Zilog, Inc.

Tom S Wei

Andre B Walker

Elisabeth Ekman

Stephen Clark

In an oscillator circuit, a high gain, high power driver is placed in parallel with a standard low gain, low power driver for driving the oscillator output. A control signal is derived from the output of the oscillator circuit and fed back to control the high gain driver. After the circuit output has achieved stable oscillations for a predetermined time period, the high gain driver is turned off. Employment of the high gain driver ensures high start-up ability. The overall power consumption remains low since the high gain driver is turned off after stable oscillations have been achieved.

Low power oscillator with high start-up ability

A CMOS N-channel, open-drain, pull-down buffer circuit is capable of pulling down voltages on an external pad in excess of the breakdown voltage of the individual N-channel field effect transistors in the buffer circuit. The circuit may be fabricated as part of a CMOS interated circuit in an industrial standard 1.5 microns CMOS process. The higher voltage acceptance is effected by using two open-drain N-transistors in series such that the external voltage is divided among the two transistors. A parallel high voltage circuit to the external pad can be independently optimized to provide a lower impedance path and a higher endurance for electrostatic discharge. While the two-transistor voltage divider exposes one of the transistor' gate to ESD via another external terminal, enhanced ESD protection is effected by having a resistor in series between the gate and the external terminal.

Growing community of inventors

San Jose, CA, United States of America

Tom S Wei