Patent ID: 7266158

Claim:
A radio communication device, comprising: a radio signal transmitting/receiving section for transmitting and receiving data via radio waves; the radio signal transmitting/receiving section communicating with an external device by transmitting and receiving data therefrom; a modulation/demodulation section, connected to the radio signal transmitting/receiving section, for modulating a transmitting signal and demodulating a receiving signal; a clock generating section for generating an RF clock signal, an operation clock signal, and a power-down clock signal, respectively, in accordance with a control signal, (i) the RF clock signal having a high frequency and serving as a reference for driving the radio signal transmitting/receiving section, (ii) the operation clock signal being for normal operation and serving as a reference for driving each section except the radio signal transmitting/receiving section, and (iii) the power-down clock signal having a low frequency for reducing power consumption; a period count section, including a high speed slot counter and a low speed slot counter, the high speed counter for counting slots corresponding to a duration of a period for transmitting and receiving, the high speed slot counter driven in accordance with the operation clock signal generated by the clock generating section, and the low speed counter for counting slots corresponding to a duration of a period for no transmitting and receiving, the low speed slot counter driven in accordance with the power down clock signal having the low frequency generated by the clock generating section; a request signal generating section for receiving a first count value of the slots counted by the high speed slot counter and a second count value of the slots counted by the low speed slot counter, and for outputting a request signal, respectively, when one of (a) the first count value counted by the high speed slot counter reaches a predetermined value and (b) the second count value counted by the low speed slot counter reaches the predetermined value; and a clock control section for outputting the control signal in accordance with the request signal.