On-Chip Voltage Reference Temperature Correction

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Solution Overview

Problem

On-chip voltage reference circuits, such as bandgap circuits, face accuracy issues due to temperature fluctuations within integrated circuits, leading to voltage references exceeding maximum or minimum tolerances, which can be costly and inefficient.

Innovation Solution

A temperature-corrected voltage reference circuit is implemented using a programmable gain amplifier and a digital control circuit that adjusts gain based on temperature measurements from sensors, ensuring the voltage reference remains within target values across varying temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an on-chip voltage reference circuit is used, then cost is reduced and package pins are minimized, but voltage reference accuracy deteriorates due to temperature fluctuations

Engineering Contradiction:

ImprovecostVSAvoidvoltage reference accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where temperature sensors continuously monitor the IC temperature and feed this information to a digital control circuit. The control circuit adjusts the gain of a programmable gain amplifier based on the temperature feedback, thereby compensating for temperature-induced voltage reference drift and maintaining accuracy without requiring external voltage references

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the gain parameter of the programmable gain amplifier dynamically based on temperature conditions. By adjusting the amplifier gain in response to temperature variations, the system compensates for the temperature coefficient of the voltage reference circuit, maintaining voltage reference accuracy across different temperature conditions while using an on-chip reference

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If traditional analog design techniques are used for temperature correction, then voltage reference accuracy is maintained, but power consumption and implementation area increase

Engineering Contradiction:

Improvevoltage reference accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces complex analog temperature compensation circuits with a digital control system. Instead of using analog components and circuits to achieve temperature compensation, the invention uses digital temperature sensors, a digital control circuit, and a programmable gain amplifier controlled by digital signals. This substitution reduces power consumption and implementation area while maintaining voltage reference accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9377795B1Temperature correction of an on-chip voltage reference

Publication Date: 2016.06.28 XILINX INC

AI summary

In an example, a temperature-corrected voltage reference circuit for use in an integrated circuit (IC) includes a voltage reference circuit, a programmable gain amplifier, and a digital control circuit. The programmable gain amplifier includes a first input coupled to the voltage reference circuit, a second input coupled to receive a control signal, and an output coupled to provide a temperature-corrected voltage reference. The digital control circuit includes an input coupled to receive a temperature signal indicative of temperature of the IC and an output coupled to the second input of the programmable gain amplifier, the digital control circuit generating the control signal in response to the temperature signal.