Bandgap Voltage Compensation via Thermal Gradient Sensing
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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 significant noise and area increases.
Innovation Solution
A thermal error cancellation circuit using temperature sensors to generate a compensation signal that counters the temperature gradient effects, minimizing voltage errors by sensing temperature differences across the circuit and applying a corrective current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are added to sense thermal gradients, then voltage error due to thermal gradients is reduced, but device complexity and area increase
Solution Approach 1:
The circuit is divided into multiple temperature zones with separate temperature sensors placed at different locations (first temperature sensor at first location, second temperature sensor at second location). This segmentation allows independent measurement of thermal gradients across different regions, enabling precise detection of voltage errors caused by thermal variations without requiring a single complex sensing mechanism.
Solution Approach 2:
Temperature sensors act as intermediary elements that convert thermal gradient information into electrical signals. These sensors mediate between the physical thermal environment and the electronic circuit, providing a bridge that allows the circuit to sense and compensate for thermal effects without direct mechanical or thermal intervention in the voltage regulation process.
2Reliability
If temperature sensors and compensation circuits are added, then thermal gradient effects are compensated, but area occupation increases
Solution Approach 1:
The temperature sensors are integrated within the existing voltage regulator circuit structure, merging the thermal sensing function with the voltage regulation circuitry. The sensors are placed at strategic locations within the circuit boundary, and their output signals are combined with the voltage regulation feedback loop, allowing dual functionality from a unified circuit architecture that minimizes additional area occupation.
Solution Approach 2:
The temperature sensors serve multiple functions: they detect thermal gradients, provide feedback signals for compensation, and enable the circuit to adapt to varying thermal conditions. This multi-functionality allows a single sensing element to perform several roles, reducing the need for separate dedicated components and thereby minimizing the overall area required for thermal compensation.
3Reliability
If thermal compensation is implemented, then line regulation and load regulation are improved, but quiescent current consumption increases
Solution Approach 1:
The thermal compensation operates by periodically sampling temperature signals from the sensors and adjusting the compensation current accordingly. Rather than continuous high-power operation, the system uses periodic measurement and adjustment cycles, allowing the compensation mechanism to function effectively while consuming minimal quiescent current during the non-adjustment periods.
Solution Approach 2:
The compensation current is dynamically adjusted based on the detected temperature gradient parameters. When thermal gradients are detected, the circuit changes the compensation current parameter to counteract the thermal effects. When thermal conditions are stable, the compensation parameter is reduced or disabled, allowing the circuit to maintain regulation precision while minimizing current consumption during steady-state operation.
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.
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 is configured to provide a signal proportional to the temperature difference between the first location and the second location.
Implementation Method 3
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.
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.