GB2200006A - Phase-controlled thyristor circuit - Google Patents
Phase-controlled thyristor circuit Download PDFInfo
- Publication number
- GB2200006A GB2200006A GB08729611A GB8729611A GB2200006A GB 2200006 A GB2200006 A GB 2200006A GB 08729611 A GB08729611 A GB 08729611A GB 8729611 A GB8729611 A GB 8729611A GB 2200006 A GB2200006 A GB 2200006A
- Authority
- GB
- United Kingdom
- Prior art keywords
- voltage
- ramp
- control circuit
- output
- supply
- 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.)
- Withdrawn
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/13—Modifications for switching at zero crossing
- H03K17/136—Modifications for switching at zero crossing in thyristor switches
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
- H02M1/092—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices the control signals being transmitted optically
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/72—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region
- H03K17/735—Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
- H03K17/79—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar semiconductor switches with more than two PN-junctions, or more than three electrodes, or more than one electrode connected to the same conductivity region
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
- H03K17/795—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar transistors
- H03K17/7955—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar transistors using phototransistors
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
A dimmer circuit for use with a three phase supply comprises, for each phase, a ramp generator (36, 42) triggered by a zero crossing detector. The zero crossing detector includes an opto-coupler. In one arrangement, the opto-coupler has a photo-transistor (30) responsive to a pair of light emitting diodes (28) which sense the voltage of the supply. In another arrangement, the pair of light emitting diodes are replaced a single light emitting diode and a full wave rectifier. The output of this ramp generator is connected to two comparators which also receive voltages from control units. The output of each comparator is supplied to a firing pulse generator which includes an opto-triac. The firing pulse generator supplies trigger pulses to the gate of a triac connected in series with a lighting unit. <IMAGE>
Description
CONTROL CIRCUIT
This invention relates to a control circuit particularly, but not exclusively, for controlling the dimming of a lighting unit.
A previously proposed dimming circuit comprises a controlled rectifier for controlling the supply of AC current to a lighting unit, a ramp generator which is reset each time the supply crosses zero, a comparator which compares the ramp voltage with a voltage related to the current required for the lighting unit, and a firing pulse generator responsive to the comparator for firing the controlled rectifier. In such a circuit, it is necessary to provide isolation between the ramp generator and the supply. Such isolation may be provided by a transformer but the provision of a transformer is both costly and inconvenient.
It is an object of this invention to provide a new or improved control circuit in which the above mentioned problem is overcome or reduced.
According to this invention, there is provided a control circuit comprising a controlled rectifier for controlling the flow of AC current from a supply to a load, a zero crossing detector for detecting zero crossings of the supply and including an opto-coupler, a ramp generator triggered by the zero crossing detector -to generate a ramp voltage, a control voltage unit for generating an output related to the desired current required for the load, a comparator for comparing the output of the control voltage unit with the ramp voltage and generating a control signal when equality is reached, and a firing pulse generator responsive to the control signal to fire the controlled rectifier.
The provision of a zero crossing detector which includes an opto-coupler avoids the cost and inconvenience associated with a transformer.
This invention will now be described in more detail, by way of example, with reference to the drawings in which:
Figures la, Ib, and ic together form a circuit diagram of a dimming circuit embodying this invention;
Fig. 2 is a circuit diagram of a voltage generator which generates reference voltages used in the circuit of Figure 1;
Fig. 3 is a circuit diagram showing a modification to the zero crossing detector forming part of the dimming circuit of Figure 1; and
Fig. 4 is a circuit diagram showing a modification to the ramp generator forming part ofthe dimming circuit of Figure 1.
Referring to Figures la, ib, and ic, the dimming circuit is arranged for controlling the supply of current from a three phase supply to six individual lighting units. The three phases of the supply will hereinafter be referred to as the Rphase, the Y-phase and the B-phase. The circuit includes a set of terminals R, Y, 3, N and E for connection to the -R-phase, Y-phase, B-phase, neutral line and earth line of the supply. The terminals R,
Y, 3, N and E are connected together by a network of capacitors 10.
The terminals R and N are connected by a pair of lines 12, 14 to the input of a zero crossing detector 16. Specifically, lines 12 and 14 are connected by a pair of resistors 18, 20, and resistor 20 is connected across the input of a Sharp type PC 814 opto-coupler 22. The output of opto-coupler 22 is connected across a pair of lines 24, 26. Line 24 is connected through a 100 kilohm resistor 28 to a positive DC supply voltage VCC. The opto-coupler comprises a pair of light emitting diodes 28 connected in parallel with opposite polarity and a phototransistor 30.
