Constant current source and solid imaging apparatus using the same

摘要

A constant current source has a first current source circuit for outputting a first current; a second current source circuit for outputting a second current according to a reference voltage; a current comparison circuit for comparing magnitudes of the first and second currents; and a current adjustment unit for adjusting a current value of the first current output from the first current source circuit in accordance with a comparison result of the current comparison circuit.

主权项

1. A constant current source, comprising:
a first current source circuit that outputs a first current; a second current source circuit that outputs a second current according to a reference voltage, said second current source circuit comprising (i) a first MOS transistor that flows the second current, (ii) a reference voltage generating unit that outputs a constant voltage, and (iii) an operational amplifier having a non-inverting input terminal connected to an output terminal of the reference voltage generating unit, an inverting input terminal connected to a source of the first MOS transistor, and an output terminal connected to a gate of the first MOS transistor; a current comparison circuit that compares magnitudes of the first current and the second current; and a current adjustment unit that adjusts a current value of the first current output in accordance with a result of the comparison of the current comparison circuit.