Weird Load Switch Problem AP22802 with Bluetooth HC-05 Module

[yagizhanugur]

Hello everyone,

I am having issues with AP22802 load switch with HC-05 Bluetooth Module

I soldered 5 boards and only 1 is having weird problem and i cannot sure about the problem is general or individual...

My board working well begining ... after couple turn on and turn off process AP22802 is getting hot staying always on(bluetooth module turning on) until AP22802 getting hot and burn. I checked short circuit for OUT for AP22802 and signal levels, but everytings looks perfect.

Do i miss something about it ? Any help is very apperciated ..

I attached schmatic used.

Note : EN signal voltage level is 5V. Same as VCC

Thank you.

[jhpadjustable]

When you say turn-off and turn-on processes, do you mean the entire board, or just the switch and HC-05 module? Is there any big difference in power/signal lead length when you test the broken board?

According to the datasheet, it's well protected against over-current and over-temperature. The power switch also has a discharge function on the output, which has always seemed like asking for problems to me. Perhaps that HC-05 has much larger input capacitors than the others. You can try adding a diode to pass current from output to input, to suppress any inductive current spikes or large capacitive charges from anything on the HC-05 side.

[yagizhanugur]

When you say turn-off and turn-on processes, do you mean the entire board, or just the switch and HC-05 module? Is there any big difference in power/signal lead length when you test the broken board?

According to the datasheet, it's well protected against over-current and over-temperature. The power switch also has a discharge function on the output, which has always seemed like asking for problems to me. Perhaps that HC-05 has much larger input capacitors than the others. You can try adding a diode to pass current from output to input, to suppress any inductive current spikes or large capacitive charges from anything on the HC-05 side.

I mean turn off HC-05 power. I measured 49uF capacitor on OUT pin of AP22802. I think it is not too much.

I tried thermal shutdown feature .(Shorted OUT and GND) Chip survived for 5 min with having any problem.

I measured resistance between AP22802 pins on board. All looks same.

Chip burns if it stays open. Maybe you are right there is an inductive effect on PCB. I soldered new one it is working good.  I will put a shotcky diode between OUT and GND and will try broken.

Also i wonder why are you curios about discharge function. If you share your ideas it will be very helpfull.