WO2012144864A2 - Led lighting apparatus capable of protecting led elements, and method for controlling the led lighting apparatus - Google Patents

Abstract

The present invention relates to an LED lighting apparatus and to a method for controlling the LED lighting apparatus, which enable the protection of LED elements by preventing LED elements from being short-circuited or opened due to a rise in internal temperature resulting from the degradation of LED elements and the resultant increase in the variation of the current in LED arrays, which might cause serious problems in the LED light as a whole. The LED lighting apparatus of the present invention comprises: a constant-current generator; current-sensing means for sensing the amplitude of the current flowing along each of the LED arrays; an analog-to-digital signal converter, which receives current voltage signals from the current-sensing means and converts the received signal into digital signals; a central processing unit which determines whether each LED array is degraded, opened, or short-circuited based on the current signal inputted from the analog-to-digital signal converter, and outputs commands for controlling the amplitude of the constant current generated by the constant-current generator or for stopping the generation of the constant current; and a digital-to-analog converter for converting the digital signal outputted from the central processing unit into an analog signal, a pulse-width modulator for converting the digital signal outputted from the central processing unit into a pulse-width modulation signal. The constant-current generator generates current or stops the generation of current in accordance with the signal outputted from the digital-to-analog converter or from the pulse-width modulator. The LED lighting apparatus and the method for controlling same according to the present invention enable other LED arrays to operate normally even when an LED element is degraded or opened, and the cut-off of lighting when an LED element is short-circuited, thereby protecting the constant-current generator.

Description

LED lighting device to protect the LED element and control method of the lighting device

The present invention relates to an LED lighting device that protects a plurality of arrays of LED devices and a method of controlling the lighting device. In particular, when the LED element is deteriorated and the current deviation increases in the LED arrays, the LED is increased due to an internal temperature increase. The present invention relates to an LED lighting device that protects an LED device from being shorted or opened so that a serious situation does not occur in the entire LED lamp, and a method of controlling the lighting device.

In general, a lighting device using a light emitting diode (LED) is configured by connecting a plurality of LEDs in parallel in the form of an LED array in which a plurality of LEDs are connected in series.

When the LED arrays in which a plurality of LEDs are connected in series are driven in a state where a plurality of LEDs are connected in parallel, the operating voltage of the LED array (forward voltage Vf of each LED) is unevenly generated as the operation time increases. The currents of the LED arrays connected in parallel become unbalanced.

Therefore, a constant-current circuit is installed in each LED array so that constant current flows to prevent problems caused by unbalance of current flowing in the LED unit.

In these LED lighting devices, the LED converts about 15% of the power consumed into light and about 85% of the power into thermal energy without generating infrared radiation.

The characteristics of the light energy generated by LEDs are very fluctuating, so basically, when the junction temperature of LED is rated as 40, white LED is 0 to 115%, 20 to 110%, 40 to 100%, 60 to 95%. , 80 to 90%, 100 to 80%, 120 to 70% of the amount of light is generated, the life is significantly reduced as the temperature increases.

The internal temperature of the LED is increased by the increase of the ambient temperature and excessive heat generation. The cause of self heat generation is due to high forward current and thermal resistance.

Increasing the internal temperature of the LED causes the interlayer separation between the LED chip and the protective film, especially in the case of white LEDs, causing an interlayer separation between the phosphor coating and the silicon protective film or between the chip and the phosphor coating. Will be lowered. In addition, excessive temperature change in the surrounding area causes the shrinkage and expansion of the silicon to cause the wire cutting inside the LED package.

In addition, when a forward current exceeds a limit value or a transient peak transient current is applied to the LED element, a problem may occur in which the chip or wire inside the LED is broken.

do.

The thermoelectric properties of such LEDs are well known facts.

In more detail, the electrical characteristics of the LED is basically a semiconductor device in which a current flows according to the applied voltage.

However, LEDs are usually controlled with constant current for the following reasons:

First, the amount of light generated by the LED is proportional to the current applied to the device. In other words, it is easy to understand and adjust the optical characteristics only when the LED is driven based on the current having the closest relation to the amount of light.

Secondly, because LEDs are more sensitive to voltage than current, it is easier to maintain the electrical characteristics of the LEDs by fixing the current.

Third, the driving voltage of the LED varies greatly depending on the current and temperature applied.

In consideration of these characteristics, LED driving circuit for preventing LED from being damaged when one or more LEDs are broken in the LED array connected in series in the LED array type lighting device connected in series. An example of is disclosed in the following patent document.

