| 摘要 |
<p>A power supply circuit of switching regulator type includes a converter transformer (3) defined by a first winding (N1) for receiving input power from a DC source and second winding (N2) for producing output power. A switching transistor (TR4) is connected to the first winding for alternately making and breaking electric connection between the DC source and the first winding by alternate turn on and off operations of the switching transistor, and a rectifier is connected to the second winding for rectifying the output power. A first detector (C3, D6, N3) is provided for detecting the rectified output DC voltage during off-period of the switching transistor and for producing an output-voltage signal representing the output DC voltage. A power supply circuit further includes a second detector (C30, D30, R37, R38, N3) for detecting the input DC voltage during on-period of the switching transistor and for producing an input-voltage signal representing the input DC voltage. The input-voltage signal and output-voltage signal are added to each other and the sum of these two signals are used for controlling the on and off operations of the switching transistor, so as to stabilize the rectified output power.</p> |
