Patent ID: 8779843

Claim:
A circuit comprising: a first current source having a first terminal coupled to a first power supply voltage terminal, and a second terminal, the first current source being a constant current source; a first transistor having a collector coupled to the second terminal of the first current source, a base, and an emitter; a first resistor having a first terminal coupled to the emitter of the first transistor, and a second terminal coupled to a second power supply voltage terminal; a second transistor having a collector coupled to the first power supply voltage terminal, a base coupled to the second terminal of the first current source, and an emitter; a second resistor having a first terminal coupled to the emitter of the second transistor, and a second terminal coupled to the base of the first transistor; an output transistor having a collector, a base coupled to the second terminal of the first current source, and an emitter for providing a bias current; and a current mirror circuit having an input terminal coupled to the second terminal of the second resistor, and an output terminal coupled to the collector of the output transistor, for providing a current proportional to a current at the second terminal of the second resistor to the collector of the output transistor.