Patent ID: 8692584

Claim:
A semiconductor integrated circuit device comprising: a clock oscillating unit, the clock oscillating unit including: a voltage control oscillator circuit that generates a clock signal based on a control voltage; a reference voltage generating circuit that generates a first reference voltage having temperature dependency and a second reference voltage having almost no power-supply and temperature dependency; a reference current generating circuit that generates a reference current having almost no power-supply and temperature dependency by using the first reference voltage generated by the reference voltage generating circuit; a frequency-voltage converting circuit that converts an oscillation frequency of the clock signal generated by the voltage control oscillator circuit to a voltage by using the reference current generated by the reference current generating circuit; and an integrating circuit that integrates the voltage output from the frequency-voltage converting circuit and generates the control voltage output to the voltage control oscillator circuit, and the frequency-voltage converting circuit including: first to Nth electrostatic capacitive units; a capacitor selecting unit that selects at least one of the second to Nth electrostatic capacitive units based on a select signal; and a switch unit that charges/discharges the first electrostatic capacitive unit and the electrostatic capacitive unit selected by the switch unit with the reference current based on a charge signal and a discharge signal.