Bootstrap Charge Pump Gate Drive for High-Power Intake Air Heater
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Solution Overview
Problem
State-of-the-art heater control module circuits are limited in their ability to reliably control power to high-power air heaters, such as those greater than 1.5 KW, for intake air heating systems in internal combustion engines.
Innovation Solution
An intake air heating system that includes a control module with a gate drive module and a power module, where the gate drive module generates a gate drive signal based on a control signal and a bootstrap charge pump module, and the power module switches power to the electric heater using field effect transistors to efficiently control the heating of intake air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If state-of-the-art heater control module circuits are used, then the circuit can control power to air heaters, but the control ability is limited for high-power applications greater than 1.5 KW
Solution Approach 1:
The power control circuit is segmented into multiple independent FET switches (Q1-Q4) arranged in a bridge configuration, where each switch handles a portion of the total power. This segmentation allows the circuit to reliably control high-power loads by distributing the power handling across multiple components rather than relying on a single high-power switch.
Solution Approach 2:
A bootstrap charge pump circuit is introduced as an intermediary component to generate the required gate drive voltages for the FET switches. The charge pump converts the input voltage to the higher voltages needed for proper FET switching, enabling reliable control of high-power heaters without requiring complex external voltage supply circuits.
2Power
If high-power air heaters greater than 1.5 KW are used, then the heating capability is improved, but the control module's ability to reliably control power is limited
Solution Approach 1:
The circuit uses dynamically controllable FET switches that can be rapidly turned on and off based on control signals. The bootstrap charge pump dynamically generates the necessary gate voltages during each switching cycle, allowing the high-power heater to be precisely controlled in terms of power delivery while maintaining ease of operation through standard control signal interfaces.
Solution Approach 2:
The circuit changes the voltage parameters available for control by using the bootstrap charge pump to generate elevated gate voltages from the input voltage. This parameter transformation enables the FETs to fully switch even at high power levels, making the high-power heater as easy to control as lower-power devices.
3Power
If a gate drive module with bootstrap charge pump module is used, then the power switching capability is improved, but the device complexity increases
Solution Approach 1:
The bootstrap charge pump module serves multiple functions: it generates the high-side gate voltages for the FET switches, provides voltage level shifting for control signals, and enables the entire power switching operation without requiring separate external voltage supplies. This multi-functionality justifies the added complexity by consolidating multiple requirements into a single integrated module.
Solution Approach 2:
The bootstrap charge pump is self-contained and uses the input voltage and switching action itself to generate the required gate drive voltages. It automatically charges its internal capacitors during the appropriate switching phases, eliminating the need for external voltage regulation circuits or additional power supply components, thereby reducing overall system complexity despite the added charge pump circuitry.
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 system effectively modulates power to high-power air heaters, ensuring reliable and efficient heating of intake air, even in high-power applications, by using a gate drive module and power module to toggle voltages and switch power based on control signals, thereby improving the control over the heating process.
Implementation Method 1
a bootstrap charge pump module that generates a second voltage based on a first voltage
Implementation Method 2
a plurality of field effect transistors that are controlled by the gate drive signal and switch an equal portion of the current on and off between the first and second terminals
Data Source
AI summary
An intake air heating system for an internal combustion engine is disclosed and includes an electric heater that heats the intake air and a control module that switches a voltage to the electric heater based on a control signal. The control module includes a gate drive module that includes a bootstrap charge pump module and generates a gate drive signal based on the control signal and that is referenced to the voltage. The control module also includes a power module that switches the power to the electric heater based on the gate drive signal.