pin u201c vcc u201d is connected to an external power source and the ground u201c gnd u201d is grounded in this embodiment a first capacitor c 1 is connected between the bootstrap pin u201c boot u201d and the phase pin u201c phase u201d to pull up a voltage of the phase pin u201c phase u201d in an alternative embodiment the second capacitor c 2 can be omitted in this embodiment the phase adjusting pin u201c ph u201d is grounded via a phase adjusting resistor r and the phase controller can automatically adjust a phase of the pwm signal received by the pulse adjusting driver circuit 150 by adjusting a resistance of the phase adjusting resistor r the adjusted pwm signal is output to the corresponding switch circuit 159 via the phase pin u201c phase u201d to adjust the phase of the first driving signal each switch circuit 159 includes a first transistor q 1 a second transistor q 2 an inductor l a second capacitor c 2 each of the first transistor q 1 and the second transistor q 2 includes a control terminal not labeled a first conducting terminal not labeled and a second conducting terminal not labeled the phase pin u201c phase u201d of the corresponding adjusting driver 157 is connected to the voltage output terminal 155 via the inductor l the two detection pins u201c cs u2212 u201d u201c cs u201d of the corresponding adjusting driver 157 are connected to two terminals of the inductor l to detect an.