KR20060007595A - Apparatus for power supply control of an exposure type led lamp - Google Patents

Abstract

The present invention is a power supply for inputting a current source generated from the constant current regulator through the isolation transformer, and supplies the power required to light the LED bulb, AC for converting the AC current source supplied from the secondary winding of the isolation transformer to direct current / DC section; A voltage limiter which constantly limits the voltage according to the instantaneous load change when a high voltage is induced; A current detector for detecting a constant output current; A step controller which outputs the effective current value of the analog value of the current detected by the current detector to the step output stage; When the step control signal is input, by turning on the corresponding switch, the current feedback for generating a current current and the reference current generating unit; A constant current controller configured to generate a reference current by supplying a PWM to the current fed back from the voltage limiter and the current fed back from the reference current generator to generate a reference current; A power supply unit connected to the voltage VDD of each component of the power supply control device and supplying the power supply voltage VCC to the power supply voltage VCC terminal of each component, so that the current is always constant through the constant voltage regulator. The circuit can be stably operated by automatically adjusting to reduce power consumption, and the brightness can be adjusted by generating a reference current corresponding to each step, thereby increasing efficiency. Provides a power supply control device such as an induction furnace to prevent exposure.

Description

Apparatus for power supply control of an exposure type LED lamp}

1 is an overall block diagram of an exposed induction furnace lamp according to the present invention,

2 is a detailed block diagram of a power supply control apparatus of an exposure type induction lamp according to the present invention;

3A is a detailed circuit diagram of a power supply control apparatus according to the present invention, and FIG. 3B is a circuit diagram of a power supply unit.

Figure 4 is a table showing the relationship between the luminous intensity according to each step of comparing the present invention with the luminous intensity of other companies lamps.

* Description of the symbols for the main parts of the drawings *

100: constant current regulator 200: insulated transformer

300: power supply control device 310: AC / DC unit

320: voltage limiting unit 330: current detecting unit

332: compensation circuit 340: step control unit

350: current feedback and reference current generator 360: constant current controller

U1: integrated circuit for voltage regulation U2: voltage regulator

U3: Integrated Circuit for Amplification U4: AVR Integrated Circuit

U5, U7: Integrated circuit for switches 400: LED bulb

U6: BCD-to-Decimal Decoder Integrated Circuits

The present invention relates to a power supply control circuit of an exposure type induction furnace, and more particularly, is installed in a high structure such as a building or an airport runway to prevent a building collision of an aircraft or to guide an aircraft on a certain route. It is installed along the runway to firmly manufacture the lights that indicate the width of the runway, and significantly reduces the light errors of the lights, further improves power consumption, maintenance and life performance, and is preset according to each step of the constant current regulator. The present invention relates to a power supply control apparatus for controlling a power supply such that an induction furnace lamp composed of a plurality of light emitting diodes has a constant brightness and a high brightness by supplying a constant current.

In general, various runway lights are installed for the safe operation of the aircraft. First, the exposed guideway light, the buried guideway light, and the buried centerline guideway light, which are installed on the airport runway, are used to guide the aircraft on a certain route at the airport runway at night. The aviation law prevents collisions of aircraft at night, such as high buildings such as buildings, steel towers, transmission towers and structures in mountainous areas, and prevents collision of aircrafts operating at night, and remotely controls lights to ensure safety of aircraft as well as high structures. It is to keep you safe.

As such, there are many lights on the runway, and there are pre-determined international standards according to the installation location and use, and the specifications and structure of the lights are basically determined according to the standard, and the lights that are exposed or purchased on the runway, the driveway, and the taxiway. Since the runway should be displayed to distinguish the runway not only at night but also in bad weather or heavy fog, the brightness of the lamp is very bright, about 5,000 to 30,000 cd, and the power consumption is about 100 to 200W.

These lamps are exposed to direct sunlight and geothermal heat during the summer, and rise to very high temperatures. In winter, the lamps have very low temperatures, so they must be able to withstand various environments and maintain high brightness. Although the bulbs are mainly used, these neon bulbs do not last as long as about 200 hours due to the high brightness and the external environment.Therefore, there are problems such as checking the lamps regularly and replacing the broken lamps immediately. LED bulbs composed of a number of light emitting diodes were used.