That is, the LED driving circuit disclosed in the following patent document has a power supply controller for supplying a DC voltage, a PWM signal generator for supplying a PWM signal, and a switching operation according to the PWM signal or a low signal as shown in FIG. 1. Or a switching unit which is turned off and includes a plurality of LED strings connected in parallel, and is supplied with the DC voltage.

The display unit which emits or is turned off as the switching unit is switched on or off, and the sensing voltage which is supplied with the PWM signal and senses and subtracts voltages of the plurality of LED columns according to a comparison result of the preset reference voltage A protection circuit unit configured to apply the PWM signal or a low signal to a switching unit, wherein the protection circuit unit detects the voltage of the plurality of LED columns and applies a sensing voltage to detect and subtract the reference voltage (Vref). ) Is applied, and a high signal is applied when the sensing voltage is smaller than the reference voltage by receiving the sensing voltage, and low when the sensing voltage is greater than the reference voltage. A comparator for applying a (Low) signal and the P signal when the PWM signal is supplied and the high signal is applied; And a switching means for applying a WM signal to the switching unit and turning off the PWM signal when the low signal is applied to block the PWM signal.

However, the LED driving circuit according to the following patent document can cut off the voltage applied to the LED columns to prevent the shortening of the life of the LED as a whole, when using the LED driving circuit in the LED lighting device, Even if only the dog is broken, there is a problem in that the LED lighting device is turned off so that it can no longer serve as a lighting device.

An object of the present invention is to solve the problems as described above, even if the LED element is deteriorated to cause a large current deviation in the LED array to prevent the LED short-circuit or open due to the internal temperature rise, etc. It is to provide an LED lighting device and a method of controlling the lighting device that protects one LED device from a situation.

Another object of the present invention is to provide an LED lighting device and a method of controlling the lighting device, which protects the LED device that prevents the degradation of another LED array due to excessive current flow to another LED array when a particular LED array is open. will be.

Another object of the present invention is to provide an LED lighting device and a method of controlling the lighting device for protecting the LED device to stop the operation of the lighting device when a particular LED array is short-circuited.

In the LED lighting device for protecting the LED device according to the present invention to achieve the above object LED lighting device comprising a plurality of LED modules connected in parallel to the LED array connected in series, the LED, A constant current generator for supplying a constant current to the module; Current sensing means for sensing the magnitude of current flowing through each of the LED arrays; An analog-to-digital signal converter which receives the current signals sensed by the current sensing means and the voltage signal applied to the LED array and converts them into digital signals; If the current flowing from the current signal input from the analog-to-digital signal converter to the first LED array is less than the first current threshold, it is determined that the first LED array includes a degraded LED element. A central processing unit for calculating a current reduced from the normal current and outputting a current of which the reduced current value is reduced from the rated current supplied to the LED module; And a pulse-width modulator for converting a digital signal commanded by the central processing unit into an analog signal or a pulse-width modulator for converting a pulse width modulated signal, wherein the constant current generator includes a digital-to-analog converter or a pulse width modulator. The magnitude of the constant current is controlled by the signal.

In the LED lighting device according to the invention, the central processing unit accumulates the reduced current value in the LED arrays having a value smaller than the first current threshold from the first LED array to the plurality of LED arrays. And instructing the constant current generator to output the current that is decreased in the rated current by the magnitude of the accumulated value of the reduced current.

In the LED lighting device according to the present invention,

The CPU determines that each LED array circuit includes an LED element open to the corresponding LED array when the LED array circuit is smaller than the second current threshold, so that the LED array number of LED arrays including the open LED element is determined. Accumulate the value of the steady current of the array in the reduced current value.

In the LED lighting apparatus according to the present invention, the central processing unit includes an LED element shorted to the corresponding LED array when the respective LED array circuit is greater than a third current threshold and the voltage signal is less than the voltage threshold. It is judged that the operation is characterized in that the command to stop the current generation of the constant current generating device.

In the LED lighting apparatus according to the present invention, the central processing unit compares the voltage applied to the LED module and the voltage threshold, and compares the temperature and temperature threshold of the heat sink installed in the LED module to the voltage applied to the LED module ( When the V _LED is less than the voltage threshold, and the temperature of the heat sink exceeds the temperature threshold, the rated current is changed to a current limit value according to the temperature rise of the heat sink.

In the LED lighting apparatus according to the present invention, the first current threshold value is less than the normal current flowing in each LED array in the LED module in the normal state, characterized in that the range of more than 95% of the normal current.

In the LED lighting apparatus according to the present invention, the second current threshold is characterized in that the current flowing in each LED array in the LED module in the steady state is in the range of 30% or less of the normal current.

