Band Gap Reference Voltage Generator Circuit Temperature Compensation
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Solution Overview
Problem
Conventional band gap reference voltage generator circuits face insufficient temperature dependency issues due to non-linear terms in the output voltage, leading to inadequate accuracy in temperature-stable reference voltage generation.
Innovation Solution
A reference voltage generator circuit is designed with first and second voltage generator circuits, operational amplifiers, and additional correction circuits using PN junction devices and resistors to control currents and generate a reference voltage based on band gap, reducing temperature deviation without increasing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional band gap reference voltage generator circuit sums two voltages with opposite temperature gradients, then a reference voltage with reduced temperature dependency is obtained, but the output voltage exhibits non-linear temperature characteristics with insufficient accuracy
Solution Approach 1:
The patent segments the temperature compensation function into multiple independent voltage generator circuits (first, second, and third voltage generator circuits), each generating voltages with different temperature characteristics. This segmentation allows independent optimization of each circuit's temperature response while combining them to achieve superior overall temperature stability and accuracy.
Solution Approach 2:
The patent combines multiple voltage generator circuits with different temperature characteristics (negative temperature coefficient from base-emitter voltages and positive temperature coefficient from voltage differences) to create a composite reference voltage output. This composite approach synthesizes a reference voltage with enhanced temperature stability by balancing opposing temperature gradients across multiple circuits.
2Measurement precision
If additional correction circuits are added to improve temperature characteristics, then temperature accuracy is enhanced, but circuit complexity increases
Solution Approach 1:
The patent merges multiple voltage generator circuits and PN junction devices into a unified reference voltage generation system. By combining the first, second, and third voltage generator circuits with shared operational amplifiers and integrated current control mechanisms, the design achieves enhanced temperature accuracy while minimizing circuit complexity through functional integration.
Solution Approach 2:
The operational amplifiers and current control mechanisms serve multiple functions simultaneously: they regulate currents in different voltage generator circuits, compensate for temperature variations, and generate the final reference voltage. This multi-functionality reduces the need for separate correction circuits and maintains circuit simplicity.
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 proposed solution effectively reduces temperature deviation in output voltage, providing a highly accurate reference voltage without enlarging the circuit size, by utilizing multiple peak voltages to stabilize temperature characteristics.
Implementation Method 1
a reference voltage generator circuit generating a reference voltage based on a band gap
Implementation Method 2
one of the voltages is a base-emitter voltage Vbe (this is a base-emitter voltage of a bipolar transistor with a temperature coefficient of −2 mV/° C.) that is a forward voltage of a PN junction and that has a negative temperature characteristic
Data Source
AI summary
A reference voltage generator circuit is provided with a first voltage generator circuit that generates a first direct-current voltage; a second voltage generator circuit that generates a second direct-current voltage; and an operational amplifier that generates a voltage difference between the first and second direct-current voltages. The reference voltage generator circuit generates a reference voltage based on a band gap by controlling currents flowing in the first and second voltage generator circuits based on the voltage difference, and includes a third voltage generator circuit including a PNP bipolar transistor, which is connected in parallel with the first voltage generator circuit. The third voltage generator circuit generates a third direct-current voltage corresponding to a base current flowing in the PNP bipolar transistor, and applies it to the operational amplifier with the first direct-current voltage.