulse 4), as shown in the figure below. During the cold-trank test, even if the battery voltage drops, the on-board electronic products, such as navigation, entertainment, dashboard and other equipment, still need to maintain safe and reliable functions, which puts forward higher requirements for the power module.

According to customer requirements, the following test specifications are used in our products, which are relatively more stringent.

Regarding this test, it is not reflected in the LM60440 Datasheet. In our product testing, it meets the testing requirements. After the input voltage drops, the output voltage also drops, but it can be output again within a certain time (less than 10ms), which is in line with the definition of system requirements.

2.1.2 Enable Threshold Test

The enable (EN-Pin) of the LM60440 controls the startup and shutdown of the chip. The input voltage of this pin is controlled by a precise threshold value and is controlled by other external power supply voltages (usually 3.3V LDO control is used). In the actual product test, the threshold voltage consistent with that in the Datasheet was obtained.

2.2. Output voltage performance

2.2.1 Output voltage ripple test

Voltage ripple (ripple voltage) is basically tested, and the data tested under no-load, light-load and heavy-load conditions are different. Different selection of inductor and output capacitors will also cause different test data of voltage ripple. How to reduce the voltage ripple will not be expanded here, and many materials have been introduced. Here we mainly discuss how to test the power module after the design is completed. When the output current is 3A, the tested ripple voltage is 38mV, which is smaller than the parameter 60mV in the Datasheet.

2.2.2 Load transient test

When the load suddenly drops and loads, it will cause the phenomenon of output voltage overshoot and drop. In the actual test, for this kind of test, the output voltage overshoot and drop amplitude are required, which cannot exceed 5%*Vout. The output current is varied from 0.28A to 2.8A, the overshoot and sag voltages are 85mV and 115[size=14.6667px]mV, all are less than 3.3*0.05=165[size=14.6667px]mV. At no load and light load, the output voltage ripple will be smaller.

2.2.3 Loop Stability Test

The power supply system is generally negative feedback. After the loop is not designed, the output voltage will fluctuate. In the engineering design, the phase margin is required to be greater than 65 degrees and the gain margin is greater than 10dB. When the load current is 2.8A, use Bode100 The loop of the power supply system is tested, and the phase margin is 82 degrees and the gain margin is 15dB. The loop system is stable. Regarding this test item, it is not reflected in the Datasheet, and it is necessary to test the actual product.

Many chips are dedicated loop compensation comp-pins to compensate when the loop is unstable. The LM60440 does not have a loop compensation pin. If the loop is unstable, a compensation network can be added to the feedback loop. As shown in the Cff in the schematic diagram above, a resistor can also be connected in series.Adjust according to the specific circuit

2.3 Switching sequence

2.3.1 Boot sequence

In power products, the boot sequence is strictly corresponding to that in the Datasheet, but the soft-start time can be adjusted to meet the needs of different projects. The data obtained from the test is consistent with the Datasheet.

2.3.2 Shutdown Sequence

The shutdown sequence is not as strict as the startup sequence, so there is no test in the Datasheet, but our actual product has completed the test, and then compared with the shutdown sequence of the EVM provided by the LM60440, which is consistent.

2.4 Protection function test

2.4.1 Overvoltage Protection Test (OVP)

The power supply chip cannot be used with overvoltage. Exceeding the maximum input voltage of the power supply chip will cause the chip to be damaged by overvoltage.

Some power chips have OVP threshold voltage, the maximum absolute value voltage (this voltage is the overvoltage damage value of the chip), LM60440 has no OVP threshold voltage, another power chip used before, when the input voltage exceeds OVP threshold, the output voltage is reduced to 0, and the flag bit of the diagnostic pin is flipped.

2.4.2 Overcurrent Protection Test (OCP)

Using the electronic load to apply more than the maximum output current of the power chip will generate OCP to ensure that the output current and output voltage are within the normal working range;

2.4.3 Short circuit protection test

Using the test fixture, short the output. The power chip detects an instantaneous overcurrent and turns off the output. Ensure the normal operation of the power module.