In the LED lighting apparatus according to the present invention, the LED lighting apparatus controls the magnitude and initial setting value of the current generated in the constant current generator through an interface connected to the central processing unit at a remote location, each LED array It is characterized by monitoring the current state of the current, the output current of the constant current generator, the output voltage and the state of the heat sink temperature.

In addition, in order to achieve the above object, a control method of an LED lighting apparatus according to the present invention includes an LED module having a plurality of LED arrays connected in parallel with a plurality of LED elements connected in series, and a constant current supplying a constant current to the LED module. A generator, a current sensing means for sensing a magnitude of current flowing through each of the LED arrays, and controlling a magnitude of a constant current supplied from the constant current generator to the LED module according to a signal detected by the current sensing means. A control method of an LED lighting apparatus including a central processing apparatus, comprising: a deciding step of determining whether or not an LED element in a first LED array of the plurality of LED arrays is deteriorated; An opening determination step of determining whether the first LED array is open when the LED device of the first LED array is not deteriorated in the deterioration determination step; A reduction current calculation step of calculating a magnitude of a current which is reduced from the normal current flowing in the first LED array by being degraded or opened when it is determined that the LED element is degraded or opened in the first LED array; A current reduction command step of outputting a signal corresponding to the magnitude of the reduction current to the constant current generator; The constant current generator includes a constant current output step of supplying a constant current reduced in accordance with the decrease current command to the LED module, wherein the deterioration determination step includes the current flowing through the respective LED array is the first LED array The first current is less than the first current threshold which is smaller than the normal current flowing in the range and is greater than or equal to 95% of the normal current, and the current flowing in the first LED array is greater than or equal to the second current threshold that is in the range less than 30% of the normal current. Characterized in that the LED element in the LED array of 1 is deteriorated.

Further, in the control method of the LED lighting apparatus according to the present invention, the step of determining whether the opening is smaller than the first current threshold value, and smaller than the second current threshold value to determine that the first LED array is open. It is characterized by.

In addition, in order to achieve the above object, a control method of an LED lighting apparatus according to the present invention includes an LED module having a plurality of LED arrays connected in parallel with a plurality of LED elements connected in series, and a constant current supplying a constant current to the LED module. A generator, a current sensing means for sensing a magnitude of current flowing through each of the LED arrays, and controlling a magnitude of a constant current supplied from the constant current generator to the LED module according to a signal detected by the current sensing means. A method of controlling an LED lighting device comprising a central processing unit, wherein the LED element shorted to the first LED array when the LED element of the first LED array is not degraded or opened among the plurality of LED arrays. A short-circuit determining step of determining whether or not to include; A current generation stop command step of instructing to stop the constant current generation of the constant current generator when it is determined that the short circuit of the array includes the LED element shorted in the first LED; The constant current generator includes an illumination stop step of stopping the illumination by stopping the generation of the constant current according to the current generation stop command, wherein the short-circuit determination step has a value greater than the normal current flowing in the first LED array It is characterized in that it is determined that the range of the normal operating voltage applied to the LED array as the voltage threshold is greater than or equal to the third current threshold, and the LED array includes a shorted LED element if it is smaller than the voltage threshold. .

As described above, according to the LED lighting device for protecting the LED device according to the present invention and the method of controlling the lighting device, when the LED device is deteriorated and the current deviation increases in the LED array, that is, the current of each LED array If the balance is not balanced, the difference between the normal current of each LED array is accumulated and the rated current of the constant current generator is reduced so that the LED does not short-circuit or open due to an internal temperature rise. Deteriorated LED arrays slow down the progress of deterioration, so that a serious situation does not occur in the entire LED lamp.

In addition, according to the LED lighting device and the method of controlling the lighting device according to the present invention, when an LED array is opened, an effect of preventing excessive degradation of another LED array due to excessive current flow to another LED array is also obtained.

In addition, according to the LED lighting device and the method of controlling the lighting device according to the present invention, when a specific LED array is short-circuited, the operation of the lighting device is stopped to prevent the failure of the constant current generator and prevent the failure of the constant current generator. The effect is that normal LED devices that are not shorted no longer fail due to overcurrent.

1 is a view showing a conventional LED driving circuit,

2 is a driving circuit diagram showing the concept of an LED lighting apparatus according to the present invention;

3 is a driving circuit diagram of the LED lighting apparatus according to the present invention;

4 is a flow chart showing the concept of a control method of the LED lighting apparatus according to the present invention;

5 is a partial flowchart of a control method of the LED lighting apparatus according to the present invention.

The above and other objects and novel features of the present invention will become more apparent from the description of the specification and the accompanying drawings.

