Title:
MANUALLY OPERATED SWITCH
United States Patent 3811054


Abstract:
The invention relates to a manually operated switch, suited for connection between a lamp load and a supply circuit in a lighting installation for alternating current and comprising a semiconducting rectifier with a gate electrode.



Inventors:
Wern, Carl Rune (115 38, Stockholm, SW)
Wern, George Herman (115 38, Stockholm, SW)
Wern, Lars Ake (115 38, Stockholm, SW)
Application Number:
05/360410
Publication Date:
05/14/1974
Filing Date:
05/15/1973
Assignee:
WERN C,SW
WERN L,SW
WERN G,SW
Primary Class:
Other Classes:
307/652, 315/291, 315/362, 327/438, 327/517, 340/332, 340/562
International Classes:
H02G3/00; H02M5/257; H03K17/96; H05B39/08; (IPC1-7): H03K17/00
Field of Search:
307/252H,252UA 328
View Patent Images:
US Patent References:
3743865PROXIMITY SWITCH1973-07-03Riechmann
3666988TOUCH SENSITIVE POWER CONTROL CIRCUIT1972-05-30Bellis
3648076CAPACITANCE-RESPONSIVE CONTROL SYSTEM1972-03-07Lester



Primary Examiner:
Rolinec, Rudolph V.
Assistant Examiner:
Davis B. P.
Attorney, Agent or Firm:
Straugh, Nolan, Neale, Nies & Kurz
Claims:
1. Manually operated switch, suited for connection between a lamp load and a supply circuit in a lighting installation for alternating current and comprising a semiconducting rectifier with a gate electrode, a counting circuit with a forward stepping input and a digital control output connected to said gate electrode of said semiconducting rectifier for controlling the conduction of the latter in dependence on the condition of activation of said digital control output as determined by that position to which the counting circuit is stepped, and a control pulse shaping circuit having a first and a second input terminal for connection to a first terminal via a manually controllable external capacitative reactance and to a second terminal respectively of said supply circuit and having an output pair of terminals connected to said forward stepping input of said counting circuit, said control pulse shaping circuit including a cascade connection of a clipper stage and a pulse counting stage for generating a control pulse for forward stepping of said counting circuit in dependence on that a temporary reduction of said external capacitative reactance has brought a predetermined number of pulses under subsequent periods of said

2. Manually operated switch according to claim 1 wherein said clipper stage in said control pulse shaping circuit comprises a peak value detector and an adding circuit with a first pair of input terminals connected to said input terminals of said control pulse shaping circuit and with a second

3. Manually operated switch according to claim 1 wherein a trigger pulse generating circuit has a digital control input connected to said digital control output of said counting circuit and an output connected to said gate electrode of said semiconducting rectifier for supplying trigger pulses to it at a phase angle within the period of said alternating current determined by the condition of activation of said digital control output of said counting circuit.

Description:
The invention relates to a manually operated switch, suited for connection between a lamp load and a supply circuit in a lighting installation for alternating current and comprising a semiconducting rectifier with a gate electrode.

A heretofore employed method to install a manually operated switch between a lamp load and a supply circuit in a lighting installation for alternating current is to draw from the lamp load to a selected place of control an auxiliary wire of substantially the same dimensions as the supply circuit and to mount the switch on the place of control and connect it to the auxiliary wire. This method is also employed to install such manually operated switches that comprise a semiconducting rectifier with a gate electrode to enable at a negligible dissipation power a control of the power supplied to the lamp load.

In said installations the dimension of the auxiliary wire, which is determined by the permitted lamp load power and electrical security regulations, is of such a magnitude that the auxiliary wire for esthetical reasons normally is drawn in cavities in the ceilings and in the walls or in spacings within the same. The considerations in connection hereto complicate considerably the planning and installation work required for a lighting installation. Furthermore it is normal that complications arise in such cases when a change of the position of the place of control is to be made in an existing installation.