A power supply device such as a lighting device using a light emitting diode may step down an AC input voltage to a desired voltage through a transformer, and pass a desired amount of voltage through a diode or a bridge circuit, and then, through a capacitor or stabilization device, a target DC voltage may be applied. It is difficult to control the brightness of LED bulbs by outputting them, but it is difficult to control the brightness of LED bulbs, and all of them are lit with constant brightness. Therefore, there is an unnecessary power loss, and the emergence of a voltage control device effective for power saving is required.

The present invention is stable operation even in the fluctuations of various loads, and in particular, absorbs the shock of sudden current, voltage and heat caused by the load fluctuations to perform safe operation, and supplies constant current to the load to maintain constant brightness, The brightness can be changed according to the environment, and it absorbs voltage fluctuations caused by current changes and overcurrents caused by this, and absorbs any abnormality in voltage and current so that the parts can be returned to normal operation to prevent damage to components. It is an object of the present invention to provide a power supply control device that prevents such a problem.

In order to achieve the above object, the technical means of the present invention is a power supply control device for supplying the power required to turn on the LED bulb, the current source generated from the constant current regulator is input through the isolation transformer, 2 of the isolation transformer An AC / DC unit for converting an alternating current source supplied from the secondary winding into direct current; A voltage limiter which constantly limits the voltage according to the instantaneous load fluctuation when the secondary winding of the isolation transformer is disconnected or the current of the load changes abruptly so that the voltage of the secondary winding of the isolation transformer rises so that a very high voltage is induced; A current detector for detecting a constant output current from a full load state to a no load state of the constant current regulator and reducing a current deviation caused by phase control of the constant current detected through a compensation circuit; A step controller which inputs an effective current value of an analog value of the current detected by the current detector, converts the effective current value into a binary code according to a preset command, and outputs the result to a step output stage corresponding to the binary code; When a step control signal is input through a step control stage corresponding to the step output stage of the step controller, the switch between the input and output terminals connected to the control stage is turned on, the current flowing through the LED bulb is detected, the detected current and the A current feedback and reference current generator for amplifying the current generated according to the step control of the step controller and returning a current according to the amplified voltage; The constant current supplied from the voltage limiter is input to the LED bulb, the current generated from the current feedback and the reference current generator is fed back, and the constant current generates a reference current by PWM control of the constant current and the feedback current to supply the LED bulb. Control unit; It is connected to the voltage VDD of each component of the power supply control device, and converts the input voltage VDD into the power voltage VCC to supply the power voltage VCC to the power voltage VCC stage of each component. It characterized in that it comprises a power supply.

According to the present invention, when the voltage of the power source changes due to an increase in internal resistance or an external factor, the current flowing through the LED bulb changes and the LED bulb does not operate. The circuit is operated and power consumption is reduced, and the brightness can be controlled by changing each step according to the change of the external environment to generate the reference current corresponding to each step, and supplying a constant current corresponding to the set brightness to the LED bulb. The efficiency can be increased by turning on and the step control side can be operated stably by electrically insulating the current measuring side and the step control side through the photocoupler, and the momentary load when very high voltage is induced By limiting the voltage according to the fluctuations constantly, the circuit of the power supply control device is broken. There can stop.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an exposed induction furnace according to the present invention is composed of a constant current regulator 100, an insulation transformer 200, a power supply control device 300 and an LED bulb 400.

The constant current regulator 100 changes the current flowing through the LED bulb because the power supply voltage is changed due to an increase in internal resistance or some external factor, or the resistance of the LED bulb is changed due to a specific cause. Constant current is supplied to the insulation transformer 200 by generating a constant current which is a constant current in order to automatically adjust the constant.

Here, the voltage having the property of constant current is called a constant current voltage, and the constant voltage does not change the voltage even if the load current changes, but the constant current voltage outputs a constant voltage as long as the resistance of the load does not change when a load is connected to the constant current voltage. When the resistance of is changed, the voltage is changed.

For example, when charging with a power source connected to a discharged battery, a large charging current flows at first, but as the charging voltage of the battery increases, the charging current decreases. It shortens and the charger gets crowded. In this case, however, when the constant current voltage is connected to the power supply, the battery is charged by the charging device that outputs the constant current voltage, and the current does not change even when the voltage changes over time.

