Patent ID: 6271716
Filing Date: 2001-08-07
Classification: G05F,H03L

Abstract:
A current source circuit comprising:a first resistor coupled to ground;a first transistor device having an emitter coupled to the first resistor, a base, and a collector, coupled to a node, wherein current flows from the node through the resistor and the transistor to ground;a second transistor device having an emitter coupled to the base of the first transistor, a base, and a collector;a second resistor coupled at one end to a supply voltage and another end coupled to the collector of the second transistor device;a third transistor having an emitter coupled to the second resistor, a base coupled to a bias voltage and a collector coupled to the collector of the first transistor;an operational amplifier having an output coupled to the base of the second transistor device and an input coupled to the emitter of the first transistor device.