2.5 Efficiency Test

The power module will generate various losses, such as MOSFET switching loss, conduction loss, inductor DC loss, AC loss and so on. This results in a change in output efficiency. Therefore customers will demand the lowest efficiency ratio. Under different input voltage conditions, the LM60440 can basically achieve an efficiency of more than 90% under heavy load.

In the actual measurement, the efficiency will be lower than that of the Datasheet.When the output current increases, the efficiency will be higher

2.6 PWM switching frequency test

The working mode of the LM60440 will change with the change of the load, and it will switch between PFM, DCM, and CCM modes to meet the needs of the load current. The PWM switching frequency also changes accordingly.

2.7 Withstand voltage test of key components

The LM60440 has a built-in MOSFET, and the voltage at the node of the chip SW-pin and the inductor will always be loaded on the drain of the MOSFET. The PWM switching process will generate an overshoot voltage. The maximum value of the measured overshoot voltage is 8.6V. The overshoot voltage cannot break down the internal MOSFET. If you want to reduce the overshoot voltage, you can add a snubber circuit to suppress it.

The output capacitor generally chooses MLCC, and it is necessary to consider that the ripple current should not exceed the rated value of the MLCC, otherwise the MLCC will heat up. The figure below shows the ripple current of MLCC, about 90mA, and the ESR of MLCC is also relatively small, so it will not generate too much heat.

3. Summary

After completing the above tests, the test values ​​meet the system requirements and customer requirements. The EMC test needs to be carried out later. The EVM board of the LM60440 provided by TI has passed the EMC test and has a large margin. But in the specific product, there is not only this power supply, but also the BOOST circuit, so the EMC data provided by the Datasheet is only for reference. Even if the product’s EMC test fails, it is generally not just a problem with the power module. It is necessary to locate the interference source and radiation source from the perspective of the entire circuit board, and then make corresponding improvements.

After completing the 2PCS test at the R&D level, the circuit board is then handed over to the TQE department for tolerance tests such as high and low temperature, humidity and life.

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Here is the solution for connecting the positive and negative poles of the power supply to the reverse burn board!

“Many projects of hardware engineers are completed on the hole-hole board, but there is the phenomenon of accidentally connecting the positive and negative poles of the power supply, causing many Electronic components to be burned, or even the entire board is scrapped, and another piece of welding has to be welded. , I don't know if there is any good way to solve it?

“

Many projects of hardware engineers are completed on the hole-hole board, but there is the phenomenon of accidentally connecting the positive and negative poles of the power supply, causing many electronic components to be burned, or even the entire board is scrapped, and another piece of welding has to be welded. , I don't know if there is any good way to solve it?

First of all, carelessness is inevitable. Although it is only to distinguish between the positive and negative wires, one red and one black, we may wire it once, and we will not make a mistake; we will not make a mistake if we connect the wire 10 times, but 1000 times? How about 10,000? It’s hard to say at this time. Due to our carelessness, some electronic components and chips are burnt out. The main reason is that the components are broken down due to excessive current. Therefore, measures must be taken to prevent reverse connection.

The following methods are commonly used:

01. Diode series anti-reverse connection protection circuit

A forward diode is connected in series with the positive power input terminal to make full use of the forward conduction and reverse cutoff characteristics of the diode. Under normal circumstances, the diode is turned on and the circuit board works.

When the power supply is connected reversely, the diode is cut off, the power supply cannot form a loop, and the circuit board does not work, which can effectively prevent the problem of reverse power connection.

02. Rectifier bridge type anti-reverse connection protection circuit

Use a rectifier bridge to change the power input into a non-polar input, no matter whether the power is connected or reversed, the circuit board works normally.

The above uses diodes for anti-reverse treatment. If silicon diodes have a voltage drop of about 0.6-0.8V, germanium diodes also have a voltage drop of about 0.2-0.4V. If the voltage drop is too large, MOS tubes can be used for anti-reverse treatment. The voltage drop of the MOS tube is very small, up to several milliohms, and the voltage drop is almost negligible.