The lines 24 and 26 are connected to a ramp generator 34. The ramp generator 34 comprises a
National Semiconductor type LM324 operational amplifier 36, whose non-inverting and inverting inputs are connected to a reference voltage V BIAS and through a resistor 40 to a reference voltage
V REF. V REF is greater than V BIAS. A capacitor 42 is connected between the inverting input and output of amplifier 36 and thus amplifier 36 is connected as an integrator. A transistor 44 is connected across capacitor 42 and the base and emitter of transistor 44 are connected to lines 24 and 26. The output of amplifier 36 is connected to a line 46 which represents the output of the ramp generator 34. Line 46 is connected to a OV line by a resistor 48.
In operation when the voltage of the Rphase of the supply is within approximately 30 of the zero crossing point, phototransistor 30 turns off, thereby turning on -transistor 44. Consequently, the output of amplifier 36 is reset to V BIAS. When the voltage of R-phase of the supply is more than 30 from the zero-crossing point, photo-transistor 30 turns on thereby turning off transistor 44.
Consequently, the output of amplifier 36 ramps negatively. The exact point at which transistor 44 turns on and turns off is determined by resistors 18, 20 and the threshold voltages of light emitting diodes 28. Because the collector and emitter of transistor 30 are connected across the base and emitter of transistor 44, the voltage excursion across the collector and emitter of transistor 30 is small and so the Miller effect associated with the transistor is negligible. Photo-transistor 30 is, in effect, controlling the supply of current to the base-emitter path of transistor 44.
The combined unit comprising the optocoupler 16 and the ramp generator 34 is indicated by a dashed line 50. The terminal Y and B are connected respectively to combined units as indicated by dashed lines 52, 54, each of which is identical to the combined unit 50. For reasons of simplicity, the circuit diagrams for unit 52, 54 are not shown. The outputs of the ramp generators in units 52, 54 are connected to lines 56, 58.
The provision of the three opto-couplers in the units 50, 52, 54 avoids providing more complex devices, such as three transformers, to isolate the ramp generators from the supply.
The control circuit includes 6 manually operated control units 61 to. 66 each of which is associated with one of the six lighting units. Each of the control units 61 to 66 may be adjusted to provide a voltage at its output indicative of the current required in the associated lighting unit.
The outputs of control units 61, 62 are connected, respectively, through resistors 68, 70 to the OV line and through resistors 72, 74 to the noninverting inputs of a pair of National Semiconductor type EM 924 operational amplifiers 76, 78. The outputs of amplifiers 76, 78 are connected through resistors 80, 82 to lines 84, 86. The inverting inputs of amplifiers 76, 78 are connected to line 46.
Each of the amplifiers 76, 78 compares the ramp voltage with the output from one of the control units 61, 62. Thus, each of the amplifers 76, 78 is arranged as a comparator.
The amplifiers 76, 78 and associated resistors form a combined comparator unit indicated by dashed line 90. The control units 63 and 64 and line 56 are connected to the inputs of a combined comparator unit 92 and the control units 65, 66 and line 58 are connected to the inputs of a combined comparator unit 94. Each of the units 92, 94 is identical to the unit 90 and, for reasons of simplicity, the circuit elements of units 92, 94 are not shown. The outputs of units 92, 94 are connected to lines 96 and 98, and 100 and 102.
The line 84 is connected to one input terminal of a Sharp type S21 MD3 opto-triac 106. The other input of opto-triac 106 is connected to the OV line. The opto-triac 106 comprises a light emitting diode connected to its two inputs, and a pair of photo silicon controlled rectifiers connected with opposite polarity across its two output terminals.
One of the outputs of opto-triac 106 is connected to the gate of a controlled rectifier in the form of a triac 108. The gate of triac 108 is connected to one of its main terminals by a resistor 110. The other output of opto-triac 106 is connected to the other main terminal of triac 108 through a current limiting resistor 112. The opto-triac 106 and resistors 110 and 112 together form a firing pulse generator 114.
A fuse 116, a choke 118 and the triac 108 are connected in series between the R-phase of the supply and a terminal 120. A pair of capacitors 122, 124 are connected in parallel across choke 118.
Choke 118 and capacitors 122, 124 together provide suppression of radio frequency interference. A lighting unit 126, which is one of the six lighting units mentioned earlier, is connected between terminal 120 and a terminal N connected to the neutral lines of the supply.
