UCC256403: UCC256403

Santhosh Kumar J

Part Number: UCC256403
Other Parts Discussed in Thread: TIDA-010081

Tool/software:

Hi, I am using TIDA-010081 reference design to drive 48V output with 20 Amps. I redesigned the LLC transformer. I am getting low voltage output of 31V and not getting the desired output of 48V. When using a small load , the power supply is not able to drive the output and fluctuating between 3 to 4 volts. I have used recommended parts by TI. LLC transformer is 4:1, using PQ3535, Primary : Secondary : BW 16:4:2, what could be the reason for low voltage at secondary.

Santhosh J

TIDA-010081

3 months ago

0 Sougata Nayak 2 months ago

TI__Intellectual 1140 points

Hi Santosh,

Can you please share the schematic of the design, design calculator used for LLC design, and PFC output voltage in the oscilloscope with full load, small load and no load as shown in the below figure:

0 Santhosh Kumar J 2 months ago in reply to Sougata Nayak

Prodigy 10 points

Dear Mr Nayak,

Thanks for your response. The current issue is that, without Load the PS is able to deliver 47.8 V, however when Load is connected and powered ON, the LLC driver pin 14 and 16 gets short circuited. I have blown up 2 chipsets. Could you suggest what is going wrong here.

0 Sougata Nayak 2 months ago in reply to Santhosh Kumar J

TI__Intellectual 1140 points

Hi, this should not happen. Please allow me 1-2 days to come back if something is wrong in the schematic.

Regards,

Sougata

Power management

Power management forum

UCC256403: UCC256403

TIDA-010081