Duty-Cycle Feedback Circuit for Stable Signal Receiving
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Solution Overview
Problem
Conventional signal receiving devices with differential amplifiers face distortion due to changes in transconductance values caused by process drift or environmental factors, leading to unstable duty cycles of output signals.
Innovation Solution
A signal receiving device comprising a first amplifier, a duty cycle adjuster, and a common mode feedback circuit that dynamically adjusts the bias voltage based on sensed changes in the output signal's duty cycle, using a capacitor to generate a sensing voltage and adjust the common reference voltage to maintain the duty cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a differential amplifier with fixed common current is used, then the circuit structure is simple, but the duty cycle of the output signal cannot be maintained when transconductance changes due to process drift or environmental factors
Solution Approach 1:
The patent implements a duty cycle feedback mechanism where the duty cycle detection circuit monitors the output signal's duty cycle, and the bias voltage adjustment circuit dynamically adjusts the bias voltage based on the detected duty cycle to compensate for transconductance variations. This closed-loop feedback system maintains duty cycle stability despite process drift or environmental changes.
Solution Approach 2:
The patent dynamically changes the bias voltage parameter in response to detected duty cycle variations. By adjusting the bias voltage, the system compensates for transconductance changes caused by process drift or environmental factors, thereby maintaining the output signal's duty cycle within the correct range.
2Reliability
If the bias voltage is dynamically adjusted to maintain duty cycle, then the duty cycle stability is improved, but the device complexity increases due to additional circuits
Solution Approach 1:
The patent divides the signal receiving device into functionally independent modules: a differential amplifier for signal amplification, a duty cycle detection circuit for monitoring, and a bias voltage adjustment circuit for compensation. This segmentation allows each module to perform its specific function efficiently while maintaining overall system stability.
Solution Approach 2:
The duty cycle detection circuit serves as an intermediary between the differential amplifier and the bias voltage adjustment circuit. It detects the duty cycle of the output signal and provides this information to the bias voltage adjustment circuit, which then makes appropriate adjustments to maintain duty cycle stability.
3Adaptability or versatility
If process drift or environmental factors cause transconductance changes, then the amplifier can adapt to different conditions, but the output signal duty cycle becomes distorted
Solution Approach 1:
The feedback mechanism continuously monitors the output signal's duty cycle and adjusts the bias voltage to compensate for transconductance variations caused by process drift or environmental factors. This ensures that the output signal maintains its correct duty cycle and accuracy despite changes in operating conditions.
Solution Approach 2:
The system takes preliminary anti-action by detecting duty cycle variations before they result in significant signal distortion and adjusting the bias voltage in advance to compensate for upcoming transconductance changes. This proactive approach prevents distortion rather than correcting it after the fact.
Data Source
AI summary
A signal receiving device includes a first amplifier, a duty cycle adjuster and a common mode feedback circuit. The first amplifier receives an input signal, a reference voltage and a bias voltage. The first amplifier generates a first common current based on the bias voltage and, based on the first common current, generates a first output signal and a second output signal complementary to each other by comparing the input signal and the reference voltage. The duty cycle adjuster charges and discharges a selected capacitor according to the first output signal or the second output signal to generate a sensing voltage, and generates a common reference voltage according to the sensing voltage. The common mode feedback circuit generates the bias voltage by comparing the common reference voltage and the reference voltage.