Band-Gap Voltage Adjustment Using Configurable Resistors
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Solution Overview
Problem
Existing electronic circuits with band-gap stages face challenges in achieving temperature-independent reference voltages due to variations in manufacturing parameters and require complex measurement processes to adjust temperature coefficients, leading to non-optimal temperature stability.
Innovation Solution
A method that involves measuring band-gap voltages at different temperatures with configurable resistors to determine an appropriate binary word for resistor configuration, ensuring a temperature-independent band-gap voltage, which is then used to adjust the reference voltage independently of temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a default value of factor K is set during circuit design to achieve temperature-independent reference voltage, then first order temperature dependence is compensated, but manufacturing parameter variations cause non-optimal temperature stability across different circuits
Solution Approach 1:
The patent applies parameter changes by measuring the actual band-gap voltage of each circuit and using this measured value to calculate a customized adjustment factor K. This measured parameter approach compensates for manufacturing variations in each individual circuit, ensuring that every circuit achieves optimal temperature stability rather than relying on a default design value that may not match actual manufacturing tolerances.
2Measurement precision
If voltage measurements are taken at different temperatures to calculate slope and adjust reference voltage, then precise reference voltage adjustment is achieved, but the adjustment process requires several measuring steps which increases complexity
Solution Approach 1:
The patent uses partial action by measuring the band-gap voltage at only two specific temperatures (room temperature and a second temperature) rather than taking multiple measurements across a full temperature range. This partial measurement approach is sufficient to calculate the temperature coefficient and achieve precise reference voltage adjustment, thereby reducing the complexity of the measurement process while maintaining accuracy.
3Adaptability or versatility
If factor K is varied to adjust the absolute reference voltage value, then reference voltage level can be tuned, but temperature stability is affected due to the interdependence of factor K and temperature coefficient
Solution Approach 1:
The patent segments the adjustment process into two independent stages: first, measuring the band-gap voltage to calculate the temperature coefficient and determine the optimal factor K for temperature compensation; second, independently adjusting the reference voltage level using this established factor K. This segmentation allows the reference voltage level to be tuned without compromising temperature stability, as the temperature compensation parameters are fixed before level adjustment.
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
This method simplifies the adjustment of reference voltages by eliminating first-order temperature dependence and manufacturing parameter variations, allowing for precise temperature-independent reference voltage adjustment with minimal measurement steps.
Implementation Method 1
a band-gap stage includes in a series arrangement between two terminals of a supply voltage source, at least one current source, a first configurable resistor and a first diode, the band-gap stage supplies a band-gap voltage, which is defined by the voltage generated by the current passing through the configurable resistor and the diode
Data Source
AI summary
A method adjusts a reference voltage of an electronic circuit based on a band-gap voltage supplied by a first band-gap stage. The band-gap stage includes in a series arrangement, between two terminals of a voltage supply source, a current source connected to a first branch, which includes a first configurable resistor in series with a first diode, and to a second branch, which includes a second configurable resistor connected to a complementary resistor in series with a second diode. The band-gap voltage is supplied to a connection node between the current source and each branch. The current source is a PMOS transistor controlled by an output voltage of a first operational amplifier of a current control loop. An appropriate binary word for configuring the configurable resistors is determined based on four band-gap voltage values measured at two different temperatures and two resistive values of the resistors configured by the same first binary word and by the same second binary word which is different from the first binary word.