| 摘要 |
PURPOSE: A circuit for protecting an FET(Field Effect Transistor) of an inverter is provided to prevent the damage of an FET by detecting an opening of a Schottky diode to stop the driving of the FET. CONSTITUTION: A diode(D1) is switched according to a voltage applied to a connecting node(a) as connecting a cathode and an anode in parallel to the connecting node(a) of a Schottky diode(3) sequentially. An end of a smoothing unit(110) is connected in parallel to the anode of the diode(D1) and the other end thereof is grounded. The smoothing unit(110) is comprised of a capacitor(C1) and a resistor(R1) so as to smooth an AC(Alternating Current) waveform signal applied through the diode(D1) into a DC(Direct Current) waveform signal. An emitter of a first transistor(Q1) is connected to the capacitor(C1) of the smoothing unit(110), a base is connected to a ground, and a collector is connected to a constant voltage terminal(Vcc). The first transistor(Q1) is switched according to a signal level outputted from the smoothing unit(110). An emitter and a base of a second transistor(Q2) are connected to the constant voltage terminal(Vcc) and a collector is connected to a control terminal of a PWM(Pulse Width Modulation) oscillation and feedback circuit(1).
|
