Bandgap Reference Thermal Gradient Compensation Circuit
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Solution Overview
Problem
Thermal gradients within integrated circuits cause errors in output voltage due to internal heating, impacting line and load regulation, and existing solutions either fail to adequately address these errors or introduce excessive electrical noise and area increases.
Innovation Solution
A thermal error cancellation circuit with temperature sensors and an amplifier system that generates a compensation signal responsive to temperature differences across the integrated circuit, minimizing voltage errors by sensing and canceling thermal gradients directly, rather than processing voltage and current separately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors and amplifier system are added to compensate thermal gradients, then voltage error reduction is improved, but device complexity increases
Solution Approach 1:
The integrated circuit is divided into multiple temperature zones by placing temperature sensors at different locations (first temperature sensor at first location, second temperature sensor at second location). This segmentation allows independent measurement of thermal conditions in different regions, enabling targeted compensation for thermal gradients without requiring a complete system redesign.
Solution Approach 2:
An amplifier system acts as an intermediary between the temperature sensors and the bandgap reference circuit. The amplifier receives temperature differential signals from the sensors, processes them, and generates compensation signals that are fed back to adjust the bandgap reference output. This intermediary component translates thermal measurements into electrical compensation without directly modifying the core reference circuit.
2Reliability
If thermal error cancellation circuit is implemented, then line regulation and load regulation are improved, but area occupation increases
Solution Approach 1:
The thermal error cancellation functionality is merged with the existing bandgap reference circuit by feeding compensation signals into the bandgap adjustment input. The temperature sensors, amplifier, and compensation logic are integrated into a unified thermal error cancellation circuit that shares the bandgap core circuit infrastructure, reducing the need for separate compensation systems and minimizing additional area requirements.
Solution Approach 2:
The bandgap core circuit serves multiple functions: it generates the reference voltage and simultaneously accepts thermal compensation signals to maintain accuracy under varying thermal conditions. The amplifier system serves dual purposes by both measuring temperature differentials and generating compensation signals, reducing the need for dedicated compensation circuitry and minimizing area occupation.
3Measurement precision
If multiple temperature sensors are placed at different locations, then thermal gradient detection is improved, but electrical noise increases
Solution Approach 1:
The amplifier system continuously monitors the differential signal between the two temperature sensors and adjusts the compensation signal fed back to the bandgap reference circuit. This feedback mechanism allows the system to dynamically counteract thermal gradients while maintaining low noise operation by only amplifying the relevant differential temperature signal rather than processing absolute temperature values from each sensor independently.
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 effectively reduces voltage errors caused by thermal gradients while maintaining low electrical noise and minimal area occupation, ensuring precise and stable output voltages across varying temperatures.
Implementation Method 1
A thermal error cancellation (TEC) circuit has a TEC output coupled to the bandgap adjustment input. The TEC circuit includes first and second temperature sensors that are located distant from each other. A signal at the TEC output is responsive to temperatures at the first and second temperature sensors.
Implementation Method 2
An amplifier has an amplifier input and an amplifier output. The amplifier input is coupled to the bandgap reference output. The amplifier output provides a compensation signal that is amplified and responsive to temperatures at the first and second temperature sensors.
Implementation Method 3
Different regions within an integrated circuit may be at different temperatures due to internal thermal heating. The temperature differences are caused by different amounts of power dissipation in components from different regions of the integrated circuit. The temperature differences within the integrated circuit produce thermal gradients that result in errors in the output voltage or reference voltage.
Data Source
AI summary
Described embodiments include an integrated circuit for temperature gradient compensation of a bandgap voltage. A bandgap core circuit has a bandgap feedback input, a bandgap adjustment input and a bandgap reference output. A resistor is coupled between the bandgap adjustment input and a ground terminal. An offset and slope correction circuit has an offset correction output that is coupled to the bandgap adjustment input. A signal at the offset correction output is trimmed at an ambient temperature. A thermal error cancellation (TEC) circuit has a TEC output coupled to the bandgap adjustment input. The TEC circuit includes first and second temperature sensors that are located apart from each other. A signal at the TEC output is responsive to temperatures at the first and second temperature sensors. An amplifier has an amplifier input and an amplifier output. The amplifier input is coupled to the bandgap reference output.