03, MOS tube anti-anti-protection circuit

Due to factors such as the improvement of the process and the nature of the MOS tube, the internal resistance of the conduction is mostly at the milliohm level or even smaller. This will cause the voltage drop and power loss of the circuit to be extremely small, or even negligible, so Choosing a MOS tube to protect the circuit is a more recommended way.

(1) NMOS protection

As shown in the figure below: At the moment of power-up, the parasitic diode of the MOS tube is turned on, and the system forms a loop. The potential of the source S is about 0.6V, and the potential of the gate G is Vbat, and the turn-on voltage of the MOS tube is extremely: Ugs = Vbat – Vs , The gate shows a high level, the ds of the NMOS is turned on, the parasitic diode is short-circuited, and the system forms a loop through the ds of the NMOS.

If the power supply is connected reversely, the on-voltage of the NMOS is 0, the NMOS is cut off, the parasitic diode is reversed, and the circuit is disconnected, thereby forming protection.

(2) PMOS protection

As shown in the figure below: At the moment of power-on, the parasitic diode of the MOS tube is turned on, and the system forms a loop. The potential of the source S is about Vbat-0.6V, and the potential of the gate G is 0, and the turn-on voltage of the MOS tube is extremely: Ugs = 0 -(Vbat-0.6), the gate is shown as low level, the ds of the PMOS is turned on, the parasitic diode is short-circuited, and the system forms a loop through the ds of the PMOS.

If the power supply is connected reversely, the on-voltage of the NMOS is greater than 0, the PMOS is cut off, the parasitic diode is reversed, and the circuit is disconnected, thereby forming protection.

Note: The NMOS tube ds is connected to the negative pole, and the PMOS tube ds is connected to the anode. The direction of the parasitic diode is toward the current direction of the correct connection.

The connection of the D pole and S pole of the MOS tube: When using an N-channel MOS tube, the current usually enters from the D pole and flows out from the S pole, and the PMOS is S in and D out. It is just right when used in this circuit. On the contrary, through the conduction of the parasitic diode to meet the voltage condition of the MOS tube conduction. The MOS tube will be completely turned on as long as a suitable voltage is established between the G and S poles. After turning on, it is like a switch is closed between D and S, and the current is the same resistance from D to S or S to D.

In practical applications, the G pole is generally connected in series with a resistor. In order to prevent the MOS tube from being broken down, a Zener diode can also be added. The capacitor connected in parallel with the voltage divider resistor has a soft-start function. At the moment when the current starts to flow, the capacitor is charged, and the voltage at the G pole is gradually established.

For PMOS, compared to NOMS, the turn-on requires Vgs to be greater than the threshold voltage. Since its turn-on voltage can be 0, the voltage difference between DS is not large, which is more advantageous than NMOS.

04, fuse protection

For many common electronic products, you can see that a fuse is added to the power supply after disassembly. When the power supply is reversed and there is a short circuit in the circuit, the fuse will be blown to protect the circuit because of the large current. It is troublesome to repair and replace.

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Nexperia expands the LFPAK56D MOSFET product series and launches a half-bridge package product that meets the AEC-Q101 standard

February 23, 2021: Nexperia, an expert in the field of key semiconductor devices, today announced the launch of a series of half-bridge (high-end and low-end) automotive MOSFETs using space-saving LFPAK56D packaging technology. A half-bridge configuration using two MOSFETs is a standard building block for many automotive applications, including motor drivers and DC/DC converters. This new package provides a single-device half-bridge solution. Compared with the dual-channel MOSFET used in the three-phase motor control topology, the PCB area is reduced by 30% due to the removal of the PCB circuit, while supporting simple automatic optical inspection (AOI) during the production process. LFPAK56D half-bridge products adopt the existing high-volume LFPAK56D packaging process and have mature automotive-grade reliability. This type of package uses flexible pins to improve overall reliability, and the internal copper clip connection between MOSFETs simplifies the PCB design and brings a plug-and-play solution. The current handling capacity reaches 98A, which is very good. .

Generally, in a half-bridge structure, the PCB connection between the source of the high-side MOSFET and the drain of the low-side MOSFET generates a large amount of parasitic inductance. However, through the internal clip-on connection, the LFPAK56D half-bridge package has successfully reduced parasitic inductance by 60%.

