EP0124864A1 - Leistungssteuerungsgerät mit opto-isolierter Rückkupplung - Google Patents

Leistungssteuerungsgerät mit opto-isolierter Rückkupplung Download PDF

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Publication number
EP0124864A1
EP0124864A1 EP84104907A EP84104907A EP0124864A1 EP 0124864 A1 EP0124864 A1 EP 0124864A1 EP 84104907 A EP84104907 A EP 84104907A EP 84104907 A EP84104907 A EP 84104907A EP 0124864 A1 EP0124864 A1 EP 0124864A1
Authority
EP
European Patent Office
Prior art keywords
trigger
power
circuit
triac
load
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Withdrawn
Application number
EP84104907A
Other languages
English (en)
French (fr)
Inventor
Donald I. Gonser
Duane E. Barber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dentsply Sirona Inc
Original Assignee
Dentsply International Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Dentsply International Inc filed Critical Dentsply International Inc
Publication of EP0124864A1 publication Critical patent/EP0124864A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current 
    • G05F1/12—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC
    • G05F1/40—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC using discharge tubes or semiconductor devices as final control devices
    • G05F1/44—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC using discharge tubes or semiconductor devices as final control devices semiconductor devices only
    • G05F1/45—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC using discharge tubes or semiconductor devices as final control devices semiconductor devices only being controlled rectifiers in series with the load
    • G05F1/455—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC using discharge tubes or semiconductor devices as final control devices semiconductor devices only being controlled rectifiers in series with the load with phase control
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B39/00—Circuit arrangements or apparatus for operating incandescent light sources
    • H05B39/04—Controlling
    • H05B39/08—Controlling by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices
    • H05B39/083—Controlling by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices by the variation-rate of light intensity