A first object with the manually operated switch according to the invention is to facilitate the planning and installation work required for a lighting installation for alternating current by reducing the dimension of the auxiliary wire that much that it can be drawn practically invisibly along ceiling and wall surfaces, and to enable the switch to be mounted together with the lamp load and the auxiliary wire to be drawn from the switch to the place of control and being left there unconnected, the control of the switch being obtained by just touching the auxiliary wire with the hand.

A second object with the invention is to enable a manual control of the light intensity in a lighting installation in for example a living room and to enable also an automatic step-down of the light intensity according to a selected time schedule in order to eliminate the hazard in that the light is cut off with no indication in advance in conventional automatic staircase and garage lighting installations.

Other objects with the invention will appear from the following part of the specification.

The characteristics of the manually operated switch of the invention will appear from the appended claims.

The invention will be explained more in detail below with reference made to the accompanying drawing where

FIG. 1 schematically shows a living room lighting installation with a manually operated switch of conventional construction,

FIG. 2 shows a living room lighting installation with a manually operated switch according to the invention,

FIG. 3 shows a block diagram over a preferred embodiment of the manually operated switch of the invention, and

FIG. 4 shows a logic diagram for the preferred embodiment of the invention according to FIG. 3.

FIG. 1 shows a living room lighting installation of a conventional type. A lamp load 1 is via a conductor joint 2 being connected partly to a supply circuit 3 and partly to an auxiliary wire 4. The auxiliary wire 4 is drawn to a selected place of control and is there connected to a manually operated switch 5 of known mechanical construction.

When the switch 5 is closed an electrical current is feeded from the supply circuit 3 through the auxiliary wire 4 to the lamp load 1. The auxiliary wire 4 has the same dimensions as the supply circuit 3 and is according to the example drawn in spacings within the ceiling and the walls of the living room as is indicated in FIG. 1.

FIG. 2 shows a living room lighting installation according to FIG. 1 modified in that aspect that the mechanical switch 5 is replaced by a manually operated switch 6 according to the invention. The switch 6 is mounted on the same place as the lamp load 1 and a thin single-conductor auxiliary wire 7 is drawn from the switch 6 along the surfaces of the ceiling and the walls of the living room to a selected place of control that is the same as in FIG. 1. The switch 6 is operated just by touching the single-conductor auxiliary wire with the hand as indicated in FIG. 2.

The dimension of the single-conductor auxiliary wire has a lower limit value that is determined only by its desired mechanical strenth. In a preferred embodiment the auxiliary wire 7 is provided with an adhesive layer so that it sticks to the surface on which it is mounted. The auxiliary wire 7 can eventually be given the form of a metallized adhesive tape.

FIG. 3 shows a block diagram over a preferred embodiment of the manually-operated switch according to the invention, the switch being shown connected between a lamp load 1 and a supply circuit 2 in a lighting installation for alternating current. The switch according to the invention comprises a semiconducting rectifier 3 of the type that is called TRIAC and has a gate electrode and is connected in series with the lamp load 1 and the supply circuit 2, a trigger pulse generating circuit 4 that has a digital control input and an output connected to the gate electrode of the semiconducting rectifier 3 to supply trigger pulses to the latter at a phase angle within the period of said alternating current determined by the condition of activation of the digital control input, a counting circuit 5 that has a forward stepping input and a control output connected to the control input of the trigger pulse generating circuit 4 so that said condition of activation is determined by that position to which the counting circuit 5 is stepped, and a control pulse shaping circuit 6 that has a first and a second input terminal connected to a first terminal 20 via a manually controllable external capacitative reactance and to a second terminal 21 respectively of the supply circuit 2, and that also has an output terminal pair that is connected to said forward stepping input of the counting circuit 5.

The control pulse shaping circuit 6 comprises a cascade connection of a clipper stage 61 and a pulse counting stage 62 between its input and output terminals to generate a control pulse for forward stepping of the counting circuit 5 in dependence on that a temporary reduction of said external capacitative reactance has brought a predetermined number of pulses under subsequent periods of said alternating current to be supplied from the clipper stage 61.