The newly introduced LFPAK56D half-bridge MOSFETs are BUK7V4R2-40H and BUK9V13-40H. Both products use the highly durable Trench 9 automotive-grade wafer process technology, with a rated voltage of 40 V, and have passed twice the verification of the automotive AEC-Q101 specification in key tests. The RDS(on) of these two devices are 4.2 mOhm (BUK7V4R2) and 13 mOhm (BUK9V13) respectively.

The Nexperia LFPAK56D half-bridge package product that meets the AEC-Q101 standard is suitable for various three-phase automotive power system applications, such as fuel pumps, water pumps, motor control, and DC/DC power conversion. The occupied PCB area is reduced by 30%, and the parasitic inductance is reduced by 60%, so it is suitable for high-performance switching applications. With the design adoption and investment of important automotive customers, this new technology has achieved success.

For more information, including product data sheets and quick learning videos, please visit www.nexperia.com/lfpak56d-half-bridge

About Nexperia

Nexperia, as a high-capacity production expert in the field of semiconductor basic component production, its products are widely used in various Electronic designs around the world. The company’s rich product portfolio includes diodes, bipolar transistors, ESD protection devices, MOSFET devices, gallium nitride field effect transistors (GaN FETs), and analog and logic ICs. Headquartered in Nijmegen, the Netherlands, Nexperia can deliver more than 90 billion products each year, and the products meet the stringent standards of the automotive industry. Its products have been widely recognized by the industry in terms of efficiency (such as process, size, power and performance), and have advanced small-size packaging technology that can effectively save power and space.

With decades of professional experience, Nexperia continues to provide high-quality companies around the world with efficient products and services, and has more than 12,000 employees in Asia, Europe and the United States. Nexperia is a subsidiary of Wingtech Technology Co., Ltd. (600745.SS). It has a large intellectual property portfolio and has obtained IATF 16949, ISO 9001, ISO 14001 and OHSAS 18001 certifications.

Nexperia: Efficiency wins.

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ROHM has developed a wireless charging module that easily realizes wireless power supply for small and thin devices

“In recent years, the adoption of wireless power supply, which can eliminate the charging port and improve water and dust resistance, has been accelerated in numerous application fields such as smartphones and smart watches. However, the lower frequencies of existing wireless power standards and the constraints on miniaturization of antennas to comply with the standards have resulted in growing expectations for standards and approaches that are better common to small devices.

“

ROHM has developed wireless charging modules “BP3621” and “BP3622” that can easily realize wireless power supply of small and thin devices

~Using the optimized antenna layout design technology, it helps to shorten the development cycle~

The world-renowned semiconductor manufacturer ROHM (headquartered in Kyoto, Japan) has developed a set of small wireless charging modules “BP3621 (transmitter module)” and “BP3622 (receiver module)” integrating antenna and circuit board. Wireless charging of small devices such as smart tags and smart cards and computer peripherals can be easily implemented.

In recent years, the adoption of wireless power supply, which can eliminate the charging port and improve water and dust resistance, has been accelerated in numerous application fields such as smartphones and smart watches. However, the lower frequencies of existing wireless power standards and the constraints on miniaturization of antennas to comply with the standards have resulted in growing expectations for standards and approaches that are better common to small devices. In addition, since the power supply efficiency of the wireless power supply function will change due to the shape, size and distance of the antenna, it is necessary to repeatedly conduct trial production, adjustment, and evaluation on the entire Electronic device before installing the wireless power supply function. In terms of layout design, the heavy development burden has always been a big problem. In this context, ROHM has developed a 13.56MHz wireless charging module, which can easily realize the wireless power supply function for small and thin devices.

The new product is a small module with a size of about 20mm to 30mm square. It uses a 13.56MHz high frequency band and adopts an optimized antenna (coil) and layout design technology, which can provide up to 200mW of power supply, which is very suitable for building a small wireless power supply system. Not only is it easy to install in small and thin devices that have been difficult to achieve wireless power supply in the past, but also the flexibility of housing design is improved by adopting a circuit board structure with a fully flat back. In addition, by using transmitter modules and receiver modules in pairs, the development time required for trial production, adjustment, evaluation, etc. required to optimize power supply efficiency can be shortened. Not only that, the built-in antenna also supports bidirectional data communication and NFC Forum Type3 Tag*1 communication, which will help expand the communication capabilities of the application.

