David Samuel Chung

US Patent:

49470639, Aug 7, 1990

Filed:

Feb 26, 1988

Appl. No.:

7/161469

Inventors:

Timothy G. O'Shaughnessy - Norco CA
David K. Chung - Lake Elsinore CA
Richard W. Hull - Laguna Hills CA
Kenneth W. Ouyang - Huntington Beach CA
Victor G. Pierotti - Anaheim CA
Joseph A. Souza - Costa Mesa CA

Assignee:

Western Digital Corporation - Irvine CA

International Classification:

H03K 426
H03K 501
H03K 1716

US Classification:

307572

Abstract:

The transient noise generated at the output drivers of an integrated circuit chip is reduced by maintaining an increasing ramp shaped current through each output driver during the entire transition interval between binary states of a capacitive load. A capacitor fed by a fixed current source is connected across the input of each output driver stage. The fixed current source and capacitor are so selected as to generate across the input of each output driver stage a linear ramp shaped control voltage that regulates the charging/discharging current through the output driver stage and package inductance in the described manner. A specially designed bias circuit reduces the sensitivity of the resulting transient noise to process variations and operating conditions. A feedback connection from the package inductance to the bias control circuit for the fixed current source adjusts the fixed current inversely with the transient noise. A dynamic clamp suppresses voltage spikes extending outside the voltage supply operating range.

US Patent:

49048848, Feb 27, 1990

Filed:

Apr 21, 1988

Appl. No.:

7/184243

Inventors:

Timothy G. O'Shaughnessy - Norco CA
David K. Chung - Lake Elsinore CA

Assignee:

Western Digital Corporation - Irvine CA

International Classification:

H03K 329
H03K 5153
H03K 19094

US Classification:

307290

Abstract:

A Schmitt trigger having first and second complementary switches is biased to exhibit hysteresis, switching at a high threshold level when the input signal increases, and switching at a low threshold level when the input decreases. The source driver for the Schmitt trigger is coupled to the input of at least one of the complementary switches by transition circuitry, such that the signal level representing one binary value is shifted closer to the level of the power supply voltage corresponding to such binary value without changing the logical value of the signal from the source driver. In one embodiment, the first inverter is a MOS transistor, the threshold level of which is set by a bias voltage applied to the gate of another MOS transistor. The second inverter is a pair of complementary CMOS transistors. In another embodiment, the first inverter also comprises a pair of complementary CMOS transistors.