First, the outline | summary of this invention is demonstrated.

In general, when driving the LED, the current is configured to flow in the constant current circuit, but in order to drive the current in the constant current circuit in a 1: 1 ratio to drive a plurality of LED elements, the cost of the circuit implementation increases, as shown in FIGS. 1 to 3. As described above, current is applied to a circuit (hereinafter referred to as "LED module" in the present invention) in which a plurality of circuits in which a certain number of LED elements are connected in series (hereinafter referred to as "LED array" in the present invention) are connected in parallel. It is common to implement it to flow.

Since the internal characteristics of the LED device vary according to temperature changes, the current balance between the parallel circuits is broken in the LED module as described above. More specifically, since the characteristics are different for each LED device, the progress of deterioration in the LED lighting having the same environment is different for each device.

That is, when a change in the forward operating voltage for each LED device occurs, each of the LED arrays causes a difference in the forward operating voltage, thereby breaking the current balance of the respective LED arrays.

When this condition occurs, abnormal normal current flows to other normal LED arrays, which increases the internal temperature of the LED, reduces the optical efficiency of all LEDs connected to the circuit, and shortens the life of the LED device.

Accordingly, the concept of the present invention is to limit the current supplied from the constant current generator to the LED module so that a current larger than normal (overcurrent) does not flow to the LED array in the LED module that is abnormally operated.

For example, in FIG. 2, when the number n of LED arrays is 10, there are 10 array circuits of LEDs in a constant current output circuit having a total current of 3.5A, and each LED array has 7 LEDs. When the devices are connected in series, when the LED devices are all normal, the current (I ₁ ~ I ₁₀ ) of the LED arrays is balanced and flows 0.35A each. Where 0.35A is the steady current of the LED arrays.

However, if the LED element deteriorates due to the increase in the usage time of the lighting, the LED array including the deteriorated LED element increases the forward operating voltage (Vf) to flow a current of less than 0.35A, and the set current of the constant current generator ( As 3.5A) does not fluctuate, deterioration continues and the reduced current in the degraded LED array causes an increase in current through other LED arrays that are not degraded.

As such, when the current flowing in the LED array is larger than the normal current, the internal temperature of the normal LED arrays is increased and excessive heat is generated, resulting in a decrease in optical efficiency and shortening the life of the LED lighting device. The upper and lower limits are determined for the normal operating current flowing through the LED array including the LED element deteriorated so as to maintain their normal current, and the lower limit (first current threshold: the normal current flowing in the steady state LED array) is set. If the current flows smaller than the range, which is smaller than 95% of the normal current, the LED device is considered to be deteriorated.

And if the current much less than the first threshold, that is, 10-30% (most preferably 20%) of the normal current as a second threshold, and flows below the second threshold, in the present invention the LED The LED array including the device is considered to be open. Although the range of the second current threshold is described as the current range of 10-30% of the normal current, it may be set to 30% or less of the normal current. As described above, when the current flowing in the LED array is less than the first current threshold or less than the second current threshold, it is regarded as a deterioration in a broad sense. However, in the present invention, when the current is less than the first threshold and more than the second threshold flows. Is defined as deterioration, and when the deterioration is further progressed and the current flowing in the LED array is further reduced to flow less than the second threshold, it is defined as open as described above.

In this way, when the current flowing in the LED array flows less than the first threshold (including the second threshold), the output current of the constant current generator (converter) is limited so that the current flowing through the normal LED arrays is the normal operating current. To flow to.

In addition, when the LED element included in a specific LED array is short-circuited, a current much larger than the normal current flows in the LED array. In the present invention, the upper limit of the normal operating current (third current threshold: If the voltage applied to the LED array is greater than the third current threshold and the voltage applied to the LED array is within the range of the normal operating voltage (voltage threshold), and less than the voltage threshold, The LED array is judged to contain a shorted LED element and stops the current supply from the constant current device so as not to supply the LED module.

The range of the voltage threshold which is the range of the normal operating voltage mentioned above has the range which satisfy | fills following (Equation 1).

{A × (1-1 / B)} to {A × (1-1 / B) + (B-1) × Vf × 0.08} -------- (Equation 1)

Where A is the rated voltage across the LED array.

        B: number of LED elements connected in series

        Vf: Forward voltage of the LED

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated in detail according to drawing.

2 is a driving circuit diagram showing the concept of the LED lighting apparatus according to the present invention.

