Patent ID: 7701737

Claim:
A DC-AC converter, comprising: a signal generating module, generating a pulse width modulation signal according to a trigger signal; a first switch, having a control terminal receiving the pulse width modulation signal for controlling whether the first switch is conducted or not, a first terminal coupled to a first voltage, and a second terminal; a first capacitor, having a first terminal and a second terminal respectively coupled to the first terminal and the second terminal of the switch; a transformer, having a primary winding coupled to a second voltage and the second terminal of the first switch, and a secondary winding coupled to a load and the first voltage for generating a driving signal to the load according to a signal variation of the primary winding; and a trigger signal generating module, coupled between the second terminal of the first switch and the signal generating module for comparing a first signal outputted from the second terminal of the first switch with a phase delay signal thereof and thereby generating the trigger signal to control the frequency of the pulse width modulation signal.