CA1113539A - Touch control switch - Google Patents
Touch control switchInfo
- Publication number
- CA1113539A CA1113539A CA307,691A CA307691A CA1113539A CA 1113539 A CA1113539 A CA 1113539A CA 307691 A CA307691 A CA 307691A CA 1113539 A CA1113539 A CA 1113539A
- Authority
- CA
- Canada
- Prior art keywords
- circuit
- input
- pulse generating
- generating circuit
- control switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT
A touch control switch suitable for connection between a lamp load and a supply circuit in a lighting installation for alternating current and comprising a semiconductor switching element with a gate electrode, a counting circuit with a forward stepping input and a digital control output connected to the gate electrode of the semiconductor switching element via a trigger pulse generating circuit for controlling the conduction of the semiconductor switch-ing element in dependence on the condition of activation of the digital control output, and a control pulse shaping circuit having an output connected to the forward stepping input of the counting circuit and a first and second input terminal for connection to a first and second, respectively terminal of the supply circuit via a touch sensitive impedance. The trigger pulse generating circuit comprises an edge-triggered mono-pulse generating circuit that has a first input for leading edge triggering and a second input for trailing edge triggering jointly connected to the supply circuit.
A touch control switch suitable for connection between a lamp load and a supply circuit in a lighting installation for alternating current and comprising a semiconductor switching element with a gate electrode, a counting circuit with a forward stepping input and a digital control output connected to the gate electrode of the semiconductor switching element via a trigger pulse generating circuit for controlling the conduction of the semiconductor switch-ing element in dependence on the condition of activation of the digital control output, and a control pulse shaping circuit having an output connected to the forward stepping input of the counting circuit and a first and second input terminal for connection to a first and second, respectively terminal of the supply circuit via a touch sensitive impedance. The trigger pulse generating circuit comprises an edge-triggered mono-pulse generating circuit that has a first input for leading edge triggering and a second input for trailing edge triggering jointly connected to the supply circuit.
Description
~` 1113S39 - TO~CH C_NTROL SWITCH
The invention relates to a touch control switch suit-able for connection between a lamp load and a supply circuit - in a lighting installation for alternating current and com-prising a semiconductor switching element with a gate electrode, a counting circuit with a forward stepping input and a digital control output connected to the gate electrode of the semiconductor switching element via a trigger pulse . generating circuit for controlling the conduction of the .semiconductor switching element in dependence on the condition of activation of the digital control output, and a control pulse shaping circuit having.an output connected to the forward .stepping input of the counting.circuit and a first and second .
input terminal for connection to a first and second, respectively terminal of the supply circuit via a touch . .-sensitive impedance. --. A touch control switch of the type defined above is described in the U.S. Patent No. 3,811,054. A large scale use of that touch control switch is complicated thereby that 20 it has a high non-load power dissipation, that it cannot cope .-with reactive loads such as fluorescent lamps, and that many of its components are not possible to integrate in a monolithic form.
.. The present invention is characterized in that the trigger pulse generating circuit comprises an edge-triggered . mono-pulse generating-circuit that has a first input for leading edge triggering and a second input for trailing edge . triggering jointly connected to the supply circuit.
. . ~ . . ~
The touch control switch according to the invention has a very low non-load power dissipation. It can cope with reactive loads and is possible to integrate in a monolithic form with the exception of only a few components.
rrhe invention, the characteristics of which appear from the appended claims, will now be explained more in detail with reference made to the accompanying ~rawing wherein Fig. 1 is a block diagram of a pre-ferred embodiment of the touch control switch according to the in-vention and Fig. 2 is a circuit diagram of a touch detecting clipper stage included in the block diagram in Yig. 1.
