Power-On-Reset Circuit for Near-Threshold Voltage Detection
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Solution Overview
Problem
Power-on-reset circuits face challenges in accurately detecting supply voltages that are only slightly higher than the MOSFET threshold voltage, leading to unreliable performance and high power dissipation, especially in newer semiconductor technology nodes.
Innovation Solution
A power-on-reset circuit design incorporating a reference voltage circuit and a comparator circuit with PMOS and NMOS transistors, along with a filter circuit and Schmitt trigger, to accurately detect supply voltage thresholds with reduced power consumption and improved reliability across various process and temperature corners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior power-on-reset circuit designs are used to detect supply voltage near MOSFET threshold voltage, then the circuit can operate at lower voltage levels, but the performance of the reference generator and comparator cannot be guaranteed across all process and temperature corners
Solution Approach 1:
The patent changes the operating parameters of the reference generator and comparator to ensure they function correctly at supply voltages only slightly above the MOSFET threshold voltage. This is achieved by designing the reference voltage generation circuitry to operate reliably in the ultra-low voltage regime, thereby resolving the contradiction between detecting lower voltages and maintaining reliable performance across process and temperature variations.
2Measurement precision
If prior power-on-reset circuit designs are used for near MOSFET threshold voltage detection, then voltage detection capability is achieved, but design complexity increases due to requirements for accurate reference generator and comparator performance
Solution Approach 1:
The patent merges the reference voltage generation and comparison functions into an integrated circuit block that is specifically optimized for ultra-low voltage operation. By combining these functions and optimizing them to work together at near-threshold voltages, the design achieves accurate voltage detection without the excessive complexity of separate, high-precision reference generators and comparators.
3Reliability
If prior power-on-reset circuit designs are used, then power-on-reset functionality is provided, but power dissipation is high which is unsuitable for low power applications
Solution Approach 1:
The patent changes the operating parameters of the power-on-reset circuit to enable ultra-low voltage operation. By designing the reference generator and comparator to function at supply voltages only slightly above the MOSFET threshold, the circuit achieves accurate power-on-reset detection while consuming minimal power, making it suitable for low-power and battery-operated applications.
Data Source
AI summary
A power supply detection circuit for an integrated circuit (IC) includes a reference voltage circuit and a comparator circuit. The reference voltage circuit produces a reference voltage from the supply voltage at a reference voltage node. The comparator circuit includes a first p-type metal oxide semiconductor (PMOS) transistor with a source coupled to a positive supply terminal, a gate receiving the reference voltage, and a drain connected to a comparator output terminal. A first n-type metal oxide semiconductor (NMOS) transistor has a drain connected to the comparator output terminal, a source connected to the negative supply terminal, and a gate receiving a second voltage that varies relative to the supply voltage. A second PMOS transistor has a source coupled to the positive supply terminal, a gate connected to the reference voltage node, and a drain providing the second voltage and coupled to a filter.