Practical process of selecting DC-DC switching power supply controller

1、 First we need to see if we need to isolate the power supply

In some cases ,DCDC It also adopts isolated power supply . for example PoE Power supply , The function of using network cable to reuse power supply . Because there are long transmission lines , So it is possible to introduce interference 、 Surge and other inputs .

In this scenario , If the unified power supply is non isolated , At this point, we will not isolate the power supply . If other equipment is isolated power supply , Never try to reduce costs 、 Or simplify the design , Select non isolated power supply .

Because when the surge comes , Using isolated power equipment is like building a dam , The surge can't even enter , So if your device is a non isolated power supply , It must be the mouth of the levee .

2、 First, let's look at the relationship between input and output voltage , boost 、 step-down 、 Pressure rise and fall .

Linear power supply can only be depressurized . Some topologies of switching power supply have the function of boosting voltage , Then we choose the boost topology .

Some scenes , It is necessary to support the pressure rise and fall at the same time , For example, some battery related scenarios . Because the voltage of the battery will change with the change of the electric quantity . So it may be necessary to increase or decrease the pressure . In this case, the basic topology will be selected Buck-Boost, It is also possible to choose four axle arms Buck-Boost.

3、 According to the output current , Select the power supply configuration .

Generally, the power supply in the board is mainly reduced , Let's take blood pressure reduction as an example ：Buck Circuits are divided into... According to the magnitude of the current 4 paragraph ：

0~1A、1A~10A、10A~20A、20A above

① If the output current ＜1A, Generally, we choose linear power supply , Or choose switching power supply with high light load efficiency .

But some manufacturers' products can be under normal load PWM, In light load is to enter PFM Pattern , however PFM In mode , It will produce audio noise and cause howling . We are iBox Choose... When designing MPS Of MP4420 It has this feature , Will cause howling . As a desktop device, I can't stand screaming , We deliberately added a dummy load , Keep it from entering light load mode . This light load mode is in vain . Developing desktop devices in Huawei , Other manufacturers have the same problem with power supply , Also use dummy loads to avoid entry PFM, To avoid .

② If the current is in 1A~10A Between , Generally, integration is selected MOSFET Voltage regulator for .

If we consider a certain derating , It will not be used directly at full rated power according to the nominal rated power of the voltage regulator , We may be in 8A The following options integrate MOSFET Voltage regulator for .

The design of this regulator is relatively simple , There are many kinds of specifications , So we need to consider the optimal cost , Normalization also needs to be considered . For example, when we were at Huawei for some time ,6A The following is used uniformly TI Of TPS54620 This chip , To achieve the purpose of device normalization . This material is small 、 High integration 、 Cheapness , But later, there were models and manufacturers with newer processes and better efficiency to replace this material .

③ If the current is in 10A~20A Scope usage scenarios , We usually choose the controller . Through external MOSFET, To design Buck circuit .

20A within , We can choose 1 Phase synchronous switching power supply controller .

The current design requires high efficiency 、MOSFET Prices are getting cheaper . So now asynchronous Buck There are fewer and fewer options for power controllers .

Single phase controller , When we select models , Generally, we choose the mainstream delivery , Reliable , The manufacturer supports good .

④ If the current is greater than 20A, You need to select a polyphase controller .

Here are two examples of domestic devices ：

For the existing market problems , Dongguan Changgong Microelectronics Co., Ltd. has independently developed and designed a series of industrial products , Large current in the telecommunications and computing power market (4A-280A) Power supply chip , Among them, the latest IS6608A The power management chip is the first chip in China that can be used for CPU Power supply multi-phase parallel power chip .

IS6608A As a fully integrated 、 compatible PMBUSTM Interface high frequency synchronous buck converter , use 4x5 Flip-Chip QFN Packaging technology , The input voltage can reach up to 16V, Achieve as much as 35A electric current ,0.4V To 5.5V Output voltage conversion of . meanwhile , Adopt innovative multi-phase parallel technology , most 8 The peak value of chips in parallel is 280A The output current of ( Pictured 1).IS6608A Within the range of rated input voltage and output current , It can be done 0.5% First class output accuracy . Its excellent dynamic phase number management technology （ Automatic lifting phase ） And comprehensive telemetry Digital communication function , It greatly improves the efficiency and convenience of the chip , Make it the first choice of domestic high current power management chip .

This material has been tried and used by many manufacturers .

In addition, according to news reports ： Jingfeng Mingyuan launched in the world 10 Phase digital control power management chip  

BPD93010, Support native 1~10 phase Buck controller 、 Digital control 、 Small package （QFN 5*5）, In the field of high current and high power computing, seize the first opportunity in the localization of power management chips .

Foreign manufacturers , Such as TI（ Acquiring country and half ）、 Reza （Intersil）、ADI（ linear 、 Mei Xin ）……

—— It feels better to write that power chip companies have been acquired ....

4、 Multi power output solutions for special scenarios

In addition, some manufacturers have unique views on solutions , Will design some controller chips with multiple power outputs for specific application scenarios .

For example, domestic manufacturers ： Quanzhi's subsidiary   Smart core has some multi power solutions for tablet computers

AXP15060 Support 23 Channel power output , contain 6 Circuit switching power supply , as well as N Much of the LDO

Through such a product portfolio in a product form , Extremely cost-effective and integrated .

5、 The voltage input range needs to be considered , For example, scenarios that need to support high voltage input .

The input voltage of some switching power supplies is 12V、16V wait , It is mainly used in the board everyday , It is commonly 5V Input 、12V Adapter input .

Some new devices are starting to support Type-C Some fast charging inputs of , It is required to support voltage up to 20V.

PD2.0

2013 year 1 month 7 Japan ,USB-IF Organized in CES Announce ,Type-C The interface will be on 2014 Annual listing ,2014 year 8 month ,PD2.0 Official release ,PD2.0 The standard passed Type-C The interface realizes two-way current transmission and maximum 100w The charging power of , The specific charging specification is ：5V3A、9V3A、15V3A、20V2.25A、20V3A、20V5A.

So as the next level DCDC The voltage range that needs to be supported changes , Need to support a wider range .

And in the field of Telecommunications , Need to support 48V Voltage input . You need a controller that supports a higher voltage input range .

For example, the material of JWT JWH6346 Support external MOSFET Switching power supply controller with wide voltage input range .

6、 The output voltage range needs to be considered .

For example, above JWH6346, In our latest circuit design , Not up to our needs .

In our earlier introduction Artificial intelligence microserver SE5 in , Just mention a chip BM1684.

Disassembly and measurement ：AI Microserver Can calculate SE5

For the sake of greater computing power 、 Better signal quality 、 Faster master frequency , therefore Core The voltage is getting smaller and smaller . So this one TPU The required Core Voltage is 0.62V,JWH6346 The voltage range is 0.8V above .