In operation, during each cycle of the ramp voltage, when the ramp voltage falls below the voltage established by control unit 61, line 84 goes high, and the firing pulse generator 114 applies a trigger pulse to triac 108, thereby causing it to conduct for the remainder of the cycle. Thus, the control unit 61 controls the on/off periods of triac 108, and the average current supplied to the lighting unit 126. The provision of resistor 110 ensures that triac 108 has a high commutation rate.
The firing pulse generator 114, the lighting unit 126 and triac 108 and associated elements together form a combined unit 130. Lines 86, 96, 98, 100, 102 are connected to combined units 132, 134, 136, 138, 140, each of which is identical to unit 130. For reasons of simplicity, the circuit elements of these units are not shown.
Referring now to Figure 2, there is shown the circuit diagram for the reference voltage generator 150. The generator 150 comprises a current limiting resistor 152 and a 2.5V band gap reference diode 154 connected between the positive supply line
VCC and the OV line. The junction of these two elements is connected to the non-inverting input of a
National Semi-Conductor type Bum324 operational amplifier 156. The output of amplifier 156 is scaled to V REP (12.07V) by a pair of feedback resistors 158, 160, and V BIAS (9.62V) is established by a voltage divider comprising resistors 162, 164.
In the zero crossing detector 16, there is likely to be a mismatch between the two light emitting diodes. This mismatch causes asymmetry in detection of the zero crossing between the two halves of each cycle of the supply. Such asymmetry may have a significant effect on the average current supplied to the lighting unit 126 at low output voltages of control unit 61. A modified zero crossing detector 170 which avoids this problem will now be described with reference to Figure 3.
In the zero crossing detector 170, the terminal R is connected through a current limiting resistor 172 to one input of a full wave rectifier 174, the other input of which is connected directly to terminal N.
A resistor 176 and a light emitting diode 178 are connected across the output of rectifier 174.
The light emitting diode 178 together with a phototransistor 180 forms an opto-coupler and the collector and emitter of photo-transistor 180 are connected to lines 24, 26.
In operation, when the voltage of the supply is within 30 of the zero crossing point, photo-transistor 180 turns off and thus operates in a similar manner to photo-transistor 30. However, by providing rectifier 174 and only a single light emitting diode 178, the problem of asymmetry is avoided. The rectifier 174 will operate at only low voltages due to the potential dividing action of resistors 172, 176 and the voltage limiting action of diode 178.
In the ramp generator 34, the slope of the ramp is determined accurately by using precision components for resistor 40 and capacitor 42. As the reference voltages V REF and V BIAS are established accurately, the final voltage at the end of each ramp cycle will normally be established accurately.
However, this accuracy will be reduced by variations in the voltage or frequency of the supply. Variation in the final voltage will cause a significant variation of the current supplied to the lighting unit at low values of the output voltage of control unit 61. A modified ramp generator 190 will now be described with reference to Figure 4 in which the need to provide precision components and variation of the final voltage with supply voltage or frequency are avoided.
The ramp generator 190 comprises an operational amplifier 192, the non-inverting input of which is connected to reference voltage V REF1, and the output of which is connected to its inverting input by a feedback capacitor 194. Thus, amplifier 192 is arranged as an integrator. Capacitor 194 is bridged by a transistor 196 whose base and emitter are connected to lines 24, 26. The output of amplifier 192 provides the ramp voltage and is connected to the line 46.
Ramp generator 190 further comprises an operational amplifier 198, the non-inverting input of which is connected to a reference voltage V REF2.
The output of amplifier 198 is connected to its inverting input by a capacitor 200. Thus, amplifier 198 is connected as an integrator. The output of amplifier 198 is connected through a resistor 202 to the inverting input of amplifier 192.
A resistor 204 and the collector-emitter path of a transistor 206 are connected between a positive supply VCC and a OV line. The base of transistor 206 is connected through a resistor 208 to line 46. The collector of transistor 206 is connected through a diode 210 to the inverting input of amplifier 198, and this inverting input is connected through a resistor 212 to the OV line.
