| 摘要 |
PURPOSE:To provide a constant current circuit causing no current short timing by providing an OFF signal from a current interrupting circuit to a current drive transistor when phase current of a step motor is switched thereby interrupting the current drive transistor forcibly. CONSTITUTION:A control circuit l is connected with a current interrupting circuit 15 having an output connected with the output terminals of comparators 8, 9. OFF signal from the current interrupting circuit 15 goes High for a short time when motor phase current signals phi1-3, phi2-4 are switched. When the OFF signals are fed to current drive transistor circuits 12, 13, the circuits 12, 13 are interrupted only when the OFF signal is provided and thereby high current flow can be interrupted at current short timing when the phase currents are switched. |