The manually-operated switch according to the invention comprises further in its preferred embodiment a second counting circuit 7 to accomplish in accord to a selected time schedule an automatically running reduction of the power that is supplied by the semidonducting rectifier 3 to the lamp load 1 with start from a maximum value initiated manually. The counting circuit 7 has a forward stepping input connected to the supply circuit 2 via an AND-gate 8, the terminal 21 of the supply circuit 2 being signal earth and the terminal 20 of the same supply circuit 2, which according to the example is a zero terminal and thus is earthed in conventional manner, constituting the signal carrying terminal.

The AND-gate 8 has a control input connected to a second control output of the counting circuit 5 and is inhibited by the latter when it is stepped to a rest position corresponding to that no trigger pulses are supplied from the output of the trigger pulse generating circuit 4 to the semiconducting rectifier 3 so that no power is supplied to the lamp load 1. According to the example, the counting circuit 5 has four counting positions including the rest position which counting positions upon a successive forward stepping of the counting circuit 5 provide that full power, medium power, low power and zero power respectively is supplied to the lamp load 1.

It is now assumed that the counting circuit 5 was stepped to its rest position when a control pulse is generated on the output terminal pair of the pulse shaping circuit 6 as a consequence of a manually provided temporary reduction of said reactance between said first input terminal of the control pulse shaping circuit 6 and the earthed terminal 20 of the supply circuit 2. The control pulse is supplied via an OR-gate 9 to the forward stepping input of the counting circuit 5 and steps the latter forward so that the lamp load 1 will be supplied with full power. The inhibition of the AND-gate 8 is then terminated and the counting circuit 7 starts to count a predetermined number of cycles of the alternating current of the supply circuit 2. When the counting process is completed a pulse is generated on an output of the counting circuit 7 which pulse is supplied via an OR-gate 9 to the forward stepping input of the counting circuit 5 with the result that the lamp load 1 now will be provided with only medium power. After two more completed counting processes of the counting circuit 7 the counting circuit 5 is brought back to its rest position and the counting process is terminated through that the AND-gate 8 is inhibited.

According to the example the counting circuit 5 comprises a binary circuit 51 consisting of two flip-flops and further two decoding circuits 52 and 53 that are connected between the flip-flops of the binary circuit 51 and said first and second control output respectively of the counting circuit 5.

FIG. 4 shows a logic diagram for the preferred embodiment of the manually operated switch of the invention as shown in FIG. 3. The switch is shown connected between a lamp load 1 and a supply circuit 2. The supply circuit 2 has a first terminal 2a which is a zero terminal and is earthed in conventional manner and a second terminal 2b which is signal earth in the logic diagram. According to the example an alternating current with an effective value of 220 volts and a frequency of 50 Hz exists between the terminals 2a and 2b of the supply circuit 2.

The switch of the invention is provided with a single conductor auxiliary wire 3 which is touched with the hand when the switch is to be operated. As a consequence of the touch a capacitance 4 existing between the auxiliary wire 3 and earth is shunted with a capacitance 5 between the hand and earth so that a reduction of the capacitative reactance between the auxiliary wire 3 and earth is provided.

The auxiliary wire 3 is connected to a signal input of a clipper stage 6 the signal earth of which is constituted by the terminal 2b of the supply circuit 2. Between the signal input terminal and signal earth of the clipper stage 6 an alternating voltage is obtained the amplitude of which depends on the relationship between the input impedance of the clipper stage 6 and the capacitative reactance between the auxiliary wire 3 and earth. The input impedance of the clipper stage 6 is determined by means of a shunt resistor 7 and a series resistor 8 to be substantially resistive and to have a value considerably lowerer than the capacitative reactance between the auxiliary wire 3 and earth, the purpose of the series resistor 8 being to limit the maximum value of the current obtained through the auxiliary wire 3 when it is connected to earth to a value that is not dangerous for the human body and can be kept well below the threshold of tactile perception.