In FIG. 2, reference numeral 20 denotes an LED module in which LED arrays 21, 22, 23, 24, ..., 2n, in which seven LED elements are connected in series, are connected in parallel, and reference numeral 30 denotes an LED array ( Resistors Rs1, Rs2, Rs3, Rs4, ..., Rsn are connected in series to 21, 22, 23, 24, ..., 2n, respectively, and reference numeral 10 denotes a current for the LED module 20. It is a constant current generator that is a constant current generator for supplying.

The resistor connected to each of the LED arrays is induced with a voltage proportional to the current flowing through the LED arrays, and the induced voltage is determined by the LED array-specific current monitoring 45 to determine the state of deterioration, openness, and short circuit. As described above, in the case of deterioration or opening, the difference with respect to the normal operating current is firstly calculated 55 and controlled by the second operation 57 so that the constant current generator 10 generates a constant current as small as the calculated current value. The signal is sent to the constant current generator 10, and if it is determined that the short circuit in the array-specific current voltage monitoring 45 together with the voltage V _LED of the LED module 20, the constant current is generated in the first operation 55. The control signal is sent to the constant current generator 10 through a quadratic operation 57 so that the device 10 does not generate a constant current.

The second operation 57 detects the temperature of the heat sink (not shown) on which the LED module 20 is installed by the heat sink temperature monitor 85 and generates a control signal so that the constant current generator 10 generates a current in inverse proportion to the temperature. Will be sent.

3 is a driving circuit diagram of the LED lighting apparatus according to the present invention.

FIG. 3 shows a detailed technical configuration of the current monitoring 45, the first operation 55, and the second operation 57 for each LED array in FIG. 2.

In FIG. 3, reference numeral 40 denotes the current magnitude of the LED arrays 21, 22, 23, 24,..., 2n coming from the current sensing means 30 and the magnitude of the voltage V _LED of the LED module 20. The analog-to-digital converter 40 converts an analog signal into a digital signal, and reference numeral 50 denotes an LED- array 21, 22, 23, 24, ..., 2n receiving a digital signal from the analog-to-digital converter 40. Deterioration of the LED arrays 21, 22, 23, 24,..., 2n by comparing the current of the current with the first current threshold and the second current threshold, and the voltage across the LED arrays with the voltage threshold. The microprocessor 50 determines whether the device is open or shorted, and calculates a current value to reduce the constant current generated by the constant current generator 10 in the case of degradation or openness, and outputs the digital value.

In addition, reference numeral 60 denotes a digital-to-analog converter for converting a digital signal output from the microprocessor 50 into an analog signal or a pulse width modulator (PWM) for controlling the constant current generator 10.

Reference numeral 70 is an interface for transmitting events processed by the microprocessor 50 to a remote location not shown, and to communicate to control the LED lighting device according to the present invention at the remote location.

Hereinafter, the constant current generator 10, the analog-to-digital converter 40, the microprocessor 50, the digital-to-analog converter 60 or the pulse width modulator 60, and the interface 70 will be described in detail.

The DC input method of the constant current generator 10 includes a series pass method and a switching constant current method. The AC input method includes a converter method, and the output method outputs a DC constant current. It has a function to adjust the magnitude of the constant current output by the external 0 ~ 5V control signal. In addition, the constant current generator 10 may use a device controlled by the PWM method.

The analog-to-digital converter 40 includes analog values such as the current of each array circuit, the output voltage of the constant current generator 10, the heat sink temperature of the LED arrays 21, 22, 23, 24,. It is scaled to a full scale of the analog-to-digital signal converter (ADC) and sequentially converted. Each digitally converted point is recomputed with a fixed scaling value. For reference, the current magnitude sensing resistors Rs1Rsn connected in series to the LED arrays 21, 22, 23, 24,..., And 2n preferably have a very small resistance value so that the lighting efficiency of the LED lighting device does not decrease. Do.

The microprocessor 50, when the power is applied, the set state of the constant current generating device 10 (the normal state, such as the output voltage, the output constant current, the range of the maximum value, the minimum value) and the LED arrays 21, 22, 23, 24 Read the number of 2n), number of LEDs per array (LEDs per string), and current threshold, voltage threshold and temperature threshold according to LED protection conditions.

Through the analog-to-digital converter 40, the currents I ₁ , I ₂ , I ₃ , I ₄ ,…, I _n and the constant current generator 10 for each of the LED arrays 21, 22, 23, 24,. ), The output voltage (V _LED ) and heat sink temperature are digitally input.

First, check the current of each array circuit to see if the current balance is correct and compare the output voltage of the constant current generator 10 when the current balance is not correct, and analyze LED degradation / short / open of the LED array in question and input current. According to the present invention, the result of the current regulation value for each condition is obtained by comparing with the current threshold.

