Patent ID: 7750608

Claim:
A low noise current source, comprising: an unregulated power supply; a voltage regulator electrically coupled to the unregulated power supply; a first heat sink thermally coupled to the voltage regulator; a current regulator which is electrically coupled in series with the voltage regulator; a second heat sink thermally coupled to the current regulator; an analog processing circuit which is electrically coupled to an input of the voltage regulator, an output of the voltage regulator and an output of the current regulator, the processing device comprising: a first summing amplifier electrically coupled to an input of the voltage regulator and an output of the current regulator, an error amplifier electrically coupled to the first summing amplifier, a second summing amplifier electrically coupled to the error amplifier, a signal driver which is electrically coupled between the second summing amplifier and the voltage regulator, a first filter electrically coupled between the error amplifier and the second summing amplifier, a limiter electrically coupled between the error amplifier and the second summing amplifier, a second filter electrically coupled between the second summing amplifier and the driver, and the processing circuit being configured to measure voltage output of the unregulated power supply, measure the voltage output of the voltage regulator and to regulate a voltage drop across the voltage regulator to simultaneously match a voltage drop across the current regulator to substantially match heat dissipation between the first heat sink and second heat sink.