The new product has been put into mass production in October 2021 and is expected to start online sales in the near future. The production base is ROHM Apollo Co., Ltd. (Fukuoka, Japan).

In the future, ROHM plans to continue to expand the product lineup of small and high-power modules to further expand the applicable range.

＜New product features＞

1.Antenna and circuit board integrated module, which can greatly shorten the development cycle and easily realize the wireless power supply function

The new product is an integrated antenna and circuit board module that uses ROHM’s own simulation-based antenna design technology and circuit board layout design technology that reduces wiring losses. By using transmitter modules and receiver modules in pairs, a power supply of up to 200mW can be achieved. Compared with the case where the antenna and control circuit are separately configured, the feeding characteristics can be guaranteed, so product evaluation can be performed without the need for antenna design, layout design, and feeding characteristics evaluation. This can significantly reduce the development cycle and the design burden of board modifications, and enables easy wireless power delivery.

2.The use of 13.56MHz high frequency band realizes the miniaturization of the module, which helps to improve the flexibility of housing design

The new product adopts the 13.56MHz high-frequency magnetic field resonance method*2, and the antenna volume is smaller, which is suitable for small devices such as smart labels and computer peripherals such as mice. The new product is a small module that integrates an antenna, a matching circuit and a wireless charging IC, which is difficult to achieve with existing wireless power supply standards. In addition, as a wireless power supply product, not only can the charging port be eliminated, and the waterproof and dustproof performance can be improved, but also by adopting a fully flat back circuit board structure, it is easier to stick to the case, which helps to simplify the case structure and improve the design. flexibility.

3.Antenna with built-in module to help expand the data communication function of application products

Since the new product uses the same 13.56MHz high frequency band as the NFC communication standard, it can support both power supply and communication functions through an antenna with a built-in module. It can carry out two-way data communication (communication speed is 212kbps, up to 256 bytes) and NFC Forum Type3 Tag communication, which helps to expand the data communication functions of application products, such as data security transmission and rewriting of sensor data, device information and authentication information, Firmware download, sending of battery output voltage value, etc.

＜Product Lineup＞

＜Disclosed technical support information＞

On ROHM’s official website, the following data required to build a wireless power supply function are provided:

◇Technical Specifications◇Application Guide

Small devices such as smart labels, smart cards and ID cards,
Computer peripherals such as mice and remote controls for small devices in healthcare

＜Explanation of terminology＞

*1) NFC Forum Type3 Tag:

NFC (Near Field Communication) is a short-range communication technology that uses a frequency of 13.56MHz to communicate within a short distance, and its specifications are defined by the NFC Forum. Type3 is one of the labeling standards.

*2) Magnetic resonance method:

A wireless charging method in which an antenna (coil) for power transmission and reception enters a resonance state to transmit magnetic field vibrations and flow current.

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How to realize the collaboration and management of multiple heterogeneous edge clouds for telecom operators?

“Recently, the 2019 OpenInfra Global Summit was held in Shanghai. Telecom operators, service providers, application developers, and community contributors from around the world participated in the summit to jointly promote the innovation and development of open source technology.

“

Recently, the 2019 OpenInfra Global Summit was held in Shanghai. Telecom operators, service providers, application developers, and community contributors from around the world participated in the summit to jointly promote the innovation and development of open source technology.

The OpenInfra Shanghai Summit focused on key open source projects, such as OPNFV, Kubernetes, ONAP, Ceph, etc., as well as open source projects hosted by the OpenStack Foundation: OpenStack, StarlingX, Airship, Kata Containers and Zuul. The agenda of this summit includes ten topics, namely: 5G, network function virtualization (NFV), edge computing; container infrastructure; artificial intelligence (AI), machine learning (ML) and high-performance computing (HPC); continuing Integration/Continuous Delivery (CI/CD); Getting Started for Novices; Open Development; Private Cloud and Hybrid Cloud; Public Cloud; Security; Practice Workshop. The theme of this conference covers application cases, special reports and live demonstrations of more than 30 open source projects such as OpenStack, Kata Containers, Kubernetes, Hadoop and StarlingX. ??

