TPS62153: Destruction of TPS62153 (maybe thermal)

Hi JB,

I think our US team is responsible for this device. Please wait a little while since it's in holiday now.

By the way, I have read your description and tried to find some clue. You mentioned that you connected a power supply (5V) directly between 5V and GND first. Was the U3 soldered on board at that time? Did you add a power source with voltage higher than 5V at Vin? Since the integrated power mos have parallel body diodes, if you only added a voltage source at 5V Vout, large current will directly go through the upper mos and cause damage.

I think you can first check if the device is damaged without power supply (short between Vin-SW or Vin-GND). If yes, change another sample on board and test again.

If you have further questions about it, please wait for the answer of the US team. 

Regards,

Andrew

Hi,

In a first time, I have powered this board with 9V applied on main power connector (J1) and U3 doesn't work as expected as board consumes more than 800mA. I have swapped fuse to a 2A one and increase current to 1A without any result. In a second time, I have tried to connect a 5V power supply after U3 to check if there is a short circuit after U3.

When I have seen there wasn't any short circuit on this board, I have tried to connect a 9V/800mA power supply on J1 without any other result (power supply directly enters in protection mode and indicates a short circuit and gives to board 3,5V/800mA). Thus, I have tried to increase voltage to 12V. And U3 has been destroyed.

Best regards,

JB

Andrew Xiong said:

Did you add a power source with voltage higher than 5V at Vin? Since the integrated power mos have parallel body diodes, if you only added a voltage source at 5V Vout, large current will directly go through the upper mos and cause damage.

A precision. When I have powered this board after U3, of course, J1 was disconnected. Thus, there was no current in MOSFET diode.

JB

Hi JB,

Thanks for providing the detailed information of your test. Please wait for the reply of US team.

Regards,

Andrew

Hi Andrew,

I have done new measurements. If I power this board after U3, even if reset button is pressed, current doesn't exceed 240 mA. Thus, after U3, this board runs as expected (in both case: reset or not).

I see only one difference between both configurations. When I try to power this board by J1 connector, PG can acts as a current sink. But I don't understand how this pin can consume more than 1mA...  Of course, I have verified that D1, R1, R2, R3 and C1 have values indicated in schematic and that cathode of D1 is connected to 5V.

Best regards,

JB

Hi,

Matt will help you here.

Thanks.

Andrew,

Can you please provide a more detailed schematic of your design? 

The schematic above does not include the "J1 connector", "reset button", or other components (D1,  R1-R3, and C1) you've referenced in your last message.

Thank you,

-Matt

Matt, I beg your pardon. You will find in attachment this part of schematic.

Best regards,

JB

JB,

Thank you, this does make this more clear.

I'm not seeing any obvious issue with the schematics, which makes me think the device was damaged prior to testing.

Are you able to replace the TPS62153 device with another IC to see if the board begins to work?

Thank you,

-Matt

I have another board (and I will buy 10 new converters). The second board shows the same issue.

On this board, I have a led connected between 5V and GND. When I connect J1 to a power supply (9V, 800mA), this led turns on and off quickly (less than 0.5s). Of course, when led switches off, power supply indicates a short circuit (or a current greater than 800 mA).

If I power this board after U3, even with 5V/200mA, this board runs as expected.

Best regards,

JB

JB,

I have sent you a private email requesting some more information for me to better understand what may be happening here. 

Thank you,

-Matt

I hope you have received board schematic (11 MB).

Best regards,

JB

JB,

I've received your files and have begun review them.

Thank you,

-Matt