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HIGH SIDE POWER SWITCH WITH CHARGE PUMP AND BOOTSTRAP CAPACITOR

  • US 20050017768A1
  • Filed: 07/22/2003
  • Published: 01/27/2005
  • Est. Priority Date: 07/22/2003
  • Status: Active Grant
First Claim
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1. A power switching circuit comprising:

  • a power semiconductor switching device;

    a charge pump circuit having a control input to control whether the charge pump is on or off and a charge pump output, the charge pump output being coupled to a control terminal of the power semiconductor switching device;

    a bootstrap power supply for supplying power to driver circuitry for the power semiconductor switching device, the bootstrap power supply comprising a bootstrap capacitor coupled to a charging current source;

    the bootstrap power supply providing power to the driver circuitry when the power semiconductor switching device is being switched by the driver circuitry in a pulsed mode; and

    the charge pump supplying a control voltage to turn on the power semiconductor switching device and maintain it on when the power switching device is to be maintained on continuously; and

    wherein a transistor switch of the driver circuitry is actively controlled to prevent the charge pump from charging the bootstrap capacitor.

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