| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drive circuit that makes the protection of a switching element from a surge voltage compatible with the protection of the switching element from a reversely-connected DC power supply. <P>SOLUTION: A diode 15 for surge absorption and a zener diode 16 for reverse-connection protection are provided on bypass wiring 13 that connects a stepping motor 2 with the DC power supply 3 while bypassing an IC 11. The diode 15 for surge absorption allows a current to flow from the stepping motor 2 to the DC power supply 3 so as to protect the IC 11 from a surge voltage generated in the stepping motor 2. The zener diode 16 for reverse-connection protection prevents a current flow generated by the reversely-connected DC power supply 3 while allowing a current to flow generated by the surge voltage being a voltage higher than a zener voltage in the current flowing from the stepping motor 2 toward the DC power supply 3 so as to protect the IC 11 from the reversely-connected DC power supply 3. <P>COPYRIGHT: (C)2008,JPO&INPIT |
