Bidirectional Interface Circuit with Charge Pump Bias

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Solution Overview

Problem

Conventional bidirectional interface circuits require bipolar power supplies, which are complex and inefficient, especially when operating with single positive supply voltage systems, and struggle to accommodate bidirectional input signals with both positive and negative swings without drawing significant power.

Innovation Solution

The use of a charge pump to convert a single positive supply voltage into a negative bias voltage, enabling a bidirectional interface circuit with an amplifier and comparator to accommodate bidirectional input signals, thereby simplifying power supply configurations and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If bipolar power supplies are used for bidirectional interface circuits, then the circuit can accommodate bidirectional input signals, but the device complexity and power consumption increase

Engineering Contradiction:

Improvebidirectional input signal accommodationVSAvoidpower supply configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the voltage reference parameter by introducing a negative bias voltage generated through a charge pump circuit. This allows the bidirectional interface circuit to accommodate both positive and negative input swings relative to this negative reference, eliminating the need for a full bipolar power supply configuration while maintaining signal accommodation capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The charge pump circuit acts as an intermediary that converts the single positive supply voltage into a negative bias voltage. This intermediary component enables the interface circuit to handle bidirectional signals without requiring direct connection to negative power supplies, simplifying the overall power supply architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If bipolar power supplies are used for bidirectional interface circuits, then the circuit can handle bidirectional signals, but the power consumption increases

Engineering Contradiction:

Improvebidirectional input signal handlingVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent modifies the voltage reference parameter to a negative bias voltage generated by a charge pump, allowing the interface circuit to operate with a single positive power supply. This parameter change enables bidirectional signal handling while significantly reducing power consumption by eliminating the need for power-hungry negative power supply circuits

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The charge pump circuit generates the required negative bias voltage from the existing positive supply voltage, making the system self-sufficient. The interface circuit serves itself by creating its own voltage reference without requiring external negative power supplies, thereby reducing overall system power consumption

Inventive Principle:

Principle #25Self-service

3Use of energy by moving object

If single positive supply voltage is used, then power consumption is reduced, but the circuit cannot accommodate bidirectional input signals with negative swings

Engineering Contradiction:

Improvepower consumptionVSAvoidbidirectional input signal accommodation

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent introduces a negative bias voltage parameter generated from the single positive supply through a charge pump. This parameter transformation allows the interface circuit to reference both positive and negative input signals against this negative baseline, enabling bidirectional signal accommodation while maintaining operation on a single power supply

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The charge pump serves as an intermediary that bridges the gap between single positive supply operation and bidirectional signal handling. It converts the positive supply voltage into a negative bias reference, enabling the interface circuit to accommodate negative signal swings without requiring actual negative power supplies

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This solution allows for flexible and efficient bidirectional interface operations with reduced power usage, suitable for low-power applications, and eliminates the need for additional negative power supplies, effectively handling input signals with both positive and negative swings.

Implementation Method 1

The IC includes a charge pump that is adapted to convert the positive supply voltage of the IC to a negative bias voltage

Methodology Applied

Scientific EffectCharge pump: Pump

Data Source

PatentUS10205386B2Apparatus for integrated circuit interface and associated methods

Publication Date: 2019.02.12 SILICON LABORATORIES INC

AI summary

An apparatus includes an integrated circuit (IC) adapted to be powered by a positive supply voltage. The IC includes a charge pump that is adapted to convert the positive supply voltage of the IC to a negative bias voltage. The IC further includes a bidirectional interface circuit. The bidirectional interface circuit includes an amplifier coupled to the negative bias voltage to accommodate a bidirectional input voltage of the IC. The bidirectional interface circuit further includes a comparator coupled to the negative bias voltage to accommodate the bidirectional input voltage of the IC.