Patent ID: 7298200
Filing Date: 2007-11-20
Classification: G05F

Abstract:
1. A circuit for selectively supplying an external voltage to an internal circuit, comprising: a pulse generation circuit that is configured to generate a pulse having a variable pulse length that varies as a function of an input pulse and an internal voltage; and a first driver circuit configured to provide the internal voltage by coupling the external voltage to the internal circuit for a variable time according to the variable pulse length in response to the pulse, wherein the pulse generation circuit generates the pulse in response to the input pulse and terminates the pulse in response to the internal voltage falling below a first reference voltage, wherein the pulse generation circuit comprises a differential amplifier configured to receive the first reference voltage and the internal voltage and a sensing unit that is configured to sense the level of the internal voltage, and wherein the sensing unit comprises at least one resistor disposed between first and second transistors of the differential amplifier.