| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive circuit capable of completely preventing vertical shorting even at soft switching operation. <P>SOLUTION: The DC motor drive circuit comprises a soft switching circuit which gradually shifts on-state of a pair of switching elements to off-state with a time constant, and a vertical shorting prevention circuit which prevents all four switching elements connected in full bridge, including a remaining pair of switching elements, from being turned on, to prevent occurrence of vertical shorting caused by the fact that no dwell time is available at soft switching. The soft switching circuit is a charging circuit composed of a resistor and a capacitor. The vertical shorting prevention circuit comprises a resistor, a diode, and a transistor, and is corresponding to two pairs of switching elements. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