Second, when the heat sink temperature is above a certain temperature and the output voltage (V _LED ) is below a certain voltage by comparing the voltage (V _LED ) applied to the LED module 20 with the heat sink temperature, it is determined that the internal temperature of the LED is increased, Compute the current limit according to the temperature rise compared to the threshold.

According to the second result, the upper limit of the initial rated current IT1 of the constant current generator 10 is first varied IdT. According to the first result, the rated current is adjusted according to the conditional processing result (IADJ).

These two results yield the following output.

Normal time: IT _(normal) = IT1

Abnormal: IT _(abnormal) = (IT1-IdT)-IADJ

IT1 = initial rated current (current that is initially set and supplied to the lamp in the normal state),

IdT = rated current limit over temperature

IADJ = current regulation value for protection due to LED deterioration (accumulated value of current value to be reduced)

IT _(abnormal) = reset output current (regulated current)

The digital-to-analog converter 60 receives an 8-bit digital signal generally from the microprocessor 50 to control the constant current control signal of the constant current generator 10 and outputs the digital input signal as an analog signal of 0-5V. do.

For example, when the constant current of the constant current generator 10 is output at 100%, the analog current of 0V, 2.5V when the output at 50% is output, and 5V when the output is not output, linearly outputs the constant current generator ( The constant current output of 10) can be controlled.

The pulse width modulator 60 converts a signal received from the microprocessor 50 into a pulse width variation by pulse width modulation (PWM) and adjusts the duty ratio of the pulse within a predetermined frequency range, thereby outputting the constant current generator 10. Can control the magnitude of the output constant current.

For example, if the constant current of the constant current generator 10 is output at 100%, the duty ratio is 0%, if it is output at 50%, the duty rate is 50%, and if it is not output, the duty ratio is 100%. By doing this, the magnitude of the output constant current of the constant current generator 10 can be controlled.

The interface 70 is a current state (I ₁ ~ I _n ) of each of the LED array of the LED lighting device according to the present invention, the total output current (IT) of the constant current generator 10, the output voltage (V) through the serial communication port _It is possible to remotely monitor the status of _LED , heat sink temperature, etc., and provide communication interface to change the current setting and environment setting of LED arrays 21, 22, 23, 24,…, 2n at remote locations. do.

Hereinafter, a control method of the LED lighting apparatus according to the present invention.

4 is a flow chart showing the concept of a control method of the LED lighting apparatus according to the present invention.

First, the concept of the control method of the LED lighting apparatus according to the present invention according to FIG.

As shown in FIG. 4, the user initializes the LED lighting device by inputting an environment setting value which is an operating condition using an input device (not shown) (S100). The operating conditions, which are operating conditions, include the number of LED elements connected in series of each of the LED arrays, the number of LED arrays 21, 22, 23, 24,..., 2n, the first current threshold, the second current threshold, and the first. Input the current threshold of 3, the voltage threshold and the heat sink temperature threshold (if necessary), etc., and set the analog values inputted to the analog-to-digital converter 40 according to the full scale of the analog-to-digital converter 40. Adjust to size.

As shown in FIG. 3, when the constant current IT generated by the constant current generator 10 is supplied to the LED module 20, the currents I ₁ and I are applied to the LED arrays 21, 22, 23, 24,. ₂ , I ₃ , I ₄ ,..., I _n flow, and the resistances R of the current sensing means 30 are caused by these currents I ₁ , I ₂ , I ₃ , I ₄ ,..., I _n . _The voltage applied to _S1 , R _S2 , R _S3 , R _S4 ,..., R _Sn ) is converted into a digital signal by the analog-digital converter 40 in an analog state and input to the microprocessor 50 (S200).

The microprocessor 50 compares the signal input from the analog-to-digital converter 40 with the first current threshold and the second current threshold stored in the microprocessor 50 to determine the first current threshold and the second current threshold. It is determined whether it is within the range of the current threshold (determination of degradation) or less than the second current threshold (open determination) (S300).

When it is necessary to adjust the magnitude of the constant current according to the determined result, the constant current generator 10 calculates the size to be outputted, that is, the constant current adjustment value (S500).

The adjustment value calculated as described above is controlled by the remote monitoring and control panel through the communication interface 70 to determine whether the current control is necessary (S600), and if necessary, to the digital-analog converter / pulse width modulator 60. Outputs a constant current control signal (S700), and proceeds to the next step of system initialization (S100) if not necessary.

The signal input to the digital-analog converter / pulse width modulator 60 is converted into an analog signal or a PWM signal and input to the constant current generator 10 to change the output value of the constant current IT output from the constant current generator 10. S800 and proceed to the next step of system initialization (S100).