Definitions

  • This invention relates to transformerless regulated power supply apparatus and, in particular, triac switching power supply apparatus for supplying power to loads which are highly voltage or current sensitive.
  • the inertia of the transformer magnetic core provides a great deal of protection to high frequency noise and voltage transients.
  • this is done only at additional cost, size, and weight compared to simpler switching regulator power supplies.
  • Simple triac switching power supplies, with a triac firing angle control circuit for controlling the ON time of the triac, are known in the art and provide a substantial reduction in size, weight and expense compared to power transformer type power supplies.
  • the simplicity of such power supplies makes them extremely vulnerable to transients, particularly in applications such as above noted where early firing of the triac for so much as only one cycle can burn open a lamp filament or otherwise shorten the life of the load.
  • a power supply apparatus with means for switchably connecting AC power from a power line in series with a load, the switching means comprising a triac or like switching device, and triac control means for generating triac gate trigger pulses with a controllable phase delay referenced to the line.power crossover.
  • the triac control circuit includes a feedback path including photo isolator means having a transient response selected to eliminate extraneous high frequency signals, thereby making the triac control immune from unwanted EMI and other interference.
  • Timing circuitry is provided for timing the on state of the regulator, the timing signal being coupled to the triac control through optical isolator means.
  • Fig. 1 there is shown a circuit diagram of a preferred embodiment of the invention.
  • Power is taken from the power line, i.e. single phase 115 volts. It is connected through magnetic elements 30, suitably Molypermalloy powder toroids typically wound with 30 turns of number 9 wire to give an inductance of about 53 microhenries.
  • the toroids are designed to take out certain high frequency transients which might be transmitted through the power line.
  • a varistor diode 32 is connected across the two lines of the single phase power, further to eliminate transients.
  • Fig. 1 The circuitry of Fig. 1 is basically broken down into two portions.
  • a timing circuit centered around IC 65 designated MC14536.
  • DC voltages for this circuit are provided through the transformer as designated at 34, the bridge rectifier circuit shown as BR-I, and associated conventional circuitry.
  • the righthand portion of the diagram includes the load circuit comprising load lamps 50 and the triac 51, and the triac control circuit which is centered around the integrated circuit 60 designated TDAl185.
  • the load is comprised of four tungsten halogen lamps 50, manufactured for rated operation at 41 volts RMS and 200 watts.
  • the circuit illustrated causes the lamps to operate at about 43 volts RM S, or about +5% of rated value.
  • These are extremely sensitive lamps, and can be burned out by overdriving during a single power line cycle. For example, one early misfire of the triac can cause instant burnout of such lamps.
  • the lamps have been designed for a power and voltage rating which results in a structurally strong filament capable of long lifetime use, and for the desired operating results, such as photo curing in dental applications, it is necessary to operate the lamp filaments close to the peak permissible power and operating color temperature. However, if excessive power is permitted to be passed to the lamp for one or more cycles, immediate burnout or at least extremely shortened lifetime can result.
  • the control circuit which controls the triggering of the triac 51 is extremely important.
  • the apparatus of this invention utilizes a silicon monolitic integrated circuit designated "triac firing angle control circuit", type TDA1185, such as made by Motorola Semiconductors.
  • the TDAl185 generates gate trigger pulses for a triac with a controllable phase delay.
  • An internal saw tooth generator provides a linear ramp for trigger point control. It provides full wave triac drive, i.e., the triac is triggered as the line voltage goes both positive and negative.
  • the trigger pulses are delivered from pin 2 and connected to the triac trigger terminal.
  • the phase angle of the trigger pulses is derived by comparison of a ramp voltage which is initiated at the crossover of the power voltage, and a required predetermined value. This comparison sets the firing angle, i.e. determines the voltage level at which the triac conducts and permits power delivery to the load.
  • the TDA1185 also provides soft-start operation, i.e., the permitted power to the load is ramped up from zero to the desired full load level.
  • pin 1 of the TDAl185 is connected to -DC voltage, which is generated by the lN4006 diode and 10K resistor connected to one side of the power line.
  • Pin 2 is the output of the trigger pulse, which is connected through a 100 ohm resistor, to the trigger lead 52 of triac 51.
  • Pin 6 is connected through the resistor to one side of the load, and pin 7 is connected through the resistor to the minus side of the power source, to provide synchronization of the ramp generation with the line zero-crossing voltage.
  • Pin 12 receives a level of voltage derived from the line signal, which determines the phase angle positioning.
  • a feedback capacitor is connected between pin 8 and the neutral side of the power line; pins 9 and 14 are connected directly to the neutral side of the power line; a resistor is connected between pin 10 and neutral; and the capacitor between pin 13 and the positive power line sets the soft-start characteristic.
  • the comparison signal is taken from the negative side of the power line, and is passed through a 560 ohm resistor and an adjustable resistor 54 to the bulb element 55 of a photo isolator combination.
  • the photo isolator utilized is suitably an CLMSHIOA, comprising an incandescent lamp 55 and a photo-transistor 56. This isolator has the requisite optical response to follow the power line, but does not respond to transients that may be on the power line or otherwise picked up by the circuitry.
  • the lamp 55 must have very stable output characteristics in order to maintain long term voltage calibration. For this reason, a incandescent lamp is the preferred light source for this circuit.
  • the photo-resistor is tied between pin 1 and pin 12, providing a voltage variation at pin 12 which the IC compares to its internally generated saw tooth ramp signal, from which the triac trigger pulse is obtained.
  • a thermistor 57 Between pin 12 and the plus side of the power line is a thermistor 57, which provides environmental temperature compensation for the characteristics of the silicon photo-resistor 55.
  • the timer circuitry is constructed around IC 65, which is suitably a programmable timer type MC14536, as made by Motorola. This is a programmable timer, comprising a flexible 24 stage ripple binary counter with 16 stages selectable by a binary code.
  • An on chip monostable oscillator circuit is provided, and by selecting the appropriate output in conjunction with the correct clock frequency, a variety of timing can be achieved. For the pin connections as shown, timing is adjusted by operator manipulation of resistor 40, which is connected between pins 4 and 5 as shown. Tne output, taken at pins 13, 14, is connected through resistor 42 to transistor amplifier 43. The output of transistor 43 is taken from the emitter, and inputted to pin 1 of photo isolator 45, suitably an IC of type H115100.
  • the -DC power which is connected to the TDAl185 chip is also connected to pin 4 of chip 45, and the output signal from pin 5 is connected to pin 12 of chip 60.
  • the output from chip 45 is held low, meaning that pin 12 of chip 60 is held low such that it is inhibited from generating trigger pulses.
  • chip 60 is enabled and operates as described above.
  • the photo isolator 45 prevents any noise or extraneous transients which are picked up in the timer circuitry from being connected through to cause premature or incorrect firing of the triac.
  • Fig. 2 there is shown a block diagram of an embodiment of this invention for supplying regulated current to a current sensitive load.
  • the power 70 taken from the power line as in Fig. 1, is connected across the current sensitive load 80 and triac 79.
  • a current transformer which provides a current signal to a resistor 74 and a bulb 72 of a photo isolator.
  • the bulb 72 is paired with photo transistor 73, which is connected to a threshold pulse generator 77.
  • Generator 77 is the same as that shown in Fig. 1, i.e., it comprises a TDA1185 IC chip with appropriate connections, and a thermistor such as thermistor 57.
  • the trigger pulses from the IC chip are connected to the gate 78 of triac 79. In this manner, the trigger pulse timing follows the sensed current flow through load 80, just as the trigger timing of Fig. 1 follows the voltage across load 50.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Voltage And Current In General (AREA)
  • Control Of Electrical Variables (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Power Conversion In General (AREA)
EP84104907A 1983-05-06 1984-05-02 Leistungssteuerungsgerät mit opto-isolierter Rückkupplung Withdrawn EP0124864A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US49228583A 1983-05-06 1983-05-06
US492285 1983-05-06

