Voltage Regulator Using MOSFET Reference for Process Variation Compensation
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Solution Overview
Problem
Bandgap references used in CMOS on-chip regulators cannot compensate for MOSFET variation in process corner and temperature, leading to significant delay time variations in digital circuits, making it difficult to achieve timing convergency.
Innovation Solution
A voltage regulator circuit using MOSFET transistors as a reference voltage, which automatically adapts to the speed of logic gates by adjusting the voltage based on transconductance and threshold voltage, reducing sensitivity to process corner and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bandgap references are used in CMOS on-chip regulators, then the reference voltage can be generated using parasitic bi-polar transistors, but the regulator cannot compensate for MOSFET variation in process corner and temperature
Solution Approach 1:
The patent changes the reference voltage generation mechanism from using parasitic bi-polar transistors (bandgap reference) to using MOSFET transistors with controlled gate voltages. By adjusting the gate voltage of the MOSFET reference transistor, the reference voltage can be tuned to compensate for MOSFET parameter variations in process corner and temperature, thereby improving adaptability while maintaining ease of manufacture in CMOS process
Solution Approach 2:
The patent introduces an intermediary control mechanism where the gate voltage of the MOSFET reference transistor is controlled by a regulator circuit. This intermediary control allows the reference voltage to be dynamically adjusted based on process corner and temperature conditions, enabling compensation for MOSFET variations without changing the fundamental bandgap reference structure
2Device complexity
If bandgap references are used, then the regulator structure is simplified, but the delay time of CMOS gates varies dramatically with different corner conditions
Solution Approach 1:
The patent modifies the reference voltage parameter generated by the regulator to compensate for MOSFET variations. By changing the reference voltage level based on process corner and temperature conditions, the delay time of CMOS gates is compensated, reducing timing variation while keeping the regulator structure relatively simple
3Ease of operation
If a fixed reference voltage is used, then the regulator is easy to implement, but it cannot adapt to different process corners and temperatures
Solution Approach 1:
The patent transforms the fixed reference voltage into a dynamic reference voltage that can adapt to different process corners and temperatures. The MOSFET-based reference voltage is controlled by a regulator that adjusts the gate voltage dynamically, enabling the system to adapt to varying conditions while maintaining ease of implementation through standard CMOS transistors
Data Source
AI summary
A voltage regulator comprises a first amplifier and a biasing unit. The first amplifier has a positive input, a negative input and an output, wherein the output of the amplifier is connected to the negative input. The biasing unit generates a reference voltage by Complementary Metal-Oxide-Semiconductor transistors, wherein the positive input of the first amplifier is configured to receive the reference voltage.