Patent ID: 7659787
Filing Date: 2010-02-09
Classification: H03K

Abstract:
1. A circuit for generating a clock of a semiconductor memory apparatus, the circuit comprising: a reference voltage generator configured to generate a reference voltage; a reference current generator configured to generate a plurality of fixed currents, each of which has a constant current value regardless of a change in temperature, the reference current generator including a plurality of switching units outputting the plurality of fixed currents respectively to output terminals, the output terminals being connected in common to output a reference current; an oscillator configured to receive the reference voltage and the reference current to generate a clock that has constant frequency; a control signal generator configured to determine a current value of the reference current by controlling the reference current generator, wherein the reference current generator further comprises: a plurality of fixed current generating units, each of which is configured to receive a positive temperature coefficient voltage and a negative temperature coefficient voltage of the reference voltage generator to generate the fixed current that has a constant current value regardless of temperature; and wherein the switching units are configured to output the plurality of fixed currents in response to the plurality of current control signals.