Trimming Temperature Dependent Voltage Reference

Solution Overview

Problem

Existing integrated circuits (ICs) face challenges in maintaining a reliable and constant reference voltage across varying temperatures due to temperature-dependent reference voltages, leading to reduced operational efficiency and increased IC yield loss.

Innovation Solution

A trimming circuit that generates a temperature and process-independent trim term signal, which is used to adjust the output reference voltage by multiplying a temperature-dependent reference voltage signal, ensuring the voltage remains compliant with specifications across a defined temperature range without altering the temperature coefficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If trimming is performed using an amplifier to apply gain to the reference voltage at a tuning temperature, then the reference voltage accuracy is improved at the tuning temperature, but the reference voltage variance increases as temperature deviates from the tuning temperature

Engineering Contradiction:

Improvereference voltage accuracyVSAvoidreference voltage compliance across temperature range

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The trimming circuit dynamically adjusts the trim term based on temperature conditions. The circuit selectively activates different trimming mechanisms depending on whether the temperature is above or below the tuning temperature, allowing the system to adapt to temperature variations and maintain reference voltage compliance across the entire temperature range rather than being fixed at a single tuning temperature

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the trimming parameter from a fixed gain adjustment to a temperature-dependent trim term that varies with temperature. By monitoring temperature and adjusting the trim term accordingly (increasing it when temperature exceeds the tuning temperature), the system maintains reference voltage accuracy across varying temperature conditions rather than relying on a single fixed trimming value

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the tuning temperature is set to a specific value (e.g., 0°C), then the reference voltage is accurate at that temperature, but the operational efficiency decreases at temperature extremes

Engineering Contradiction:

Improvereference voltage accuracy at tuning temperatureVSAvoidoperational efficiency across temperature range

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The trimming circuit dynamically adjusts the trim term based on temperature conditions. The circuit selectively activates different trimming mechanisms depending on whether the temperature is above or below the tuning temperature, allowing the system to adapt to temperature variations and maintain reference voltage compliance across the entire temperature range rather than being fixed at a single tuning temperature

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the trimming parameter from a fixed gain adjustment to a temperature-dependent trim term that varies with temperature. By monitoring temperature and adjusting the trim term accordingly (increasing it when temperature exceeds the tuning temperature), the system maintains reference voltage accuracy across varying temperature conditions rather than relying on a single fixed trimming value

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9634648B1Trimming a temperature dependent voltage reference

Publication Date: 2017.04.25 XILINX INC

AI summary

A circuit includes a divider circuit block configured to generate a trim term signal (VBG_TRIM) that is temperature and process independent. The circuit further includes a processing circuit block configured to multiply a temperature dependent reference voltage signal (TAP_GG) by a factor, and to sum the trim term signal with a result of the multiplication to generate an output reference voltage (VGG).