| 摘要 |
A voltage regulator for an internal combustion engine having a permanent magnet alternator and utilizing an SCR/diode bridge rectifier includes crowbar SCR overvoltage protection means. To assure that the crowbar SCR has an adequate period in which to cool off after triggered on by an overvoltage surge, crowbar SCR operation is detected to generate a control signal to activate a timer which shuts off gate drive to the main bridge SCR's and thereby shuts down the bridge for a period of time sufficient to provide crowbar SCR recovery and cool off. In its preferred embodiment, the control signal is provided by the crowbar SCR gate to cathode voltage drop during protective operation, which signal is of relatively long duration, thus allowing the use of filters to eliminate spurious triggering of the timer by transient noise signals. Feedback from the switch means supplying gate drive to the bridge SCR's is used to provide a tapered charging characteristic. Temperature detection of the mounting base temperature of the semiconductors in the SCR/diode bridge may be used to shut off the gate drive to the main bridge SCR's to prevent excessive temperature rise of the semiconductor junctions.
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