Low Power Voltage Generator Circuit with Flat Temperature Coefficient
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Solution Overview
Problem
Existing voltage generators for battery-powered applications face challenges in providing high linearity, dynamic range, low offset, and thermal stability while minimizing power consumption, especially in ultra-low power modes where full state retention is crucial for extended battery life.
Innovation Solution
A voltage generator circuit is designed with a circuit loop of transistors and resistors, where the current through the resistor has a signed temperature coefficient, and an output transistor is coupled to another transistor to achieve a substantially flat temperature coefficient output voltage, implemented as a low drop-out (LDO) voltage regulator with trimming components for stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional voltage generators are used in battery-powered applications, then power consumption is reduced, but thermal stability and temperature drift performance deteriorate
Solution Approach 1:
The patent changes the temperature coefficient parameters of the circuit components to achieve thermal stability. Specifically, it uses a PTAT current source (with positive temperature coefficient) combined with a resistor to generate a voltage with positive temperature coefficient that compensates for the negative temperature coefficient of the bandgap reference, thereby achieving zero temperature drift at the output while maintaining ultra-low power consumption.
2Temperature
If voltage regulation components are added to improve temperature stability, then thermal stability improves, but power consumption increases
Solution Approach 1:
The patent merges the temperature compensation function with the existing voltage reference generation function. By integrating the PTAT current source and compensation resistor directly into the bandgap reference circuit, it achieves temperature stability without adding separate regulation stages, thereby avoiding additional power consumption while maintaining ultra-low power operation.
3Stability of the object's composition
If compensation components are added to flatten temperature coefficient, then output voltage stability improves, but circuit complexity increases
Solution Approach 1:
The patent performs temperature compensation in advance within the voltage reference generation stage itself, rather than requiring post-regulation or additional compensation stages. The PTAT current source and compensation resistor are configured to pre-correct the temperature drift of the bandgap reference, delivering a temperature-stable output directly from the reference circuit without requiring additional complex regulation components.
Data Source
AI summary
A voltage generator circuit can be structured to provide an output voltage having a substantially flat temperature coefficient by use of a circuit loop having transistors and a resistor arranged such that, in operation, current through the resistor has a signed temperature coefficient. The current behavior can be controlled by an output transistor coupled to another transistor, which is coupled to the circuit loop, with this other transistor sized such that, in operation, a voltage of this other transistor has a signed temperature coefficient that is opposite in sign to the signed temperature coefficient of the current through the resistor. Embodiments of voltage generator circuits can also include additional components to trim output voltage, to provide unconditional stability, or other features for the respective voltage generator circuit. In various embodiments, a voltage generator circuit can be implemented as a low drop-out (LDO) voltage regulator.