Patent ID: 7940135
Filing Date: 2011-05-10
Classification: H03K

Abstract:
1. An oscillation circuit for generating a clock signal with a rectangular waveform, comprising: a triangular wave generation circuit that includes a capacitor, switches the charging or discharging state of the capacitor according to the voltage value of the clock signal, and generates a triangular wave signal; a comparison circuit that receives the triangular wave signal outputted from the triangular wave generation circuit, receives a first reference voltage and a second reference voltage, and generates the clock signal having a voltage value that corresponds to a comparison of the voltage value of the triangular wave signal with the value of the first reference voltage, and to a comparison of the voltage value of the triangular wave signal with the value of the second reference voltage; a current adjusting circuit that is connected to a reference current source outputting a reference current, is connected to a power supply for the comparison circuit, and generates an adjusted current in which the value of the reference current has been changed according to the change in voltage of the power supply; and a reference voltage generation circuit that generates the first reference voltage and the second reference voltage having a voltage differential that corresponds to the value of the adjusted current outputted from the current adjusting circuit, wherein the current adjusting circuit increases the adjusted current when the voltage of the power supply for the comparison circuit rises, and reduces the adjusted current when the voltage of the power supply drops, and the reference voltage generation circuit increases the voltage differential between the first reference voltage and the second reference voltage when the adjusted current increases, and reduces the voltage differential between the first reference voltage and the second reference voltage when the adjusted current decreases.