In addition, when it is determined that the current balance is greater than or equal to the third current threshold value (S300), and the voltage (V _LED ) applied to the LED module 20 is measured (S400) and smaller than the voltage threshold value, the LED array is short-circuited. The constant current adjustment value calculation (S500) proceeds to reduce the constant current generator 10 so as not to generate a constant current to calculate the size to be output (that is, the constant current generation stop command) to proceed to step S600.

5 is a partial flowchart of a control method of the LED lighting apparatus according to the present invention.

The partial flowchart of the present invention according to FIG. 5 is for explaining the dotted block BL part in FIG. 4 in detail, and whether the LED arrays 21, 22, 23, 24,..., 2n are deteriorated, opened, or shorted. And calculating a magnitude of a signal to be sent to the constant current generator 10 according to the determination result.

As shown in FIG. 5, when the current value of the LED array 21 is compared with the first current threshold value (S310), if the current value of the LED array 21 is greater than or equal to the first current threshold value, the process proceeds to step S200. If it is small, proceed to the next step.

When the current value of the LED array 21 is compared with the second current threshold value (S320), if the current value of the LED array 21 is greater than or equal to the second current threshold value, it is determined to be deteriorated, and the constant current adjustment value according to the deterioration degree is determined. Accumulate (S510). Although only the LED array 21 has been described herein, when there are a large number of deteriorated LED arrays from the LED array 21 to the LED array 2n, the constant current adjustment value according to the deterioration degree is accumulated (S510). do. Here, the accumulated constant current adjustment value (S550), that is, the constant current decrease

to be.

I (x): currents I ₁ , I ₂ , I ₃ , I ₄ ,…, I _n flowing in the LED arrays 21, 22, 23, 24,..., 2n

The microprocessor 50 outputs a signal corresponding to the constant current reduction to the digital-analog converter / pulse width modulator 60 in order to maintain a normal current in the normal LED arrays (S550).

If the current value of the LED array 21 is smaller than the second current threshold in step 320, it is determined to be open and the constant current adjustment value is accumulated (S520). Although only the LED array 21 has been described herein, when there are a large number of open LED arrays determined from the LED array 21 to the LED array 2n, the constant current adjustment value according to each opened number is accumulated (S510). do.

Here, the constant current adjustment value (S550) according to the accumulation of the open circuit, that is, the constant current decrease

Constant current reduction = rated current × (number of open circuits / total array circuits)

to be.

Also, the microprocessor 50 outputs a signal corresponding to the constant current reduction due to the open LED array to the digital-analog converter / pulse width modulator 60 to maintain a normal current in the normal LED arrays (S550).

Then, the current value of the LED arrays 21, 22, 23, 24,..., 2n and the third current threshold value are compared (S330) to determine the LED arrays 21, 22, 23, 24,. If the current value is smaller than the third current threshold, the process proceeds to step S200. If the current value of the LED arrays 21, 22, 23, 24,..., 2n is greater than or equal to the third current threshold, the process proceeds to the next step.

In addition, LED arrays, and proceeds to (21, 22, 23, 24 , ..., 2n) if the voltage (V _LED) and the voltage threshold value for comparison (S410) to voltage (V _LED) or more voltage threshold S400 step applied to, If it is small, proceed to the next step.

If both signals are input in steps S330 and S410, the LED array under measurement among the LED arrays 21, 22, 23, 24,..., And 2n is determined to be short-circuited (S420), and the normal LED of the shorted LED array is determined. For the protection of the device, a stop command signal is generated so that the constant current generator 10 stops the generation of the constant current (here, the stop command signal means a magnitude to be outputted by reducing the constant current from the constant current generator 10). (S530) (S550).

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

Claims (11)

1. In the LED lighting device comprising a plurality of LED modules connected in series a plurality of LED elements connected in parallel LED module,

   A constant current generator for supplying a constant current to the LED module;

   Current sensing means for sensing the magnitude of current flowing through each of the LED arrays;

   An analog-to-digital signal converter which receives the current signals sensed by the current sensing means and the voltage signal applied to the LED array and converts them into digital signals;

   If the current flowing from the current signal input from the analog-to-digital signal converter to the first LED array is less than the first current threshold, it is determined that the first LED array includes a degraded LED element. A central processing unit for calculating a current reduced from the normal current and outputting a current of which the reduced current value is reduced from the rated current supplied to the LED module;

   And a pulse-width modulator for converting a digital signal commanded by the central processing unit into a digital-to-analog converter for converting an analog signal or a pulse width modulated signal.

