| 摘要 |
PROBLEM TO BE SOLVED: To subject a low voltage battery to a trickle charge without increasing the power consumption of a current limiting resistor. SOLUTION: A battery charging circuit includes a power supply circuit 2 being connected via a switching element 4 and a current-limiting resistor 5 to a battery 1 to subject the battery 1 to a trickle charge, and a control circuit 3 turning on and off the switching element 4 on a given duty cycle to subject the battery 1 to the trickle charge using a pulsed charge. The control circuit 3 includes an on-timing adjustment circuit 6 detecting a battery voltage to control the duty cycle of turning on and off the switching element 4. The on-timing adjustment circuit 6 makes a duty cycle ratio smaller in a state of a low battery voltage than in a state of a high battery voltage and turns on and off the switching element 4 to perform the trickle charge by using the pulsed charge. COPYRIGHT: (C)2009,JPO&INPIT |
