Reference voltage shifter

摘要

A reference voltage generator for producing a reference voltage that is a preselected amount below a power supply voltage. A reference voltage source produces a first reference voltage that is VREF above the ground potential. A first load device coupled to the ground node and generates an internal reference signal that is determined by the magnitude of current flowing in the first load device. A differential amplifier produces a signal determined by a difference between the signals on the first and second inputs. A current regulating switch having a control node coupled to the differential amplifier output, and coupled to determine the current through the first load device. A second load device coupled in series with the first load device and coupled to the power supply node has an impedance selected to cause the second load device to generate the second reference voltage.