Patent ID: 7821797
Filing Date: 2010-10-26
Classification: H02M

Abstract:
1. An isolated DC-DC converter comprising: a transformer including at least a primary winding and a secondary winding; a switching circuit connected to the primary winding of the transformer and arranged to switch an input power supply; a digital control circuit including a switching controller arranged to output control pulses to the switching circuit; a rectifying/smoothing circuit arranged to rectify and smooth an alternating voltage generated at the secondary winding of the transformer by switching the switching circuit and outputting an output voltage to an output terminal; an output-voltage detecting circuit arranged to detect the output voltage output via the rectifying/smoothing circuit; and an isolation member arranged to transmit the control pulses output from the digital control circuit to a primary side of the transformer while isolating a secondary side of the transformer from the primary side; wherein the digital control circuit is disposed at the secondary side of the transformer, and includes a receiving member arranged to receive signals detected by the output-voltage detecting circuit or digital values of the detected signals, and an input power-supply voltage calculating member arranged to calculate a voltage of the input power supply from at least an on-duty cycle of the control pulses, the output voltage, and a ratio of the number of turns of the primary winding to the number of turns of the secondary winding of the transformer.