Frequency-Control Circuit Using Delay-Line Feedback for Constant Output

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Solution Overview

Problem

Existing frequency-control circuits in signal generation devices face challenges in achieving stable frequency control across wide voltage ranges, particularly in PWM-type voltage converters, where large capacitors and resistors occupy significant space and result in slow transient responses, while hysteretic converters struggle to maintain a fixed constant frequency.

Innovation Solution

A frequency-control circuit comprising a pulse generator, frequency controller, charge pump, and voltage-controlled delay line, which generates a control signal to adjust the output signal frequency based on a comparison between a reference voltage and the output signal voltage, using flip-flops to detect frequency discrepancies and adjust the control voltage to match the desired frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PWM-type voltage converter uses operation amplifier circuit with large capacitors and resistors for stable frequency control, then frequency stability is improved, but circuit area increases and transient response becomes slow

Engineering Contradiction:

Improvefrequency stabilityVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts the frequency control function from the traditional operation amplifier circuit and implements it separately using a dedicated frequency control circuit with voltage-controlled delay line, allowing the main converter circuit to use smaller components while frequency stability is maintained by the specialized control circuit

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional RC-based frequency control mechanism with a voltage-controlled delay line using digital logic circuits (flip-flops, counters), substituting analog RC timing with digital time-delay control to reduce component size while maintaining frequency stability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If PWM-type voltage converter uses operation amplifier circuit with large capacitors and resistors for stable frequency control, then frequency stability is improved, but transient response becomes slow

Engineering Contradiction:

Improvefrequency stabilityVSAvoidtransient response

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent replaces the analog RC integration and compensation circuits with digital logic-based frequency control, eliminating the slow transient response inherent in large RC time constants while maintaining frequency stability through digital control mechanisms

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements dynamic frequency control by using a voltage-controlled delay line that can rapidly adjust the timing of control signals in response to load changes, enabling fast transient response while maintaining stable frequency operation through continuous feedback adjustment

Inventive Principle:

Principle #15Dynamics

3Area of stationary object

If hysteretic voltage converter uses hysteretic comparator to reduce design area, then circuit area is reduced, but output signal frequency becomes variable and difficult to control

Engineering Contradiction:

Improvecircuit areaVSAvoidfrequency stability

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the output signal frequency is continuously monitored and compared with a reference frequency, and the frequency control circuit adjusts the control signal timing based on the frequency error to maintain stable output frequency while keeping the circuit area small

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the hysteresis-based frequency determination with a digital frequency control mechanism using voltage-controlled delay line and counter circuits, enabling precise frequency control while maintaining the compact circuit area advantage of hysteretic converters

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8952734B2Frequency-control circuits and signal generation devices using the same

Publication Date: 2015.02.10 VIA TECH INC

AI summary

A signal generation device is provided to generate an output signal with constant frequency. The signal generation device includes a frequency-control circuit and a voltage-controlled delay line. The frequency-control circuit includes a pulse generator, generating a reference pulse signal according to a transition of the reference signal and a comparison pulse signal according to a transition of the comparison result signal, to re-shape the reference signal and the comparison result signal into narrow pulses suitable for clocking and resetting flip-flops.