| 摘要 |
PURPOSE:To enhance the efficiency of a DC stabilized power source by connecting a dummy resistor to the output side of an output filter of a switching regulator only at the no load and light load times, thereby reducing the loss due to the dummy resistor. CONSTITUTION:An output voltage is fed back, the duty is controlled in response to the output voltage by a comparison and pulse width controller 14, a switching transistor 5 is controlled ON or OFF through a drive circuit 6 to maintain the output voltage constant. A transistor 11 is connected in series with a dummy resistor 12, the state that the duty of a pulse controller 14 is short, i.e., that a load is light is detected to turn the transistor 11 ON through a drive circuit 13 to connect the resistor 12, the transistor 11 is turned OFF at the heavy load time to open the resistor 12, thereby alleviating the loss due to the resistor 12. |
