Patent ID: 6765432
Filing Date: 2004-07-20
Classification: G05F

Abstract:
A semiconductor device capable of transition to a low-power operation mode in which the semiconductor device operates on a power lower than a power in a normal operation, comprising:a time-counting circuit for activating a control signal for transition to said low-power operation mode when a prescribed signal input to the semiconductor device is activated for a prescribed time period; and an internal circuit for reducing power consumption in response to said control signal; wherein said time-counting circuit includes a CR-type time constant circuit including a capacitive element and a resistance element, in which electric charges are charged and discharged to/from said capacitive element in accordance with a time constant determined by a capacitance value of said capacitive element and a resistance value of said resistance element; a signal output circuit for activating said control signal based on a voltage level determined by a charge state of said capacitive element; and another capacitive element, connected to an input node of said signal output circuit, for canceling noise fluctuation of a power supply voltage or a around voltage, wherein said prescribed time period is determined by said time constant of said CR-type time constant circuit.