Programmable Temperature Slope Current Reference Circuit

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Solution Overview

Problem

Existing analog current reference circuits lack the ability to provide predictable current variations with temperature, often resulting in large size, high power inefficiencies, and sensitivity to process variations, failing to offer effective temperature slope control.

Innovation Solution

A current reference circuit that includes a resistor with a known temperature coefficient, coupled with a bandgap voltage circuit and a bias voltage circuit, allowing for the generation of a current with a programmable temperature slope by combining bandgap voltage and variable-polarity bias voltage, enabling positive, zero, or negative temperature slopes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If independent circuits are used for producing proportional to absolute temperature current references, constant current references, and complementary to absolute temperature current references, then temperature slope control is achieved, but device complexity and area increase

Engineering Contradiction:

Improvetemperature slope controlVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple independent current reference circuits (PTAT, constant, and CTAT) into a single integrated circuit structure. The bandgap voltage circuit generates a reference voltage that is coupled with a resistor to produce a current reference, while the bias voltage circuit provides variable-polarity bias voltages to control the temperature slope. This merging eliminates the need for separate independent circuits, thereby reducing device complexity and area while maintaining temperature slope control capability.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple resistors with different temperature coefficients are used, then temperature slope control is achieved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvetemperature slope controlVSAvoidprocess variation sensitivity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent uses a single resistor with a known temperature coefficient and controls the temperature slope by changing the bias voltage parameter. The bias voltage circuit generates variable-polarity bias voltages that are applied to the bandgap voltage circuit, allowing electronic control of the temperature slope without requiring multiple resistors with different temperature coefficients. This approach reduces manufacturing precision requirements and process variation sensitivity.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If complex circuits are used to achieve temperature slope control, then adaptability is improved, but power consumption increases

Engineering Contradiction:

Improvetemperature slope controlVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent designs a multi-functional circuit where the bandgap voltage circuit serves multiple purposes: generating the reference voltage for the current reference and providing the temperature compensation function. The bias voltage circuit provides variable-polarity bias voltages to control the temperature slope while being integrated into the same circuit structure. This universal design allows temperature slope control without requiring additional power-consuming components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution provides a low-area, low-complexity circuit capable of generating currents with programmable temperature slopes, suitable for various applications, including non-volatile memory sensing, with high accuracy and low power consumption, while maintaining stability across environmental and process variations.

Implementation Method 1

a bandgap voltage circuit configured to generate a bandgap voltage and coupled to the resistor

Methodology Applied

Scientific EffectBandgap voltage:

Implementation Method 2

The bandgap voltage circuit is configured to add the variable-polarity bias voltage to the bandgap voltage to generate the reference current through the resistor

Methodology Applied

Scientific EffectOhm's law: Ohm's Law

Implementation Method 3

a resistor with a known temperature coefficient, coupled with a bandgap voltage circuit and a bias voltage circuit, allowing for the generation of a current with a programmable temperature slope

Methodology Applied

Scientific EffectTemperature coefficient:

Data Source

PatentUS8531235B1Circuit for a current having a programmable temperature slope

Publication Date: 2013.09.10 LONGITUDE FLASH MEMORY SOLUTIONS LTD

AI summary

A current reference circuit configured to generate a reference current with a programmable temperature slope is disclosed. The current reference circuit includes a resistor. The current reference circuit includes a bandgap voltage circuit configured to generate a bandgap voltage and coupled to the resistor. The current reference circuit includes a bias voltage circuit configured to generate a variable-polarity bias voltage and coupled to the bandgap voltage circuit. The bandgap voltage circuit is configured to add the variable-polarity bias voltage to the bandgap voltage to generate the reference current through the resistor.