The isolation transformer 200 is a buried type insulation transformer, and the input voltage and the input current of the primary winding are output to the secondary winding as they are, and a voltage corresponding to the winding ratio appears in each winding, but the windings change at the same frequency as the voltage waveform. Since they are coupled by a magnetic field but are not connected by wires, they are electrically separated from each other, so that the relative potentials of the two voltages can be arbitrarily changed freely, even though the voltages at both ends of the primary and secondary windings are the same. The voltage is supplied to the power supply control device 300.

When the voltage and current are input through the isolation transformer 200, the power supply control device 300 converts the input AC current into DC, and PWM-controls the feedback current according to the constant current and step control to LED the generated current. The detailed description of the configuration by applying to the bulb 400 will be further described with reference to FIGS. 2 and 3.

The LED bulb 400 is turned on by the luminous intensity corresponding to each step by inputting a reference current corresponding to each step generated in the power supply control device 300.

2 is a detailed block diagram of a power supply control apparatus of an exposure induction furnace according to the present invention, the AC / DC unit 310, the voltage limiting unit 320, the current detecting unit 330, the step control unit 340, the current It is composed of a feedback and reference current generating unit 350, a constant current control unit 360 and a power supply (not shown) will be described in detail with reference to FIG.

In order to supply the current source supplied from the constant current regulator 100 to the LED bulb, the AC / DC unit 310 receives the input AC current source when the voltage and current are input to the transformer T1 through the secondary winding of the isolation transformer. The conversion is supplied to the voltage limiting unit 320. The transformer T1 used here is single winding and the input current is up to 6.6A.

When the secondary winding of the isolation transformer is disconnected or the current of the load changes abruptly, the voltage limiting unit 320 suddenly increases the voltage of the secondary winding of the isolation transformer to induce a very high voltage and breaks the circuit of the power supply unit. In order to prevent the supply voltage to the constant current control unit 360 by limiting the voltage according to the instantaneous load fluctuation.

The current detector 330 detects a current from the full load state to the no load state of the constant current regulator 100, reduces the deviation of the detected current according to phase control through the compensation circuit 332, and the effective current value of the detected current. Is transmitted to the step controller 340 as an analog value.

The step controller 340 applies the AVR integrated circuit U4 to program the user to arbitrarily perform a specific function, presets a specific command, and executes the output current of the constant current regulator 100 detected by the current detector 330. When the current value is input, the effective current value input according to a specific command is converted into a binary code, and the binary code is input by being connected to an input terminal of the integrated circuit U6 set to the same bit as the output terminal for outputting the binary code from the integrated circuit U4. The integrated circuit U6 converts the binary code into an analog value and outputs the analog code to the step output terminal of the integrated circuit U6, which represents the analog value, and then inputs the preset step control terminal to the integrated circuit U5 and U7. do.

The current feedback and the reference current generator 350 detects the current flowing in the LED bulb 400, and according to the instruction of the step controller 340, the integrated circuit corresponding to the analog value corresponding to the detected current of the constant current regulator 100. When the high signal output from the output terminal of U6 is transmitted to the corresponding control stage among the plurality of control stages of the switch integrated circuits U5 and U7, it is set by turning on the switch between the input and output terminals of the corresponding control stage. A current corresponding to the step is generated, and the current of the LED bulb output from the constant current controller 360 and the current according to the step control are amplified and fed back to the voltage adjusting integrated circuit U1.

When the current generated by the current feedback and the reference current generator 360 is fed back according to the step control, the constant current controller 360 generates a constant reference current according to the step set by PWM control with the constant current input from the voltage limiter. By supplying to the bulb 400, the LED bulb 400 is turned on with a constant brightness according to the step.

The power supply unit (not shown) is connected to the voltage VDD of each component, and when the voltage VDD is input to the input terminal of the integrated circuit U2 which is a constant voltage regulator, the power supply unit converts the power supply voltage VCC through the output terminal. The supplied power supply voltage VCC is supplied to the circuits of the respective components (for example, U4 and PC1).

3A is a detailed circuit diagram of a power supply control device and FIG. 3B is a circuit diagram of a power supply unit.

