| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synchronous rectification type full-wave rectification circuit with a small number of components. <P>SOLUTION: A synchronous rectification circuit includes synchronous rectification elements M1-M4, a current detection circuit 4 and a polarity detection circuit 5. The synchronous rectification elements M1-M4 are bridge-configured so that an AC voltage is inputted to a first node and a second node, a rectification voltage is outputted from a third node and a fourth node is grounded. The current detection circuit 4 is a control circuit to control ON/OFF of the synchronous rectification elements on a full-wave rectification circuit including a smoothing capacitor C1, in which a timing control circuit 2 detects a voltage drop of the synchronous rectification elements M3 and M4 and outputs a control signal to turn ON/OFF the synchronous rectification elements M1-M4 according to detected values. The polarity detection circuit 5 detects polarity of an AC voltage on the basis of a potential of the fourth node and outputs a polarity signal. A gate drive circuit 3 selects and performs ON/OFF driving of a pair of elements from among the synchronous rectification elements M1-M4 connected between the individual nodes by using an ON/OFF control signal from the current detection circuit 4 and a detection signal of the AC voltage from the polarity detection circuit 5. <P>COPYRIGHT: (C)2013,JPO&INPIT |
