Hi team,
In order to improve the input voltage range, customer tried to replace the ground of TPS2121 by a 5.1V zener diode. And they disconnect the output capacitance on the EVM and increase the value of output capacitance to 100-330uF to the real GND.
The test results show that it is impossible to start with load (all loads above 1A fail).
They also tried to increase the input capacitance of IN1 by 100uF, which can realize start-up with load with a wider range. When adding increases more capacitance to realize switch, it starts slowly and cannot start with load. Below is the question:
1. Is the way of replacing the ground of TPS2121 by a 5.1V zener diode to realize wider input range OK?
2. Why when adding input capacitance of IN2 by 100uF, TPS2121 can not start with load?
