Delay Circuit Compensation Resistor PVT Variation
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Solution Overview
Problem
Delay circuits are affected by process, voltage, and temperature variations, leading to inconsistent output signals due to changes in transistor operating characteristics, which complicates front-end circuit design, especially as processing technology advances to smaller geometries.
Innovation Solution
A delay circuit design incorporating a compensation resistor, capacitor, and current sources to maintain a fixed delay time, independent of process, voltage, and temperature variations, by adjusting the voltage reference point using a compensation resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional delay circuit design is used, then the circuit is simple to design, but the delay time varies with process, voltage, and temperature changes
Solution Approach 1:
The patent introduces a compensation resistor that changes its resistance characteristics with temperature to counterbalance the PVT variations in the delay circuit. By carefully selecting the resistance temperature coefficient of the compensation resistor, the circuit achieves temperature-compensated delay time without requiring complex control mechanisms
Solution Approach 2:
The compensation resistor acts as an intermediary element that mediates between the PVT variations and the delay time. It introduces a compensating effect that offsets the harmful variations, allowing the delay circuit to maintain consistent performance across different process, voltage, and temperature conditions
2Loss of time
If transistor operating speed is increased to reduce delay time, then the delay time decreases, but the circuit becomes more sensitive to temperature and process variations
Solution Approach 1:
The patent uses the temperature-dependent resistance characteristics of the compensation resistor to counterbalance the temperature-dependent operating speed variations of the transistors. This allows the circuit to achieve fast delay times while maintaining output signal consistency across temperature variations
Data Source
AI summary
A delay circuit includes an inverting receiving circuit, a reference point generating circuit, a first buffer gate and a first inverter. An inverting receiving circuit includes a first transistor and a first switching circuit. The reference point generating circuit includes a compensation resistor, a capacitor element, and a first current source. In response to the input signal being at a first potential, a voltage of the output node starts to decrease from a voltage reference point. In response to at least one of a manufacturing process, the first reference voltage, and a temperature being changed, the compensation resistor is configured to correct the voltage reference point.