Asymmetrical Charge Pump CDR for Low-Power Frequency Lock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional clock and data recovery (CDR) circuits consume high power due to the use of frequency detectors operating at high frequencies, which is inefficient and places a heavy load on the system, especially in devices that require reduced power consumption and limited space for data processing without a reference clock.
Innovation Solution
A CDR circuit using asymmetrical charge pumps that sweep through frequency ranges without a frequency detector or reference clock, employing a phase detector, charge pump with asymmetrical current sources, and a voltage-controlled oscillator to lock frequencies, allowing for reduced power consumption and efficient data recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a frequency detector is used to track input data rate and match VCO frequency, then frequency tracking capability is improved, but power consumption increases significantly
Solution Approach 1:
The patent removes the frequency detector component from the CDR circuit entirely. Instead of using a frequency detector to track and match frequencies, the invention employs an asymmetrical charge pump with different pull-up and pull-down currents that can sweep through frequency ranges directly, eliminating the power-hungry frequency detector while maintaining frequency tracking capability through the VCO's natural sweeping behavior.
Solution Approach 2:
The VCO is configured to automatically sweep through frequency ranges without external frequency detection. The asymmetrical charge pump creates a natural frequency sweeping mechanism where the VCO self-adjusts its frequency by responding to phase detector outputs, eliminating the need for separate frequency tracking components and reducing overall power consumption.
2Measurement precision
If traditional frequency detectors operate at high frequencies to track data rate, then frequency tracking accuracy is improved, but device complexity and system load increase
Solution Approach 1:
The patent extracts and removes the frequency detector from the system, replacing it with a simplified architecture using asymmetrical charge pump currents. The frequency tracking function is integrated into the phase-locked loop mechanism itself, where the VCO sweeps through frequencies and locks onto the correct frequency through phase detection, reducing device complexity while maintaining tracking accuracy.
Solution Approach 2:
The VCO serves multiple functions: it generates the output clock signal, performs frequency sweeping, and enables frequency tracking through its interaction with the phase detector and asymmetrical charge pump. This multi-functionality eliminates the need for separate frequency detector components, reducing overall system complexity while maintaining frequency tracking capability.
3Use of energy by moving object
If asymmetrical charge pumps are used to sweep frequency ranges, then power consumption is reduced, but frequency range coverage must be maintained
Solution Approach 1:
The asymmetrical charge pump uses dynamic current switching with different pull-up and pull-down currents to sweep the VCO through a wide frequency range. The phase detector dynamically controls the charge pump switches to adjust the control voltage, enabling the VCO to adaptively sweep through and lock onto any frequency within the required range while maintaining low power consumption through the asymmetrical current design.
Solution Approach 2:
The invention changes the current parameters of the charge pump to be asymmetrical, with different magnitudes for pull-up and pull-down currents. This parameter change enables the VCO to sweep through a wide frequency range by creating a net frequency shift in one direction while maintaining the ability to cover the full required frequency range through controlled sweeping and locking mechanisms.
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 solution enables efficient clock and data recovery across a wide frequency range with reduced power consumption, minimizing bit errors and extending device usage time by eliminating the need for a reference clock and frequency detectors.
Implementation Method 1
a charge pump comprising a first current source configured to pull up an oscillator control signal towards a first predetermined voltage; and a second current source configured to pull down the oscillator control signal towards a second predetermined voltage
Data Source
AI summary
Introduced here are techniques for implementing a clock and data recovery circuit with improved tendencies, such a pull up and/or pull down tendencies. In various embodiments, the CDR circuit includes a phase detector that receives an input signal and a output reference clock signal. The phase detector then outputs two signals to charge pump. The output from the charge pump drives an oscillator control voltage up or down depending the current from the charge pump. A lock detector detects whether a lock has occurred by comparing the oscillator control voltage to a predetermined threshold voltage. A lock can occur when the circuit has settled into a frequency substantially near the frequency of the input signal and the oscillator control voltage is substantially near the threshold voltage. A controller circuit can control a sweeping of an available frequency range by the circuit until a lock occurs.