Power Semiconductor Driving Circuit for Independent dV/dt and dI/dt Control
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Solution Overview
Problem
Conventional driving circuits for power semiconductor devices cannot individually control dV/dt and dI/dt in both turn-on and turn-off modes, limiting the reduction of switching loss due to noise and surge voltage constraints.
Innovation Solution
A driving circuit design that includes a capacitor and switches to control the charging and discharging times of the control electrode, allowing for separate control of dV/dt and dI/dt in both modes by using different resistors for the control electrode and capacitor, enabling independent adjustment of switching speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the switching speed is increased to reduce switching loss, then the product of current and voltage becomes small, but a large dI/dt causes parasitic inductance to produce large surge voltage that breaks the device
Solution Approach 1:
The patent segments the control of dV/dt and dI/dt into independent controllable parameters by introducing separate resistors (R1, R2) and a capacitor (C1) in the driving circuit. This allows independent optimization of voltage rise rate and current rise rate, enabling high-speed switching while controlling surge voltage through separate dV/dt and dI/dt adjustment.
Solution Approach 2:
The capacitor C1 connected between the gate and source acts as an intermediary element that controls the dV/dt during switching. By adjusting C1 and the associated resistors, the voltage rise rate is controlled independently from the current rise rate, mediating between the need for high switching speed and the need to limit surge voltage.
2Speed
If the gate resistance is adjusted to control switching speed, then the switching speed changes, but both dV/dt and dI/dt change simultaneously, requiring gate resistance to be large for noise restriction and small for high-speed switching
Solution Approach 1:
The patent divides the single gate resistance control into separate dV/dt control (via C1 and R1) and dI/dt control (via R2). This segmentation allows R2 to be optimized for high-speed switching while R1 and C1 are optimized for noise and surge voltage restriction, resolving the contradiction between switching speed and harmful factors.
Solution Approach 2:
The patent changes the control parameters from a single gate resistance to multiple independent parameters (R1, R2, C1). By adjusting these parameters, the circuit can achieve high switching speed through optimized R2 while limiting noise and surge voltage through optimized R1 and C1, allowing both contradictory requirements to be satisfied simultaneously.
3Loss of energy
If dV/dt and dI/dt are controlled individually in turn-on mode, then switching loss in turn-on mode is reduced, but dV/dt and dI/dt in turn-off mode cannot be controlled
Solution Approach 1:
The patent makes the driving circuit dynamic by using switches (S1, S2) that can selectively connect different resistors during turn-on and turn-off modes. During turn-on, R1 controls dV/dt while R2 controls dI/dt; during turn-off, the switches reconfigure the circuit to maintain independent control capability, enabling adaptive optimization for both switching modes.
Solution Approach 2:
The patent enables parameter changes between turn-on and turn-off modes through the switchable circuit configuration. Different resistor combinations are activated in different modes, allowing independent dV/dt and dI/dt control in both turn-on and turn-off, thereby achieving versatility and adaptability across different operating conditions.
4Loss of energy
If a capacitor is added between gate and source and gate resistance is adjusted to maintain the same switching speed, then dI/dt and dV/dt are controlled individually, but turn-on and turn-off modes cannot be controlled separately
Solution Approach 1:
The patent segments the control functions by assigning different resistors to different functions: R1 with C1 for dV/dt control and R2 for dI/dt control. The switches S1 and S2 further segment the control paths, enabling independent optimization of turn-on and turn-off modes while maintaining individual dV/dt and dI/dt control capability.
Solution Approach 2:
The patent introduces dynamic switching capability through switches S1 and S2 that can reconfigure the circuit topology between turn-on and turn-off modes. This dynamic reconfiguration allows separate control of turn-on and turn-off modes while maintaining the capacitor-based dV/dt control and resistor-based dI/dt control, achieving both individual parameter control and mode-specific optimization.
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 design allows for increased switching speeds in both turn-on and turn-off modes, reducing switching loss by enabling individual control of dV/dt and dI/dt, even under noise or surge voltage limitations.
Implementation Method 1
a capacitor (Ca) whose one end is connected with the first main electrode or the second main electrode
Implementation Method 2
a first resistor (R11), a first diode (D11), and a second resistor (R12) are connected in series and in that order
Implementation Method 3
a first diode (D11), and a second resistor (R12) are connected in series and in that order between the other end of the first switch and the other end of the second switch, and the first diode is connected forward with respect to the control power source
Data Source
AI summary
A power semiconductor device driving circuit has a capacitor whose one end is connected with a first or a second main electrode of a power semiconductor device, a first switch for charging the capacitor and a control electrode of the power semiconductor device with electric charges, and a second switch for discharging electric charges; in the case where when the first switch turns on, the control electrode and the capacitor are charged with electric charges through different resistors, electric charges are discharged from the control electrode and the capacitor through one and the same resistor when the second switch turns on; in the case where when the first switch turns on, the control electrode and the capacitor are charged with electric charges through one and the same resistor, electric charges are discharged from the control electrode and the capacitor through different resistors when the second switch turns on.