Patent ID: 7030707
Filing Date: 2006-04-18
Classification: G06F,G11C,H03K

Abstract:
1. An oscillator comprising: a comparison voltage generating circuit, which is driven by a power source voltage, and generates comparison voltages that change in response to clock signals which have a frequency that varies in inverse proportion to the power source voltage, and a first reference voltage; a comparing circuit, which compares levels of the comparison voltages to a second reference voltage that is different from the first reference voltage and outputs logic signals having logic levels as a result of the comparison; a clock switching circuit, which outputs the clock signals which have a frequency that varies in inverse proportion to the power source voltage, in response to the logic signals; and a reference voltage generating circuit that generates the first reference voltage and the second reference voltage in response to a control signal, wherein the reference voltage generating circuit comprises: a constant current generating circuit, which generates a constant current in response to the control signal; a first current mirror circuit, which generates a first reference current proportional to the constant current in response to the control signal and outputs the first reference voltage, which is determined by the first reference current; and a second current mirror circuit, which generates a second reference current proportional to the constant current in response to the control signal and outputs the second reference voltage, which is determined by the second reference current.