Miscellaneous active electrical nonlinear devices – circuits – and – Gating – Utilizing three or more electrode solid-state device
Reexamination Certificate
1999-07-19
2001-02-06
Tran, Toan (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Gating
Utilizing three or more electrode solid-state device
C327S109000
Reexamination Certificate
active
06184740
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a control circuit for controlling a semiconductor component which comprises an emitter, a collector and a gate, the control circuit comprising a gate driver the output of which is connected to the gate of the semiconductor component to be controlled.
Currently used power semiconductors, such as IGB transistors, are components where turn-on and turn-off are so fast that for example when they are used in pulse width modulated frequency converters, voltage change rates with a value exceeding 10 volts per nanosecond may appear in the output voltage of the frequency converter. Such a change rate causes a significant strain on the load of the frequency converter. The frequency converter load is typically a motor, high voltage change rates thus causing a strain on the motor's winding insulation and strong voltage reflections in the motor cables. In addition, high change rates cause electromagnetic interference to radiate to the environment.
It is known to restrict the voltage change rates in power semiconductors by increasing the resistance of a gate resistor connected between the output of the gate driver controlling a semiconductor component and the gate of the semiconductor component to be controlled. This slows down the rate of increase of the power component's gate charge, whereby the gate voltage also increases slower. A shortcoming of this connection method is that it is dependent on the power component's properties and their distribution which makes the accuracy of the end result fairly poor. In addition, the resistance in the coupling unnecessarily increases losses.
BRIEF DESCRIPTION OF THE INVENTION
An object of the present invention is to provide a control circuit that allows the above shortcomings to be avoided and a semiconductor component to be reliably controlled in manner independent of the component and by using only simple and inexpensive passive components. This is achieved with a control circuit of the invention which is characterized in that the control circuit further comprises
a resistance coupling where two series connections of a diode and a resistor are in an antiparallel connection and connected between an emitter of the semiconductor component and a zero potential of a gate driver, and
a feedback capacitor connected between the collector of the semiconductor component and the end of the resistance coupling connected to the zero potential of the gate driver.
The invention is based on the idea that a change in the collector-emitter voltage of the semiconductor component produces a current flowing through a feedback capacitor Cl, the current also flowing through resistors coupled to the emitter. The direction of the voltage change determines which one of the two resistors the current will pass through. In both cases the current causes a voltage drop in the resistors which reduces positive gate voltage of the semiconductor component on turn-on, i.e. when the collector-emitter voltage decreases, and negative gate voltage on turn-off, i.e. when the collector-emitter voltage increases. The structure of the control circuit of the invention is fairly simple and therefore cost-effective. Due to the simple structure the control circuit is also easy to implement and operationally reliable. Furthermore, in an appropriately dimensioned control circuit losses are considerably small, therefore the operating efficiency of a device utilizing the control circuit of the invention does not decrease significantly due to the limited voltage growth rate provided with the circuit.
REFERENCES:
patent: 4922365 (1990-05-01), Moru
patent: 5646514 (1997-07-01), Tsunetsugu
patent: 5675244 (1997-10-01), Piton
patent: 5808504 (1998-09-01), Chikai et al.
patent: 5825539 (1998-10-01), Bijlenga et al.
patent: 5977814 (1999-11-01), Ishii
patent: 195 12911 (1996-05-01), None
patent: 0 493 185 (1992-07-01), None
patent: 0 614 278 (1994-09-01), None
patent: 743 751 (1996-11-01), None
patent: 0 814 564 (1997-12-01), None
patent: 96/27230 (1996-09-01), None
patent: 98/01940 (1998-01-01), None
DATABASE WPI, Section EI, Week 199828, Derwent Publications Ltd., London, GB; Class U21, AN 1998-320949 XP002120425.
ABB Industry OY
Dinh Paul
Dykema Gossett PLLC
Tran Toan
LandOfFree
Control Circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control Circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control Circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2611324