   And the constant current generator controls the magnitude of the constant current by the signal of the digital-analog converter or the pulse width modulator.
2. The method of claim 1,

   The central processing unit accumulates the reduced current value in LED arrays having a value less than a first current threshold from a first LED array to the plurality of LED arrays, and provides the constant current generator with the reduced current value. And the constant current generator outputs a current which is reduced in rated current by a magnitude of a cumulative value.
3. The method of claim 1,

   The CPU determines that each LED array circuit includes an LED element open to the corresponding LED array when the LED array circuit is smaller than the second current threshold, so that the LED array number of LED arrays including the open LED element is determined. And accumulate the value of the stationary current of the array in the reduced current value.
4. The method according to any one of claims 1 to 3,

   The central processing unit determines that each of the LED array circuits includes a LED element shorted to the corresponding LED array when the voltage signal is greater than a third current threshold and the voltage signal is smaller than the voltage threshold. LED lighting device, characterized in that the command to stop the generation.
5. The method of claim 4, wherein

   The central processing unit compares the voltage applied to the LED module and the voltage threshold, and compares the temperature and the temperature threshold of the heat sink installed in the LED module, the voltage applied to the LED module (V _LED ) is less than the voltage threshold, the heat sink When the temperature exceeds the temperature threshold, the rated current is changed to a current limit value according to the temperature rise of the heat sink.
6. The method of claim 5,

   The first current threshold value is less than the normal current flowing in each LED array in the LED module in the normal state, LED lighting device, characterized in that the range of more than 95% of the normal current.
7. The method of claim 3, wherein

   The second current threshold value is a LED lighting device, characterized in that the current flowing in each LED array in the steady-state LED module is less than 30% of the normal current range.
8. The method of claim 1,

   The LED lighting device controls the magnitude and initial setting value of the current generated by the constant current generator through an interface connected to the central processing unit at a remote location, the current state of each LED array, the output current of the constant current generator, LED lighting device for monitoring the status of the output voltage and the heat sink temperature.
9. An LED module in which a plurality of LED arrays connected in series are connected in parallel, a constant current generator supplying a constant current to the LED module, and a current for sensing the magnitude of the current flowing through each of the LED arrays In the control method of the LED lighting device comprising a sensing means and a central processing unit for controlling the magnitude of the constant current supplied from the constant current generator to the LED module according to the signal detected by the current sensing means,

   Degradation determination step of determining whether the LED device in the first LED array of the plurality of LED arrays is degraded;

   An opening determination step of determining whether the first LED array is open when the LED device of the first LED array is not deteriorated in the deterioration determination step;

   A reduction current calculation step of calculating a magnitude of a current which is reduced from the normal current flowing in the first LED array by being degraded or opened when it is determined that the LED element is degraded or opened in the first LED array;

   A current reduction command step of outputting a signal corresponding to the magnitude of the reduction current to the constant current generator;

   The constant current generating device includes a constant current output step of supplying a constant current reduced in accordance with the decrease current command to the LED module,

   The deciding step of determining whether the current flows through each of the LED arrays is less than a first current threshold that is less than a normal current flowing through the first LED array and is in a range of 95% or more of the normal current, and to the first LED array. And determining that the LED element in the first LED array is deteriorated if the current flowing through is greater than or equal to a second current threshold of 30% or less of the normal current.
10. The method of claim 9,

    The determining whether the opening is smaller than the first current threshold value, and less than the second current threshold value determines that the first LED array is open.
11. An LED module in which a plurality of LED arrays connected in series are connected in parallel, a constant current generator supplying a constant current to the LED module, and a current for sensing the magnitude of the current flowing through each of the LED arrays In the control method of the LED lighting device comprising a sensing means and a central processing unit for controlling the magnitude of the constant current supplied from the constant current generator to the LED module according to the signal detected by the current sensing means,

    A short-circuit determining step of determining whether the first LED array includes a shorted LED element when the LED element of the first LED array is not deteriorated or opened among the plurality of LED arrays;

    A current generation stop command step of instructing to stop the constant current generation of the constant current generator when it is determined that the short circuit of the array includes the LED element shorted in the first LED;

    The constant current generating device comprises: an illumination stopping step of stopping the illumination by stopping the generation of the constant current according to the current generation stop command;

    The short-circuit determining step is a case where the current is greater than or equal to a third current threshold having a value greater than the normal current flowing in the first LED array, and sets a range of the normal operating voltage applied to the LED array as a voltage threshold, and is greater than the voltage threshold. If it is small, the LED array is judged to include a shorted LED element.

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