The clipper stage 6 comprises an amplifier that is provided with a so-called Darlington input stage and has three transistors 9, 10 and 11, three resistors 12, 13 and 14 and an isolation diode 15, a top value detector consisting of a rectifying diode 16 and a capacitor 17, and an adding circuit comprising two resistors 18 and 19 by means of which the Darlington input stage of the amplifier is connected partly to the capacitor 17 of the top value detector and partly to the shunt resistor 7 at the input. The rectifying diode 16 is so polarized that the amplifier normally is kept blocked by the output voltage of the capacitor 17. Upon a temporary increased amplitude of the alternating voltage over the shunt resistor 7 as a consequence of a temporary reduction of the capacitative reactance between the auxiliary wire 3 and earth provided by touching the auxiliary wire 3 with the hand, the amplifier is brought to conduct so that a number of pulses under subsequent periods of the alternating current is supplied from the amplifier to the output of the clipper stage 6 until the capacitor 17 has been charged sufficiently to block the amplifier again.

The clipper stage 6 is connected to a pulse counting stage 20 that comprises a counting circuit consisting of four cascade-coupled flip-flops 21, 22, 23 and 24, a NOR-gate 25 that is connected to the forward stepping input of the counting circuit and that has an inhibiting input connected to the output of the counting circuit, a reference pulse generating circuit that has two inverting gates 26 and 27 that are cascade-connected via a differentiator link consisting of a series capacitor 28 and a shunt resistor 29 and that are feeded via a resistive voltage divider of a series resistor 30 and a shunt resistor 31 with an alternating voltage derived from the alternating voltage of the supply circuit 2, and a logic circuit constituted by two NOR-gates 32 and 33 that has a first input connected to the output of the reference pulse generating circuit and a second input connected to the output of the clipper stage 6 and that has a first and a second output that is connected to the NOR-gate 25 and to a reset input of the flip-flops 21, 22, 23 and 24 respectively, the output pulses of the reference pulse generating circuit appearing on the first and second output respectively of the logic circuit in dependence on whether the pulses arrive from the output of the clipper stage or not.

The necessary coincidence in time between the pulses from the clipper stage 6 and the pulses from the reference pulse generating circuit is obtained thereby that the latter pulses are generated in such a manner that they constitute zero level indicating pulses for the alternating voltage of the supply circuit 2 and thus can be brought to occur within the pulse time of the former pulses which constitute top value indicating pulses for an alternating voltage that is phase-shifted approximately 90° in relation to the alternating voltage of the supply circuit 2 as a consequence of the low value of the resistive input impedance of the clipper stage 6 as compared with the capacitative reactance between the auxiliary wire 3 and earth.

The last flip-flop 24 of the counting circuit is set after that eight pulses have arrived from the clipper stage 6 and the forward stepping input of the counting circuit is then blocked by inhibiting the NOR-gate 25. As a frequency of 50 Hz is assumed for the alternating voltage of the supply circuit 2 it is necessary that the auxiliary wire 3 is touched under a time interval of at least 8/50 seconds, equal to 160 milliseconds, in order to set the flip-flop 24.