AC / DC unit 310 is a non-linear semiconductor resistor that is connected to both ends of the voltage in series and whose resistance is changed by the voltage applied to both ends of the power supply. ZNR (Zinc Oxide Nonlinear Resistor) absorbs transformer switching surge to prevent damage to peripheral devices. Abbreviation, for example, 20D471) (ZNR); and a transformer (T1) including a primary winding supplied with an input voltage and a secondary winding connected to a terminal of a bridge diode; and a current flowing in one direction and in the other direction. A first bridge diode (BD1) for rectifying the voltage by connecting four diodes for converting an AC voltage into a DC voltage in the form of a bridge, having the ability to cut off the current; And a terminal connected to the terminal d of the bridge circuit BD1 and connected in series between the voltage VDD and the ground, and charged to the peak value of the input voltage within the voltage drop of the first bridge diode BD1, and the input is peak value. When the first bridge diode BD1 becomes smaller and is reverse biased, a ripple removing capacitor C1 discharges the charged voltage through an arbitrary load.

The voltage limiting unit 320 is connected to a gate terminal of a MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) (MOSFET) connected in series between the voltage VDD and ground. A zener diode D1 which maintains a constant voltage across the diode with respect to a reverse range of a reverse current value; And a resistor R1 connected in series between the voltage VDD and the zener diode D1; and a resistor R3 connected in series between the zener diode D1 and ground.

Here, the MOSFET is a high-speed switching and a small area compared to the transistor, and as the gate source voltage increases, the conductivity of the channel increases, so that the amount of pulses to charge or remove the input charge that attracts more electrons to the channel is increased. Moss field effect transistors with light electrons are about 2.7 times better because they require a gate input voltage, turn on when the voltage VDD is input, and the current driving capability is electron carrier.

The current detector 330 has a primary winding connected to the transformer T1 and the input voltage (-) terminal to detect the current value of the current generated by the constant current regulator, and the input voltage and the input current of the primary winding are output as they are. A detector (T2) including a primary winding; and a resistor (R13) connected to both ends of the secondary winding of the detector (T2); and a specific stage (for example, pin 1) and the detector (T2) that function as ADCs of the step controller 340. A second bridge including a terminal f connected to one end of the secondary winding of the circuit), a terminal g connected to the other end of the secondary winding of the detector T2, and a terminal h grounded through the resistor R20 and the diode D6. A capacitor C9 connected in series between the diode BD2 and the e terminal of the second bridge diode BD2 and the ground; and the plurality of resistors R9, R10, respectively connected in parallel with the e terminal of the second bridge diode BD2. R11); and a plurality of resistors R15, R16, and R17 connected in parallel to the h terminal of the second bridge diode BD2, respectively. A plurality of diodes D3, D4 and D5 connected in series between the number of resistors R9, R10 and R11 and ground, respectively; and a resistor R18 connected in series between the h terminal of the second bridge diode BD2 and ground. And a resistor (R24) and a diode (D7) connected in series at both ends of the secondary winding of the detector (T2); and the stage and the resistance of the secondary winding of the detector (T2) to which the second terminal of the second bridge diode is connected ( A resistor R22 connected in parallel between R24; and a photocoupler that is a switch means including a photo transistor connected between the resistor R22 and the diode D7 and grounded through a power supply voltage VCC and a resistor; PC1); and the output signal of the photo coupler PC1 is input to the input terminal (for example, pin 5) and the output signal of the amplifying integrated circuit (U3B) to the input terminal (for example, pin 6) and amplified An amplifying integrated circuit U3B for outputting to an output terminal (eg, pin 7); and outputting of the amplifying integrated circuit U3B. It is composed of a resistance (R26) a variable resistor (R27) connected in series between the ground; and the resistor (R26) and the capacitor (C10) connected in series between the ground; resistance (R26) connected to the stage.

In addition, a compensation circuit for reducing the current deviation of the current detected through the detector T2 of the current detector 330 includes a plurality of resistors R9, R10, and R11 connected in parallel to terminals e of the second bridge diode BD2, respectively. And a plurality of resistors R15, R16, and R17 connected in parallel to terminal h of the second bridge diode BD2, respectively; and a plurality of resistors connected in series between the plurality of resistors R9, R10, and R11 and ground, respectively. A resistor R18 connected in series between the diodes D3, D4, and D5; and the terminal h of the second bridge diode BD2 and ground; and connected in series between the terminal h and the ground of the second bridge diode BD2. Resistor R20 and diode D6; and capacitor C9 connected in series between e terminal of second bridge diode BD2 and ground.

