TPS552882-Q1: Boost Regulator TPS552882QWRPMRQ1

Hi Tagore,

Thank you for reaching out. May I know what is the application here? What is the current load?

Can you provide the schematic so that I can check the design problem. Also please provide part number and datasheet of output capacitor and inductor.

Regards,

Mulin

Hi Mulin,

Sorry for this delay,

PFA

And my application is to charge the battery with 12V,6A input, to generate 18.8V,6A  and communicate with SMBus to control the charging.

Regards,

Tagore.

4S6P BATTERY CHARGER (100W)_V0.1_SCH.pdf

Hi Tagore,

From schematic I didn't see obvious concern. Make sure C3 effective capacitance is larger than 2uF with 5V DC bias. Recommend to add RC snubber in SW 1 and SW2.

What is the load current when you do the test?

Can you help provide Vin Vout SW1 SW2 inductor current waveforms? It will be good to capture output failure moment. I want to check device working performance.

Regards,

Mulin

Hi Mulin,

Yes C3 is 4.7uF and i did not added RC snubber in SW1 and SW2 due to my part is damaged.

1. Can i get these Vin Vout SW1 SW2 responses from your side so that i can verify my self after getting my part shipment.

2. when i saw your design for TPS552882EVM-2MHz,it is designed for 2.7V - 36V as input and 22V/3A. But my input is 12V with 6A and output is 18.8V with 6A. can i get this exact with this design

3.From my charger IC BQ25720RSNR,not getting the output voltage.i verified the voltages at MOSFET (Q7) getting 18.8V at pin 5,6,7,8 and at pins 1,2,3 voltage is 0.

4.When i tried to communicate with MCU(PIC16F18046-E/ML)  the boost IC i.e, TPS552882QWRPMRQ1 is damaged.2364.4S6P BATTERY CHARGER (100W)_V0.1_SCH.pdf

Can you help in this to resolve.

Thanks and regards,

Tagore.

Hi Tagore,

1. Please refer to 8.2.3 in datasheet. Please provide the waveforms when your part is ready.

2. TPS552882 can support 18.8V/6A output with 12V input voltage. But the input current should be around 18.8*6/0.9/12=10.4A. 6A input current is not enough. Also, in this power, recommend to use 400kHz switching frequency and 4.7uH inductor. Set R6=49.9k and L1=4.7uH. Set R5=26.4k to get 12.5A inductor current limit.

3.What is working condition when you did the test?

Regards,

Mulin

Hi Mulin,

Thanks for your support,i will do these changes after getting the part.

Please clarify about the poin 3 and 4.?

And do i need program to get the output without MCU at charger IC side?

Regards,

Tagore.

Hi Tagore,

About point 3, recommend to raise a new thread about BQ25720RSNR. This thread can not be assigned to two product line at the same time.

About point 4, do you mean PG and CC function? TPS552882 is not controlled by MCU.

Regards,

Mulin

When i giving the 12V/200 mA it is working fine but after increasing the current to 3A it is getting short,

Hi Tagore,

Please help provide the Vin Vout SW1 SW2 inductor current waveforms? It will be good to capture output failure moment.

Please change R6 to 49.9k and L1 to 4.7uH for thermal consideration.

Can you provide layout file of TPS552882Q? I want to check if there is any layout issue.

Regards,

Mulin

Hi Mulin,

Please find attached layout file.

4S6P BATTERY CHARGER (100W)_V0.1_ALL LAYERS.pdf

Regards,

Tagore.

Hi Tagore,

Thank you for feedback, we will look into this and reply to you later.

BRs,

Bryce

Hi Bryce,

May i get any feedback points on my layout file.

Regards,

Tagore.

Hi Tagore,

Thanks, since Mulin is OoO, please expect a delay response next Monday.

BRs,

Bryce

Hi Tagore,

Layout is very important for DCDC IC working normally. I think current layout is really bad. Please refer to our layout guideline and my comments.

Also please provide waveforms that I need so that we can find out how IC is working.

TPS552882Q layout reiview 07292024.pptx6320.TPS55288 Layout Guideline (Rev B).pdf

Regards,

Mulin

Hi Mulin,

Thank you for your review in Layout side.

Also please find waveforms at SW1(C1),SW2(C5) and output(FB2). And give me suggestions.While capturing this input is 12V/200mA.current drawn by IC is  50mA.

Regards,

Tagore.

Hi Tagore,

Thank you for your waveforms. Since the input voltage is 12V, sw1 should be 12V as well, why the waveform shows 17V?

The input 12V/200mA means the power supply current limit is 200mA, right? There is no load?

Can you clarify when will the IC fail? Do you means you change power supply current limit to 3A or load current is 3A? The IC will fail immediately or it works for a while? Can you help provide Vin Vout SW1 SW2 inductor current waveforms at the moment when IC failed?

Please check impendence of SW1, SW2, Vin, Vout, VCC to check failure mode.

Regards,

Mulin

Hi Mulin,

yes, limited the current to 200mA in power supply.and not connected any load at output.

when i gave 3A input current then the ic is failing after 2min.

the impendence of SW1,Sw2,Vin,Vout,Vcc is ok after removing the IC and Mosfets from PCB.

Regards,

Tagore.

Hi Tagore,

Can you help provide Vin Vout SW1 SW2 inductor current waveforms at the moment when IC failed?

Please check the impendence with IC and MOSFETs in the PCB because we want to check IC condition. After 2 min, will the IC be able to restart afterwards or it will never start up again?

Regards,

Mulin

Hi Mulin,

Yes i tested the impedance,failed at that condition. Also IC removed from PCB and checked pin to pin,again the impedance is not coming for both IC and Mosfets.
After 2 min also it is getting the same issue,not starting.

Do you mean need these waveform after failure condition?.

Regards,

Tagore.

Hi Tagore,

Mulin Yuan said:

Since the input voltage is 12V, sw1 should be 12V as well, why the waveform shows 17V?

How about this question? 

Is there any other circuit between power supply and TPS55288? Is there any other device working at the same time? Can you provide a picture showing how the device is connected?

Since you know about 2 min the IC will damage, please observe waveforms to see if there is any abnormal. Please capture abnormal waveforms before failure. Also, set trigger Vout falling edge to capture the failure moment. Make the scale longer to see  more information. Use four probes at the same time. Observe inductor current.

We can not analyze the root cause without useful waveforms. Thank you for your effort.

Regards,

Mulin