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Fast switching, overshoot-free, current source and method

  • US 8,237,376 B2
  • Filed: 03/19/2010
  • Issued: 08/07/2012
  • Est. Priority Date: 03/20/2009
  • Status: Active Grant
First Claim
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1. A current source circuit configured to receive drive pulses for an electrical load, the current source circuit comprising:

  • a sensing resistor;

    a current amplifier includingan amplifier, anda power switch configured to be controlled by an output of said amplifier and being coupled in series with the electrical load and to said sensing resistor and between the electrical load and a first reference voltage,said amplifier being input with a second reference voltage and with a feedback signal corresponding to a voltage drop on said sensing resistor;

    a reference voltage switch being coupled to a control terminal of said power switch and configured to be controlled by the drive pulses;

    a replica branch being coupled between a power supply node of the current source circuit and the first reference voltage, said replica branch including a scaled replica power switch having a control terminal coupled to the output of said amplifier, and a scaled replica sensing resistor coupled in series with said scaled replica power switch;

    a first control switch coupled between the output of said amplifier and the control terminal of said power switch; and

    second and third control switches configured to be driven in phase and in phase opposition, respectively, with said first control switch for coupling in a mutually exclusive mode an input of said amplifier to said sensing resistor and to said scaled replica sensing resistor.

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