The invention discloses a phase detection and correction circuit for out-of-phase driving of a pulse width modulator. The phase detection and correction circuit is characterized by comprising a phase detection circuit consisting of two diodes Dm and Ds and a phase correction circuit consisting of a resistor R1 and a triode N1, wherein the cathode of the first diode Dm is connected with the driving end Drm of a master pulse width modulator (Master PWM); the cathode of the second diode Ds is connected with the driving end Drs of a slave pulse width modulator (Slave PWM); both the anodes of the first and second diodes Dm and Ds are connected with the base b of the triode N1 and one end of the resistor R1; the other end of the resistor R1 is connected with the collector c of the triode N1; the collector c of the triode N1 is connected with the voltage reference Vrefm of the master pulse width modulator (Master PWM) or the voltage reference Vrefs of the slave pulse width modulator (Slave PWM); and the emitter e of the triode N1 is connected with the fixed frequency triangular wave signal end OSCs of the slave pulse width modulator (Slave PWM).