In operation, the voltage reference V REF1 establishes the ramp voltage at the start of each ramp cycle. The slope of the ramp voltage is determined by capacitor 194, resistor 202 and the output voltage of amplifier 198. All the time that transistor 206 is on, the output of amplifier 198 will rise linearly, at a rate determined by the values of capacitor 200 and resistor 212 and reference voltage V REF2. The value of resistor 212 is chosen so that this rate is relatively slow. The gradual increase in the output of amplifer 198 will cause a gradual increase in the slope of the ramp voltage. Eventually, the final voltage at the end of a ramp cycle will fall below the VBE cut-off voltage of transistor 206 turning it off.Consequently, a current will flow via resistor 204 and diode 210 into capacitor 200 causing the output of amplifier 198 to fall at a rate determined by the voltage of supply
VCC and the value of resistor 204 and capacitor 200.
The value of resistor 204 is chosen so that this rate is relatively high. Thus, a state is reached in which the final voltage at the end of each cycle is close to the VBE cut off voltage of transistor 206.
At initial power-up, the output of amplifer 198 is equal to reference voltage V REF2. V REF2 is chosen so that the initial slope of the ramp voltage, and hence the final voltage at the end of each cycle, are close to the desired values.
Al-though the dimmer circuit and modifications have been described with reference to a three phase supply, the present invention is not limited to this. For example, the zero crossing detector 16, the ramp generator 34, the comparator unit 90, and the combined units 130 and 132 may be used on their own with a single phase supply. Also, although each zero crossing detector and ramp generator control two lighting units, the circuit may be modified so that they control a single lighting unit or more than two lighting units.
Claims (11)
1. A control circuit comprising a controlled rectifier for controlling the flow of AC current from a supply to a load, a zero crossing detector for detecting zero crossings of the supply and including an opto-coupler, a ramp generator triggered by the zero crossing detector to generate a ramp voltage, a control voltage unit for generating an output related to the desired current required for the load, a comparator for comparing the output of the control voltage unit with the ramp voltage and generating a control signal when equality is reached, and a firing pulse generator responsive to the control signal to fire the controlled rectifier.
2. A control circuit as claimed in Claim 1, in which, in the opto-coupler of the zero crossing detector, a photo-transistor is switched OFF each time a zero crossing point is detected.
3. A control circuit as claimed in Claim 2, in which the zero-crossing detector includes a rectifier the input of which is responsive to the supply voltage and the opto-coupler comprises said phototransistor and a single light emitting diode responsive to the output rectifier.
4. A control circuit as claimed in Claim 2 or
Claim 3, in which the collector and emitter of the photo-transistor are connected across the input terminals of a -switch element of the ramp generator.
5. A control circuit as claimed in Claim 4, in which the switch element is a transistor the base and emitter of which are connected directly to the collector and emitter of the photo-transistor.
6. A control circuit as claimed in any one of the preceding claims, in which the firing pulse generator includes a opto-coupler.
7. A control circuit as claimed in Claim 6, in which the controlled rectifier is a triac and the opto-coupler in the firing pulse generator includes a photo-receptive element in the feedback path between an input and the gate of the triac and light generating means for illuminating the photo-receptive element to cause conduction thereof in response to the control signal.
8. A control circuit as claimed in any one of the preceding claims, in which the ramp generator includes means for varying the slope of the ramp voltage in accordance with the final voltage at the end of each cycle of the ramp voltage.
9. A control circuit as claimed in Claim 8, in which the ramp generator comprises a first amplifier arranged as an integrator, the output of the first amplifier providing the ramp voltage, a second amplifier arranged as an integrator, the output of the second amplifier being connected to an input of the first amplifier so as to control the slope of the ramp voltage, means for applying a relatively low bias current t6 an input of the second amplifier so as to cause its output to vary in one direction, and means responsive to said final voltage for applying a pluse of relatively high bias current to said input of the second amplifier so as to cause its output to vary in the other direction in the event that the ramp voltage passes a desired value.
10. A control circuit as claimed in any one of the preceding claims arranged for controlling the flow of AC current from a polyphase supply to a set of loads, in which the circuit includes an individual zero crossing detector and an individual ramp generator for each phase of the supply, and at least one control voltage unit, at least one comparator and at least one firing pulse generator for each phase of the supply.
