| 摘要 |
PROBLEM TO BE SOLVED: To properly protect respective switching devices constituting a bridge circuit for driving an inductance load and perform stable PWM driving. SOLUTION: The bridge circuit is constituted by switching devices (FET Q1 to Q4), a middle connecting point between Q1 and Q3 and a middle connecting point between Q2 and Q4 are connected via the inductance load (an actuator ACT), and flywheel diodes D1 to D4 are connected in parallel with each of Q1 to Q3. When a phase difference occurs in the current and voltage of a control signal of a sinewave to generate mutually different signals under an OFF-condition of a pulse width modulation signal, one switching device (e.g. Q3) on a lower arm is turned off, the other switching device (e.g. Q4) on the lower arm is turned on, and current is regulated so as to circulate through the other switching device (Q4), the flywheel diode (D3) and the inductance load (ACT). |