The step controller 340 is composed of an AVR integrated circuit (eg, ATtiny15L) U4 and a CMOS integrated circuit (eg, 4028) (U6).

The AVR integrated circuit U4 is a microprocessor. Pin 1 of the ADC (ie, Analog-to-Digital Conversion) selected according to a user's instruction is connected to the current detector 330. Pin 2 of the ADC is a microprocessor. It is connected to the variable resistor R27 of the current detector 330, and a plurality of output terminals (e.g., pins 5, 6 and 7) are connected to a plurality of input terminals (e.g., 10 times) of the CMOS integrated circuit U6. , Pins 11, 12 and 13) are respectively connected to transmit the binary code of the detected effective current value. Pin 8 is supplied with the supply voltage VCC and pin 4 is grounded.

The CMOS integrated circuit U6 may output an analog value corresponding to the input binary code (for example, pin 1, pin 2, pin 3, pin 4, pin 6, pin 7, pin 14, Pin 15) to the corresponding control stages (eg pins 5, 6, 12 and 13) of the switch integrated circuits U5 and U7 of the current feedback and reference current generators.

For example, the detected current value converted into the binary code through the output stage preset in the AVR integrated circuit U4 is high at the input terminal Sel1, low at sel2, high at sel3, and low at sel4 (i.e., When inputted as binary 0101), a high signal is output to a specific output stage representing an analog value corresponding to a binary code, that is, output stage 6step is a high circuit (ie, an output stage representing analog value 5). U5, U7) is output to the specific control stage, that is, the stage set to 6step, and the input / output stage corresponding to 6step is turned on, and the other control stage is closed and the corresponding input / output stage is turned off to open the circuit. Becomes

The current feedback and reference current generator 350 is composed of an amplifier integrated circuit (for example, LM2904) (U3A) and two switch integrated circuits (for example, 4066) (U5, U7).

The amplifier integrated circuit U3A outputs the output signal of the constant current controller 360 and the output signals of the switch integrated circuits U5 and U7 to the non-inverting terminal (for example, pin 3) and the inverting terminal (for example, pin 2). When inputted to amplified and output to the output terminal (for example, pin 3) is fed back to the constant current control unit 360, the power supply terminal (for example pin 8) is connected to the voltage (VDD), the ground terminal (for example 4 Pin 1) is grounded.

In addition, the resistor R6 is connected to the output terminal of the amplifier integrated circuit U3A, and is fed back to the input terminal (for example, pin 2) through the capacitor C8, and the resistor R6 and the integrated circuit ( Multiple input / output stages of U5, U7 (e.g., pins 1, 11, 4, 8 and U7 pins 1, 11, 4 and 8) A plurality of resistors (R8, R12, R14, R19, R21, R23, R25, R29) are respectively connected between them, and the input terminal (e.g. pin 2) is connected to a plurality of outputs / inputs of the integrated circuits U5 and U7. (E.g. pin 2, pin 10, pin 3, pin 9 of U5 and pin 2, pin 10, pin 3, pin 9 of U7) and at the same time connect resistor R7 Grounded through the control stages (e.g., pins 13, 12, 5, 6 of U5 and 13, 12, 5 of U7) , Pin 6) when the high or low signal is input according to the output of the step controller, the switch is turned on and off. When being connected to the output stage is turned on, the current flows through a closed circuit fed back to the amplifier integrated circuit (U3A) for the input terminals (e.g., pin 3).

The constant current controller 360 is composed of five pins. The first pin is supplied with the input voltage and is grounded through the ripple cancellation capacitor C2. The pin 2, which is the output terminal, is connected to the positive terminal of the LED bulb through the inductor. Connected to the ground at the same time through the diode (D2), pin 3 is grounded, pin 4 is the current feedback and the feedback signal of the reference current generator 350 is input, pin 5, the on / off end is grounded The voltage regulation integrated circuit U1 (e.g., LM2576 / TO); and two capacitors C3 and C4 connected in parallel between the voltage VDD and ground; and a resistor R2 connected in series across the LED bulb. It consists of a resistor (R4) connected in series between the negative terminal of the bulb and the ground.

