Gate Driver Protection Circuit for Automotive Ignition
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Solution Overview
Problem
Conventional power supply protection systems for high voltage applications, such as automotive ignition coils, face issues with momentary battery voltage drops causing the gate of high voltage switches to discharge, leading to dangerous and damaging sparks due to floating high voltage conditions, which are typically addressed by using large capacitors that increase costs and physical space.
Innovation Solution
A power supply protection system with a gate controller that includes internal power supply circuitry, low voltage detection, and tri-state controller circuitry to maintain an uninterrupted gate control signal during battery voltage drops, using highside and lowside driver circuitry to keep the switch active and prevent discharging, thereby isolating the gate control signal from the power supply fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large capacitor is used to maintain the high voltage switch on during battery voltage drops, then the reliability of power supply protection is improved, but the device complexity and physical space requirements increase
Solution Approach 1:
The patent introduces an intermediary power supply circuit between the battery and the high voltage switch gate. This intermediary circuit includes voltage detection circuitry that monitors battery voltage and activates when voltage drops are detected, providing compensating voltage to maintain the gate voltage and keep the switch conducting during transient undervoltage conditions
Solution Approach 2:
The power supply circuit is designed to automatically detect undervoltage conditions and activate without external intervention. The voltage detection circuitry self-monitors the battery voltage and autonomously enables the power supply circuit when needed, eliminating the need for manual intervention or complex external control systems
2Reliability
If a large capacitor is used to act as a battery during voltage drops, then the gate discharge problem is prevented, but the cost and physical space requirements increase
Solution Approach 1:
The patent introduces an intermediary power supply circuit between the battery and the high voltage switch gate. This intermediary circuit includes voltage detection circuitry that monitors battery voltage and activates when voltage drops are detected, providing compensating voltage to maintain the gate voltage and keep the switch conducting during transient undervoltage conditions
Solution Approach 2:
The patent changes the operational parameters of the power supply circuit by monitoring voltage levels and dynamically adjusting the power supply activation threshold. The circuit detects when battery voltage drops below a predetermined threshold and automatically activates to maintain gate voltage, providing precise control without requiring oversized passive components
Data Source
AI summary
Devices and methods provide a protection device for maintaining a steady output on a gate driver terminal despite fluctuations in a power supply, the protection device including low voltage detection circuitry configured to monitor the power supply and detect fluctuations in the power supply; and gate isolation circuitry configured to isolate the gate driver terminal from the power supply if the low voltage detection circuitry detects a fluctuation in the power supply, wherein a voltage of the gate driver terminal is maintained within a preselected range when the gate is isolated.