Patent ID: 8374002
Filing Date: 2013-02-12
Classification: H02M

Abstract:
1. An isolated switching power supply apparatus comprising: a direct-current input power supply; a power transmission transformer including a primary winding and a secondary winding; at least one main switching element configured to perform switching control on a direct-current voltage applied to the primary winding of the power transmission transformer; a rectification circuit that includes at least one rectification switching element and is connected to the secondary winding of the power transmission transformer; a smoothing circuit connected to the secondary winding of the power transmission transformer; a power conversion circuit configured to obtain an output voltage from the smoothing circuit; and a control circuit configured to control an operation of the power conversion circuit; wherein an input/output conversion ratio is controlled in accordance with a duty ratio of the at least one main switching element; the control circuit includes a timing signal transmission transformer that is connected between a primary controller and a secondary controller and includes a primary winding and a secondary winding; the primary controller includes at least one primary drive switch configured to drive the timing signal transmission transformer, a primary digital control unit configured to control a time of driving of the at least one primary drive switch, and a primary winding voltage detection unit configured to detect a change in voltage output from the timing signal transmission transformer; the secondary controller includes at least one secondary drive switch configured to drive the timing signal transmission transformer, a secondary digital control unit configured to control a time of driving of the at least one secondary drive switch, and a secondary winding voltage detection unit configured to detect a change in voltage output from the timing signal transmission transformer; a pulse signal is generated by the at least one primary drive switch or the at least one secondary drive switch when or immediately before the main switching element is turned on or off, and is transmitted from one of a primary circuit and a secondary circuit to the other one of the primary circuit and the secondary circuit by the timing signal transmission transformer; and the at least one primary drive switch, the at least one secondary drive switch, and the timing signal transmission transformer define an auxiliary switching power supply circuit, the timing signal transmission transformer defines a reactance element in the auxiliary switching power supply circuit, and the auxiliary switching power supply circuit performs voltage conversion or regeneration of driving energy of the main switching element.