Hysteresis Comparator Circuit for Stable Common-Mode Thresholds
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Solution Overview
Problem
Conventional hysteresis comparators experience changes in hysteresis voltage with common mode voltage changes, requiring additional circuit elements to maintain a fixed hysteresis voltage, increasing manufacturing costs and design complexity.
Innovation Solution
A hysteresis comparator design comprising an input stage, a hysteresis current generating circuit with a common mode voltage detecting circuit, and an output stage, which adjusts differential current signals to maintain a fixed ratio of hysteresis current to tail current, stabilizing the hysteresis voltage with fewer circuit elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hysteresis comparator designs are used, then the circuit structure is simple, but the hysteresis voltage changes with common mode voltage changes
Solution Approach 1:
The patent implements a feedback mechanism where the common mode voltage detecting circuit continuously monitors the common mode voltage and adjusts the hysteresis current accordingly. This feedback loop ensures that the hysteresis voltage remains stable despite variations in common mode voltage, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The hysteresis current generating circuit automatically adjusts its output based on the detected common mode voltage without requiring external intervention. The circuit self-regulates by using the common mode voltage signal to control the hysteresis current, thereby maintaining stable hysteresis voltage while avoiding additional complex control circuits.
2Reliability
If additional circuit elements are added to maintain fixed hysteresis voltage, then the hysteresis voltage stability is improved, but the manufacturing cost increases
Solution Approach 1:
The common mode voltage detecting circuit serves multiple functions: it detects the common mode voltage, generates the hysteresis current based on the detected voltage, and adjusts the differential current signal. This multi-functionality reduces the need for separate dedicated circuits, thereby lowering manufacturing costs while maintaining hysteresis voltage stability.
Solution Approach 2:
The patent merges the common mode voltage detection function and the hysteresis current generation function into a single integrated circuit block. By combining these functions, the patent reduces the total number of discrete circuit elements required, which directly lowers manufacturing costs while achieving the goal of stable hysteresis voltage.
3Reliability
If additional circuit elements are added to maintain fixed hysteresis voltage, then the hysteresis voltage stability is improved, but the design complexity increases
Solution Approach 1:
The patent divides the hysteresis comparator into distinct functional modules: an input stage for receiving differential signals, a common mode voltage detecting circuit for monitoring common mode voltage, a hysteresis current generating circuit for producing adjusted differential current signals, and an output stage for generating the output signal. This segmentation allows each module to be designed and analyzed independently, reducing overall design complexity while maintaining stable hysteresis voltage through coordinated operation of the modules.
Data Source
AI summary
The present invention discloses a hysteresis comparator comprising an input stage, a hysteresis current generating circuit and an output stage. In the operation of the hysteresis comparator, the input stage is configured to receive a pair of differential input signals to generate at least one differential current signal; the hysteresis current generating circuit is configured to generate at least one hysteresis current to adjust the differential current signal to generate an adjusted differential current signal, wherein the hysteresis current generating circuit includes a common mode voltage detecting circuit for detecting a common mode voltage of the differential input signal for generating the hysteresis current; and the output stage is configured to generate an output signal according to the adjusted differential current signal.