Fig. 1 shows a touch control switch the principal function of which is with the exception of the improvements accoding to the invention to be described below explained in detail in the U.S. Patent No~
3,811,084 and which is interconnected between a lamp load 1 and a supply circuit 2 in a lighting installation for alternating current and comprises a semiconductor switching element 3 with a gate elect-rode. The touch control switch comprises further a counting circuit 4 with a forward stepping input and a digital control output connected to the gate electrode of the semiconductor switching element 3 via a triyger pulse generating circuit 5 for controlling the conduction of the semiconductor switching element 3 in dependence on the condition of activation of the digital control output, and a control pulse shap-ing circuit 6 having an output connected to the forward stepping input of the counting circuit 4 and a first and second input terminal with a connection to a first terminal 7 and to a second terminal 8, re-spectively of the supply circuit 2 via a touch sensitive external capacitative reactance.
The control pulse shaping circuit 6 comprises a touch detecting clip-per stage 9 in which, a~ it will be described later on in connection with Fig. 2, a peak value detector and an adding circuit are included with a respective input connected to the input of the control pulse shaping circuit 6, a second input of the adding circuit being connect-ed to the output of the peak value detector.
The output of the control pulse shaping circuit 6 is connected to the output of the clipper stage 9 via a pulse counting circuit 10 and an ~D-circuit 11 with an inhibiting input connected to the supply cir-cuit 2 via a second clipper stage 12 given the same internal structure ~ :lil3~;~9 as the clipper stage 9 and having the purpose to inhibit a malfunction caused by false control pulses occurring as a consequence of a voltage rise on the supply circuit 2 upon, for example, a disconnection of electric ovens.
In the preferred embodiment of the invention, the touch control switch has the trigger pulse generating circuit 5 arranged to comprise a mono-stable flip-flop 13 with a first input for leading edge trigger-ing and a second input for trailing edge triggering jointly connected to the supply circuit 2 in shunt with the semiconductor switching ele-/O ment 3 and in series with the lamp load 1 in order to be controlledby the current through the latter that can be an incandescent lamp or a fluorescent lamp with a phase compensating capacitor. The connect-tion of the trailing edge triggering input of the mono-stable flip-flop 13 to the supply circuit 2 is arranged via a resistive voltage divider in which a shunt link is connected to a biasing potential in order to provide a symmetrical triggering for the positive and nega-tive half periods of the alternating current through the lamp load 1.
According to the example, the mono-stable flip-flop is of the C-MOS
type, the biasing potential is the supply voltage VDD -~ the flip-ao flop and the resistance of the shunt link is substantially half the value of the resistance of the series lin~ in the voltage divider.
The trigger pulse generating circuit 5 comprises further an AND-cir-cuit 14 that has a first input connected to the output of the mono-stable flip-flop 13 and a second input connected to the digital con-trol output of the counting circuit 4 and that has an output connected to the gate electrode of the semiconductor element 3 via a driver stage 15. The latter supplies a trigger pulse when a predetermined voltage has been built up over the semiconductor element 3 that accord-ing to the example is a TRIAC. The duration of the trigger pulse can ~a be very short as compared with the duration of the half period of the alternating current, for example 100 /us and 10 ms, respectively, im-plying that the non-load power dissipation of the touch control switch can be brought down to a very low value since the demand on its supply of current to the control circuitry pertaining to the semiconductor element 3 will be modest.
The supply of current to the control circuitry in the touch control switch is, according to the example, arranged via a rectifier diode 16, a smoothing capacitor 17, a voltage dropping resistor 18 for the connection to the supply circuit 2 and a voltage limiting zener diode 113S~9 19. The non-load power dissipation of the touch control switch is substantlally equal to the power dissipation of the voltage droppinq resistor 18 and can in the preferred embodiment of the invention be kept below 1~2 watt at 240 VAC and driving a TRIAC capable of supply-ing 2.5 A.
