Versatile system for output energy limiting circuitry

Abstract

The present invention provides a system for limiting energy levels across the output of a driver circuitry segment (100). The system provides an output structure (102) adapted to drive an output load (104). A transconductance component (106) is communicatively coupled to the output structure, and adapted to output a transconductance current that is proportional to the voltage across the output structure. A scaling component (108) is communicatively coupled to the output structure, and adapted to output a scaled current that is proportional, by some scaling factor, to the current through the output structure. A qualifying component (110) is communicatively coupled to the scaling component, and adapted to activate a trigger component (112) when the scaled current passes a first threshold. The trigger component is communicatively coupled to the qualifying component, the transconductance component, and the output structure. Responsive to activation from the qualifying component, the trigger component receives the transconductance current and accumulates charge, for an amount of time inversely proportional to the transconductance current's magnitude, and triggers shut off of the output structure when the accumulated charge passes a second threshold.

Description

TECHNICAL FIELD OF THE INVENTION [0001] The present invention relates generally to the field of semiconductor devices and, more particularly, to a versatile system of apparatus and methods for limiting energy overload across driver output circuitry. BACKGROUND OF THE INVENTION [0002] The continual demand for enhanced integrated circuit performance has resulted in, among other things, a dramatic reduction of semiconductor device geometries, and continual efforts to optimize the performance of every substructure within any semiconductor device. A number of improvements and innovations in fabrication processes, material composition, and layout of the active circuit levels of a semiconductor device have resulted in very high-density circuit designs. Increasingly dense circuit design has not only improved a number of performance characteristics, it has also increased the importance of, and attention to, semiconductor material properties and behaviors. [0003] The increased packing density...

AI Technical Summary

Benefits of technology

The present invention provides a versatile system for limiting output energy levels across high-voltage driver circuitry, without over or under correction. The system includes circuitry that protects driver output structures from exposure to excessive output energy levels that might damage or destroy those output structures. The system dynamically monitors both current and voltage levels across output structures to determine whether those output structures should be shut off to avoid exposure to excessive energy levels. The system recognizes that the energy across any given structure is a function of current, voltage, and time, and provides robust protection while accommodating temporary signal variances that commonly occur. The system includes a transconductance component, a scaling component, and a qualifying component that activates a trigger component when the scaled current passes a threshold. The system also includes a method of limiting energy levels across a driver circuitry output structure, a circuitry configuration with multiple voltage supplies and comparators, and a controlled current source. The technical effects of the invention include improved device and system performance, reduced device and system inefficiencies, and easy and cost-effective implementation.

Problems solved by technology

The increased packing density of the integrated circuit generates numerous challenges to the semiconductor manufacturing process.

Often, such new applications place a number of unique demands on circuitry components and substructures.

Unfortunately, however, there are a large number of variables in semiconductor device manufacturing that can affect any given performance parameter.

Commonly, performance specifications require that driver circuitry consume relatively low power while driving a significant load.

Depending upon the design and fabrication processes used, however, certain adapted circuitry components may be susceptible to performance degradation or break down if non-standard conditions (e.g., overload, short) cause output circuitry to exceed the standard operating range.

For example, sustained power overload on certain output circuitry can cause a significant rise in operating temperature, which can—over time—begin to break down transistor structures.

Even over a relatively short amount of time, an excessive output energy drop can degrade the performance of output transistor structures, or render them completely inoperable.

In addition, increased energy drop across a driver output can significantly increase overall system power consumption.

This can cause a number of system inefficiency or reliability issues, or cause significant process yield problems for the device manufacturer.

Using such schemes, even instantaneous variations in current that exceed the threshold cause output shutdown—even though such variations may still be marginally within the operational capability of the output components, or may last for such a brief period that no damage would actually accrue to the output components if left unchecked.

Utilizing conventional output protection schemes in such applications could result in a potentially high degree of system inefficiency or cause system malfunction if the signal integrity is sufficiently degraded, as driver output components are repeatedly cycling off and on every time an arbitrary threshold is exceeded.

Other conventional protection schemes err on the side of less comprehensive protection—choosing instead to set protective thresholds well outside of the specified operating range of driver circuitry.

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