MP2225 chip output problem! .

燕园技术宅

MP2225 chip output problem! . [Copy link]

I recently used the MP2225 chip as a power chip to convert DC12V to DC5V. After soldering the circuit and connecting it to the 12V input, it initially output 5V, but after a while it outputs 12V directly. The chip is not hot and there are no other signs of damage. I changed to a new chip and used the 8V input, and it was still the same except that it became 500mV this time. The schematic diagram and data sheet are attached. I hope someone can point out where the problem is! Thank you.

燕园技术宅

The data sheet gives you a reference circuit. The polarity capacitors used are tantalum capacitors. I used SMD aluminum electrolytic capacitors. The rest are based on the reference circuit.

topwon

It depends on the load you are testing. If you use aluminum electrolytic capacitors, the capacity should be increased.

topwon

Special attention should be paid to the selection of inductor to ensure that its saturation current is greater than the peak current in the circuit.

a354343938

I am working on Taiwan Yuanxiang's step-up and step-down IC chips. If there is an opportunity for cooperation, I can provide you with samples and test engineering to help you solve the problem throughout the process.

燕园技术宅

topwon posted on 2018-8-1 09:47 It depends on what the load is when you test. In addition, if you switch to aluminum electrolytic, the capacity should be increased.

I re-soldered a board and found that there is no problem. It’s just that the voltage will drop after being powered on for a long time (3 hours), from 5.0039V to 4.9989V.

燕园技术宅

topwon posted on 2018-8-1 09:50 Pay special attention to the selection of inductors. Make sure that their saturation current is greater than the peak current in the circuit.

Inductors are rated for more than 5.5A