mertkan65
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Hi,
We are working on a class AB amplifier circuit to drive acoustic sensors. Our schematic is attached below.
Analog_In is 2.5Vpp 140kHz Sinewave, and we have to get 250Vrms at the output of the transformer. 50k Resistor and 231pF Capacitor simulates the load model of sensor at 140kHz. R5 is for current sensing.
Everything was fine until connecting 231pF load capacitance. After that our darlington pairs U3 and/orU4 are blowing up with resistors R6 and/or R7. Blowing up scenario usually occurs at first power up, or when there is not any analog_input (floating or output of at signal generator at High Z), or sometimes power off and then power on again.
Do you have any idea to make this circuit operational? Thanks in advance.
We are working on a class AB amplifier circuit to drive acoustic sensors. Our schematic is attached below.
Analog_In is 2.5Vpp 140kHz Sinewave, and we have to get 250Vrms at the output of the transformer. 50k Resistor and 231pF Capacitor simulates the load model of sensor at 140kHz. R5 is for current sensing.
Everything was fine until connecting 231pF load capacitance. After that our darlington pairs U3 and/orU4 are blowing up with resistors R6 and/or R7. Blowing up scenario usually occurs at first power up, or when there is not any analog_input (floating or output of at signal generator at High Z), or sometimes power off and then power on again.
Do you have any idea to make this circuit operational? Thanks in advance.