Publications (1)

Publication Number Publication Date
EP0124864A1 true EP0124864A1 (de) 1984-11-14

Family

ID=23955685

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84104907A Withdrawn EP0124864A1 (de) 1983-05-06 1984-05-02 Leistungssteuerungsgerät mit opto-isolierter Rückkupplung

Country Status (5)

Country Link
EP (1) EP0124864A1 (de)
JP (1) JPS6089221A (de)
AU (1) AU2760184A (de)
BR (1) BR8402089A (de)
ZA (1) ZA843313B (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0375289A3 (de) * 1988-12-20 1991-08-28 Strand Lighting Limited Elektrische Beleuchtung mit Leistungssteuerungen
US5237244A (en) * 1988-12-20 1993-08-17 Bertenshaw David R Electric lighting and power controllers therefor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4064404A (en) * 1976-04-19 1977-12-20 Chamberlain Manufacturing Corporation Accessory for a garage door opener
US4224563A (en) * 1978-09-01 1980-09-23 Polaroid Corporation Regulator circuit for photographic illumination
US4344071A (en) * 1980-07-10 1982-08-10 Roger A. Heller Light switching mechanism

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4064404A (en) * 1976-04-19 1977-12-20 Chamberlain Manufacturing Corporation Accessory for a garage door opener
US4224563A (en) * 1978-09-01 1980-09-23 Polaroid Corporation Regulator circuit for photographic illumination
US4344071A (en) * 1980-07-10 1982-08-10 Roger A. Heller Light switching mechanism

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
ELECTRICAL DESIGN NEWS, vol. 26, no. 9, 29th April 1981, pages 176-178, Boston, USA; T. HOPKINS: "Regulate lamp output with one IC" *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0375289A3 (de) * 1988-12-20 1991-08-28 Strand Lighting Limited Elektrische Beleuchtung mit Leistungssteuerungen
US5237244A (en) * 1988-12-20 1993-08-17 Bertenshaw David R Electric lighting and power controllers therefor

Also Published As

Publication number Publication date
AU2760184A (en) 1984-11-08
BR8402089A (pt) 1984-12-11
JPS6089221A (ja) 1985-05-20
ZA843313B (en) 1984-12-24

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19851015

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Inventor name: GONSER, DONALD I.

Inventor name: BARBER, DUANE E.