| 摘要 |
PURPOSE:To improve the conversion efficiency by switching a conversion system according to the amplitude of an input voltage by a DC/DC converter. CONSTITUTION:A DC input voltage 1 is controlled by control transistor (Tr)8, and supplied through smoothing circuits 13, 14 to a load. Divided voltages 1 divided by dividers 16, 18 and a reference voltage by a constant-voltage diode 11 are input to a comparator 2, and divided output voltage divided by dividers 21, 22 and the reference voltage are input to an error amplifier 4. Further, the output of the amplifier 4 and the output of a sawtooth wave oscillator 5 are input to the comparator 3. Thus, when the voltage 1 is higher than the prescribed voltage, Trs 9, 7 are turned OFF, Tr6 is controlled to be intermittently interrupted to intermittently interrupt the Tr8, thereby operating in a series chopper swtiching system. When the input voltage 1 is lower than the prescribed voltage, the Tr9 is turned ON,and the Tr6 is turned OFF, the Tr7 is continuously controlled by the output of the amplifier 4, and operated as the normal series regulator through the Tr8. |
