Part Number:LM2937
Hello,
A problem has happened to the output of LM2937 (the 5V output one). The schematic is shown below.
The TP106 is connected to a signal generator which outputs a pwm signal. The frequency and duty of the pwm signal could be adjusted manually.
When the frequency is below 30kHz, everything seems ok. But as the frequency goes up, The output voltage of the LDO (LM2937ES-5.0/NOPB) also goes up until the VIN voltage.
As you can see, when the frequency is 31kHz (GATE_IN is the voltage signal at TP106), the max voltage at the gate of the MOSFET (V_GATE) is 5.6V.
As the frequency goes up to 40kHz, the voltage at the gate of the MOSFET goes up to 12.8V. The output of the LDO is also 12.8V as measured by the multimeter.
Could anyone explain this strange phenomenon and give a solution?
Many thanks!