Fig. 2 is a circuit diagram over the clipper stage 9 in Fig. 1 in an embodiment suited for a monolithic integration together with the above described trigger pulse generatinq circuit 5 and the majority of the other elements of the touch control switch. Two voltage comparators /O 20 and 21 have a respective signal input jointly connected to a con-trol input 22 of the clipper stage 9 via a protection circuit consist-ing of a resistor 23 and a capacitor 24. They have further a respect-ive reference input jointly connected to the output of the one compa-rator 20 via a peak value detector consisting of a rectifier diode 25, a capacitor 26, a charge resistor 27 and a discharge resistor 28 keyed by a switching diode 29 as it will be explained more in detail below, the connection of the s$gnal input of the other comparator 21 to the control input 22 being arranged via a resistive voltage divider con-sisting of a series resistor 30 and a shunt resistor 31. The voltage O comparator 21 constitutes the above-mentioned adding circult and ha~
an output 32 with a current-feeding resistor 33 connected to the output of the clipper stage.
The sensitivity of the touch detecting clipper stage 9 is inversely proportional to the attenuation in the above-mentiomed resistive volt-aqe divider which can with a maintained margin to a generation of false control pulses be reduced in an inverse proportion to an in-crease of the time constants for charge and discharge in the above-mentioned peak value detector. In the latter, the charge time constant must in any case be considerably greater than the period time of the ~k~ alternating current in the supply circuit 2. The resistance of the discharge resistor 28 can, however, be considerably smaller than the resistance of the charge resistor 27 thanks to the fact that the form-er resistor 28 ls keyed by the switching diode 29 that is arranged to conduct only during a very short time interval of the period of the alternating current in the supply circuit 2 corresponding to the dura-tion of the trigger pulse for the negative half period applied to the semiconductor element 3. This is accomplished thereby that the switch-ing diode 29 is connected to the output of an AND-circuit 34 which has a signal input 35 arranged to be connected to the output of the mono-3r~ 3 stable flip-flop 13 in Fig. 1 and an inhibiting input 36 arranged to be connected to the tralllng edge trlggerinq lnput of the fllp-flop 13.
The clrcuit structure of the clipper stage in Fig. 2 can be modlfied thereby that the rectifier diode 25 and the switching dlode 29 are re-placed by analog MOS-gates with low leakage currents. In addition, the series resistor 30 can possibly be replaced by a direct wire connect-ion and a negative biasing of thè signal input of the voltage compara-tor 21 relatively its reference input.
The function of the clipper stage in Fig. 2 corresponds to the function 1~ of a clipper stage described in the above-mentloned U.S. Patent No.
3~811,054 but works with a lower signal volta~e and with larger tole-rances in the circuit resistors, which makes it suited for a monollthic ntegration. It is essential that variations in the external capacit-ance on the input of the touch detecting clipper stage 9 influences the phase position of the control pulses supplied from this only to a small extent in order to insure a correct signal processing in the AND-circuit 11 and in the pulse counting stage 10. This is accomplished by selecting the resistance of all the resistors 23, 30 and 31 con-siderably lower than the reactance of the capacitor 24 the capacitance of which in its turn is selected substantially equal to the maximum external capacitance, according to the example 500 pF. In addition, the input of the clipper stage 9 can be provided with a shunt circuit with a variable attenuation produced, for example, by means of a field effect transistor controlled by the voltage over the capacitor 26 of the peak value detector in a known manner described in Electronics, Vol. 50, No. 7, pp. 107. A constant ratio between a varying external series reactance and a shunt resistance varying proportionally there-to in the input circuitry of the clipper stage is then obtained and results in that the phase position of the control pulses supplied from ~k~ this is malntained constant relatively the phase of the alternating current in the supply current 2 which makes it possible for the AND-circuit 11 andthe clipper stage 12 to increase the margin in inhibit-ing false control pulses produced as a consequence of voltage transi-ents in the supply circuit 2.
