Current-Mode Bandgap Reference Generating PTAT and ZTC Currents

Solution Overview

Problem

Conventional bandgap voltage reference circuits typically require a high supply voltage and generate either a proportional-to-absolute-temperature (PTAT) current or a zero-temperature-coefficient (ZTC) current, but not both, leading to increased power consumption and circuit complexity due to the need for additional components to duplicate the missing current.

Innovation Solution

A current-mode bandgap reference integrated circuit that generates both PTAT and ZTC currents with minimal additional components, capable of operating with a supply voltage as low as 1V, utilizing a configuration of bipolar junction transistors and metal oxide semiconductor field effect transistors to produce a flat bandgap voltage and temperature-independent currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional bandgap voltage reference circuits generate only one type of current (PTAT or ZTC), then the circuit complexity is reduced, but additional components are required to generate the missing current type, leading to increased power consumption and area

Engineering Contradiction:

Improvecircuit complexityVSAvoidpower consumption

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent combines the generation of both PTAT and ZTC currents within a single bandgap voltage reference circuit architecture. The current-mode operation allows simultaneous extraction of both current types from the same core circuit, eliminating the need for separate duplicate circuits and reducing overall power consumption while maintaining both current types available for use

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bandgap voltage reference circuit is designed to provide multiple functions simultaneously: it generates the reference voltage while also producing both PTAT and ZTC currents. This multi-functional approach eliminates the need for additional dedicated circuits for current generation, reducing both power consumption and component count

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Area of stationary object

If conventional bandgap voltage reference circuits generate only one type of current (PTAT or ZTC), then the power consumption is reduced, but additional components must be added to generate the other current type, increasing area requirements

Engineering Contradiction:

Improvearea requirementsVSAvoidcircuit complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the generation of both PTAT and ZTC currents within a single bandgap voltage reference circuit architecture. The current-mode operation allows simultaneous extraction of both current types from the same core circuit, eliminating the need for separate duplicate circuits and reducing overall area while maintaining both current types available for use

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bandgap voltage reference circuit is designed to provide multiple functions simultaneously: it generates the reference voltage while also producing both PTAT and ZTC currents. This multi-functional approach eliminates the need for additional dedicated circuits for current generation, reducing both area and component count

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If conventional bandgap voltage reference circuits are designed to generate both PTAT and ZTC currents using additional components, then both current types are available, but the circuit complexity and power consumption increase significantly

Engineering Contradiction:

Improvecurrent generation capabilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the generation of both PTAT and ZTC currents within a single bandgap voltage reference circuit architecture. The current-mode operation allows simultaneous extraction of both current types from the same core circuit, eliminating the need for separate duplicate circuits and reducing overall circuit complexity while maintaining both current types available for use

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bandgap voltage reference circuit is designed to provide multiple functions simultaneously: it generates the reference voltage while also producing both PTAT and ZTC currents. This multi-functional approach eliminates the need for additional dedicated circuits for current generation, reducing circuit complexity while maintaining versatility

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If conventional bandgap voltage reference circuits are designed to generate both PTAT and ZTC currents using additional components, then both current types are available, but the power consumption increases

Engineering Contradiction:

Improvecurrent generation capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent combines the generation of both PTAT and ZTC currents within a single bandgap voltage reference circuit architecture. The current-mode operation allows simultaneous extraction of both current types from the same core circuit, eliminating the need for separate duplicate circuits and reducing overall power consumption while maintaining both current types available for use

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bandgap voltage reference circuit is designed to provide multiple functions simultaneously: it generates the reference voltage while also producing both PTAT and ZTC currents. This multi-functional approach eliminates the need for additional dedicated circuits for current generation, reducing power consumption while maintaining versatility

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

This solution reduces power consumption and area requirements while enabling efficient generation of both PTAT and ZTC currents, improving the usability and efficiency of input devices such as touchscreens and other electronic systems.

Implementation Method 1

a proportional to absolute temperature current generator configured to generate a proportional to absolute temperature current

Methodology Applied

Scientific EffectThermal voltage: Temperature Gradient

Implementation Method 2

a bandgap voltage generator is configured to generate a bandgap voltage

Methodology Applied

Scientific EffectBandgap voltage:

Implementation Method 3

a zero-temperature coefficient current generator configured to generate a zero-temperature coefficient current

Methodology Applied

Scientific EffectZero temperature coefficient:

Data Source

PatentUS9817428B2Current-mode bandgap reference with proportional to absolute temperature current and zero temperature coefficient current generation

Publication Date: 2017.11.14 OMNIVISION TDDI ONTARIO LLP

AI summary

In a current-mode bandgap reference integrated circuit: a bandgap voltage generator is configured to generate a bandgap voltage, a zero-temperature coefficient current generator configured to generate a zero-temperature coefficient current, and a proportional to absolute temperature current generator configured to generate a proportional to absolute temperature current. The integrated circuit includes a first pair of bipolar junction transistors (BJT) comprising a first BJT and a second BJT. The integrated circuit also includes a second pair of bipolar junction transistors, comprising a third BJT and a fourth BJT. The first pair of BJTs matches the second pair of BJTs.