| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power supply device of an electric apparatus reduced in circuit scale and manufacturing cost using a single resistor both as rush current prevention resistors for preventing rush currents, in the power supply device equipped with a main power supply circuit and a standby power supply circuit. <P>SOLUTION: A standby current is fed to the standby power supply circuit 30 from an AC power supply 1 via the rush current prevention resistor 2. When a power supply switch 3-1 is turned on from a standby state, a temporary excessive overcurrent (rush current) flows in a rectifying and smoothing circuit of the main power supply circuit 20 from the AC power supply 1 via the rush current prevention resistor 2, but the excessive overcurrent is restrained by the resistor 2, and a diode that constitutes a rectifying circuit 4 is protected. When the charging voltage of a smoothing capacitor 6 reaches a steady value, the excitation coil 5-2 of a short-circuiting switch means 5 is excited, a short-circuiting switch 5-1 is turned on, and power can be fed to the main power supply circuit 20 not via the resistor 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