Among them, edge computing is one of the protagonists of this summit. ZTE and industry partners shared the theme of “How to achieve coordination and management of?heterogeneous and multi-vendor cloud on telco edge” at this summit. Speak. ZTE said that telecom operators can provide network services, MEC computing power, IaaS, PaaS, SaaS and many other services at the edge. Edge infrastructure is the underlying support for all these upper-layer services. The edge infrastructure of telecommunications is very different from the core infrastructure. The latter will only have a small number of clouds and solutions. In contrast, the edge infrastructure is more open and diversified. The number and types of telecom edge clouds are more than those of core clouds. How to manage these heterogeneous edge clouds from multiple cloud service providers will be a problem that telecom operators need to face when they provide various clouds and services on the edge.

Specifically, it can be achieved through the following ways:

1) Realize the LCM management of heterogeneous cloud platforms: a cloud management platform/installation and deployment tools, management of virtual machine clouds and container clouds, implementation of application deployment and resource expansion.

2) Unified monitoring of heterogeneous cloud platforms: With the help of the existing OpenStack ceilometer and CNCF Prometheus and other existing cloud platform monitoring indicators, and then shield the difference in monitoring indicators of the underlying cloud resources, report and report in a generally unified format. show.

Mainly include the following functions:

vMEC edge cloud management supports the connection of heterogeneous resource pools (through community native interfaces);

vMEC edge cloud management supports image management and distribution deployment (via community native interface);

vMEC edge cloud management supports flexible resource management configuration (through community native interface);

vMEC edge cloud management supports unified user authentication;

vMEC edge cloud management supports unified operation and maintenance (through community native interfaces and interface enhancements).

The structure diagram of heterogeneous resource pool management is as follows.

On the core side, there are NFVO/VNFM/EMC/OSS, etc.; at the edge city level, the edge cloud management is deployed to realize edge resource management and operation and maintenance management; at the district/county access level, there will be heterogeneous resource pools. Due to the need to meet various different applications, different computing resources, storage resources and network resources are required to meet the requirements. So there will be different resource pools, the current mainstream ones are OpenStack, Kubernetes, VMWare, etc.

Since the resource pool is on the edge access side, everyone is currently paying more attention to its existence, and the community also has different implementations. Here we will discuss the implementation of heterogeneous resource pools.

The first is Kubernetes + Openstack. In Kubernetes based on physical machine deployment, Director manages OpenStask and Kubernetes resource pools uniformly, and provides tenants with two different types of resources, of which the physical resources are completely independent.

The second is K8S over OpenStack. Deploy Kubernetes on OpenStack, and Director manages the Kubernetes resource pool in a unified manner.

The Kubernetes cluster is deployed in a project of OpensStack, the computing & storage & network are all provided by OpenStack, and the application runs in the container POD. The advantage of this solution is that you can quickly co-sign K8S clusters, and use OpenStack’s tenant isolation and network functions.

The third type is: OpenStack over K8S. OpenStack is deployed on Kubernetes, and Director manages the OpenStask resource pool in a unified manner. The current form of existence in the community is StalingX

First, a Kubernetes cluster is deployed in the infrastructure, and then the OpenStack service runs on the Minion node of the cluster in the form of POD, and the application runs on the virtual machine created by OpenStack. The advantage of this solution is that it can quickly co-sign OpenStack, and flexibly implement resource orchestration through the Kubernetes Helm chart function.

Edge cloud management can provide edge cloud management capabilities after managing different types of resource pools for northbound orchestration and other resource applicants. Its functions include:

1) Image management

2) Authentication and authentication

3) Resource management

4) Operation and maintenance management

Edge cloud management can also realize southbound interface docking with different types of resource pools for resource management and operation and maintenance management, including:

Openstack, Kubernetes and other third-party vendor resource pools.

Features include:

1) Unified certification management

2) Mirror management (upload, query, distribute, delete, etc.)

