Bandgap Reference Circuit Clamp Voltage Stabilization

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Solution Overview

Problem

Conventional bandgap reference circuits consume significant power in low power modes due to continuous operation of the bandgap reference voltage source, which shortens the standby time of portable electronic devices and makes it challenging to maintain a stable source voltage without drawing power from the bandgap reference voltage source.

Innovation Solution

A bandgap reference circuit incorporating a clamp circuit with a digital calibration engine that shuts down the bandgap reference voltage source in low power modes, using a clamp circuit with a reference generator, operational amplifier, comparator, and output switch to adjust the reference voltage and minimize power consumption, while ensuring a stable source voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the bandgap reference voltage source continuously operates to provide stable reference voltage, then the source voltage stability is improved, but the power consumption increases significantly in low power modes

Engineering Contradiction:

Improvesource voltage stabilityVSAvoidpower consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The clamp circuit performs preliminary action by pre-charging or pre-setting the source voltage node before the bandgap reference voltage source is fully activated. This allows the system to quickly establish a valid voltage level during wake-up from low power mode, reducing the time the bandgap reference must operate and thereby reducing overall power consumption while maintaining voltage stability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements periodic action by alternately switching between the bandgap reference voltage source and the clamp circuit based on operational modes. During normal operation, the bandgap reference provides stable voltage. During low power modes, the clamp circuit takes over to maintain minimal voltage levels, creating a periodic switching pattern that optimizes both stability and power consumption.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If the bandgap reference voltage source is shut down in low power mode to reduce power consumption, then the power consumption is reduced, but the source voltage stability deteriorates due to reference voltage variation

Engineering Contradiction:

Improvepower consumptionVSAvoidsource voltage stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The clamp circuit serves as an intermediary component that bridges the gap between the bandgap reference voltage source and the load during mode transitions. It provides a intermediate voltage stabilization mechanism that maintains source voltage stability when the bandgap reference is shut down, using its capacitor to hold the voltage within acceptable ranges during low power operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system applies parameter changes by dynamically adjusting the operating parameters of the clamp circuit based on the operational mode. During low power mode, the clamp circuit operates with specific capacitance and voltage levels optimized for power savings, while during normal mode, parameters are adjusted to work in conjunction with the bandgap reference, thereby maintaining stability across different operating conditions.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the clamp circuit operates without power from the bandgap reference voltage source, then the power consumption is minimized, but the circuit complexity increases due to additional calibration requirements

Engineering Contradiction:

Improvepower consumptionVSAvoidcircuit complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The clamp circuit is merged with the existing bandgap reference circuit architecture, sharing common components such as transistors, capacitors, and control logic. This integration allows the clamp circuit to operate independently during low power mode without requiring entirely separate circuitry, thereby minimizing additional complexity while achieving power consumption reduction.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The clamp circuit is designed with multi-functionality to serve different purposes in different operational modes. During normal mode, it works alongside the bandgap reference for voltage stabilization. During low power mode, it independently maintains voltage levels. This universal design reduces the need for separate dedicated circuits for each function, thereby reducing overall circuit complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10386875B2Bandgap reference circuit and sensor chip using the same

Publication Date: 2019.08.20 PIXART IMAGING INC

AI summary

A bandgap reference circuit including a clamp circuit is provided. The bandgap reference circuit performs the calibration only for one time in a normal mode to store a control code of a reference generator of the clamp circuit. In a suspend mode, the control code is used for controlling the reference generator to cause the clamp circuit to provide a desired source voltage, and a bandgap reference voltage source is shut down to reduce the power consumption.