Low-average-current controller for vehicular electric motor - incorporates time constant redn. network for improvement of load current decay behaviour after switching of drive

摘要

The load (22) is connected in the diagonal of a bridge circuit (20) in which four MOSFETs (28, 30, 40, 52) are gated by signals (66, 68, 70, 72) from a control unit (10) responsive to operating parameters (12-14). In series with the load is an additional network (48) which accelerates the decay of load current in the free-wheeling phase, so that the time-averaged current is reduced and control is feasible even at very low current levels. USE/ADVANTAGE - Esp. for a throttle-flap or fuel-injection-pump stepping motor, cost is reduced by the MOS bridge circuit with shortened current decay time.