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Level shifter

  • US 10,312,913 B2
  • Filed: 10/02/2017
  • Issued: 06/04/2019
  • Est. Priority Date: 10/17/2016
  • Status: Active Grant
First Claim
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1. A level shifter comprising:

  • a level shifter section that is driven by a first power source voltage, and that, in accordance with switching of an input signal of a voltage lower than the first power source voltage, switches an output signal that has been level-shifted, from the first power source voltage to a voltage lower than the first power source voltage; and

    a threshold voltage changing circuit that, in accordance with a switching direction of the input signal, changes a threshold voltage of the input signal for switching the output signal,wherein the level shifter section includes a differential amplifier circuit and a current mirror circuit, andwherein the threshold voltage changing circuit includes;

    a constant current source having an input connected to the first power source voltage;

    a first transistor having a first electrical conductivity type and having a first main electrode connected to an output of the constant current source, a second main electrode connected to a second power source voltage having a voltage lower than the first power source voltage, and a first control electrode connected to a node between an output terminal where the output signal is output and the differential amplifier circuit; and

    a second transistor having a second electrical conductivity type opposite to that of the first electrical conductivity type and having a third main electrode connected to the differential amplifier circuit, a fourth main electrode connected to the differential amplifier circuit and the output terminal, and a second control electrode connected to a node between the output of the constant current source and the first main electrode.

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