High-Side Gate Driver Voltage Control for Automotive Load Dump
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Solution Overview
Problem
Automotive load dump events can cause high voltages in power conversion circuits, potentially damaging components due to the disconnection of a vehicle battery from the alternator during charging, which existing technologies have not adequately addressed.
Innovation Solution
The implementation of a power converter control circuit that dynamically adjusts its configuration and operation to limit the voltage supplied to a high-side gate driver during overvoltage conditions, using techniques such as decoupling a charge pump capacitor from the input voltage lead and coupling it to a reference voltage, or turning off power converter switches to prevent excessive voltage levels, thereby protecting the gate driver and other circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the power converter uses existing components for high-input voltage applications, then cost and size are reduced, but the components cannot withstand overvoltage conditions during load dump events
Solution Approach 1:
The control circuit proactively detects overvoltage conditions before they can damage components and preemptively takes protective action by adjusting the charge pump operation and turning off switches. This preliminary detection and response prevents damage while allowing the use of standard-voltage-rated components, reducing cost and size while maintaining reliability.
Solution Approach 2:
The control circuit acts as an intermediary protective layer between the input voltage source and the gate driver components. It monitors input voltage conditions and intervenes by regulating the charge pump output and switching states to prevent harmful voltage propagation to sensitive components, enabling the use of lower-voltage-rated (cheaper, smaller) components.
2Reliability
If the charge pump capacitor is decoupled from the input voltage lead and coupled to a reference voltage during overvoltage conditions, then the gate driver is protected from excessive voltage, but the circuit configuration becomes more complex
Solution Approach 1:
The circuit configuration dynamically changes based on operating conditions. During normal operation, the charge pump capacitor remains coupled to the input voltage lead for simple charging. During overvoltage conditions, the control circuit reconfigures the connections to protect the gate driver. This dynamic adaptability provides protection while minimizing complexity, as the additional switching elements are only actively used when needed.
3Reliability
If power converter switches are turned off during overvoltage conditions, then voltage levels are limited and components are protected, but the power converter cannot operate during these events
Solution Approach 1:
The overvoltage condition, which would normally be harmful, is converted into a protective signal. The detection of overvoltage triggers a protective mode where switches are turned off, which inadvertently protects the components. The system transforms a dangerous condition into an opportunity for protection, allowing safe operation once the overvoltage event passes.
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
This solution reduces the voltage compliance requirements for components and processes, allowing the use of existing components for high-input voltage applications without specialized high-compliance components, leading to cost and size reductions in power converters while ensuring component safety during overvoltage events.
Implementation Method 1
a charge pump capacitor having a first terminal coupled to a power input of the gate driver
Implementation Method 2
a switching circuit having a control input, a first terminal coupled to a reference voltage lead, a second terminal coupled to the charge pump capacitor, and a third terminal coupled to an input voltage lead
Data Source
Figure 1
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AI summary
In described examples, a power supply voltage is controlled for a high-side gate driver (18) that is used in a power converter (10). In response to an overvoltage condition that occurs on an input voltage lead (42) of the power converter (10), the power converter (10) may decouple a terminal of a charge pump capacitor (32) from the input voltage lead (42), and couple the terminal of the capacitor (32) to a reference voltage lead (38).