Upon the setting of the flip-flop 24 a control pulse is supplied from the pulse counting stage 20 via a NOR-gate 34 to a forward stepping input of a counting circuit 35 consisting of two D-flip-flops 36 and 37 and four NOR-gates 38, 39, 40 and 41 the respective outputs of which are activated in their mentioned sequential order upon forward stepping of the counting circuit 35. The outputs of the NOR-gates 39, 40 and 41 are connected to a respective input terminal of a digital input of a power regulator unit 42 that comprises a semiconducting rectifier 43 of the type that is called TRIAC and has a gate electrode and is connected in series with the lamp load 1 and the supply circuit 2, a noise suppresion circuit that is connected between the anode and the cathode of the semiconducting rectifier 43 and consists of a resistor 44 in a series connection with a capacitor 45, and a trigger pulse generating circuit that comprises a trigger diode 46 of the type that is called DIAC that is connected to the gate electrode of the semiconducting rectifier 43 and a phase-shifting network with an input connected to the anode and the cathode of the semiconducting rectifier 43 and an output of which is connected to the trigger diode 46 and drives the latter to generate trigger pulses for the semiconducting rectifier 43. The phase-shifting network consists of two shunt capacitors 47 and 48 and two series resistors 49 and 50, the latter resistor being photoconductive and in combination with a light source 51 forming an optical coupler 52 which is connected to said input terminals of the digital input of the power regulator unit 42 via a driver transistor 53 and three branches to the base electrode of the latter each having a respective adjustable resistor 54, 55 and 56 and a respective isolation diode 57, 58 and 59.

The adjustable resistors 57, 58 and 59 are according to the example set to such values that a successive forward stepping of the counting circuit 35 will provide such an operation of the optical coupler 52 and the trigger diode 46 that the lamp load 1 will in sequential order be supplied with full power, medium power, low power and finally zero power. In order to obtain an automatically running forward stepping of the counting circuit 35 and thereby an automatic step-down of the power that is supplied to the lamp load 1 a counting circuit 60 is arranged a forward stepping input of which is connected via a NOR-gate 61 to said reference pulse generating circuit in the pulse counting stage 20 to be stepped by its pulses. The NOR-gate 61 has a control input connected to the output of the NOR-gate 38 and is inhibited by the latter when the counting circuit 35 is stepped to its rest position.

It is now assumed that the counting circuit 35 has left its rest position as a consequence of that the auxiliary wire 3 has been touched. The counting circuit 60 starts then a counting process that terminates with the generation of a control pulse on an output connected to the NOR-gate 34 to step the counting circuit 35. According to the example the counting circuit 60 has 12 flip-flops in a cascade connection and as a frequency of 50 Hz is assumed for the alternating voltage of the supply circuit 2 a total lighting time interval of approximately four minutes is provided for the lamp load 1 corresponding to three subsequently completed counting processes for the counting circuit 60 before the counting circuit 35 is brought back to its rest position. The return of the counting circuit 35 to its rest position provides besides inhibiting the NOR-gate 61 that the counting circuit 60 is reset through a rest input to its 12 flip-flops connected to an output of the NOR-gate 38.

The clipper stage 6, the pulse counting stage 20, the counting circuit 35, the driver transister 53 in the power regulator unit 42 and the counting circuit 60 are all energized by a voltage of +5 volts according to the example from a power supply unit 62 comprising a transformer 63, a rectifier bridge 64, a charge capacitor 65, and a series regulator consisting of a series transistor 66, a control transistor 67, a zener diode 68, a potentiometer 69, a second charge capacitor 70 and two circuit resistors 71 and 72. The power supply unit 62 the construction of which is conventional is provided with a tap on the secondary winding of the transformer 63 to supply the earlier mentioned driving voltage for the reference pulse generating circuit in the pulse counting circuit 20.

The manually operated switch of the invention is suitably given a compact design by manufacturing all the included semiconducting components in just a few substrates optimized for their respective functions and by using current-saving circuits and components so that the transformer 63 of the power supply unit 62 can be replaced by a capacitor voltage divider for reducing the alternating voltage of the supply circuit 2 to such a level that it after rectification can energize the semiconducting components.

The described embodiment of the manually operated switch of the invention can be modified in many ways within the scope of the invention. It is for example suitable that the counting circuit 35 in FIG. 4 is provided with a reset input and that a monostable flip-flop is connected to that reset input and is activated when the alternating voltage of the supply circuit 2 appears again after a temporary power failure in order to bring the counting circuit 35 to its rest position corresponding to that zero power is supplied to the lamp load. The activation of the monostable flip-flop can be accomplished via a differentiator circuit the input of which is connected to the energizing voltage +5 volts from the power supply unit 62.