Texas Instruments Incorporated
Circuit and method for generating a reference voltage with a voltage regulator and a sample and hold circuit

Abstract:

A reference generator provides a reference output voltage that is continuously available while providing certain efficiencies of a duty-cycled voltage regulator. The reference output voltage is generated by a sample-and-hold circuit that is coupled to a voltage regulator. On command, the sample-and-hold circuit samples a low dropout voltage regulator that may be referenced by a bandgap circuit. During hold periods of the sample-and-hold circuit, the voltage regulator, in particular the bandgap circuit, may be disabled in order to conserve power. A sample cycle by the sample-and-hold circuit may be triggered by a signal received from a configurable finite state machine. The reference generator is effectively duty cycled in a manner that conserves available battery power, while still providing a constant reference output that is always available. The reference generator is especially suited for low-power, battery operated applications.