Constant voltage generating device

摘要

A constant voltage generating device has a reference voltage generating circuit, a constant current circuit unit and a current/voltage converter circuit unit. The reference voltage generating circuit generates a desired reference voltage. The constant current circuit unit has a differential amplifier to which that reference voltage which is generated by the reference voltage generating circuit is applied as the reference potential, as well as a first current regulating MOS transistor which is provided with a gate electrode to which an output signal of the differential amplifier is applied, and a standard resistor, which is connected in series with the first current regulating MOS transistor. The constant current circuit unit generates a reference current for regulating a differential amplifier, so that a constant current can be caused to flow through the latter. The current/voltage converter unit has a second current regulating MOS transistor which forms a current mirror circuit (balanced circuit) together with the first current regulating MOS transistor of the constant current circuit unit, as well as a current/voltage converter MOS transistor, which is connected in series with the second current regulating MOS transistor and forms a current mirror circuit together with an active element unit/current regulating MOS transistor of the differential amplifier. <IMAGE>