BACKGROUND

Field of the Invention

The embodiments disclosed herein relate to a driving circuit for a semiconductor element, a method for driving a semiconductor element, and a motor control apparatus using the driving circuit and/or the method.

Discussion of the Background

JP 4713347B discloses a configuration of a driving circuit that controls the switching speed of a switching element based on a conduction state of main current.

SUMMARY

According to one aspect of the present invention, a driving circuit for a semiconductor circuit including a pair of main terminals through which a main current is conducted and a control terminal to which a control voltage is applied to control a circulation state of the main current, includes: driving voltage switching circuitry that receives a control signal, instructs switching between driving voltages based on a change in the control signal, and outputs a driving voltage, among the driving voltages, that has been selected in the switching; low-speed control circuitry that instructs an increase-decrease change in the control voltage at a low speed; speed-increase control circuitry that executes a speed-increase control of increasing a speed of the increase-decrease change made by the low-speed control circuitry; and speed-increase switching circuitry that instructs switching between an execution and a non-execution of the speed-increase control, and instructs switching between levels of a speed-increase change caused by the speed-increase control.

According to another aspect of the present invention, a motor control apparatus includes: a semiconductor circuit that performs a power conversion of DC power into AC power supplied to a motor, and includes a pair of main terminals through which a main current is conducted, and a control terminal to which a control voltage is applied to control a circulation state of the main current; a driving circuit that drives the semiconductor circuit and includes driving voltage switching circuitry that receives a control signal, instructs switching between driving voltages based on a change in the control signal, and outputs a driving voltage, among the driving voltages, that has been selected in the switching, low-speed control circuitry that instructs an increase-decrease change in the control voltage at a low speed, speed-increase control circuitry that executes a speed-increase control of increasing a speed of the increase-decrease change made by the low-speed control circuitry, and speed-increase switching circuitry that instructs switching between an execution and a non-execution of the speed-increase control, and instructs switching between levels of a speed-increase change caused by the speed-increase control; and control circuitry that outputs the control signal. The semiconductor circuit further performs the power conversion by controlling the circulation state of the main current.

According to yet another aspect of the present invention, a method for driving a semiconductor circuit including a pair of main terminals through which a main current is conducted and a control terminal to which a control voltage is applied to control a circulation state of the main current, includes: receiving a control signal; switching between driving voltages based on a change in the control signal; outputting a driving voltage, among the driving voltages, that has been selected in the switching; executing an increase-decrease change in the control voltage at a low speed; switching between an execution and a non-execution of speed-increase control; and when executing speed-increase control, increasing a speed of the executed increase-decrease change in the control voltage and switching between levels of the executed speed-increase change caused by the speed-increase control.

