Patent ID: 6661208
Filing Date: 2003-12-09
Classification: H02M,H03K,Y02B

Abstract:
A synchronous dcâ€”dc converter circuit for converting an input dc voltage of predetermined polarity to an output dc voltage, the synchronous dcâ€”dc converter circuit comprising:a dc input and a ground input for supplying the input dc voltage; a control FET having source and drain connected between the dc input and a switch node, the switch node being for connection through an inductor to a dc output for supplying the output dc voltage; a sync FET having source and drain connected between the switch node and the ground input; a switching input for inputting an alternating control signal; a comparator for detecting a voltage change on the switch node of opposite polarity to the dc input voltage and sending out a trigger signal in response; and at least one driver for driving the control and sync FETs alternately in response to the alternating control signal on the switching input, wherein the driver, in response to a change in the alternating control signal of a predetermined polarity, switches off the sync FET, and then waits for the trigger signal before switching on the control FET.