Voltage Reference Circuit Using Stacked Gate Devices
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Solution Overview
Problem
Integrated circuits face challenges in generating reference voltages with reduced temperature-dependency due to the sensitivity of existing voltage reference circuits to temperature changes, which affects their reliability and performance.
Innovation Solution
A voltage reference circuit is implemented using stacked gate devices, comprising temperature-sensitive devices that generate voltages monotonically increasing or decreasing with temperature, with their coefficients adjusted to minimize temperature-dependency, and dynamic element matching techniques are applied to fine-tune the voltage-temperature curves, reducing the output voltage's sensitivity to temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing voltage reference circuits are used, then the circuit can generate reference voltage, but the reference voltage has high temperature-dependency and poor stability
Solution Approach 1:
The voltage reference circuit is segmented into multiple temperature-sensitive devices with different temperature coefficients. Each device contributes a portion of the reference voltage with distinct temperature characteristics, allowing the overall temperature-dependency to be minimized through proper weighting and combination of these segmented components.
Solution Approach 2:
The invention changes the parameters of temperature-sensitive devices by adjusting their dimensions (width, length) and operating conditions to achieve desired temperature coefficients. By modifying these parameters, the circuit generates voltages with monotonically increasing or decreasing temperature dependencies that can be combined to reduce overall temperature sensitivity.
2Reliability
If stacked gate devices are used to reduce temperature-dependency, then the reference voltage stability improves, but the device complexity increases
Solution Approach 1:
Multiple temperature-sensitive devices are merged into a unified voltage reference circuit architecture. The stacked gate devices are combined in a systematic arrangement where their individual temperature-sensitive characteristics work together to produce a stable reference voltage, reducing overall complexity compared to using separate compensation circuits.
Solution Approach 2:
The stacked gate devices serve multiple functions simultaneously: they generate the reference voltage, provide temperature compensation, and establish proper biasing conditions for other circuit elements. This multi-functionality reduces the need for additional dedicated components, thereby managing device complexity while improving reliability.
3Object-affected harmful factors
If dynamic element matching techniques are applied to fine-tune voltage-temperature curves, then the temperature-dependency reduces further, but the manufacturing precision requirements increase
Solution Approach 1:
Dynamic element matching techniques incorporate feedback mechanisms that adjust device operating points based on measured temperature coefficients. This feedback allows for post-fabrication tuning that compensates for manufacturing variations, reducing the stringency of manufacturing precision requirements while achieving low temperature-dependency.
Solution Approach 2:
The circuit employs dynamic adjustment of device parameters through biasing and control voltages that can be tuned after fabrication. This dynamic capability allows the system to adapt to manufacturing variations and fine-tune the voltage-temperature curves, reducing the need for extremely precise manufacturing while achieving the desired temperature independence.
Data Source
AI summary
An integrated circuit includes a first temperature-sensitive device having a first stacked gate device formed and a second stacked gate device, and a second temperature-sensitive device having a third stacked gate device. The first temperature-sensitive device is configured to generate a first voltage which monotonically increases with an absolute temperature. The second temperature-sensitive device is configured to generate a second voltage which monotonically decreases with the absolute temperature. The integrated circuit also includes an output terminal configured to generate a reference voltage which is based on the first voltage from the first temperature-sensitive device and the second voltage from the second temperature-sensitive device. Each of the first stacked gate device, the second stacked gate device, and the third stacked gate device is formed with a first group of field-effect transistors stacked together.