Variable Pulse Width Generator Using Delay Line
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Solution Overview
Problem
Existing pulse generators that use an SR flip-flop, capacitor, and comparator struggle to generate very short pulse widths, such as those in the range of a few nanoseconds, due to limitations in varying pulse width in response to external conditions.
Innovation Solution
A pulse generator design that includes a delay line, pulse circuit, oscillator, and phase detector/charge pump circuit, which varies the delay time and pulse width in response to changes in phase shift current and input voltage, allowing for generation of pulsed signals with adjustable widths down to 20 ns and up to 66 ns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an SR flip-flop, capacitor, and comparator are used to generate pulses, then the pulse width can be kept substantially constant, but the ability to generate very short pulse widths (a few nanoseconds) is limited
Solution Approach 1:
The patent applies dynamics by making the pulse width adjustable rather than fixed. The delay time of the delay line is made variable through control signals that adjust the delay amount, allowing the pulse width to be dynamically changed between a first value and a second value. This resolves the contradiction by enabling both constant pulse width operation (when needed) and very short pulse width generation (when required), with the pulse width adaptability allowing the system to achieve minimum pulse widths in the nanosecond range that were not achievable with fixed RC time constant circuits.
2Device complexity
If a fixed delay line is used, then the circuit is simple, but the pulse width cannot be varied in response to control signals
Solution Approach 1:
The patent implements a controllable delay line where the delay time can be adjusted in response to control signals. The delay line includes delay elements that can be selectively activated or bypassed based on control signals, allowing the delay time to be varied between different values. This provides pulse width variation capability while maintaining relatively simple circuit architecture, resolving the contradiction by introducing minimal complexity to achieve the desired adaptability.
Solution Approach 2:
The patent uses preliminary action by pre-configuring multiple delay paths or delay element combinations in the delay line. Control signals selectively activate specific delay paths or numbers of delay elements before the pulse generation occurs, allowing the delay time to be preset to different values. This enables pulse width variation without requiring complex real-time adjustment mechanisms, balancing circuit simplicity with adaptability.
Data Source
AI summary
A pulse generator generates a square-wave pulsed signal that has a variable pulse width. The pulse width, which is defined by the delay through a delay line, varies in response to variations in an input voltage, as well as in response to phase differences between a reference clock signal and a trigger signal.