Duty Ratio Correction Circuit Without Low-Pass Filter Delay
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Solution Overview
Problem
Existing duty ratio correction circuits face a tradeoff between high-precision correction and high-speed stabilization due to the difficulty in balancing the parameters of low-pass filters and integral capacitors, leading to increased jitter and ripple in control voltages.
Innovation Solution
A duty ratio correction circuit that utilizes a delay circuit to align the phases of clock and inverted clock signals, combined with a differential amplifier to suppress high-frequency components, thereby omitting the need for low-pass filters and large integral capacitors, enabling high-precision and high-speed stabilization of duty ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low-pass filters and large integral capacitors are used in traditional duty ratio correction circuits, then high-precision correction is achieved, but stabilization speed decreases and jitter increases
Solution Approach 1:
The patent extracts and removes the low-pass filter component from the traditional duty ratio correction circuit. By eliminating this component, the circuit achieves rapid stabilization without the time delays and jitter that filters introduce, while still maintaining high-precision correction through the differential amplifier architecture
Solution Approach 2:
The patent replaces the mechanical filtering approach (low-pass filters and large capacitors) with an electrical differential amplification approach. The differential amplifier directly processes the clock signals to generate the control voltage, substituting the need for physical filtering and energy storage components
2Stability of the object's composition
If low-pass filters are used to suppress high-frequency components, then ripple in control voltages is reduced, but circuit complexity and time delay increase
Solution Approach 1:
The patent extracts and removes the low-pass filter from the circuit, achieving control voltage stability through the differential amplifier's inherent ability to process differential signals and reject common-mode noise, thereby simplifying the circuit architecture
Solution Approach 2:
The differential amplifier performs multiple functions simultaneously: it amplifies the duty ratio difference signal, suppresses high-frequency components through its bandwidth characteristics, and generates the control voltage, replacing what traditionally required separate filter and amplifier stages
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 proposed circuit achieves precise and rapid stabilization of duty ratios by suppressing high-frequency components and reducing ripple in control voltages, allowing for efficient duty ratio correction without the time delays associated with traditional methods.
Implementation Method 1
a delay circuit to align the phases of clock and inverted clock signals
Implementation Method 2
a differential amplifier to suppress high-frequency components
Data Source
AI summary
A duty ratio correction circuit includes: a duty ratio adjustment circuit that adjusts a duty ratio of an input first clock, based on a control signal, and outputs a second clock being the first clock in which the duty ratio is adjusted; an inverted signal generation circuit that receives the second clock, and outputs an output clock having a phase of the second clock, and an inverted clock being a signal in which a phase of the output clock is inverted; a delay circuit that causes a delay of a delay amount associated to a half cycle of the output clock between the output clock and the inverted clock; and a differential amplifier that outputs, to the duty ratio adjustment circuit, as the control signal, a signal in which a difference in amplitude between the output clock and the inverted clock that are output from the delay circuit is amplified.