IGBT Gate Control Circuit With Breakdown Clamp for VCE Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control circuits for power semiconductor switches face challenges in minimizing the influence of parasitic capacitances, achieving stable response times, and efficiently implementing VCE monitoring and dynamic active clamping functions, particularly for high-voltage IGBTs, due to complex designs and high thermal loads.
Innovation Solution
A control circuit with a resistor series circuit and semiconductor components that operate in breakdown when a specific collector-emitter voltage is exceeded, connected to a signal processing unit, which stabilizes the potential at the output of the resistor series circuit and reduces the impact of parasitic capacitances, allowing for constant response times and efficient active clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a voltage divider with high resistance values is used to reduce power loss, then power loss is reduced, but the time constant increases leading to signal delay
Solution Approach 1:
The voltage divider is segmented into two parts: a high-resistance voltage divider for power reduction and a low-resistance series resistor for timing control. This segmentation allows each part to optimize its function independently.
Solution Approach 2:
A series resistor is introduced as an intermediary element between the voltage divider and the measurement input. This resistor mediates the timing function while allowing the voltage divider to maintain its power-efficient high resistance values.
2Loss of time
If parasitic input capacitance is reduced to decrease signal delay, then signal delay is reduced, but the circuit becomes more sensitive to noise and manufacturing variations
Solution Approach 1:
The circuit performs preliminary action by establishing a controlled voltage level through the voltage divider before the actual measurement occurs. This preliminary voltage establishment reduces the impact of parasitic capacitance effects during the critical measurement phase.
Solution Approach 2:
The invention changes the resistance parameters of the voltage divider to very high values (MΩ range), which fundamentally alters the time constant behavior and reduces the influence of parasitic capacitance on signal delay.
3Reliability
If the switch-on time is limited to 10 μs to prevent destruction, then component safety is ensured, but the collector-emitter voltage may not have decayed to desired low values
Solution Approach 1:
The invention replaces direct voltage measurement with a derived measurement approach. Instead of measuring the high collector-emitter voltage directly, it measures a scaled-down voltage from a voltage divider, enabling accurate monitoring without the limitations of direct high-voltage measurement.
4Measurement precision
If direct measurement of high collector-emitter voltage is used, then measurement accuracy is maintained, but the circuit requires high voltage tolerance and increased complexity
Solution Approach 1:
A voltage divider acts as an intermediary that transforms the high-voltage measurement problem into a low-voltage measurement task. The divider scales down the collector-emitter voltage to a level suitable for standard measurement circuits, reducing complexity and voltage tolerance requirements.
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 simplifies the response time management over a wide range of collector-emitter voltages, reduces parasitic capacitance effects, and enables efficient VCE monitoring and active clamping, enhancing stability and reducing thermal loads, while maintaining a compact and cost-effective design.
Implementation Method 1
which comprises a resistor series circuit, which can be connected to a power connection for supplying current, in particular collector current, of the power semiconductor switch and whose output is connected - at least indirectly - to a first input of the signal processing unit, and at least one semiconductor component, which is designed in such a way that it is operated in breakdown when a specific, predetermined collector-emitter voltage of the power semiconductor switch is exceeded
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The driving circuit has a semiconductor device which is operated in breakdown in response to exceedance of collector-emitter voltage of a power semiconductor switch (S). An output section of the semiconductor device is connected through a conductive interconnect (100) to a terminal (300) between the resistors (RVCE2,RVCE3) of a resistor series circuit. The breakdown voltage of the semiconductor device is selected, such that potential at the output of the semiconductor device is greater than potential at a gate of the power semiconductor switch. An independent claim is included for method for driving power semiconductor switch.