| 摘要 |
A technique for charging a Li-Ion or Li-Ion polymer battery (1) by means of a charging circuitry comprising a power transistor (2) is proposed. Li-Ion or Li-Ion polymer batteries need a so called trickle charge when overdischarged, i.e. a charging with low current, to protect the battery capacity and safety. The required smaller charging current in the trickle charge mode is achieved by a pulse charge mode. The charging circuit according to the present invention uses the same power transistor (2) for trickle charging, i.e. when the Li-Ion battery voltage is not higher than the predetermined threshold voltage VTHR, and for normal charging, i.e. when the battery voltage is higher than the predetermined threshold voltage VTHR. According to the invention the charging circuit effects a pulsed charging in the trickle charge mode. The current settings and voltage settings can be the same as in the case of normal charging. By pulse charging in the trickle charged mode the average load of the power transistor (2) can be lowered and the transistor (2) and its casing can be designed smaller as the average load and heat dissipation is reduced. <IMAGE> |