The power supply of FIG. 3B consists of an integrated circuit for a constant voltage regulator (e.g., LM78L05AB) (U2) with three pins, a plurality of capacitors (C5, C6, C7) and a resistor (R5) to improve stability and transient response. .

That is, pin 1 of the integrated circuit U2, which is a constant voltage regulator, is grounded through the capacitors C6 and C7 and the resistor R5 connected in parallel, respectively, and simultaneously outputs a power supply voltage VCC (maximum voltage 5V) to provide various integrated circuits. It is connected to the supply voltage (VCC) terminal of to supply power, pin 2 is grounded, pin 3 is grounded through the capacitor (C5), and at the same time, the voltage (VDD) higher than the supply voltage (VCC) (approximately 3V to 15V) ) Is input and simultaneously connected to voltage (VDD) terminals of various integrated circuits.

Figure 4 is a relationship table showing the brightness of the third-party lamps and the brightness of the LED bulb according to each step according to the present invention.

The current according to each step is set up to 6.6A maximum current that the transformer of AD / DC section can withstand, and LED brightness becomes 100% when maximum current 6.6A flows.

When the constant current corresponding to each step is input through the constant current regulator, it is controlled as described in the above operation description to turn on the LED bulb constantly at the brightness corresponding to each step. This can be seen through.

Looking at the schematic operation configuration of the power control device of the present invention configured as described above are as follows.

When the voltage VDD and the power voltage VCC are supplied to each component through the power supply unit, and the constant current generated from the constant current regulator is input to the secondary winding of the transformer T1 of the AC / DC unit through the isolation transformer, The AC current source is converted into a DC current source through the bridge diode BD1 and supplied to the power supply limit.If the voltage of the secondary winding of the isolation transformer rises sharply, the circuit of the power supply control device is damaged due to a very high voltage. In order to prevent this from happening, the MOS field effect transistor and the zener diode were installed to form a closed circuit so that the voltage according to the instantaneous load fluctuation was constantly limited, and the constant DC current of the constant current controller 360 regulates the voltage adjusting integrated circuit (U1). The current generated by the current feedback and the step control of the reference current generator 350 is supplied to the input terminal of the If the feedback is input to the PWM control is the reference current which corresponds to the step output from the output stage to light the LED lamp 400 with a constant brightness according to the step.

In addition, the current detector 330 detects the output current from the full load state to the no load state of the constant current regulator through the detector T2, and converts the AC current detected through the second bridge diode BD2 into a DC current. When the converted current is supplied to the compensating circuit 332, the ADC current (eg, 1) of the AVR integrated circuit U4 of the step controller 340 is reduced to an analog value by reducing the current deviation according to phase control. Pin) and a current detected by the detector T2 is emitted by flowing to the photodiode to turn on the electrically insulated phototransistor, and when the phototransistor is turned on, the amplification integrated circuit U3B The voltage is inputted to the non-inverting terminal of (eg pin 5) and the output voltage is input to the inverting terminal (eg pin 6) of the amplifying integrated circuit U3B. Integrated circuit (U4) ADC stage is input to the (e. G., Pin 2).

In addition, an amplification integrated circuit (VP) is provided between the output terminal of the amplifying integrated circuit U3B (for example, pin 7) and ground and the ADC terminal (for example, pin 2) of the AVR integrated circuit U4. U3B) adjusts the voltage value amplified, and user specific specific operation and command is programmed in AVR integrated circuit (U4), and the effective current value inputted according to the set function is converted into analog code and output through the output stage. When the integrated circuit U6 is connected to an input terminal (for example, pins 10, 11, 12 and 13) set to the same bit, a binary code is input, and the binary code input by the function of the integrated circuit U6 is analog. Generates current feedback and reference current by outputting to the output terminal (for example, pin 1, pin 2, pin 3, pin 4, pin 6, pin 7, pin 14, pin 15) corresponding to the value Control stages corresponding to the negative switch integrated circuits U5 and U7 (e.g., 5, 6 and 12) When input to pin 13), the switch connecting the input / output with the high signal is turned on to generate an amplification integrated circuit and a closed circuit to generate a current according to a set step, and the current generated according to the step control is amplified integrated circuit ( U3A) is input to the non-inverting terminal (eg, pin 2), and the current of the LED bulb detected by the constant current controller 360 is input to the inverting terminal (eg, pin 3) to the amplifying integrated circuit U3A. The current according to the voltage amplified through the output terminal is fed back to the integrated circuit (U1) of the constant current control unit 360, and the constant current and current feedback input from the power limiter 320 and the current fed back from the reference current generator PWM control generates a constant reference current corresponding to the step of the constant current regulator, and turns on the LED bulb with a constant brightness corresponding to the step.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

