TPS23753A: No output issue

FRANK1

Part Number: TPS23753A
Other Parts Discussed in Thread: TL431, TPS23753,

Hi Team，

Our customer has a design problem on TPS23753A.
He reviewed this design some times and still can not find the reason why his design can not get output.
He can not post due to he doesn't have a company email,
I think you have more design experience and application experience on this device.
Can you take time to confirm this design review？

His design is based upon our evaluation board design.
www.ti.com/.../slvu315a.pdf -001

Attachment:
1. PDF schematic file.
2. Allego PCB file ( I will share you via email)
3. Measured ripple on each pin of TPS23753A

Test process:
1. Supply 12V DC power to the board card through J1 terminal, There is no output on secondary of V1.1 board transformer.

2. The board works normally before this design change, V1.1 the RCD circuit (R830, C339, D182) was added, and the RC absorption circuit (R4, C9) was added at the DS end of MOSFET in the previous version,
the board does not work after this change.

3. In order to facilitate the test during debug, I short circuited the GND of the primary stage and secondary stage together (C1 is short circuited with 0ohm resistor)

4. TL431 confirms that the package is correct, and the transformer and MOSFFET are in accordance with the official recommendations.

7624.TPS23753A.pdf

TPS23753引脚波形图.zip

Thanks a lot in advance.
Regards,

over 3 years ago

+1 Michael Pahl over 3 years ago

TI__Mastermind 21320 points

Hello Frank,

The J1 input connector is on the primary side. In the TPS23753AEVM-001, the adapter voltage is connected to the secondary side.

In order for a 12V adapter to work on the primary side, the DCDC needs to be wide-Vin. That means it can accept an input from 12V-57V. The TPS23753AEVM-001 is not designed for this. Therefore, this is expected behavior.

Additionally, I note that the output is 5V. We typically recommend a synchronous flyback, instead of a diode flyback for 5V outputs. I would recommend the PMP8896.

Let me know if you have any questions.

If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

Regards,

Michael P.

Applications Engineer

Texas Instruments

0 FRANK1 over 3 years ago in reply to Michael Pahl

TI__Expert 8555 points

Hi Michael,

Thank you for your suggestion.

customer found the issue that he mount the MOS-FET in wrong pins.

Thank you for your support.

0 Michael Pahl over 3 years ago in reply to FRANK1

TI__Mastermind 21320 points

Hey Frank,

Thank you for the confirmation. That is interesting that the design works for wide-Vin. Glad the customer was able to solve the issue.