Bandgap Reference Voltage Circuit With Temperature Curve Compensation
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Solution Overview
Problem
Conventional referential voltage generating devices exhibit a bending voltage/temperature curve at high and low temperatures, leading to inaccuracies and potential misoperations or calculation errors.
Innovation Solution
A referential voltage generating device that utilizes a bandgap-voltage generating unit, control-comparison unit, and differential current generating unit to compensate for temperature variations by generating differential currents proportional to the voltage difference between internally generated positive or negative temperature coefficient voltages and bandgap-voltage, thereby flattening the voltage/temperature curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional bandgap-voltage generating circuit is used, then bandgap-voltage is less vulnerable to temperature, but referential voltage still bends at high and low temperature due to nonlinear BJT influence
Solution Approach 1:
The patent introduces a feedback mechanism where the referential voltage is continuously compared with the bandgap-voltage, and the difference is used to generate a compensation current that adjusts the referential voltage output. This closed-loop feedback system eliminates the nonlinear temperature effects of BJTs by dynamically compensating for voltage deviations, achieving both temperature stability and high precision across the full temperature range.
Solution Approach 2:
The patent changes the operational parameters of the circuit by introducing a dynamic compensation current that varies with temperature. The compensation current is generated based on the voltage difference between referential voltage and bandgap-voltage, and this current adjusts the output to maintain accuracy. This parameter change approach transforms the static bandgap-voltage into a dynamically adjusted referential voltage that remains accurate across temperature variations.
2Measurement precision
If differential current compensation is added, then voltage/temperature curve bending is reduced, but device complexity increases
Solution Approach 1:
The patent merges the temperature compensation function with the existing bandgap-voltage generation circuit by integrating the differential current generation directly into the voltage generation path. The compensation current is generated within the same circuit block that produces the bandgap-voltage, and both currents are combined to form the final referential voltage. This merging approach adds functionality without creating a completely separate compensation system, thereby limiting the increase in complexity.
Solution Approach 2:
The circuit performs self-compensation by using its own output voltage (referential voltage) as one of the inputs for generating the compensation current. The difference between the referential voltage and bandgap-voltage automatically generates the necessary compensation signal, eliminating the need for external temperature sensors or separate compensation circuits. This self-service mechanism reduces complexity while maintaining high accuracy.
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 device outputs a more accurate referential voltage with minimal temperature-dependent bending, reducing the likelihood of misoperations and calculation errors in circuit systems operating across varying temperatures.
Implementation Method 1
The bandgap-voltage generating unit is arranged to internally generate a first positive temperature coefficient current and a negative temperature coefficient voltage, and generate a second positive temperature coefficient current and a bandgap-voltage based on the first positive temperature coefficient current and the negative temperature coefficient voltage
Implementation Method 2
The differential current generating unit is electrically connected to the control-comparison unit, and arranged to receive the control voltage and generating a differential current based on the control voltage, wherein the differential current is proportional to an absolute voltage value of the control voltage
Data Source
AI summary
A referential voltage generating device includes a bandgap-voltage generating unit, a control-comparison unit, a difference current generating unit and a referential voltage generating unit. The bandgap-voltage generating unit generates a second proportional to absolute temperature (PTAT) current and a bandgap-voltage based on a first PTAT current and a complementary to an absolute temperature (CTAT) voltage, both of which are generated in the bandgap-voltage generating unit. The control-comparison unit generates a PTAT voltage based on the second PTAT current, and generates a control voltage based on a difference voltage value between the PTAT voltage and the bandgap voltage. The difference current generating unit generates the difference current based on the control voltage, wherein the difference current is proportional to an absolute voltage value of the control voltage. The referential voltage generating unit generates a referential voltage based on the bandgap voltage and the differential current.