The invention relates to a touch control switch suit-able for connection between a lamp load and a supply circuit - in a lighting installation for alternating current and com-prising a semiconductor switching element with a gate electrode, a counting circuit with a forward stepping input and a digital control output connected to the gate electrode of the semiconductor switching element via a trigger pulse . generating circuit for controlling the conduction of the .semiconductor switching element in dependence on the condition of activation of the digital control output, and a control pulse shaping circuit having.an output connected to the forward .stepping input of the counting.circuit and a first and second .
input terminal for connection to a first and second, respectively terminal of the supply circuit via a touch . .-sensitive impedance. --. A touch control switch of the type defined above is described in the U.S. Patent No. 3,811,054. A large scale use of that touch control switch is complicated thereby that 20 it has a high non-load power dissipation, that it cannot cope .-with reactive loads such as fluorescent lamps, and that many of its components are not possible to integrate in a monolithic form.
.. The present invention is characterized in that the trigger pulse generating circuit comprises an edge-triggered . mono-pulse generating-circuit that has a first input for leading edge triggering and a second input for trailing edge . triggering jointly connected to the supply circuit.
. . ~ . . ~
The touch control switch according to the invention has a very low non-load power dissipation. It can cope with reactive loads and is possible to integrate in a monolithic form with the exception of only a few components.
rrhe invention, the characteristics of which appear from the appended claims, will now be explained more in detail with reference made to the accompanying ~rawing wherein Fig. 1 is a block diagram of a pre-ferred embodiment of the touch control switch according to the in-vention and Fig. 2 is a circuit diagram of a touch detecting clipper stage included in the block diagram in Yig. 1.
Fig. 1 shows a touch control switch the principal function of which is with the exception of the improvements accoding to the invention to be described below explained in detail in the U.S. Patent No~
3,811,084 and which is interconnected between a lamp load 1 and a supply circuit 2 in a lighting installation for alternating current and comprises a semiconductor switching element 3 with a gate elect-rode. The touch control switch comprises further a counting circuit 4 with a forward stepping input and a digital control output connected to the gate electrode of the semiconductor switching element 3 via a triyger pulse generating circuit 5 for controlling the conduction of the semiconductor switching element 3 in dependence on the condition of activation of the digital control output, and a control pulse shap-ing circuit 6 having an output connected to the forward stepping input of the counting circuit 4 and a first and second input terminal with a connection to a first terminal 7 and to a second terminal 8, re-spectively of the supply circuit 2 via a touch sensitive external capacitative reactance.
The control pulse shaping circuit 6 comprises a touch detecting clip-per stage 9 in which, a~ it will be described later on in connection with Fig. 2, a peak value detector and an adding circuit are included with a respective input connected to the input of the control pulse shaping circuit 6, a second input of the adding circuit being connect-ed to the output of the peak value detector.
The output of the control pulse shaping circuit 6 is connected to the output of the clipper stage 9 via a pulse counting circuit 10 and an ~D-circuit 11 with an inhibiting input connected to the supply cir-cuit 2 via a second clipper stage 12 given the same internal structure ~ :lil3~;~9 as the clipper stage 9 and having the purpose to inhibit a malfunction caused by false control pulses occurring as a consequence of a voltage rise on the supply circuit 2 upon, for example, a disconnection of electric ovens.
In the preferred embodiment of the invention, the touch control switch has the trigger pulse generating circuit 5 arranged to comprise a mono-stable flip-flop 13 with a first input for leading edge trigger-ing and a second input for trailing edge triggering jointly connected to the supply circuit 2 in shunt with the semiconductor switching ele-/O ment 3 and in series with the lamp load 1 in order to be controlledby the current through the latter that can be an incandescent lamp or a fluorescent lamp with a phase compensating capacitor. The connect-tion of the trailing edge triggering input of the mono-stable flip-flop 13 to the supply circuit 2 is arranged via a resistive voltage divider in which a shunt link is connected to a biasing potential in order to provide a symmetrical triggering for the positive and nega-tive half periods of the alternating current through the lamp load 1.
According to the example, the mono-stable flip-flop is of the C-MOS
type, the biasing potential is the supply voltage VDD -~ the flip-ao flop and the resistance of the shunt link is substantially half the value of the resistance of the series lin~ in the voltage divider.
