Clock Divider Circuit Using Diode-Connected FETs for Low-Power Switching

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Solution Overview

Problem

Existing AND gates and clock divider circuits consume excessive power and are slow in response to input signal changes, particularly in applications with low power budgets.

Innovation Solution

The implementation of field effect transistors and diodes in a direct connection configuration for AND gates, and a specific circuit design for clock dividers that reduces the number of loads, utilizing diode-connected transistors and FETs to enhance speed and reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional AND gate configurations are used, then the circuit is simple to manufacture, but the switching speed is slow and power consumption is high

Engineering Contradiction:
Improveswitching speedVSAvoidcircuit complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The AND gate is segmented into multiple parallel FET paths (direct connection path and diode-connected path) that operate simultaneously. This segmentation allows the circuit to achieve fast switching through the direct path while maintaining proper logic levels through the diode-connected path, resolving the contradiction between speed and complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Diode-connected FETs are introduced as intermediary elements that mediate between the direct FET connection and the output. These intermediaries provide the necessary logic level control and signal conditioning without significantly impacting the switching speed, thus resolving the speed-complexity tradeoff.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If conventional AND gate configurations are used, then the circuit structure is simple, but power consumption is excessive

Engineering Contradiction:
Improvepower consumptionVSAvoidcircuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The circuit utilizes the periodic switching nature of digital signals to activate different FET paths at different times. During switching transitions, the direct connection path provides fast switching with low power, while during stable states, the diode-connected path maintains proper logic levels, achieving low overall power consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention changes the operational parameters of the FETs by configuring them in different modes (direct connection vs. diode-connected). This parameter change allows the same FETs to serve multiple functions - fast switching and logic level control - thereby reducing power consumption without significantly increasing circuit complexity.

Inventive Principle:
Principle #35Parameter changes

3Speed

If fast switching is achieved through direct FET connection, then switching speed improves, but power consumption increases

Engineering Contradiction:
Improveswitching speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The current path is segmented into multiple parallel FET configurations. The direct connection FETs provide the fast switching path with minimal resistance, while the diode-connected FETs provide an alternative path that consumes less power during steady states. This segmentation resolves the contradiction by allowing fast switching only when necessary.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circuit dynamically switches between different FET paths based on the input signal state. During transitions, the direct connection path is activated for fast switching. During stable states, the diode-connected path is utilized for lower power consumption. This dynamic behavior resolves the speed-power contradiction.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed solution results in faster AND gates and clock dividers that operate with significantly reduced power consumption, enabling efficient clock division even in low power environments.

Implementation Method 1

a respective gate terminal to which a voltage may be applied to control a conductivity of a respective channel between the respective first terminal and the respective second terminal

Methodology Applied
Scientific EffectField effect: Electric Field

Implementation Method 2

first and second diodes, each having a respective first terminal and a respective second terminal, and having a forward conduction direction from the respective second terminal to the respective first terminal

Methodology Applied
Scientific EffectDiode conduction: Diode

Data Source

PatentEP3794727B1Clock divider and apparatus
Publication Date: 2025.07.02 PRAGMATIC SEMICON LTD
  • EP3794727B1 patent drawingFigure 1
  • EP3794727B1 patent drawingFigure 2
  • EP3794727B1 patent drawingFigure 3A~3B

AI summary

An AND gate comprises:a first input;a second input;an output; and a plurality of field effect transistors, FETs, each having a respective first terminal, a respective second terminal, and a respective gate terminal to which a voltage may be applied to control a conductivity of a respective channel between the respective first terminal and the respective second terminal. The plurality of FETs comprises: a first FET having its first terminal directly connected to the first input, its second terminal directly connected to the output, and its gate terminal directly connected to the second input; a second FET having its first terminal directly connected to the first input, its second terminal directly connected to the output, and its gate terminal directly connected to the output; and a third FET having its first terminal directly connected to the second input, its second terminal directly connected to the output, and its gate terminal directly connected to the output. Also disclosed is a clock divider stage for receiving a first clock signal oscillating at a first frequency and a second clock signal, the second clock signal being an inversion of the first clock signal, and generating a first output clock signal oscillating at half of the first frequency.