Dear all,
Attached is the schematic diagram. On page 5, it is the circuit diagram of TPS65140. The following is the screenshot.Arrow P5V is 5V power input, output VOFFSET, VRST, VBAIS and P3P3V_TPS. The power chip enable pin is powered by DMD_PWR_EN.When DMD_PWR_EN pulls high, the P5V is pulled down, resulting in a drop in the input 5V voltage.
Now I find this phenomenon through debugging:
1. Remove the Q18 of the circle in the picture below, and P5V voltage drop still occurs;
2. Remove the Q18 of the circle in the figure below and disconnect the enabling pin of TPS65140 without P5V voltage drop;