The trigger pulse generating circuit 5 comprises further an AND-cir-cuit 14 that has a first input connected to the output of the mono-stable flip-flop 13 and a second input connected to the digital con-trol output of the counting circuit 4 and that has an output connected to the gate electrode of the semiconductor element 3 via a driver stage 15. The latter supplies a trigger pulse when a predetermined voltage has been built up over the semiconductor element 3 that accord-ing to the example is a TRIAC. The duration of the trigger pulse can ~a be very short as compared with the duration of the half period of the alternating current, for example 100 /us and 10 ms, respectively, im-plying that the non-load power dissipation of the touch control switch can be brought down to a very low value since the demand on its supply of current to the control circuitry pertaining to the semiconductor element 3 will be modest.
The supply of current to the control circuitry in the touch control switch is, according to the example, arranged via a rectifier diode 16, a smoothing capacitor 17, a voltage dropping resistor 18 for the connection to the supply circuit 2 and a voltage limiting zener diode 113S~9 19. The non-load power dissipation of the touch control switch is substantlally equal to the power dissipation of the voltage droppinq resistor 18 and can in the preferred embodiment of the invention be kept below 1~2 watt at 240 VAC and driving a TRIAC capable of supply-ing 2.5 A.
Fig. 2 is a circuit diagram over the clipper stage 9 in Fig. 1 in an embodiment suited for a monolithic integration together with the above described trigger pulse generatinq circuit 5 and the majority of the other elements of the touch control switch. Two voltage comparators /O 20 and 21 have a respective signal input jointly connected to a con-trol input 22 of the clipper stage 9 via a protection circuit consist-ing of a resistor 23 and a capacitor 24. They have further a respect-ive reference input jointly connected to the output of the one compa-rator 20 via a peak value detector consisting of a rectifier diode 25, a capacitor 26, a charge resistor 27 and a discharge resistor 28 keyed by a switching diode 29 as it will be explained more in detail below, the connection of the s$gnal input of the other comparator 21 to the control input 22 being arranged via a resistive voltage divider con-sisting of a series resistor 30 and a shunt resistor 31. The voltage O comparator 21 constitutes the above-mentioned adding circult and ha~
an output 32 with a current-feeding resistor 33 connected to the output of the clipper stage.
The sensitivity of the touch detecting clipper stage 9 is inversely proportional to the attenuation in the above-mentiomed resistive volt-aqe divider which can with a maintained margin to a generation of false control pulses be reduced in an inverse proportion to an in-crease of the time constants for charge and discharge in the above-mentioned peak value detector. In the latter, the charge time constant must in any case be considerably greater than the period time of the ~k~ alternating current in the supply circuit 2. The resistance of the discharge resistor 28 can, however, be considerably smaller than the resistance of the charge resistor 27 thanks to the fact that the form-er resistor 28 ls keyed by the switching diode 29 that is arranged to conduct only during a very short time interval of the period of the alternating current in the supply circuit 2 corresponding to the dura-tion of the trigger pulse for the negative half period applied to the semiconductor element 3. This is accomplished thereby that the switch-ing diode 29 is connected to the output of an AND-circuit 34 which has a signal input 35 arranged to be connected to the output of the mono-3r~ 3 stable flip-flop 13 in Fig. 1 and an inhibiting input 36 arranged to be connected to the tralllng edge trlggerinq lnput of the fllp-flop 13.
The clrcuit structure of the clipper stage in Fig. 2 can be modlfied thereby that the rectifier diode 25 and the switching dlode 29 are re-placed by analog MOS-gates with low leakage currents. In addition, the series resistor 30 can possibly be replaced by a direct wire connect-ion and a negative biasing of thè signal input of the voltage compara-tor 21 relatively its reference input.
The function of the clipper stage in Fig. 2 corresponds to the function 1~ of a clipper stage described in the above-mentloned U.S. Patent No.
