Integrated switch for selecting a fixed and an adjustable voltage reference at a low supply voltage

摘要

A fixed and a user adjustable voltage reference is alternatively provided by an integrated switch which switches between two current sources according to an input voltage. A fixed reference voltage is achieved by amplifying the current of one of the two current sources according to a predetermined voltage difference between the output terminal and an internal reference voltage. An adjustable reference voltage is achieved by amplifying the current of other of the two current sources according to a voltage difference between the internal reference voltage and an user adjustable voltage. In one embodiment, the user adjustable voltage is achieved by a user adjustable voltage divider circuit.