| 摘要 |
PURPOSE:To obtain a stabilized output in high efficiency in a wide input voltage range by operating a switching regulator when an input voltage is high, and operating as a series regulator when the voltage difference of the input and output becomes low. CONSTITUTION:A transistor (TR) 2 operates as the switch element of a chopper type switching regulator when an input voltage is high, and a TR3 operates as a series control element of a series regulator when the difference of the input voltage and the output voltage becomes low. A control circuit 101 compares a sawtooth wave voltage obtained from a timing capacitor of an oscillator in a pulse width modulator with a control signal (b) detected from the output voltage to control the TR2 OFF and ON. A control circuit 102 compares the signal (b) with a dead time voltage to operate a TR8, thereby controlling the TR3. Thus, a stabilized output of high efficiency can be obtained in a wide input voltage range. |