11. A control circuit substantially as hereinbefore described with reference to, and as shown in, Figures 1 and 2, or Figures 1 and 2 as modified by Figures 3 and 4, of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB868630462A GB8630462D0 (en) | 1986-12-19 | 1986-12-19 | Control systems |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8729611D0 GB8729611D0 (en) | 1988-02-03 |
| GB2200006A true GB2200006A (en) | 1988-07-20 |
Family
ID=10609333
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868630462A Pending GB8630462D0 (en) | 1986-12-19 | 1986-12-19 | Control systems |
| GB08729611A Withdrawn GB2200006A (en) | 1986-12-19 | 1987-12-18 | Phase-controlled thyristor circuit |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868630462A Pending GB8630462D0 (en) | 1986-12-19 | 1986-12-19 | Control systems |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8630462D0 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0563633A1 (en) * | 1992-04-02 | 1993-10-06 | TEMIC TELEFUNKEN microelectronic GmbH | Circuit arrangement for phase angle control |
| WO1998045934A1 (en) * | 1997-04-10 | 1998-10-15 | Rittal-Werk Rudolf Loh Gmbh & Co. Kg | Fan cooler |
| EP1313205A2 (en) * | 2001-11-17 | 2003-05-21 | Merten GmbH & Co. KG | Dimmer with load type detection |
| EP1928076A2 (en) * | 2006-11-29 | 2008-06-04 | Spiros Kofinas | Circuit controlling the firing angle of semiconductors |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1455213A (en) * | 1973-02-01 | 1976-11-10 | Xerox Corp | Electric isolation device |
| GB1547641A (en) * | 1977-05-16 | 1979-06-27 | Secr Defence | Electronic switching circuits |
| GB2018072A (en) * | 1979-03-02 | 1979-10-10 | Ibm | Control circuit |
| GB1555885A (en) * | 1977-07-15 | 1979-11-14 | V Elektrotech I V I Lenina | High voltage zero crossing detector |
| GB2111258A (en) * | 1981-10-27 | 1983-06-29 | Thomas Mark Empson | A power controller |
| SU1181124A1 (en) * | 1982-11-11 | 1985-09-23 | Специальное Опытное Проектно-Конструкторско-Технологическое Бюро Со Васхнил | Pulse shaper |
| EP0186740A1 (en) * | 1982-12-30 | 1986-07-09 | Sharp Kabushiki Kaisha | Power frequency detection system |
-
1986
- 1986-12-19 GB GB868630462A patent/GB8630462D0/en active Pending
-
1987
- 1987-12-18 GB GB08729611A patent/GB2200006A/en not_active Withdrawn
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1455213A (en) * | 1973-02-01 | 1976-11-10 | Xerox Corp | Electric isolation device |
| GB1547641A (en) * | 1977-05-16 | 1979-06-27 | Secr Defence | Electronic switching circuits |
| GB1555885A (en) * | 1977-07-15 | 1979-11-14 | V Elektrotech I V I Lenina | High voltage zero crossing detector |
| GB2018072A (en) * | 1979-03-02 | 1979-10-10 | Ibm | Control circuit |
| GB2111258A (en) * | 1981-10-27 | 1983-06-29 | Thomas Mark Empson | A power controller |
| SU1181124A1 (en) * | 1982-11-11 | 1985-09-23 | Специальное Опытное Проектно-Конструкторско-Технологическое Бюро Со Васхнил | Pulse shaper |
| EP0186740A1 (en) * | 1982-12-30 | 1986-07-09 | Sharp Kabushiki Kaisha | Power frequency detection system |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0563633A1 (en) * | 1992-04-02 | 1993-10-06 | TEMIC TELEFUNKEN microelectronic GmbH | Circuit arrangement for phase angle control |
| US5331270A (en) * | 1992-04-02 | 1994-07-19 | Temic Telefunken Microelectronic Gmbh | Circuit array for limiting a load current by reverse phase angle control |
| WO1998045934A1 (en) * | 1997-04-10 | 1998-10-15 | Rittal-Werk Rudolf Loh Gmbh & Co. Kg | Fan cooler |
| EP1313205A2 (en) * | 2001-11-17 | 2003-05-21 | Merten GmbH & Co. KG | Dimmer with load type detection |
| EP1313205A3 (en) * | 2001-11-17 | 2003-12-03 | Merten GmbH & Co. KG | Dimmer with load type detection |
| EP1928076A2 (en) * | 2006-11-29 | 2008-06-04 | Spiros Kofinas | Circuit controlling the firing angle of semiconductors |
| GR20060100650A (en) * | 2006-11-29 | 2008-06-18 | Σπυριδων Κοφινας | Control layout of the firing angle of semiconductors. |
| EP1928076A3 (en) * | 2006-11-29 | 2008-11-12 | Spiros Kofinas | Circuit controlling the firing angle of semiconductors |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8729611D0 (en) | 1988-02-03 |
| GB8630462D0 (en) | 1987-01-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |