External Power Transistor Driver Impedance Control for Ringing
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Solution Overview
Problem
Existing driver circuits for external power transistors suffer from ringing artifacts due to parasitic inductors and capacitors, requiring additional external components and measurement pins for explicit measurement, which is complex and inefficient.
Innovation Solution
A driver circuit with an oscillation detection unit and resistance control unit that adjusts the output resistance to minimize oscillations in the drive signal, eliminating the need for external resistors and additional measurement pins by detecting oscillations directly within the driver circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an external transistor is switched on fast with a steep step function driver signal, then the switching speed is improved, but ringing artifacts occur due to parasitic inductors and capacitors
Solution Approach 1:
The driver circuit applies preliminary anti-action by detecting ringing artifacts and responding with countermeasures. When ringing is detected through the oscillation detection unit, the driver circuit adjusts its output impedance to dampen the oscillations, effectively counteracting the harmful ringing effect before it can cause damage or performance degradation.
Solution Approach 2:
The driver circuit dynamically changes the output impedance parameter based on detected ringing conditions. The resistance control unit adjusts the output impedance between a first value (when no ringing is present) and a second value (when ringing is detected), allowing the circuit to optimize both switching speed and ringing suppression based on real-time conditions.
2Measurement precision
If explicit measurement of ringing is performed using an external resistor and additional measurement pin, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The driver circuit merges the measurement function with the existing driver circuitry. The oscillation detection unit is integrated within the driver circuit itself, utilizing the same output impedance control mechanisms, thereby eliminating the need for separate external measurement components and reducing overall system complexity while maintaining measurement capability.
Solution Approach 2:
The driver circuit performs self-measurement and self-correction of ringing artifacts. By incorporating the oscillation detection unit and resistance control unit within the driver circuit, the system monitors its own output and automatically adjusts its parameters to suppress ringing, eliminating the need for external measurement equipment and making the system self-sufficient.
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
Effectively reduces ringing artifacts at the external power transistor while minimizing power losses and component count, enhancing the efficiency and simplicity of the driver circuit operation.
Implementation Method 1
the parasitic capacitances and inductances in the external power transistor and the circuitry in the neighborhood of the external power transistor may cause ringing artifacts on the source current of the external transistor
Implementation Method 2
the parasitic capacitances and inductances in the external power transistor and the circuitry in the neighborhood of the external power transistor may cause ringing artifacts on the source current of the external transistor
Implementation Method 3
the resistance control unit is configured to adjust the output resistance of the driver circuit based on the degree of oscillation on the drive signal
Data Source
Figure 1
Figure 2~4
Figure 3a
AI summary
The present document relates to the control of an external power transistor. In particular, the present document relates to a method and system for avoiding ringing at the external power transistor subsequent to switching of the external power transistor. A driver circuit (160) configured to generate a drive signal (601) for switching a driven switch (104) between an off-state and an on-state is described. The driver circuit (160) comprises a drive signal generation unit (110) configured to generate a high drive signal triggering the driven switch (104) to switch to the on-state; wherein an output resistance of the driver circuit (160) is adjustable; an oscillation detection unit (130) configured to detect a degree of oscillation (602) on the drive signal (601); and a resistance control unit (610) configured to adjust the output resistance of the driver circuit (160) based on the degree of oscillation (602) on the drive signal (601).