Electric lamp and discharge devices: systems – Current and/or voltage regulation
Reexamination Certificate
1999-12-08
2001-03-20
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Current and/or voltage regulation
C315S20000A
Reexamination Certificate
active
06204612
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a discharge device, and especially to a discharge device arranged in a power module for discharging charges from the power module when the power module is extracted from a system, which is still powered on.
BACKGROUND OF THE INVENTION
A power module is constituted by many electronic devices modularized together with only one connector, e.g. a golden finger, so that people can use the power module conveniently and easily. Nowadays, the power module is further designed as a live line operating module which can allow that the power module to be extracted from or attached onto a power frame of a power system when the system is not powered off.
However, there exists some risks in operating the conventional live line operating module when the system is not powered off. Taking the conventional live line power supply module for example, while the power supply module is connected to a system, a lot of charges will be stored in capacitors built inside the module. When the power module is suddenly extracted from the system, those charges can not be discharged completely since there is no discharge passageway.
These charges can be very dangerous and harmful. If the golden finger of power supply module unwarily touches the metal part of the system frame while being extracted, the charges will be discharged into the system suddenly and the devices inside the system will be damaged by the unexpectedly large current.
In addition, if the golden finger of power supply module touches a human body, the man will get an electric shock.
It is therefore attempted by the applicant to deal with the above situation encountered with the prior art.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a discharge device arranged in a power system for discharging charges from a capacitor of the power system when the power system is suddenly powered off.
The discharge device includes a discharge loop electrically connected to the capacitor for providing a discharging passageway for the charges to be safely discharged therethrough, and a control loop electrically connected to the capacitor for actuating the discharge loop to discharge said charges when the power system is suddenly powered off.
According to the present invention, the capacitor is used for storing charges when the power system is in use.
According to the present invention, the discharge loop includes a field effect transistor (FET) having a drain terminal connected to a positive pole of the capacitor, and a first resistor having a first terminal connected to a source terminal of the field effect transistor and a second terminal connected to ground and a negative pole of the capacitor.
In accordance with the present invention, the discharge loop further includes a bipolar transistor having a collector terminal connected to a gate terminal of the FET, a base terminal connected to the source terminal of the FET, and a emitter terminal connected to the second terminal of the first resistor for controlling the charges to be discharged with a constant current.
According to the present invention, the control loop includes a Zener diode having a first terminal connected to the gate terminal of the FET, and a second terminal connected to the emitter terminal of the bipolar transistor, and a second resistor connected in parallel with the Zener diode for generating a voltage drop at the gate terminal of the FET to enable the FET and the bipolar transistor to control said charges to be discharged as a constant current.
In accordance with the present invention, the discharge device further includes a second Zener diode and a plurality of resistors serieswoundly connected between the drain terminal and the gate terminal of the FET.
Another object of the present invention is to provide a discharge device arranged in a power module for discharging charges from a capacitor of the power module when the power module is suddenly extracted from a power system which is still powered on.
According to the present invention, the discharge device includes a discharge loop electrically connected to the capacitor for providing a discharging passageway for the charges to be safely discharged therethrough, and a control loop electrically connected to the capacitor for actuating the discharge loop start to discharge when the power module is suddenly extracted from the power system.
In accordance with the present invention, the power system includes a system frame for allowing the discharge module to be attached therein.
Preferably, the power module of the present invention is a live line operating module, such as a live line power supply module.
The present invention may best be understood through the following description with reference to the accompanying drawings, in which:
REFERENCES:
patent: 3714459 (1973-01-01), Gerstenberger et al.
patent: 3869645 (1975-03-01), Collins
patent: 3962601 (1976-06-01), Wrzesinski
patent: 3983473 (1976-09-01), Sanderson
patent: 5422547 (1995-06-01), Brownell
patent: 6013988 (2000-01-01), Bucks et al.
Delta Electronics , Inc.
Laff, Whitesel & Saret, Ltd.
Tran Thuy Vinh
Whitesel J. Warren
Wong Don
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