3~811,054 but works with a lower signal volta~e and with larger tole-rances in the circuit resistors, which makes it suited for a monollthic ntegration. It is essential that variations in the external capacit-ance on the input of the touch detecting clipper stage 9 influences the phase position of the control pulses supplied from this only to a small extent in order to insure a correct signal processing in the AND-circuit 11 and in the pulse counting stage 10. This is accomplished by selecting the resistance of all the resistors 23, 30 and 31 con-siderably lower than the reactance of the capacitor 24 the capacitance of which in its turn is selected substantially equal to the maximum external capacitance, according to the example 500 pF. In addition, the input of the clipper stage 9 can be provided with a shunt circuit with a variable attenuation produced, for example, by means of a field effect transistor controlled by the voltage over the capacitor 26 of the peak value detector in a known manner described in Electronics, Vol. 50, No. 7, pp. 107. A constant ratio between a varying external series reactance and a shunt resistance varying proportionally there-to in the input circuitry of the clipper stage is then obtained and results in that the phase position of the control pulses supplied from ~k~ this is malntained constant relatively the phase of the alternating current in the supply current 2 which makes it possible for the AND-circuit 11 andthe clipper stage 12 to increase the margin in inhibit-ing false control pulses produced as a consequence of voltage transi-ents in the supply circuit 2.
Claims (4)
1. Touch control switch suitable for connection between a lamp load and a supply circuit in a lighting installation for alternating current and comprising a semiconductor switching element with a gate electrode, a counting circuit with a forward stepping input and a digital control output connected to the gate electrode of the semi-conductor switching element via a trigger pulse generating circuit for controlling the conduction of the semiconductor switching element in dependence on the condition of activation of the digital control output, and a control pulse shaping circuit having an output connected to the forward stepping input of the counting circuit and a first and second input terminal for connection to a first and second, respective-ly terminal of the supply circuit via a touch sensitive impedance, characterized in that the trigger pulse generating circuit comprises an edge-triggered mono-pulse generating circuit that has a first input for leading edge triggering and a second input for trailing edge trigg-ering jointly connected to the supply circuit.
2. Touch control switch according to claim 1, characterized in that said joint connection to the supply circuit of the inputs of the mono-pulse generating circuit is arranged in shunt with the semicon-ductor switching element and in series with the lamp load.
3. Touch control switch according to claim 1, characterized in that the mono-pulse generating circuit is a mono-stable flipflop of the C-MOS type, that the connection of its second input for trailing edge triggering to the supply circuit is arranged via a resistive voltage divider in which a shunt link is connected to the supply volt-age VDD of the flipflop, and that the resistance of the shunt link is substantially half the value of the resistance of the series link in the voltage divider in order to provide a symmetrical triggering for the positive and negative half periods of the alternating current.
4. Touch control switch according to claim 3, characterized in that an AND-circuit has a signal input connected to an output of the mono-pulse generating circuit and an inhibiting input connected to the voltage divider jointly with the second input for trailing edge triggering in the trigger pulse generating circuit, and that an out-put of the AND-circuit is arranged to key a reset link of a memory circuit of the control pulse shaping circuit.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7708952-2 | 1977-08-05 | ||
| SE7708952A SE407318B (en) | 1977-08-05 | 1977-08-05 | TOUCH-CONTROLLED POWER SWITCH |
| US885,806 | 1978-03-13 | ||
| US05/885,806 US4210822A (en) | 1977-08-05 | 1978-03-13 | Touch control switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1113539A true CA1113539A (en) | 1981-12-01 |
Family
ID=26656850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA307,691A Expired CA1113539A (en) | 1977-08-05 | 1978-07-19 | Touch control switch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1113539A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113568515A (en) * | 2021-08-04 | 2021-10-29 | 深圳市绘王动漫科技有限公司 | Electronic handwriting pen and handwriting device |
-
1978
- 1978-07-19 CA CA307,691A patent/CA1113539A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113568515A (en) * | 2021-08-04 | 2021-10-29 | 深圳市绘王动漫科技有限公司 | Electronic handwriting pen and handwriting device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |