Gate Driver Circuit for Multiphase Intelligent Power Module
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Solution Overview
Problem
Conventional gate driver circuits face issues with uncontrollable negative turn-off voltage, which can lead to overcharge of passive devices and affect the reliability of power transistors, especially when dealing with high output voltages.
Innovation Solution
A gate driver circuit and multiphase intelligent power module design that includes a first switch unit connected in series with capacitors, where the power supply charges these capacitors to provide a controlled gate voltage for turning on and off power transistors, using buffers and power transistors to manage the voltage effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional passive devices (diodes and inductors) are used to provide negative turn-off voltage, then the power transistor can be turned off, but the negative turn-off voltage becomes uncontrollable and may cause overcharge of passive devices
Solution Approach 1:
The patent changes the parameter of voltage control by replacing fixed passive devices with controllable active devices (MOS transistors Q3 and Q4). The gate voltages of these transistors can be dynamically adjusted to precisely control the negative turn-off voltage applied to the power transistor, transforming an uncontrollable parameter into a controllable one.
Solution Approach 2:
The patent substitutes the mechanical/passive device system (diodes and inductors) with an electronic control system using MOS transistors. This replacement allows for active control of the negative turn-off voltage through gate voltage modulation, eliminating the uncontrollable nature of passive components while preventing overcharge conditions.
2Reliability
If inductance is added to alleviate overcharge problem, then passive devices are protected from overcharge, but the maximum on-time of power transistors is limited
Solution Approach 1:
The patent changes the control parameter from fixed inductance value to dynamically adjustable transistor gate voltages. By controlling the gate voltages of MOS transistors Q3 and Q4, the negative turn-off voltage can be precisely regulated, protecting against overcharge without imposing fixed time limitations on power transistor operation.
Solution Approach 2:
The patent introduces dynamic control through MOS transistors that can be actively switched and regulated. The gate voltages of these transistors can be dynamically adjusted during operation, allowing the system to adaptively control the negative turn-off voltage without the static limitations imposed by fixed inductance values, thereby extending the maximum on-time capability.
3Device complexity
If bootstrap circuit with passive devices is used, then the circuit structure is simple, but the negative turn-off voltage is uncontrollable and affects reliability
Solution Approach 1:
The patent enhances the functionality of the bootstrap circuit by integrating controllable MOS transistors that serve multiple purposes: they provide the necessary negative turn-off voltage while simultaneously enabling precise control over its magnitude. This multi-functional approach maintains circuit simplicity while adding controllability and reliability.
Solution Approach 2:
The patent introduces MOS transistors Q3 and Q4 as intermediary control elements between the power supply and the power transistor gate. These intermediary devices mediate the negative turn-off voltage, allowing for controlled voltage application that protects the power transistor while maintaining a relatively simple circuit architecture.
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 allows for adaptive conversion of external voltage to drive field-effect transistors with stable voltage, improving the reliability and controllability of power transistor operations, reducing the risk of overcharge and enhancing system reliability.
Implementation Method 1
the first capacitor is configured to increase the gate voltage of the first power transistor when the first buffer drives the first power transistor to an on state
Implementation Method 2
the second capacitor is configured to provide a negative turn-off voltage for the first power transistor when the first buffer drives the first power transistor to an off state
Data Source
AI summary
The application provides a gate driver circuit and a multiphase intelligent power module. When a first switch unit is closed, a power supply charges a first capacitor and a second capacitor, and a first buffer provides a gate voltage for a first power transistor. The first capacitor can improve the potential of the gate of the first power transistor, so that the first power transistor is turned on; second capacitor can provide a negative turn-off voltage for the first power transistor, and can adaptively convert external voltage into voltage that can drive the power transistor. Moreover, the circuit can be realized easily and the voltage of the first power transistor is stable.