Solution: Besides the voltage-stabilizing circuit, the following factors would also cause the output voltage too low.
1. When there is short circuit happened on switching power supply load ( especially short circuit or poor performance on DC/DC conventer ), it should disconnect all load with switching power supply circuit to check if the fault is on the power supply circuit or the load circuit. If the output voltage is normal, the load capacity is over, otherwise the fault is on power supply circuit.
2. Failure on rectifier diode & filter capacitor of output voltage side, it can be test through replacement.
3. The performance of the switch tube is decreased, which inevitably leads to the failure of the switch tube to guide the power supply and increases the internal resistance of the power supply, then decreases the load capacity.
1. If the protective tube is normal, the power supply is not working or under protection state.
Solution: First check whether starting pin of power control chip have starting voltage, if the voltage is too low or no, need to check the starting resistance and components connected with starting pin to see if there is electric leakage, such as power supply control chip is normal, after the examination users can find the fault quickly.
2. If there is voltage when starting
Solution: Need to check whether the output of the control chip is under high and low level jump when booting, if yes, it is caused by fault control chip, periphery circuit components or protection circuit problem. And replace the control chip, then check the periphery circuit components. If there is a jump, generally the switching tube is fault or broken.
Solution: Generally caused by voltage-stabilzing sampling and voltage-stabilizing control circuit. Fault on a closed control looped circuit including DC output, sample resistance and error sampling amplifier etc, it will lead to the output voltage rise.