Encoder Circuit With Feedback DAC For Temperature Sensing
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Solution Overview
Problem
Existing temperature sensing technologies face challenges in providing precise temperature-indicating electrical signals without using front-end sample-and-hold amplifiers and in efficiently utilizing the resolution of analog-to-digital converter (ADC) circuits.
Innovation Solution
The implementation of multiple on-die and off-die temperature sensing circuits coupled to a common encoder circuit, which includes an offset voltage generator and a digital-to-analog converter (DAC) feedback circuit to subtract offset signals from measured temperature-indicating signals, allowing for high-resolution digital output without the need for sample-and-hold amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a front-end sample-and-hold amplifier circuit is used to measure temperature-indicating signals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent removes the front-end sample-and-hold amplifier circuit from the temperature sensing system. Instead of using this complex circuit component, the invention directly feeds the temperature-indicating signal from the semiconductor junction into the ADC circuit, thereby achieving temperature measurement without the added complexity of sample-and-hold amplifiers while maintaining measurement capability through the ADC's inherent conversion process
Solution Approach 2:
The patent changes the measurement approach by using the ADC circuit's full-scale input range to accommodate the entire expected range of temperature-indicating signals. By properly scaling and conditioning the input signal to match the ADC's input characteristics, the system achieves accurate temperature measurement across the full temperature range without requiring additional buffering or holding circuitry
2Adaptability or versatility
If the ADC circuit input range is configured for a full range of expected temperature-indicating signals, then adaptability is improved, but measurement precision deteriorates due to insufficient resolution utilization
Solution Approach 1:
The patent segments the measurement process into two stages: first, the DAC circuit generates an offset voltage that represents the minimum expected temperature-indicating signal; second, the ADC circuit measures only the difference between the actual signal and this offset. This segmentation allows the ADC to focus its resolution on measuring the variable portion of the signal, thereby improving precision while maintaining full-range adaptability
Solution Approach 2:
The patent applies partial action by having the DAC circuit provide only the offset portion of the total signal range, while the ADC circuit handles the remaining measurement task. The DAC operates at a lower resolution (fewer bits) since it only needs to cover the offset range, while the ADC uses its full resolution to measure the temperature variations, thereby efficiently utilizing the available resolution for the measurement task
3Device complexity
If multiple temperature sensing circuits are coupled to a common encoder circuit, then device complexity is reduced, but measurement precision deteriorates due to signal interference
Solution Approach 1:
The patent applies preliminary action by having the DAC circuit pre-generate the offset voltage corresponding to the minimum expected temperature signal before the ADC measurement process begins. This offset is subtracted from the incoming temperature-indicating signals, thereby pre-conditioning the signals to eliminate interference and ensure accurate measurement when multiple sensing circuits share the common encoder
Solution Approach 2:
The patent introduces the DAC circuit as an intermediary element between the multiple temperature sensing circuits and the common ADC encoder. The DAC generates offset signals that are combined with the temperature signals, acting as a mediator that prepares the signals for accurate conversion. This intermediary processing allows multiple sensors to share the encoder without signal interference, as each signal is properly conditioned before conversion
Data Source
AI summary
A temperature sensing system can include first and second temperature sensing circuits and a digitizing encoder. The first and second temperature sensing circuits can include respective devices with semiconductor junction areas. Temperature information can be determined from one or more characteristic signals measured from the temperature sensing circuits. A feedback circuit can be configured to provide one or more offset signals to the digitizing encoder. The one or more offset signals can correspond to components or characteristics of the first and second temperature sensing circuits. In an example, at least one of the first and second temperature sensing circuits can include an adjustable load circuit for use with the other of the first and second temperature sensing circuits.