Patent ID: 7545199
Filing Date: 2009-06-09
Classification: G11C,H02M

Abstract:
1. A power supply circuit for an oscillator, comprising: an internal power supply source for supplying an internal power supply voltage with a predetermined level; a voltage divider for dividing a voltage between an external power supply and ground; a driver being a P-channel Metal Oxide Semiconductor (PMOS) transistor connected between the internal power supply source and an output node of an internal voltage, whereby the P-channel Metal Oxide Semiconductor (PMOS) transistor is turned on by receiving directly a signal of the voltage divided by the voltage divider; and a capacitor coupled between the output node and the ground, wherein the internal voltage is a source voltage for a chain of inverters arranged within the oscillator and the oscillator generates a pulse signal with an increased cycle length as the external power supply voltage is increased.