Electric charger and power supply device for portable terminal

  • US 7,183,748 B1
  • Filed: 02/07/2000
  • Issued: 02/27/2007
  • Est. Priority Date: 02/07/2000
  • Status: Expired due to Term
First Claim
Patent Images

1. An electric charger, comprising:

  • a charging circuit outputting a charging voltage in correspondence with the number of battery cells incorporated in a battery in a supply state of an external power supply;

    a charging control unit which, upon detection of connection of said battery functioning normally, said battery is charged by turning on a switch unit provided in a connection path extending from the charging circuit to the battery; and

    a cutoff releasing circuit which, upon detection of connection of said battery in a cutoff state caused by overdischarge, outputs a releasing voltage for releasing the cutoff state set by over-discharge of the battery,wherein the cutoff releasing circuit comprises;

    a first FET switch connecting a drain to the output of the charging circuit;

    a second FET switch which has a source connected to the source of the first FET switch and a drain connected to the battery and which is ON/OFF-controlled by the charging control unit, anda switch control circuit which, upon connection of said battery in a cutoff state caused by over-discharging, turns on the first FET switch in accordance with a battery abnormal signal outputted from the battery, thereby applying a charge voltage for releasing the cutoff state to the battery via a parasitic diode of the second FET switch in an OFF state.

View all claims
    ×
    ×

    Thank you for your feedback

    ×
    ×