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SOI-type semiconductor device with variable threshold voltages

  • US 5,814,899 A
  • Filed: 03/05/1997
  • Issued: 09/29/1998
  • Est. Priority Date: 01/27/1995
  • Status: Expired due to Fees
First Claim
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1. A bias voltage generating apparatus, comprising:

  • a first power supply means for supplying first power supply voltage;

    a second power supply means for supplying a second power supply voltage;

    a first output terminal;

    a second output terminal;

    a first switching element connected between said first power supply means and said first output terminal, said first switching element being turned ON in a standby mode and being turned OFF in an active mode;

    a first diode means formed by a P-channel MOS transistor and connected between said first power supply means and said first output terminal;

    a second diode means formed by a PNP-type transistor and connected between said first power supply means and said first output terminal, an absolute value of a threshold voltage of said first diode means being smaller than a forward voltage of said second diode means;

    a switching element connected between said first output terminal and said second power supply means, said second switching element being turned OFF in said standby mode and being turned ON in said active mode;

    a third switching element connected between said second output terminal and said second power supply means, said third switching element being turned ON in said standby mode and being turned OFF in said active mode;

    a third diode means formed by an N-channel MOS transistor and connected between said second output terminal and said second power supply means;

    a fourth diode means formed by an NPN-type transistor and connected between said second output terminal and said second power supply means, a threshold voltage of said third diode means being smaller than a forward voltage of said fourth diode means; and

    a fourth switching element connected between said first power supply means and said second output terminal, said fourth switching element being turned OFF in said standby mode and being turned ON in said active mode.

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