Low-Voltage Push-Pull Output Driver for HCSL Power Reduction

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Solution Overview

Problem

Existing HCSL output driving circuits face excessive power consumption issues due to their current-mode structure, which leads to high dynamic power consumption and poor signal integrity during high-speed data transmission.

Innovation Solution

The proposed output driving circuit employs a low-voltage push-pull module and output isolation module with low-voltage transistors, eliminating the need for termination resistors and using adaptive impedance calibration with high-voltage native NMOS transistors to maintain constant output impedance, thereby reducing power consumption and enhancing signal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional current-mode HCSL output driving circuits are used, then high-speed data transmission capability is achieved, but power consumption becomes excessive

Engineering Contradiction:

Improvedata transmission rateVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent changes the fundamental operating mode from current-mode to voltage-mode, and transitions from high-voltage to low-voltage operation. The low-voltage push-pull module operates at low voltage with high impedance output, eliminating the need for termination resistors and significantly reducing dynamic power consumption while maintaining high-speed transmission capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the conventional current-mode driving mechanism with a voltage-mode push-pull mechanism. Instead of using current sources and termination resistors, the invention uses complementary low-voltage transistors in push-pull configuration to directly drive the transmission line, replacing the mechanical/current-based system with a voltage-based system that has lower power consumption

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If high-voltage transistors are used for output isolation, then output isolation capability is improved, but parasitic power consumption increases

Engineering Contradiction:

Improveoutput isolation capabilityVSAvoidparasitic power consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the voltage level parameter of the isolation transistors from high-voltage to low-voltage. The low-voltage push-pull module provides sufficient voltage swing and driving capability at low voltage, eliminating the need for high-voltage transistors and their associated parasitic capacitances and power consumption, while maintaining reliable output isolation

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If termination resistors are used in HCSL output, then signal level matching is achieved, but dynamic power consumption increases

Engineering Contradiction:

Improvesignal level matchingVSAvoiddynamic power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes the termination resistors from the HCSL output structure. The low-voltage push-pull module is designed to directly drive the transmission line with high impedance output, eliminating the need for termination resistors. Signal level matching is achieved through the inherent voltage swing capability of the push-pull transistors rather than through resistive termination

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a simplified version of the traditional HCSL output by replacing the complex current-mode circuit with termination resistors with a simple voltage-mode push-pull circuit. This copied function achieves the same signal level matching and driving capability without the power-consuming termination resistors

Inventive Principle:

Principle #26Copying

Data Source

PatentUS20240429903A1Output driving circuit, clock chip, and electronic device

Publication Date: 2024.12.26 MONTAGE ELECTRONICS (SHANGHAI) CO LTD

AI summary

An output driving circuit, a clock chip, and an electronic device are provided. The output driving circuit includes a low-voltage push-pull module and an output isolation module, wherein the low-voltage push-pull module is connected to a low-voltage bias voltage and is configured to receive and process a high-speed input signal, and to output an intermediate signal having a target level, wherein the low-voltage push-pull module includes one or more push-pull units, each including a low-voltage transistor pair, wherein the output isolation module is connected between an output terminal of the low-voltage push-pull module and an output terminal of the output driving circuit, wherein the output isolation module is configured to be turned on when the output driving circuit works normally, and to output the intermediate signal as a target output signal of the output driving circuit. The output driving circuit has lower power consumption.