High-Side Driver Circuit With EMI Oscillation Detection
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Solution Overview
Problem
Existing high side driver circuits are not robust enough to maintain reliable operation under strong ElectroMagnetic Interference (EMI) disturbances, leading to inadvertent changes in logic states during 'ON' and 'OFF' conditions.
Innovation Solution
The driver circuit incorporates a detection circuit to sense EMI-induced oscillations, utilizing pull up and pull down circuits with transistors and capacitors to maintain the logic state of the power switch, preventing unintended changes by controlling the power switch through oscillation detection and parasitic capacitance management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing high side driver circuit designs are used, then the circuit structure is simple, but the reliability under EMI disturbances is insufficient leading to inadvertent logic state changes
Solution Approach 1:
The driver circuit is segmented into functionally independent units: a power switch control unit with separate pull-up and pull-down circuits, and a detection circuit for EMI monitoring. This segmentation allows each unit to perform its specific function reliably without interfering with others, improving overall reliability under EMI while keeping individual circuit blocks manageable in complexity
Solution Approach 2:
A detection circuit is introduced as an intermediary component that monitors for EMI-induced oscillations and triggers appropriate response actions. This intermediary layer isolates the core power switch control from direct EMI interference, allowing the circuit to maintain reliability by detecting and responding to disturbances without being directly affected by them
2Reliability
If the driver circuit is designed to be robust against EMI, then reliability improves, but the circuit complexity increases due to additional detection and control mechanisms
Solution Approach 1:
The pull-up and pull-down circuits are designed to serve multiple functions: they control the power switch state during normal operation and simultaneously respond to EMI-induced oscillations when triggered. This multi-functionality allows the circuit to maintain robustness against EMI without requiring entirely separate protection circuits, thereby limiting the increase in overall complexity
Solution Approach 2:
The detection circuit automatically detects EMI disturbances and triggers the appropriate pull-up or pull-down response without external intervention. The circuit serves itself by monitoring its own state and autonomously correcting EMI-induced errors, which improves reliability while avoiding the need for complex external control systems
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 solution effectively prevents inadvertent changes in the logic state of the driver circuit during EMI disturbances, ensuring reliable operation by stabilizing the power switch state even under wide frequency oscillations, as demonstrated by flat spectral responses in testing methods.
Implementation Method 1
a capacitor device arranged to couple said second power supply to said control terminal
Implementation Method 2
operation under strong ElectroMagnetic Interference (EMI) disturbances
Data Source
AI summary
A driver circuit is provided that receives an ON or OFF logic control signal and further has: an output arranged to be connected to a load; a power switch, having a control terminal with a first current terminal connected to a first power supply and a second current terminal arranged to be connected to the output to drive the load; a control circuit of a first type arranged between the control terminal of the power switch and a second power supply; and a control circuit of a second type, arranged to couple the control terminal of the power switch to the first power supply when the control signal is in the OFF state.