MONOLITHICALLY INTEGRATED RC OSCILLATOR OF IMPROVED STABILITY

Abstract

The invention relates to a monolithically integrated RC oscillator in which the frequency is of reduced dependency upon process variations, supply voltage variations or temperature. The circuit employs two RC circuits, typically not integrated, each capacitor of which is alternately charged via a transistor switch to the supply potential. The discharge of each capacitor takes place through the shunting resistance to a potential set by the switching voltages of two buffer amplifiers in the forward gain path of the oscillator. If the switching voltages are set midway between the supply voltages, and identical buffer amplifiers are employed, the temperature, voltage and other process variables tend to produce compensatory changes in frequency. The circuit is also optimized to minimize transient delays and thereby further decrease the dependence of oscillator frequency upon voltage, temperature, or process variations affecting the integrated active circuitry. The circuit is carried out in the (CMOS) process.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1THEORDORE J. WYMAN

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