VIPER38HD does not regulate output voltage when increase the output current

[PPowe.3]

I used the ST eDesignSuite to make a o 90V-265V AC power input to +12V with 0.8A and -12V with 0.2A output. So I purchased all the components and soldered the pcb as below,

fig1. Soldered PCB

Circuit - Schematic which was taken by eDesignSuite as below,

fig2. Circuit - Schematic

If don't take any current trought output the output voltage is +12V but when I increase the outpiut current using electronic dc load then the +12Output Voltage will decrease and -12Output voltage will increase. I have attached the waveforms of +12Output Voltage and Feedback pin with different output current. please help me to find the solution.

(1). Output Current = 0.0A

i. +12Output Voltage

ii. Feedback pin

 

(2). Output Current = 0.1A

i. +12Output Voltage

ii. Feedback pin

(3). Output Current = 0.4A

i. +12Output Voltage

ii. Feedback pin

 

(4). Output Current = 0.4A

i. +12Output Voltage

ii. Feedback pin

 

[Marco FICHERA]

Hi @PPowe.3​ ,

The e-design schematic refers to a double output with identical outputs: +12V/9.6W for a total delivered output power of 19.2W, while your prototype total output power is 12W, shared between a +12V (9.6W) and a -12V (2.4W), so they cannot have same schematic and BoM.

It could be some mistake in the prototype final schematic. For better understanding, it should be shared together with BoM and transformer specs.

I hope this helps.

Regards

Marco

[PPowe.3]

Hi,

Above attached Circuit - Schematic should be corrent as below,

 

and the BOM of above Circuit - Schematic as below,

 

And also the transformer specs which we used attached in below,

 

I think above information will help you to identify the problem. so, please help me to find the solution.