| 摘要 |
PURPOSE:To embody a power supply circuit reducing power consumption at a light load. CONSTITUTION:An output So of an audio output circuit 31 energized by power supply voltages Va, Vb outputted from a couple of switching power supplies 2a, 2b of a power supply circuit 1 is fed back to bias level control sections 4a, 4b to generate a bias level proportional to the output So. The level is added to the output So to generate control signals VSa, VSb shifted from the output So by the bias level and the signals are inputted to arithmetic operation control sections 3a, 3b to allow the level of the power supply voltages Va, Vb to trace a level of the control signals VSa, VSb to be equal to each other. Thus, a level margin of a power supply voltage at a large output is secured and the bias level is decreased at a light load such as a non-signal to reduce power consumption. |
