| 摘要 |
PROBLEM TO BE SOLVED: To achieve low power consumption and high efficiency charging.SOLUTION: A current control MOSFET (14) and current detection resistor (16) are serially connected to a primary side of a flyback transformer (12). A MOSFET (20) is connected to the resistor (16) in parallel. A charge control circuit (18) turns on the MOSFET (14) while the MOSFET (20) is in an off state, before starting charging. The charge control circuit (18) clocks a time that elapses before a primary-side current reaches a predetermined value after a voltage drop of the resistor (16) at this point; and holds it in a memory (44). In order to charge a capacitor (24), the charge control circuit (18) turns on the MOSFET (20) and performs switching control of the MOSFET (14) according to an on time based on the time that is stored in the memory (44). |
