DC DC power supply using DPA426R
Dear Sir,
I wish to design a DC-DC power supply whose input range is from 16VDC to 72VDC and output is 12V 2.5Amps.
I am using DPA426R.
I used PI SW and generated the design whose schematic & design is as attached.
Now i am getting output as 12Vdc without load but giving any load, brings the output voltgae down to 3-4 VDC.
I have desgined the transformer exactly as generated by the PI sw. ALso used the same components.
Could you please help as to where things are falling.
Thanks,
Hitesh
Comments
Dear Terry,
I got 12V output for input from 17VDC to 34 VDC. I have not tried for input above 34 Volts.
But the above is true for no load only.
As soon as i give load, the outputs starts swtiching i.e the output led starts blinking.
sorry i could not attach the wave forms as my osilloscope is gone for repair.
but one thing which i observed is that, as soon as i give load below happens
1> the output led starts blinking and so does the output voltage measured by multimeter.
2> at this time the bais votlage, which was 11VDC when no load and output was deliverd correctly, now start rising and i have observed it to go to some 30VDC by multimeter.
Hi,
The bias winding voltage will be changed with output load condition, this is due to the cross regulation, which is common for flyback power supply.
I really need the waveforms to determine what really happen with the load, would you attach the waveforms when you get you scope back?
Hi,
I saw there is a warning about the OV in the design, you may need to correct them by changing the resistor on V pin. But the issue you described may not relate to this fault.
What is the input voltage you applied when you did this test? Would you please attach the waveforms for the drain voltage and drain current at both no load and full load conditoin?