Constant current source circuit

摘要

A current source includes a first MOS transistor of a first channel type including a drain connected to an output terminal, and a source directly connected to a first power supply, a second MOS transistor of the first channel type including a drain connected to a gate, the gate of the second MOS transistor being connected to the gate of the first transistor, and a source directly connected to the first power supply, a third MOS transistor of a second channel type opposite the first channel type including a drain connected to the drain of the second MOS transistor, a fourth MOS transistor of the second channel type including a drain connected to the source of the third MOS transistor, a gate connected to a first bias voltage, and a source directly connected to second power supply voltage, and a control voltage generator that detects an output voltage on the output terminal and provides a shifted version of the output voltage to the gate of the third MOS transistor.

主权项

1. A current source comprising:
a first MOS transistor of a first channel type including:
a drain connected to an output terminal; anda source directly connected to a first power supply voltage; a second MOS transistor of the first channel type including:
a drain connected to a gate, the gate of the second MOS transistor being connected to the gate of the first MOS transistor; anda source directly connected to the first power supply voltage; a third MOS transistor of a second channel type opposite the first channel type including:
a drain connected to the drain of the second MOS transistor; a fourth MOS transistor of the second channel type including:
a drain connected to the source of the third MOS transistor;a gate connected to a first bias voltage; anda source directly connected to a second power supply voltage; and a control voltage generator that detects an output voltage on the output terminal and provides a shifted version of the output voltage to the gate of the third MOS transistor.