| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply in which harmonic components are reduced, even for the low input voltage part. SOLUTION: In the low-voltage section of a full-wave rectifier circuit 1, voltage of a second capacitor C2 drops as the voltage of a first capacitor C1 drops, with respect to the filing voltage of a charging capacitor C3. Consequently, the amplitude is increased by an inductance L2, and the second capacitor C2 and the input decreases but flows continuously. When the voltage of a capacitor C8 drops and a Zener diode ZD1 is turned off, for example, and a transistor Q5 is turned on to connect a capacitor C14 in parallel with a capacitor C7, a combined capacitance is increased and the base amount of a transistor Q1 is increased, thus increasing the output from an inverter circuit 3. Since the voltage of the second capacitor C2 approaches 0V at the time of zero-cross, an input current is supplied from an AC commercial power supply e) side and the second capacitor C2 resonates, even at a low input voltage part. Consequently, a substantially sinusoidal continuos input current having no pause is provided, and harmonic components are reduced. |