3) Computing & Storage & Network Management

4) Resource organization

5) Service Management (Chart)

6) Application management, etc.

The edge cloud management can easily realize the management of the edge resource pool, which greatly improves the efficiency of users. There are more functions to be tapped through edge cloud management, which will bring more benefits to users.

As a gold member of the OpenStack Foundation and one of the main code contributors, ZTE is committed to promoting the evolution and development of OpenStack. Edge computing is an innovation that applies cloud computing technology to edge infrastructure, and it is still in the early stages of development. With the advancement of 5G network construction and large-scale commercial deployment, various applications are accelerating, and edge computing is expected to continue to suffer for a long time. In the future, ZTE will continue to increase its investment in the edge computing open source community and actively promote the maturity of community technology.

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The design of the dynamic liquid level depth tester based on the digital signal processor

“The digital signal processor-based dynamic liquid surface depth tester introduced in the article uses digital signal processing technology to overcome the inherent shortcomings of traditional instruments and provides a reliable, accurate, and highly automated method for the dynamic liquid surface depth test of pumping wells. Testing means.

“

Author: Pan Zhuojin, Zhu Guoxin

1 Introduction

The depth of the movable liquid level is the distance from the wellhead of the oil well to the surface of the downhole oil layer, and it is an important parameter in the regular test of the oil well. The average sound velocity in the well pipe can also be calculated from the depth of the moving liquid surface. The combination of the depth of the liquid surface, the average sound velocity in the well pipe and the results of other test items can fully reflect the working status and output of the pumping well, and provide a basis for the diagnosis and maintenance of the oil well.

2 Measuring principle of dynamic liquid surface depth

The dynamic liquid surface depth test instrument finds out the location of the wellhead by collecting the nodal wave signal reflected by the well pipe joint and the liquid surface wave signal reflected by the oil layer surface (as shown in Figure 1) from the gun gun installed at the wellhead. Using formula (1) to calculate the depth of the moving liquid surface and the reference nodal hoop wave.

Figure 1 Schematic diagram of the hoop wave and liquid surface wave waveforms

In formula (1), A, B, C, and D represent wellhead position, liquid level position, reference start point of reference nodal hoop wave and end point of reference nodal hoop wave respectively. L is the length of a single-section well pipe, and N is between C and D. The number of reference nodal hoop waves between. Since each hoop corresponds to a section of well pipe, N is the number of well pipes between C and D.

Due to the existence of various noise sources such as the noise of the sensor itself, environmental noise, etc., the collected waveforms are not always easy to find the above-mentioned feature points as shown in Figure 1, especially the reference nodal hoop wave, which is accurate It is difficult to calculate the depth of the dynamic liquid surface, and sometimes it is impossible to calculate it at all. Therefore, the filtering processing of the sensor output signal becomes the key to accurately calculating the dynamic liquid surface depth.

3 The structure of the traditional dynamic liquid level tester

Currently, the commonly used dynamic liquid level testers have an analog circuit-based structure as shown in Figure 2 and a microcontroller-based structure as shown in Figure 3.

Figure 2 Block diagram of the dynamic liquid level depth tester based on analog circuit

Figure 3 The principle block diagram of a micro-controller-based dynamic liquid surface depth tester

In the structure of Figure 2, the microphone picks up the low-frequency sound wave signal that is emitted by the gun and returned to the wellhead after being reflected by the well pipe joint and the oil layer surface. The signal is amplified by the amplifier and enters two narrow-band filters: band-pass filter BPF and low-pass filter LPF. The output of the band-pass filter is the hoop wave signal, and the output of the low-pass filter is the surface wave signal. The data acquisition is completed by the driving circuit to control the drawing pen to draw the hoop wave and liquid surface wave curve on the paper tape. The extraction of characteristic positions such as the position of the wellhead, the position of the liquid level, the starting point of the reference nodal hoop wave, and the end point of the reference nodal hoop wave, as well as the calculation of the depth of the moving liquid surface and the average sound velocity in the well pipe are completely manually completed by the technicians.

