Compensated Delay Circuit for Voltage and Temperature Stability
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Solution Overview
Problem
Conventional delay circuits in integrated circuits face challenges in maintaining a constant delay due to variations in supply voltage and temperature, which affects the synchronization of internal and external signals.
Innovation Solution
A temperature and voltage compensated delay circuit is designed using a constant current source with temperature-dependent and inverse temperature-dependent current generators, ensuring that the current provided to the delay stages is independent of temperature variations, and the delay is maintained constant by adjusting the relative weights of these currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional delay circuits are used, then the circuit design is simple, but the delay varies with voltage and temperature changes
Solution Approach 1:
The patent changes the electrical parameters of the delay circuit by introducing temperature-dependent current mirrors and adjustable current sources. The current mirror ratio is made temperature-dependent to compensate for delay variations, and the current source magnitude is adjustable to fine-tune the delay. This transforms the fixed-parameter conventional circuit into a variable-parameter compensated circuit that maintains constant delay despite temperature and voltage changes.
Solution Approach 2:
The patent implements feedback mechanisms through temperature-dependent current mirrors that sense temperature changes and automatically adjust the current flow to compensate for delay variations. The system monitors the thermal state and feeds this information back to the current control elements, creating a closed-loop system that maintains stable delay characteristics without external intervention.
2Loss of time
If delay stages are added to increase total delay, then the delay period increases, but the circuit complexity increases
Solution Approach 1:
Instead of adding more delay stages to increase delay, the patent changes the current parameter of the existing stages. By adjusting the current magnitude from the current source and modifying the current mirror ratio, the delay period is extended without adding structural complexity. The delay is controlled by electrical parameter adjustment rather than structural expansion.
3Object-affected harmful factors
If long channel length transistors are used to provide high resistance, then the voltage sensitivity is reduced, but the transistor size increases
Solution Approach 1:
The patent addresses voltage sensitivity not by changing transistor geometry but by changing the operating current parameter. The temperature-dependent current mirrors and adjustable current sources control the current flow to compensate for voltage variations, allowing the use of shorter channel length transistors while maintaining voltage insensitivity through electrical parameter control rather than geometric design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The delay circuit provides a constant delay that is insensitive to temperature and voltage changes, ensuring reliable synchronization of signals in integrated circuits, such as memory devices and oscillators, regardless of environmental conditions.
Implementation Method 1
A temperature and voltage compensated delay circuit is designed using a constant current source with temperature-dependent and inverse temperature-dependent current generators
Implementation Method 2
ensuring that the current provided to the delay stages is independent of temperature variations
Data Source
AI summary
A delay circuit provides a voltage and temperature compensated delayed output signal. The delay circuit includes a first delay stage that receives an input signal, and generates a delayed output signal from the input signal. The delay circuit also includes a second delay stage that receives the delayed output signal of the first delay stage, and generates a delayed output signal from the output of the first delay stage. The first delay stage and the second delay stage are coupled a voltage supply. The magnitude of the delay of the second delayed signal is inversely proportional to the magnitude of the supply voltage to substantially the same degree that the delayed output signal of the first delay stage is proportional to the magnitude of the supply voltage.