CMOS Reference Voltage Circuit for Low Line Sensitivity
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Solution Overview
Problem
Conventional bandgap reference voltage generators are sensitive to process variations and require larger physical chip space due to the use of BJTs, necessitating complex compensation and higher supply voltages, while they can only generate a single stable voltage level across temperature ranges.
Innovation Solution
The use of CMOS transistors in a reference voltage generator design that operates in the saturation region, reducing physical dimensions and process-induced variations, enabling stable DC reference voltage generation across multiple voltage levels with reduced sensitivity to PVT variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BJT-based bandgap reference voltage generators are used, then stable reference voltage can be generated across temperature ranges, but the circuit occupies larger physical chip space and exhibits higher sensitivity to process variations
Solution Approach 1:
The patent changes the fundamental operating parameters by using CMOS transistors in saturation region instead of BJTs, operating at supply voltages of 0.4V-0.6V instead of traditional 1.2V-2.5V. This parameter change enables achieving temperature-stable reference voltages with significantly reduced chip area and process sensitivity while maintaining reliability
Solution Approach 2:
The patent substitutes the BJT-based bandgap reference mechanism with a CMOS-based saturation-region operation mechanism. This substitution replaces the traditional bipolar transistor physics with CMOS transistor saturation characteristics, eliminating the need for large physical structures and complex temperature compensation circuits
2Reliability
If BJT-based bandgap reference voltage generators are used, then stable reference voltage can be generated, but complex compensation circuits and higher supply voltages are required
Solution Approach 1:
The patent extracts and eliminates the complex temperature compensation circuits that are traditionally required in BJT-based bandgap references. By using CMOS transistors in saturation region, the design inherently achieves temperature stability without requiring additional compensation components or complex circuit topologies
Solution Approach 2:
The patent replaces the BJT saturation mechanism with CMOS transistor saturation-region operation, fundamentally changing the physical mechanism from bipolar junction physics to MOSFET channel conduction. This substitution simplifies the overall circuit architecture by eliminating the need for complex compensation networks
3Reliability
If BJT-based bandgap reference voltage generators are used, then reference voltage can be generated across temperature ranges, but sensitivity to process variations increases
Solution Approach 1:
The patent changes the manufacturing process parameters by utilizing standard CMOS fabrication processes instead of bipolar processes. CMOS transistors in saturation region exhibit better matching and lower sensitivity to process variations, enabling temperature-range coverage with improved manufacturing precision and reduced process sensitivity
Solution Approach 2:
The patent substitutes the BJT physical mechanism with CMOS transistor saturation-region operation, replacing bipolar junction physics with MOSFET channel conduction physics. This substitution inherently reduces sensitivity to process variations while maintaining temperature range coverage
4Reliability
If conventional reference voltage generators are used, then single stable voltage level can be generated, but power consumption is higher
Solution Approach 1:
The patent changes the supply voltage parameter to 0.4V-0.6V, which is significantly lower than conventional 1.2V-2.5V operating voltages. By operating CMOS transistors in saturation region at these low voltages, the design achieves both voltage stability and reduced power consumption simultaneously
Solution Approach 2:
The patent replaces the high-power BJT-based bandgap reference mechanism with low-power CMOS saturation-region operation. This substitution fundamentally changes the energy consumption characteristics by utilizing MOSFET's voltage-controlled resistance特性 in saturation region, enabling stable reference voltage generation at much lower power levels
Data Source
AI summary
Systems and methods are provided for generating a stable DC reference voltage that has low sensitivity to operating temperature and supply voltage variations and is stable across process corners using complimentary metal-on-semiconductor field-effect transistors (MOSFETS). In an example implementation, a reference voltage generator circuit is provided that includes complimentary MOSFETs including a first complimentary MOSFET connected to a first node and having a first threshold voltage, and a second complimentary MOSFET connected to a second node and having a second threshold voltage that is greater than the first threshold voltage. The reference voltage generator circuit feeds the first node a first current based on mirroring a second current at the second node and outputs a stable DC reference voltage based on the first and second complimentary MOSFETs and configured operating in respective saturation regions.