| 摘要 |
<p>A current control device for an automotive electromagnetic clutch includes a first and a second transistor 8 and 13 and a current detector resistor 14, which are coupled in series with the electromagnetic clutch 4. A PWM modulator 7 controls the ON/OFF of the first transistor to control the amount of excitation current flowing through the electromagnetic clutch. The second transistor turns off the excitation current in response to the disconnection signal SO for the electromagnetic clutch. The current detector 6 detects the current flowing through the resistor 14, and the amount of current through the electromagnetic clutch is controlled to a target valve via the calculation means 2, the deviation amplifier 5, and the PWM modulator 7. The error in current detection due to the current flowing through the reverse excitation resistor 12 is eliminated by the insertion of a transistor 17 controlled in response to the clutch disconnection signal SO by a transistor 19 (FIG. 2). Alternatively, the effect of the base current to the current detection is eliminated by an adoption of a second transistor 70 of the field effect type (FIG. 3).</p> |
