High Voltage Comparator Using Current Mirror for Precision Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing DC-DC step-down converter circuits face challenges in accurately detecting high-voltage differences without using high-voltage comparators, leading to low precision, complex circuitry, and high component count, which introduces errors and delays due to resistive dividers and parasitic capacitance.
Innovation Solution
A buck switching DC-DC converter design using low-voltage components with a high-voltage PMOS transistor to compare voltage differences, maintaining low sensitivity to temperature and process variations, and reducing component count by relying on current mirrors and PMOS transistors for accurate threshold detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistive divider is used to scale down high-voltage to low-voltage range, then the voltage can be detected by low-voltage components, but the offset voltage, reference voltage error, and resistance ratio error are amplified by the division ratio
Solution Approach 1:
The patent introduces a high-voltage current mirror as an intermediary device that transfers the high-voltage signal to the low-voltage domain without requiring resistive division. This current mirror acts as a mediator that preserves signal integrity while enabling compatibility between high-voltage and low-voltage circuits, avoiding the error amplification problem inherent in resistive divider approaches.
Solution Approach 2:
The patent replaces the mechanical/resistive voltage division approach with a transistor-based current mirror system. This substitution eliminates the need for precise resistance ratios and reduces sensitivity to component tolerances, as the current mirror provides inherent signal transformation without the error propagation characteristics of resistive networks.
2Measurement precision
If a resistive divider is used to scale down high-voltage, then voltage detection is enabled, but delay is introduced due to parasitic capacitance
Solution Approach 1:
The high-voltage current mirror serves as an intermediary that provides a low-impedance signal path, minimizing the interaction with parasitic capacitance. By transforming the voltage signal into a current signal that is then mirrored, the system avoids the RC time constant problem that plagues resistive divider circuits, achieving faster response times.
3Measurement precision
If a resistive divider is used for high-voltage detection, then voltage scaling is achieved, but a large number of components are required
Solution Approach 1:
The patent merges the functions of voltage scaling, signal transformation, and protection into a single high-voltage current mirror structure. This consolidation eliminates the need for separate resistive divider components, reducing the overall component count while maintaining detection precision through the integrated current mirror mechanism.
4Reliability
If cascode transistor structures are used to protect low-voltage components, then high-voltage protection is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the protection function from the main signal path by using the high-voltage current mirror to handle the high-voltage signal independently before transferring it to the low-voltage domain. This separation allows the low-voltage components to be protected without requiring complex cascode structures in the signal path, as the high-voltage handling is isolated to the current mirror stage.
Data Source
AI summary
A voltage comparator for detecting a voltage difference in a high-voltage domain, wherein said comparator receives an input voltage and compares it with a reference voltage also received in input, in which the output voltage from the comparator assumes the logic value 1 if the input voltage is greater than the reference voltage and assumes the logic value 0 if the input voltage is less than or equal to the reference voltage, wherein said comparator comprises low-voltage components and a single high-voltage component. In particular, the low-voltage components are MOS transistors and the high-voltage component is a high-voltage PMOS.