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Semiconductor memory device employing clamp for preventing latch up

  • US 7,417,909 B2
  • Filed: 12/23/2004
  • Issued: 08/26/2008
  • Est. Priority Date: 04/27/2004
  • Status: Active Grant
First Claim
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1. A semiconductor memory device comprising:

  • means for precharging and equalizing a pair of bit lines; and

    means for generating a control signal which controls enable and disable of the precharging/equalizing means,wherein the control signal generating means includesa CMOS transistor; and

    a clamping means wherein the clamping means to clamp a source voltage transferred to the CMOS transistor uses a bulk bias voltage of the CMOS transistor in order to reduce a latch-up phenomenon caused by the CMOS transistor,wherein the control signal generating means includesa PMOS transistor; and

    an NMOS transistor whose gates commonly form an input node and drains commonly form an output node of the control signal generating means, the PMOS transistor using a boosted voltage as a bulk bias and receiving an output voltage of the clamping means as its source voltage, and the NMOS transistor using a reduced voltage as its bulk bias and receiving a ground voltage as its source voltage.

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