Segmented Output Driver Circuit for Symmetrical Delay

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Solution Overview

Problem

Existing output drivers face challenges in managing high supply voltages, leading to asymmetrical propagation delay and high quiescent current consumption, particularly in automotive applications where low power requirements and fast turn-on and turn-off delays are crucial.

Innovation Solution

The implementation of an integrated circuit chip with high-side and low-side current driver circuits that activate and deactivate specific current drivers based on detected voltage levels to manage output signals, using static and sloped current drivers to achieve symmetrical propagation delay and zero quiescent current during power-down modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reference voltages are generated to protect output devices from high voltage, then device protection is improved, but quiescent current consumption increases

Engineering Contradiction:

Improvedevice protectionVSAvoidquiescent current consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The circuit dynamically switches between different operational states (protection mode and normal mode) based on voltage conditions. During power-up or high-voltage events, the protection circuit activates to generate reference voltages. Once normal operation is detected, the circuit transitions to a low-power state where the reference voltage generation is disabled, thus protecting devices while minimizing quiescent current consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The protection circuit operates periodically or event-driven rather than continuously. It activates when voltage thresholds indicate potential damage (power-up, over-voltage conditions) and remains inactive during normal operation. This periodic activation pattern ensures device protection is provided when needed while avoiding continuous current consumption.

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If devices are scaled for equal output current at consistent temperature, then output current matching is improved, but propagation delay symmetry deteriorates over voltage and temperature ranges

Engineering Contradiction:

Improveoutput current matchingVSAvoidpropagation delay symmetry

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The circuit incorporates compensation mechanisms that dynamically adjust operating parameters based on detected voltage and temperature conditions. By sensing environmental changes and modifying current sources, transistor biases, or timing references accordingly, the circuit maintains symmetrical propagation delay across varying voltage and temperature ranges, preventing the asymmetry that would otherwise result from simple device scaling.

Inventive Principle:

Principle #35Parameter changes

3Speed

If a current mirror with 1:10 ratio is used for fast turn-on, then turn-on delay is reduced, but turn-off delay increases significantly

Engineering Contradiction:

Improveturn-on delayVSAvoidturn-off delay

Core Design Contradiction:

SpeedVSDuration of action of moving object

Solution Approach 1:

The current driver is segmented into multiple parallel current sources rather than using a single current mirror. This segmentation allows different current paths to be independently controlled - one path optimized for fast turn-on and another for rapid turn-off. By dividing the current driving function into separate segments, both fast turn-on and fast turn-off characteristics can be achieved simultaneously without the trade-off inherent in single current mirror configurations.

Inventive Principle:

Principle #1Segmentation

4Duration of action of moving object

If a high-voltage level shifter is added to actively short gate-source for faster turn-off, then turn-off delay is improved, but circuit complexity and additional delay are introduced

Engineering Contradiction:

Improveturn-off delayVSAvoidcircuit complexity

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The level shifter function and the gate-source shorting function are merged into a single integrated circuit block. Rather than adding a separate level shifter component and separate switching mechanism, the patent combines these functions within the same circuit architecture, using shared transistors and control logic. This integration achieves fast turn-off capability while minimizing the increase in overall circuit complexity and avoiding additional propagation delays that would result from cascaded separate components.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8970260B1Output drivers

Publication Date: 2015.03.03 NXP BV

AI summary

Various aspects of the disclosure are directed to methods and apparatuses involving communications. As consistent with one or more embodiments, first and second sets of multiple current drivers are implemented respectively in a high-side and a low-side circuit. Current is driven via an output port in the high-side circuit by activating the first set of multiple current drivers until a steady-state high voltage is detected, and by deactivating one of the current drivers in the first set when the steady-state high voltage is detected. Current is driven in the low-side circuit by activating the second set of multiple current drivers until a steady-state low voltage is detected, and by deactivating one of the current drivers in the second set when the steady-state low voltage is detected.