Electric lamp and discharge devices: systems – Periodic switch in the supply circuit – Impedance or current regulator in the supply circuit
Patent
1983-06-06
1986-09-16
Chatmon, Saxfield
Electric lamp and discharge devices: systems
Periodic switch in the supply circuit
Impedance or current regulator in the supply circuit
315DIG4, 315362, 333175, 333181, H05B 3702, H05B 3904, H05B 4136
Patent
active
046124802
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a circuit arrangement for the radio interference suppression in brightness control devices for incondescent lamps according to the phase gating principle, wherein a semiconductor switch is connected in series with an interference suppression choke and the load circuit, and having a capacitor shunted across the semiconductor switch and the interference suppression choke.
The known brightness control devices of this general type, which can be operated manually, have a disconnect switch, by which the circuit arrangement can be separated from the power line.
Brightness control devices which are designed as remote-controlled switches and are switched remotely by means of a high frequency transmitter, using low-voltage lines for transmitting transmitting frequencies are on the other hand continuously connected to the line. In the latter case, the radio interference suppression components of these brightness control devices, consisting of a choke and a capacitor, are continuously connected to the line, and due to the resistance of incandescent bulbs which have low resistance in the "off" condition, the transmitting voltage is heavily attenuated by the capacitor.
Thereby, the number of brightness control devices which can maximally be connected within a remote-control system is greatly limited. Within such a system, the a transmitter which can operate, for instance, 256 switching points, at most 16 brightness control devices can therefore be connected. In many cases, however, a larger number of brightness control devices must be able to be connected. Since the transmitter voltage within a system must not fall below the response threshold, the arrangement of brightness control devices is limited due to the described conditions.
In order to overcome this problem, it has been attempted to design the radio interference suppression circuit in such a way that a capacitor is used which has substantially less capacitance, for instance, only about 30% of that customary capacitance, but using instead a radio interference suppression choke with more coil turns. The suppression circuit values that were required were obtained thereby, but the radio interference suppression choke was made more expensive due to both the larger number of turns and the additional material required as well as the increased manufacturing costs. In addition, a problem of greater temperature rise in the coil arose, so that the overall size of the entire circuit was adversely affected thereby.
Finally, by this measure it was not achieved to operate a number greater than maximally 16 brightness control devices within a system.
It is an object of the invention to increase the number of remotely controllable brightness control devices in a remote-controlled system with carrier-frequency utilization of low-voltage lines without heavily loading the high-frequency transmitting voltage.
According to the invention, the problem is solved by the provision that the attenuation of the radio interference suppression components, is cancelled in devices using high-frequency utilization of low-voltage lines, if the semiconductor switch does not conduct, by arranging a further choke in the load circuit. Because of this arrangement, the series circuit of choke and capacitor becomes high-impedance in the "off" condition. Thus, the heavy loading of the high-frequency transmitting voltage, on the low-voltage line is cancelled.
The invention further includes a ferrite core with only few coil turns as the further choke. Due to the fact that the ferrite core has the effect of quickly saturating the choke when current flows, it is achieved that the further choke loses its detrimental effect on the radio interference suppression circuit when the remote-controlled brightness control device is switched on, and thereby, effective radio interference suppression is achieved in the switched-on condition.
The circuit arrangement according to the invention is shown in the drawing in several embodiment examples, where
FIG. 1 shows a schematic circuit diagram, of
REFERENCES:
patent: 3525900 (1970-08-01), Skirvin et al.
patent: 3886405 (1975-05-01), Kubo
patent: 3909623 (1975-09-01), Wagner
patent: 4383203 (1983-05-01), Stanley
patent: 4394631 (1983-07-01), Paulic
patent: 4410839 (1983-10-01), Dobkin
patent: 4490625 (1984-12-01), Dilly
patent: 4491903 (1985-01-01), Montague
Brown Boveri & Cie AG
Chatmon Saxfield
Greenberg Laurence A.
Lerner Herbert L.
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