Isolated Gate Driver ADC Triggering for Noise-Accurate Measurements
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Solution Overview
Problem
In safety-critical power systems with power switches, the diagnosis capability is reduced due to noise effects from switching behavior and commutation noise, which impairs analog-to-digital converter (ADC) measurements, making it complex and costly to implement effective diagnostics across galvanic isolation barriers.
Innovation Solution
A driver system with a primary side and a secondary side separated by a galvanic isolation barrier, where a communication circuit is used to forward trigger signals from the primary side to the ADC on the secondary side, allowing synchronized ADC measurements to mitigate noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If ADC measurements are implemented in the secondary side of gate driver, then diagnostic capability is improved, but measurement precision deteriorates due to noise effects from switching behavior and commutation noise
Solution Approach 1:
The patent applies preliminary action by triggering the ADC measurement before the power switch commutation event occurs. The control device sends a trigger signal to the ADC via the communication circuit to initiate measurement at a predetermined time point prior to switching. This allows the ADC to capture analog values before commutation noise and current changes (several kV/μs) occur at the phased node, thereby preserving measurement precision while maintaining diagnostic capability.
Solution Approach 2:
The patent uses a communication circuit as an intermediary to transfer trigger signals from the primary side to the ADC on the secondary side across the galvanic isolation barrier. This intermediary mechanism enables precise timing control of ADC measurements without direct electrical connection, allowing synchronization of measurements with switching events while maintaining galvanic isolation and reducing noise interference.
2Reliability
If galvanic isolation barrier is implemented between primary side and secondary side, then safety and electrical isolation are improved, but device complexity and cost increase
Solution Approach 1:
The communication circuit serves multiple functions: it provides galvanic isolation between primary and secondary sides, transfers trigger signals for ADC measurements, and enables timing synchronization. By integrating these functions into a single communication interface, the patent reduces overall system complexity while maintaining electrical isolation safety and ADC measurement capability.
3Measurement precision
If ADC measurement is synchronized with trigger signal, then measurement timing precision is improved, but susceptibility to noise during switching increases
Solution Approach 1:
The system triggers ADC measurements in advance before the power switch commutation event. The control device determines a predetermined time point prior to switching and sends a trigger signal to the ADC at this time point. This preliminary timing ensures measurements are completed before commutation noise and current changes (several kV/μs) occur, achieving both timing precision and noise reduction.
Solution Approach 2:
The patent rushes through the measurement process by completing ADC conversion quickly before the switching event occurs. The ADC is configured to perform measurements and complete conversions within a short time window prior to commutation, thereby skipping through the critical measurement phase before noise becomes significant, reducing susceptibility to harmful noise factors.
Data Source
AI summary
A driver for a switch includes a primary side having a trigger input and a secondary side comprising an analog-to-digital converter (ADC). The primary side and the secondary side are separated by a galvanic isolation barrier and communicate via a communication circuit. The primary side is configured to receive a trigger signal at the trigger input and forward the trigger signal to the ADC of the secondary side of the driver via the communication circuit. The ADC is configured to start a measurement upon receiving the trigger signal.