Bandgap Reference Feedback Circuitry for Base Current Compensation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional bandgap reference voltage generators face issues with power supply rejection ratio degradation, high power consumption, and increased size and manufacturing cost due to significant base currents in bipolar transistors, requiring additional current compensation circuits.

Innovation Solution

A bandgap reference voltage generator is designed with a bandgap core circuit and feedback circuitry that includes a current replica circuit, allowing for the generation of control voltages and currents to produce a bandgap reference voltage without additional circuits, thereby eliminating significant base currents and reducing the need for current compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional circuits (resistors, bipolar transistors, current summing circuits) are utilized to generate bandgap reference voltages at different voltage levels, then the bandgap reference voltage generator can operate at various operating voltages, but significant base currents are generated in the bipolar transistors of the bandgap core circuit

Engineering Contradiction:

Improveoperating voltage rangeVSAvoidbase current consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent implements feedback circuitry that senses the base currents generated by the additional circuits and generates compensating currents to cancel out these base currents. This feedback mechanism allows the generator to operate at various voltage levels while maintaining low power consumption by actively compensating for the harmful base current effects.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces current compensation circuits as intermediary elements between the bandgap core circuit and the additional voltage generation circuits. These intermediary circuits act as mediators that isolate the core circuit from the high current demands of voltage level conversion, enabling multi-voltage operation without significant base current generation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If current compensation circuits are implemented to compensate for base currents, then the base current effects are compensated, but the power supply rejection ratio degrades

Engineering Contradiction:

Improvebase current compensationVSAvoidpower supply rejection ratio

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the parameters of the current compensation circuits, specifically the transconductance values and bias currents, to achieve effective base current compensation while maintaining high power supply rejection ratio. By carefully selecting and adjusting these parameters, the system achieves both compensation and rejection performance.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If current compensation circuits are implemented to compensate for base currents, then the base current effects are compensated, but the power consumption increases

Engineering Contradiction:

Improvebase current compensationVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent implements current compensation circuits that provide just enough compensation to cancel the base current effects without excessive current generation. The compensation is precisely controlled to match the actual base current magnitude, avoiding unnecessary power consumption while achieving complete compensation of the harmful effects.

Inventive Principle:

Principle #16Partial or excessive action

4Reliability

If current compensation circuits are implemented to compensate for base currents, then the base current effects are compensated, but the size and manufacturing cost increase

Engineering Contradiction:

Improvebase current compensationVSAvoidcircuit size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the current compensation functions with the existing feedback circuitry and voltage generation circuits. By merging multiple functions into shared circuit blocks, the overall device size is reduced while maintaining complete base current compensation capability. The compensation circuits are integrated rather than added as separate discrete blocks.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11449088B2Bandgap reference voltage generator with feedback circuitry

Publication Date: 2022.09.20 NXP BV

AI summary

A bandgap reference voltage generator can include a bandgap core circuit configured to output at least one control voltage. The bandgap reference voltage generator can further include feedback circuitry that can be configured to receive a control voltage outputted by the bandgap core circuit or another control voltage generated based on the control voltage, and output a current. The current can be outputted such that the current is sourced to or sank from the bandgap core circuit. The feedback circuitry can be further configured to generate a bandgap reference voltage. When the current is sourced to the bandgap core circuit, the bandgap reference voltage can be greater than a threshold value. Similarly, when the current is sank from the bandgap core circuit, the bandgap reference voltage can be less than the threshold value.