Tool/software:
Dear Expert
We encountered issues while using the TPS552872 chip.
The first version prototype TPS552872 chip is working normally and the output voltage is normal; The second version prototype TPS552872 has just been powered on and is working normally, with normal voltage output. However, after multiple uses of power on and off, it cannot output voltage; The layout of the two versions of PCB is basically the same.
The following are the first and second versions of the schematic diagram; The main difference is that the second version adds 4 output filtering capacitors and adds a transistor to enable output on/off.
First Version Sch
Second version sch
Abnormal situation: The second version has just been powered on and can work normally several times, but cannot output voltage afterwards; (Input voltage VCC_SYS=15V)
Several abnormal points after the problem occurred:
1. The EN/UVLO pin voltage is 1.8V (normally it should be divided into 2.5V);
2. VCC pin has no voltage output (normally should be 5.2V)
3. The voltage of EXTVCC is 3.23V (normally it should be 5.2V)
