Bandgap Generator Temperature Sensor Integration
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Solution Overview
Problem
Existing integrated circuits require significant real estate for both bandgap generators and temperature sensors, which differ in temperature sensitivity, leading to inefficiencies in design and potential operational issues due to independent implementation.
Innovation Solution
Combining bandgap generator and temperature sensor circuits using temperature-sensitive elements to eliminate the need for separate temperature sensors, allowing the same elements to indicate integrated circuit temperature without loss of performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate bandgap generator and temperature sensor circuits are used, then each circuit can be optimized for its specific function, but the integrated circuit real estate required increases significantly
Solution Approach 1:
The patent combines the bandgap generator and temperature sensor into a single integrated circuit block. The temperature sensor shares the same P-N junction structures (diodes D1-D4 and transistors Q1-Q4) with the bandgap generator, allowing both functions to coexist in the same physical space without interfering with each other's optimization
Solution Approach 2:
The P-N junction structures serve dual purposes: they are used by the bandgap generator to create a temperature-stable reference voltage, and simultaneously by the temperature sensor to detect temperature through their inherent temperature-sensitive voltage characteristics. This multi-functionality eliminates the need for separate dedicated components
2Adaptability or versatility
If temperature-sensitive elements are used in bandgap generator, then temperature sensing capability is achieved, but the reference voltage stability is compromised
Solution Approach 1:
The patent divides the circuit into two independent functional segments: the bandgap generator segment that produces the stable reference voltage Vbg, and the temperature sensor segment that monitors temperature through voltage VD1. Each segment processes signals independently, allowing temperature sensing without affecting reference voltage stability
Solution Approach 2:
The patent uses separate operational amplifiers (op-amps) as intermediary components: one op-amp buffers the reference voltage Vbg to maintain its stability, while another op-amp processes the temperature-sensitive voltage VD1 for temperature detection. These intermediaries prevent cross-interference between the two functions
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 combination saves space on the integrated circuit while maintaining the temperature-independent reference voltage and temperature-sensitive output, preventing runaway temperature conditions and potential damage.
Implementation Method 1
diodes have a known temperature dependence. More specifically, the voltage across the diode, VD1, is essentially about 0.6 V at a nominal temperature (e.g., 50 degrees Celsius), and varies by about −2 mV/C
Data Source
AI summary
A combined bandgap generator and temperature sensor for an integrated circuit is disclosed. Embodiments of the invention recognize that bandgap generators typically contain at least one temperature-sensitive element for the purpose of cancelling temperature sensitivity out of the reference voltage the bandgap generator produces. Accordingly, this same temperature-sensitive element is used in accordance with the invention as the means for indicating the temperature of the integrated circuit, without the need to fabricate a temperature sensor separate and apart from the bandgap generator. Specifically, in one embodiment, a voltage across a temperature-sensitive junction from a bandgap generator is assessed in a temperature conversion stage portion of the combined bandgap generator and temperature sensor circuit. Assessment of this voltage can be used to produce a voltage- or current-based output indicative of the temperature of the integrated circuit, which output can be binary or analog in nature.