Hybrid Frequency Monitoring Circuit for Fast Wide-Range Detection
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Solution Overview
Problem
Conventional frequency monitoring circuits face challenges in increasing resolution without increasing latency, which is typically achieved by reducing the frequency of the reference clock signal or increasing the bit width of the clock counters, leading to inefficiencies in design.
Innovation Solution
The integration of a voltage-based frequency monitoring circuit and a coarse frequency monitoring circuit, where the voltage-based circuit performs fast frequency detection using a comparator with capacitive and resistive components, and the coarse circuit covers extreme frequencies, combined with digital output logic to handle a wide range of frequencies efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency of the reference clock signal is reduced to increase resolution, then measurement precision is improved, but latency increases
Solution Approach 1:
The frequency monitoring function is divided into two independent circuits: a voltage-based frequency monitoring circuit for fast detection and a coarse frequency monitoring circuit for extreme frequencies. Each circuit operates independently with its own optimization, avoiding the trade-off that plagues single conventional circuits.
Solution Approach 2:
The voltage-based frequency monitoring circuit transforms the frequency measurement problem into a voltage comparison problem by charging a capacitor through a current source during a fixed time period and comparing the resulting voltage to a reference. This parameter transformation enables fast frequency detection without the latency inherent in conventional counter-based methods.
2Measurement precision
If the bit width of clock counters is increased to increase resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical counter-based frequency measurement system with a voltage-based comparison system. Instead of counting clock cycles and storing results in wide counters, the system charges a capacitor and compares voltages, achieving frequency measurement without complex counter infrastructure.
Solution Approach 2:
A capacitor is introduced as an intermediary element that converts frequency information into voltage information over a fixed time period. This capacitor acts as a mediator between the input clock signal and the comparison operation, simplifying the overall circuit architecture while maintaining measurement capability.
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
This approach enables fast and accurate frequency monitoring across a wide range of frequencies, overcoming limitations of conventional methods by using a hybrid circuit design that includes voltage-based and coarse frequency monitoring, ensuring reliability and speed without compromising accuracy.
Implementation Method 1
a capacitor coupled to the first comparator input... configured to provide a reference current to the capacitor during a first time period
Implementation Method 2
The voltage based frequency monitoring circuit can include a comparator having a first comparator input and a second comparator input... The comparator can output a first voltage in response to detecting that the input clock frequency is greater than a reference frequency
Implementation Method 3
a resistor selectively coupled to the second comparator input... configured to provide a reference current to the resistor during a second time period
Data Source
AI summary
An integrated circuit can include frequency monitoring circuitry. The frequency monitoring circuitry may include a voltage based frequency monitoring circuit for monitoring an input clock signal having an input clock frequency within a first set of frequencies and a coarse frequency monitoring circuit for monitoring an input clock signal having an input clock frequency within a second set of frequencies different than the first set of frequencies. The voltage based frequency monitoring circuit can be configured to generate an output voltage having a first value when the input clock frequency is greater than a reference frequency and having a second value when the input clock frequency is less than the reference frequency. The coarse frequency monitoring circuit can include a reference counter and an input clock counter that generates a count value used to compute the input clock frequency.