As described in detail above, when the voltage of the power source changes due to an increase in internal resistance or some external factor, the current flowing through the LED bulb changes and the LED bulb does not operate. The circuit can be stably operated and the power consumption is reduced, and the brightness can be controlled by changing each step according to the change of the external environment to generate the reference current corresponding to each step. By supplying the LED bulb with the brightness according to the step, the efficiency can be increased, and the step control side can be operated stably as the current measurement side and the step control side are electrically insulated through the photocoupler. When very high voltage is induced, the power is limited by the constant limiting of the voltage due to the momentary load change. Class it is possible to prevent the circuit is broken, of a control device.

Claims (6)

In the power supply control device for supplying the power required to turn on the LED bulb, the current source generated from the constant current regulator is input through the isolation transformer, An AC / DC unit for converting an AC current source supplied from a secondary winding of the insulation transformer into direct current; A voltage limiter which constantly limits the voltage according to the instantaneous load change when the secondary winding of the insulation transformer is disconnected or the load current changes abruptly to increase the voltage of the secondary winding of the insulation transformer so that a very high voltage is induced; A current detector for detecting an output current from a full load state to a no load state of the constant current regulator and reducing a current deviation caused by phase control of the current detected through a compensation circuit; The effective current value of the analog value of the current detected by the current detector is input, the effective current value is converted into a binary code according to a preset command, and the specific step corresponding to the converted analog value by converting the converted binary code into an analog value A step controller which outputs an output terminal as a high signal and outputs a remaining signal as a low signal; When a low or high step control signal is input through the step control terminal corresponding to the step output terminal of the step controller, the switch between the input terminal and the output terminal of the control terminal to which the high signal is input is turned on according to the step control signal, The remaining switch of the control stage where the signal is input is turned off, the current flowing through the LED bulb is detected, the current detected by the LED bulb and the current generated by the step control are amplified and the current according to the amplified voltage is fed back. Current feedback and reference current generator; The constant current is input to the LED bulb from the voltage limiting unit, the current amplified by the current feedback and the reference current generating unit is fed back, and PWM control the input constant current and feedback current to generate a reference current to supply the LED bulb. Constant current control unit; It is connected to the voltage VDD of each component of the power supply control device, and converts the input voltage VDD into the power voltage VCC to supply the power voltage VCC to the power voltage VCC stage of each component. Power supply control device of the exposed induction furnace comprising a; power supply unit. The method of claim 1, wherein the voltage limiting unit An apparatus for controlling power supply of an exposed induction furnace lamp comprising a MOS field effect transformer and a zener diode. The method of claim 1, wherein the step control unit A power supply control device of an exposed induction lamp including an AVR integrated circuit and a BCD-to-Decimal Decoder integrated circuit operating according to a programmed control command. The method of claim 1, wherein the current feedback and the reference current generating unit An input terminal and an output terminal are connected by a switch, the power supply control device of an exposed induction lamp, characterized in that it comprises a plurality of switch integrated circuit is switched on / off according to the control signal input to the control terminal. The method of claim 1, wherein the constant current control unit Power supply control device of an exposed induction furnace, characterized in that it comprises a voltage regulation integrated circuit capable of PWM control. The method of claim 1, wherein the current detection unit An exposure type induction comprising a detector for detecting the output current of the constant current regulator, a photocoupler electrically insulating the current detection side and the step control side and a plurality of diodes connected in parallel with a plurality of resistors. Power supply control device of furnace.

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