Patent ID: 9148132
Filing Date: 2015-09-29
Classification: H03B,H03K

Abstract:
1. A method, comprising: providing a first constant current flowing from a positive power supply node, the first constant current independent of a variation in a positive power supply node voltage; providing a second constant current flowing from a positive power supply node and independent of variations in the positive power supply node voltage, the second constant current flowing to a second electrode of a capacitor, a first electrode of the capacitor connected directly to the positive power supply node, the second constant current mirroring the first constant current and charging the capacitor by reducing a voltage across the capacitor; providing a third constant current flowing from the positive power supply node through a first NMOS transistor and mirroring the first constant current, the first NMOS transistor having a gate connected directly to the second electrode of the capacitor; and generating an oscillating signal with a period independent of variations in the positive power supply node voltage by turning on the first NMOS transistor when the capacitor reaches a predetermined and constant voltage level.