Dual Delay-Locked Pulse Circuit for Stable ToF Timing
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Solution Overview
Problem
Existing pulse generation circuits in Time of Flight (ToF) systems face challenges in accurately generating delayed pulses with consistent delay times, especially when the clock signal frequency varies, leading to fluctuations in delay amounts and pulse widths, which affect ranging accuracy and can cause radio disturbances.
Innovation Solution
The proposed pulse generation circuit includes a first delay-locked loop circuit and a second delay-locked loop circuit connected in series, allowing for precise control of delay amounts by adjusting current ratios in charge pumps, ensuring consistent delay times even with frequency variations in the clock signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pulse generation circuit is used, then the circuit structure is simple, but the delay time becomes unstable when clock frequency varies
Solution Approach 1:
The patent implements dynamic delay adjustment by introducing a delay amount adjustment unit that modifies the delay time of the delay circuit based on detected clock frequency variations. This dynamic adaptation ensures stable delay output despite frequency changes, resolving the contradiction between simple structure and stable performance.
Solution Approach 2:
The patent employs a feedback mechanism where the output signal is fed back to detect clock frequency, and this frequency information is used to adjust the delay amount in real-time. The feedback loop compensates for frequency variations, maintaining delay stability without requiring a completely complex circuit redesign.
2Measurement precision
If delay time is increased to improve ranging accuracy, then ranging precision improves, but pulse width becomes inconsistent
Solution Approach 1:
The patent changes the delay time parameter independently of the pulse width parameter by using a dedicated delay circuit with adjustable delay amount. This allows precise control of delay time for improved ranging accuracy while maintaining consistent pulse width through separate control mechanisms.
3Productivity
If clock frequency is increased to improve productivity, then signal processing speed improves, but delay time becomes unstable
Solution Approach 1:
The patent makes the delay circuit dynamic by continuously adjusting its delay amount based on real-time clock frequency detection. This allows the system to operate at high clock frequencies for improved productivity while maintaining stable delay times through active compensation.
Solution Approach 2:
The patent applies preliminary anti-action by pre-adjusting the delay amount in response to detected frequency changes before they affect the delay output. The frequency detection and adjustment mechanism proactively compensates for upcoming frequency variations, preventing delay instability.
Data Source
AI summary
Provided is a pulse generation circuit that receives a clock signal and outputs a delayed pulse signal, including: a first delay-locked loop circuit that receives the clock signal and generates a first delay signal obtained by delaying the clock signal; a second delay-locked loop circuit that generates a second delay signal with reference to the first delay signal; and an output circuit that outputs the delayed pulse signal according to the first delay signal and the second delay signal. The second delay-locked loop circuit may have: a second charge pump that outputs a current according to the clock signal and the delayed pulse signal; and a second delay circuit that outputs the second delay signal obtained by delaying the clock signal according to a current output by the second charge pump.