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Circuit for generating identical output currents

  • US 7,436,248 B2
  • Filed: 04/19/2006
  • Issued: 10/14/2008
  • Est. Priority Date: 05/06/2005
  • Status: Expired due to Fees
First Claim
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1. A current driving circuit supplied with power having a first potential and a second potential and receiving a reference voltage, the current driving circuit having a bias voltage generator and a plurality of constant current drivers, the bias voltage generator receiving the reference voltage, generating a bias voltage, and using the bias voltage to regulate a reference current, the constant current drivers receiving the bias voltage and outputting driving currents related to the reference current, wherein each constant current driver comprises:

  • a first node;

    a first transistor of a first conductive type, having a first main electrode receiving the first potential, a second main electrode connected to the first node, and a control terminal receiving the bias voltage;

    a second transistor of a second conductive type, having a first main electrode receiving the second potential, a second main electrode connected to the first node, and a control terminal connected to the first node; and

    a third transistor of the second conductive type, having a first main electrode receiving the second potential, a second main electrode outputting one of the driving currents, and a control terminal connected to the first node,wherein the bias voltage generator comprises;

    a second node;

    a third node;

    an operational amplifier having a non-inverting input terminal receiving the reference voltage, an inverting input terminal connected to the second node, and an output terminal outputting the bias voltage;

    a fourth transistor of the first conductive type, having a first main electrode receiving the first potential, a second main electrode connected to the third node, and a control terminal connected to the output terminal of the operational amplifier;

    a fifth transistor of the second conduetive type, having a first main electrode receiving the second potential, a second main electrode connected to the third node, and a control terminal connected to the third node;

    a sixth transistor of the first conductive type, having a first main electrode receiving the second potential, a second main electrode connected to the second node, and a control terminal connected to the third node; and

    a resistor having one terminal connected to the second node and another terminal receiving the first potential.

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