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Output circuit for use in a semiconductor integrated circuit

  • US 5,661,414 A
  • Filed: 02/15/1995
  • Issued: 08/26/1997
  • Est. Priority Date: 02/16/1994
  • Status: Expired due to Term
First Claim
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1. An output circuit comprising:

  • a first MOS transistor having a source, a drain, a gate and a back gate isolated from both said source and said drain in terms of potential;

    a first switch coupled between said back gate and said gate of said first MOS transistor, said first switch being ON/OFF controlled by a control signal;

    a potential-applying circuit for applying a potential to said gate of said first MOS transistor;

    a second switch coupled between an output node of said potential-applying circuit and said gate of said first MOS transistor;

    a first node supplied with a first reference, potential;

    a third switch coupled between said back gate of said first MOS transistor and said first node; and

    a second MOS transistor of the same conductivity type as said first MOS transistor, said second MOS transistor having a source coupled to one end of said third switch and a drain and a gate both coupled to said back gate of said first MOS transistor,wherein a potential is generated at said back gate of said first MOS transistor so that said source and said back gate of said first MOS transistor have a voltage difference which is substantially equal to a junction voltage of a parasitic pn-junction diode formed between said source and said back gate of said first MOS transistor, and the potential at said back gate is applied to said gate of said first MOS transistor through said first switch, thereby to orate said first MOS transistor in a sub-threshold region.

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