Patent ID: 8207787
Filing Date: 2012-06-26
Classification: G05F

Abstract:
1. A low-voltage operation constant-voltage circuit, comprising: a band-gap reference voltage circuit having a resistor-diode series circuit as a main component in which a resistor and a diode-connected bipolar transistor are connected in series to create a constant current, one end of the resistor-diode series circuit being grounded; and an output circuit connected in parallel to the resistor-diode series circuit and configured so that a current flowing through the output circuit becomes equal to the constant current flowing through the resistor-diode series circuit, one end of the output circuit being grounded, wherein the output circuit includes a diode-connected MOS transistor configured to cancel a positive temperature coefficient of the current flowing through the output circuit and an output terminal connected to a drain terminal of the diode-connected MOS transistor to output a reference voltage as a low reference voltage source for an external device, and wherein the diode-connected MOS transistor within the output circuit has a desired temperature characteristic specified by a set ratio of a width W of the diode-connected MOS transistor to a length L thereof, the set ratio (W/L) being within a range from 2.5/70 to 2.5/65.