Bandgap Reference Voltage Circuit with Segmented Temperature Correction
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Solution Overview
Problem
Existing reference voltage generating circuits exhibit significant temperature dependence, particularly in automotive and industrial applications, where stability across a wide temperature range is crucial, and current solutions are not sufficient to meet these requirements.
Innovation Solution
A reference voltage generating circuit that includes a bandgap reference voltage generating circuit, high temperature correction circuit, and bias circuit to adjust the reference voltage by supplying temperature-dependent correction currents and bias voltages, ensuring stability across varying temperatures by compensating for transistor and resistor temperature coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bandgap reference voltage generating circuit uses the temperature coefficients of Vbe and resistors to cancel each other, then the reference voltage is stable at room temperature, but the reference voltage exhibits second-order temperature dependence and decreases at high and low temperature regions
Solution Approach 1:
The patent divides the temperature compensation function into multiple segments: the main bandgap circuit handles room temperature stability, while separate high-temperature correction circuits and low-temperature correction circuits address extreme temperature regions. This segmentation allows each circuit segment to optimize for its specific temperature range, resolving the second-order temperature dependence issue.
Solution Approach 2:
The patent changes the operational parameters of transistors and resistors based on temperature conditions. By using temperature-dependent biasing and activating different correction circuits at different temperature thresholds, the circuit dynamically adjusts its parameters to maintain reference voltage stability across the full temperature range, compensating for the second-order temperature effects.
2Reliability
If temperature correction circuits are added to improve reference voltage stability at extreme temperatures, then the reference voltage becomes stable across a wider temperature range, but the device complexity increases
Solution Approach 1:
The patent merges multiple correction functions into a unified reference voltage generating circuit. The high-temperature correction circuit, low-temperature correction circuit, and main bandgap circuit are integrated to work together, sharing common elements like the reference voltage node and control mechanisms, thereby reducing overall complexity compared to separate independent correction systems.
Solution Approach 2:
The correction circuits are designed to automatically activate based on temperature conditions without external control. The circuits use inherent temperature-dependent characteristics of transistors and resistors to self-regulate, eliminating the need for complex external temperature sensing and control logic, thus reducing device complexity while maintaining reliability.
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 flat and stable reference voltage characteristic over a wide temperature range, enhancing the applicability of integrated circuits in demanding environments.
Implementation Method 1
a bandgap reference voltage generating circuit main body configured to generate a reference voltage at room temperature which is substantially constant and a reference voltage which is lower than the reference voltage at room temperature as temperature increases, by cancelling a negative temperature coefficient of a voltage between a base and an emitter of a transistor with a positive temperature coefficient of a resistor
Implementation Method 2
a high temperature correction circuit configured to increase a reference voltage generated by the reference voltage generating circuit main body at a high temperature by supplying a high temperature correction current that increases as the temperature increases to the resistor
Implementation Method 3
a bias circuit configured to generate a bias voltage according to the temperature, so as to control the high temperature correction current by supplying the bias voltage to the high temperature correction circuit
Data Source
AI summary
a reference voltage generating circuit that includes a bandgap reference voltage generating circuit main body (10) configured to generate a substantially constant reference voltage at room temperature, a high temperature correction circuit (30) configured to increase a reference voltage generated by the reference voltage generating circuit main body at a high temperature by supplying a high temperature correction current that increases as the temperature increases to the resistor, a low temperature correction circuit (40) configured to increase a reference voltage generated by the reference voltage generating circuit main body at a low temperature by supplying a low temperature correction current that increases as the temperature decreases to the resistor, and a bias circuit (20) configured to generate a bias voltage according to the temperature, so as to control the high temperature correction current and the low temperature correction current at the same time.