Hello! I tried to use NB650A as buck converter with output voltage from 3.6 to 8.5 V.
Input voltage is 12V.
With low output voltages IC starts and works without load. But when I connect some load it stops. Looks like it enters in Short Circuit Protection mode.
With output voltages higher 5.5 volts it stops immediately after startup without any load. With 1-2A load situation is same.
I tried some changes, like changing On Time, removing Rump circuitry, adding filtering capacitor 100pF to FB pin, but all of it does not change situation significantly.
What can I do with this trouble?
There is my circutry:
Hello,
Are you using your own board or our evaluation board?
A SCP condition is triggered when the output is shorted to ground.
Please make sure that there are no from output to ground on your board and that your capacitors are rated for 2-3 times the voltage they will see.
The evaluation board datasheet would be a useful guide if you have any questions about layout and component sizing.
I hope this helps.
Eliza