Feedback Delay Circuit for Stable Timing Across PVT Variation
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Solution Overview
Problem
Existing delay circuits in semiconductor components, particularly in DRAM, face significant challenges in maintaining accurate delay time due to variations in power supply voltage, operating temperature, and manufacturing process, leading to unpredictable changes in delay time T.
Innovation Solution
A control circuit and delay circuit design that incorporates a potential generation circuit and feedback loops to adjust the substrate potential of transistors, compensating for changes in power supply voltage, temperature, and manufacturing process, thereby stabilizing the delay time T by adjusting the current flowing through the transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional delay circuit is used, then the circuit structure is simple, but the delay time changes significantly with power supply voltage, temperature, and manufacturing process
Solution Approach 1:
The patent implements feedback control by detecting the actual delay time of the delay circuit and comparing it with a target delay time. Based on the comparison result, the control circuit adjusts the substrate potential of transistors in the delay circuit to compensate for delay time deviations caused by power supply voltage changes, temperature variations, and manufacturing process differences, thereby maintaining stable delay time performance
Solution Approach 2:
The patent changes the substrate potential parameter of transistors dynamically to compensate for delay time variations. By adjusting the substrate potential (e.g., from -0.5V to -1.5V), the transistor threshold voltage and current characteristics are modified, which directly affects the delay time. This parameter adjustment allows the delay circuit to maintain consistent performance across different operating conditions
2Measurement precision
If the delay time is adjusted to compensate for parameter changes, then the delay time accuracy is improved, but the control circuit complexity increases
Solution Approach 1:
The control circuit uses feedback control to achieve precise delay time adjustment. The delay time detection unit measures the actual delay time, the comparison unit compares it with the target value, and the substrate potential control unit adjusts the transistor substrate potential based on the comparison result. This closed-loop feedback mechanism enables high-precision delay time control while keeping the circuit design systematic and organized
Solution Approach 2:
The patent introduces a substrate potential control unit as an intermediary between the detection/comparison units and the delay circuit. This intermediary component translates the comparison results into appropriate substrate potential adjustments, simplifying the overall control architecture and making the system more manageable while achieving precise delay time control
3Stability of the object's composition
If feedback control is implemented, then the delay time stability is improved, but the circuit complexity and power consumption increase
Solution Approach 1:
The patent implements feedback control to maintain consistent delay time by detecting actual delay time, comparing it with target value, and adjusting substrate potential accordingly. This feedback mechanism compensates for variations caused by power supply voltage, temperature, and manufacturing process, ensuring stable delay time performance across different operating conditions
Solution Approach 2:
The substrate potential control unit dynamically adjusts the substrate potential of transistors based on real-time delay time detection results. This dynamic adjustment capability allows the delay circuit to adapt to changing operating conditions (power supply voltage, temperature) and maintain consistent delay time, transforming a static circuit into a dynamically adjustable system
Data Source
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AI summary
Provided are a control circuit and a delay circuit. The control circuit includes a control unit, a first feedback unit, and a second feedback unit. The first feedback unit outputs a first feedback signal according to a voltage of the control unit and a first reference voltage; a first terminal of the first feedback unit is connected to a first terminal of the control unit, a second terminal of the first feedback unit serves as an input terminal of the first reference voltage, and an output terminal of the first feedback unit is connected to a second terminal of the control unit. The second feedback unit outputs a second feedback signal according to a voltage output by the first feedback unit and a second reference voltage; a second terminal of the second feedback unit serves as an input terminal of the second reference voltage, and an output terminal of the second feedback unit is connected to a third terminal of the control unit. The control unit is configured to adjust a voltage of the second terminal of the control unit according to the first feedback signal and adjust a voltage of a third terminal of the control unit according to the second feedback signal, to make a change value, changing along with a first parameter, of a current of the control unit be within a first range.