Single-Ended DCR Sensing Compensation for Multiphase Current Accuracy
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Solution Overview
Problem
Existing multiphase switching power supplies face challenges in accurately measuring inductor current due to temperature-induced variations in sense signals, which affect the precision of power management and load balancing.
Innovation Solution
A temperature compensation circuit is implemented for single-ended DC resistance (DCR) sensing networks in multiphase switching power supplies. This circuit calculates a compensation adjust signal based on temperature differences and applies correction signals to sense signals, ensuring they have zero temperature coefficient over a specified frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation is applied to sense signals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The temperature compensation is applied separately to each phase's sense signals through individual compensating impedance networks, allowing independent compensation for each phase while maintaining overall system precision
Solution Approach 2:
A temperature sensor serves as an intermediary element that detects temperature variations and provides input to the compensation calculator, which then generates correction signals to offset temperature-induced measurement errors
2Reliability
If temperature compensation circuit is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The compensation calculator receives temperature sensor input and generates correction signals that are fed back to the sense signals through compensating impedance networks, creating a closed-loop feedback system that continuously compensates for temperature variations
Solution Approach 2:
The compensating impedance networks dynamically adjust their impedance parameters based on temperature conditions, changing the electrical characteristics of the compensation path to match varying temperature coefficients of the sense signals
3Measurement precision
If broad frequency range compensation is provided, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The compensating impedance networks are designed with dynamic characteristics that allow them to effectively compensate for temperature variations across a broad frequency range from DC to 10 MHz, adapting their response to different frequency components of the sense signals
Data Source
AI summary
A circuit for providing temperature compensation to sense signals in a single-ended DC resistance (DCR) sensing network for a multiphase switching power supply includes a temperature compensation calculator circuit generating a compensation adjust signal indicative of a sensed temperature; a compensating impedance network receiving the positive sense signals for all the phases and generating a correction signal for each phase in response to at least the positive sense signal for each phase and the compensation adjust signal; an average circuit coupled to average the correction signals of all phases, where copies of the average correction signal are applied to modify the positive sense signals; and an amplifier circuit receiving a summed positive sense signal being the sum of the modified positive sense signals for all the phases and a summed negative sense signal to generate an output signal having substantially zero temperature coefficient over the first frequency range.