Self-clocked charge pump for vehicle battery charging - uses switched transistors controlling charging and discharging of charges storage capacitors connected in series

摘要

The charge pump uses a number of charge storage capacitors (C1,C2,C3) connected in series, selectively coupled to the DC voltage source (S) via respective transistor switches (T1...T6). The charge held by each storage capacitor (C1,C2,C3) is compared during charging with a reference value, allowing the charging to be interrupted upon reaching a threshold value. The storage capacitors (C1,C2,C3) are charged in succession until a second threshold value is reached, the obtained charge transferred to the parallel battery (V) in parallel with the charging of the individual storage capacitors (C1,C2,C3). ADVANTAGE - Allows battery recharging from DC source with varying impedance e.g. vehicle dynamo.