In the structure of Figure 3, the picking, amplifying and filtering parts of the analog signal are exactly the same as the structure shown in Figure 2, but the data acquisition part is completed by the microcontroller system. The microcontroller system consists of a microcontroller, A/D converter, memory, Display and printing interface. In this structure, as long as each characteristic position is found, the calculation of the depth of the moving liquid surface and the speed of sound can be automatically completed by the microcontroller. In the case that the collected waveform is ideal, the feature location extraction can be automatically completed by the microcontroller after the data collection is completed, but in most cases, due to the poor filtering effect, the automatically extracted feature location is inaccurate, requiring technical personnel Manual intervention.

Although these two structures are quite different in data acquisition methods, the quality of the acquired waveforms depends on the frequency response characteristics of the two analog filters in the signal processing channel. Because the frequency bands of the two signals are very narrow, this leads to the need for higher orders in the realization of the two filters, and because the higher-order filters are more sensitive to changes in device parameters, they are designed and debugged. It is more difficult to come.

4 Structure of dynamic liquid surface depth tester based on digital signal processor

The structure of the dynamic liquid surface depth tester based on the digital signal processor is shown in Figure 4. The microphone output signal passes through the preamplifier and anti-aliasing filter and then enters the A/D converter. The A/D conversion result is sent to the digital signal processor for digital filtering and sampling frequency conversion, and then stored in the nonvolatile Flexible memory for feature location extraction, dynamic liquid surface depth calculation, sound velocity calculation in well pipe, waveform display and printing, and other post-processing.

Figure 4 The principle block diagram of the dynamic liquid surface depth tester based on the digital signal processor

In this structure, the function of the traditional analog filter is completed by a digital filter realized by a digital signal processor, which uses an oversampling digital signal processing technique. The system samples the input signal at a very high sampling rate, and the sampled data is filtered through two narrowband digital filters implemented by the digital signal processor, namely the section band band pass filter BPF and the liquid surface wave low pass filter LPF. The latter two sampling data enter two sampling rate compressors respectively.

Suppose the output sampling frequency of the system is fs, the input sampling frequency is Mfs, the impulse response of the nodal band wave filter BPF is hB(k), the impulse response of the liquid surface wave filter LPF is hL(k), and the input sampling data is x (N), the sampling data of the output nodal hoop wave is yB(n), and the sampling data of the output liquid surface wave is yL(n), then the data flow diagram of the digital filtering and sampling rate conversion part of the digital signal processor is shown in Figure 5. .

Figure 5 Signal processing flow diagram in DSP

The input-output relationship of the system in the time domain is:

yB(m)=wB(mM)=∑hB(k)x(mM-k)

wB(n)=∑hB(k)x(nk)

yL(m)=wL(mM)=∑hL(k)x(mM-k)

wL(n)=∑hL(k)x(nk)

Since the digital signal processor is a processor designed for digital signal processing algorithms, it has a very high MAC (multiply and accumulate) operation speed, so it is easy to complete the operation of these two high-order narrowband digital filters in real time. Since the output sampling frequency of this system is not high, the over-sampling M value can be very large, so that the anti-aliasing filter can be implemented with a simple second-order active analog low-pass filter. A wide margin can be left in the passband during design. Even if the parameters of the analog components in the anti-aliasing filter drift with time or temperature, it will not affect the performance of the entire signal processing system. As the main process of signal processing adopts digital processing, the performance of the system is stable and reliable, and it overcomes the inherent inoperability of the system caused by the drift or inconsistency of the filter component parameters inherent in the two structures shown in Figure 2 and Figure 3. Stability or difficulty in design and debugging.

This structure uses a digital signal processor to replace the traditional analog filter and microcontroller, and only uses one analog-to-digital converter. Due to the good filtering effect, the success rate of automatically extracting the feature position is greatly improved compared with the structure based on the microcontroller, and the work efficiency is improved.

5 concluding remarks

The digital signal processor-based dynamic liquid surface depth tester introduced in the article uses digital signal processing technology to overcome the inherent shortcomings of traditional instruments and provides a reliable, accurate, and highly automated method for the dynamic liquid surface depth test of pumping wells. Testing means.

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