Patent ID: 9614470
Date: 2017-04-04
CPC Classifications: H02P

Claim:
1. A motor current controller comprising: an H-bridge circuit that includes a switching element and is connected to a motor coil provided in a motor; and a control unit that drives the switching element every PWM cycle and designates an operation mode from among a plurality of modes including a charge mode, in which a motor current flowing in the motor coil increases, and a decay mode, in which the motor current is decreased for the H-bridge circuit, wherein the control unit includes: an operation mode selector that selects the decay mode as the operation mode when the motor current is equal to or greater than a reference current value in a period in which a predetermined maximum duty time elapses after each PWM cycle starts; an invalidator that sets, as an invalidation period, a period from a time point at which a first predetermined time elapses after the first PWM cycle starts to a time point at which a second predetermined time elapses after the subsequent second PWM cycle starts, during which the selection of the decay mode by the operation mode selector is disabled; a charge mode designator that designates the operation mode to the charge mode during the invalidation period; and a maximum duty time designator that selects the decay mode as the operation mode with higher priority over the operations of the invalidator and the charge mode designator during a period in which the PWM cycle ends after the maximum duty time elapses from the start of each PWM cycle.