Control circuit for electric tool

Abstract

A control circuit for an electric tool according to the present invention, includes a permanent magnet synchronous motor, a plurality of switching elements, and a PWM inverter circuit that drives the permanent magnet synchronous motor. The control circuit includes a current detector that detects a current flowing through the PWM inverter circuit. When braking the permanent magnet synchronous motor, the control circuit limits a current flowing through the permanent magnet synchronous motor and the PWM inverter circuit, to a predetermined current limit value. At the same time, by switching low-side switching elements or high-side switching elements of the PWM inverter circuit, the control circuit boosts an induced electromotive voltage of the permanent magnet synchronous motor, and regenerates a regenerative current to the battery.

Dependencies are inferred from the claim text.