Digital Isolator Protection Circuit for Common-Mode Transient Clamping
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Solution Overview
Problem
Existing digital isolators are susceptible to damage from common-mode transient interference due to high-voltage signals affecting low-voltage devices in the drive circuit.
Innovation Solution
A common-mode transient suppression protection circuit is designed with a linear voltage regulator structure and power supply clamp to protect low-voltage devices by clamping and regulating output voltages, using a clamping module and voltage regulation follower to stabilize voltages during interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a drive circuit with low-voltage devices is used in the modulation circuit, then the circuit operates efficiently at low voltage, but the low-voltage devices are susceptible to damage from high-voltage signals generated by common-mode transient interference
Solution Approach 1:
A protection circuit is introduced as an intermediary between the drive circuit and the isolation capacitor. This protection circuit includes a first clamp circuit connected in parallel with the drive circuit output and a second clamp circuit connected in parallel with the isolation capacitor, which mediates the high-voltage transient interference before it reaches the low-voltage devices, thus protecting them while maintaining efficient operation
Solution Approach 2:
The clamp circuits are designed to activate before the high-voltage transient signals can damage the low-voltage devices. By setting appropriate clamping voltage thresholds, the protection circuit creates a voltage buffer that absorbs and limits transient voltage spikes in advance, preventing them from reaching the vulnerable low-voltage drive circuit components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The protection circuit effectively prevents low-voltage devices from being damaged by high-voltage signals, ensuring stable operation of the drive circuit during common-mode transient interference.
Implementation Method 1
a linear voltage regulator structure having a power supply clamp and a drive circuit having a clamping module are arranged in the protection circuit
Implementation Method 2
a power supply clamp and a drive circuit having a clamping module are arranged in the protection circuit, such that low-voltage devices in the drive circuit can be protected from being damaged by high-voltage signals
Data Source
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AI summary
The present invention provides a common-mode transient suppression protection circuit for a digital isolator, including a modulation circuit, a demodulation circuit and an isolation capacitor connected between the modulation circuit and the demodulation circuit. The modulation circuit includes a modulation circuit front-end and a drive circuit, which are connected in sequence, and a clamping module is arranged in the drive circuit. The protection circuit further includes a linear voltage regulator structure connected with the drive circuit, and a power supply clamp is arranged in the linear voltage regulator structure. By providing the linear voltage regulator structure having the power supply clamp and the drive circuit having the clamping module in the protection circuit, low-voltage devices in the drive circuit can be protected from being damaged by high-voltage signals generated by common-mode transient interference.