Bandgap Reference Circuit With Mixed Tempco Currents for PVT Stability
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Solution Overview
Problem
Semiconductor devices face challenges in maintaining stable operation across varying Process, Voltage, and Temperature (PVT) conditions, affecting the performance of bandgap reference circuits used in analog and digital systems, particularly in generating reference currents or voltages.
Innovation Solution
A bandgap reference circuit with multiple current sources having different temperature coefficients, trimmers to adjust current amounts, and a mixer to combine currents based on an aggregate ratio, ensuring stable output across temperature changes, is integrated into semiconductor devices to compensate for PVT variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a bandgap reference circuit is used to generate reference current or voltage, then the circuit can operate at low voltage to compensate for temperature changes, but the operation stability deteriorates when PVT (Process, Voltage, Temperature) conditions vary
Solution Approach 1:
The patent adjusts the operating parameters of the bandgap reference circuit by controlling the current mode (subthreshold or saturation region) of transistors through adjustable current sources. By changing the bias current parameters dynamically, the circuit maintains stable reference output across PVT variations while preserving temperature compensation capability
Solution Approach 2:
The patent introduces dynamic adaptability by making the bias current adjustable rather than fixed. The current sources can be tuned to operate in different regions (subthreshold or saturation) based on temperature and process conditions, allowing the circuit to adapt its operating point to maintain stability across varying PVT conditions
2Stability of the object's composition
If multiple current sources with different temperature coefficients are used to compensate for temperature changes, then temperature stability improves, but device complexity increases
Solution Approach 1:
The patent combines multiple current sources with different temperature coefficients (PTAT and CTAT) into a unified reference current generation circuit. By merging these current sources and using adjustable biasing, the circuit achieves temperature compensation while maintaining a relatively compact structure that doesn't excessively increase complexity
Solution Approach 2:
The adjustable current sources serve multiple functions: they provide temperature compensation, enable operation in different transistor regions, and allow adaptation to process variations. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall device complexity
Data Source
AI summary
A bandgap reference circuit includes a plurality of current sources including different temperature coefficients, a first trimmer, and a mixer. The first trimmer adjusts current amounts for a plurality of currents, which are individually output from each of the plurality of current sources, to be equal to each other. The mixer adjusts an aggregate ratio and combines the plurality of currents based on the aggregate ratio.