| 摘要 |
PROBLEM TO BE SOLVED: To start a switching power supply circuit reliably and stably to supply a DC stabilized voltage to an electronic apparatus, and to reduce the power loss in the starter circuit. SOLUTION: This power supply has a starter circuit that is made up of a power supply structured with a first resistor connected to the high-voltage side of an input voltage, a series circuit of first and second constant-voltage elements, and a third resistor connected in parallel to the second constant- voltage element to treat the voltage of the second constant-voltage element as a reference voltage; a control IC that generates PWM signals; a bias circuit that impresses a voltage to the IC via the windings of a transformer after starting the IC; and a switch circuit that lowers the reference voltage sufficiently with a constant delay time after the start of the IC.
|
