3624481 is referenced by 20 patents and cites 13 patents.

A battery charger more particularly for use in charging batteries of the nickel-cadmium type in order to avoid the undesired effects caused by overcharging, wherein a variable reference voltage is derived across a resistor from a constant-current device whose current may be controlled and this derived reference voltage is compared with the terminal voltage existing across the battery being charged, the result of this comparison causing the charging current to be switched off until the battery voltage drops below the reference voltage, whereby the state of charge of the battery is sensed through the ON/OFF ratio of the charging current and appropriate adjustments may be made to the reference voltage in order to achieve a substantially complete charging of the battery in the minimum time without any overcharging occuring.

Controlled-current battery chargers
Application Number
Publication Number
Application Date
May 23, 1969
Publication Date
November 30, 1971
Macharg James A
H02j 07/10
H02J 07/00
View Original Source