JP5738032B2 - LED lighting device - Google Patents

Description

  The present invention relates to an LED lighting device that uses an LED as a light source.

In conventional lighting devices for fluorescent lamps, the lamps to be used are those defined in standards such as JIS, and the lighting devices have been optimally designed according to these lamps.
However, in recent years, light emitting diode lighting devices have begun to spread. Unlike the lighting device for fluorescent lamps, in the light emitting diode lighting device, the number of light emitting diodes to be connected has been arbitrarily determined by the user. For this reason, the light emitting diode lighting device is required to be connectable if the number of light emitting diodes connected to the output is within a certain number range. With respect to this point, there is an example in which the current flowing through the LED is changed by connecting a resistor for model determination to a connected light emitting diode (hereinafter referred to as LED) and reading the resistance value (for example, Patent Document 1).

JP 2004-158840 A

  In the LED lighting device, when the number of series of LEDs is arbitrary under the constant condition of the current flowing to the LED, the output voltage of the boost chopper is constant. There is a problem that the voltage handled by the lighting circuit increases, switching loss increases, and circuit conversion efficiency decreases.

  An object of this invention is to provide the LED lighting device which prevents the fall of circuit conversion efficiency, when the number of connection of LED changes.

The LED lighting device of the present invention is
In an LED lighting device in which an LED module having a plurality of LED elements connected in series is detachably connected,
A DC voltage is input, the magnitude of the input DC voltage is converted, and the DC voltage after the magnitude conversion is applied to a plurality of LED elements connected in series of the connected LED modules to light them. A lighting circuit;
The DC voltage rectified from a rectifier circuit that rectifies an AC voltage into a DC voltage is input, the magnitude of the input DC voltage is converted, and the DC voltage after the magnitude conversion is input to the lighting circuit A rectified voltage conversion circuit that outputs the voltage to the lighting circuit;
When the LED module is connected, a connection number detection unit that detects a connection number equivalent value corresponding to the number of connections of the plurality of LED elements connected in series;
The rectified voltage conversion circuit includes a control unit that controls the magnitude of the DC voltage output to the lighting circuit based on the connection number equivalent value detected by the connection number detection unit. .

  According to the present invention, since the output voltage of the power factor correction circuit is varied according to the number of LEDs constituting the LED module, the circuit efficiency of the circuit constituting the LED lighting device can be improved.

FIG. 3 is a circuit diagram of the LED lighting device 110 according to the first embodiment. The figure which shows the table 410 which the output setting part 4-1 of Embodiment 1 has. FIG. 4 is a circuit diagram of an LED lighting device 120 according to a second embodiment. The figure which shows the table 420 which the output setting part 4-2 of Embodiment 2 has. FIG. 6 is a circuit diagram of an LED lighting device according to a third embodiment.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram of the LED lighting device 110 according to the first embodiment.
The LED lighting device 110 is
(1) an input filter circuit 1 to which an AC power supply AC is input;
(2) a rectifier circuit 60 connected to the input filter circuit 1 for full-wave rectification of the input AC power supply;
(3) A power factor improving circuit 70 (rectified voltage converting circuit) that is connected to the rectifying circuit 60, inputs the output voltage of the rectifying circuit 60, boosts the voltage to a voltage higher than the output voltage, and improves the power factor;
(4) a smoothing capacitor 9 connected to the power factor correction circuit 70 and smoothing the chopper output voltage output from the power factor correction circuit 70;
(5) a lighting circuit 2 connected to the smoothing capacitor 9 and supplying power to the connected LED module 200;
(6) Connected to the output terminal of the lighting circuit 2 and connected to the connection number determination circuit 3 (connection number detection unit) for determining the number of LEDs connected in series in the LED module 200 and the connection number determination circuit 3 to improve the power factor An output setting unit 4-1 (control unit) that sets a chopper output voltage output from the circuit 70.

  The input filter circuit 1 is a noise filter composed of an inductor (not shown) and a capacitor (not shown), and is a circuit that removes noise.

  The rectifier circuit 60 is composed of four diodes 5 to 8 and is a circuit for full-wave rectifying the power supply voltage.

  The power factor correction circuit 70 is a chopper circuit that includes the inductor 20, the diode 21, the FET 22, the control IC 23, and the resistors 24-25. The control IC 23 controls the chopper output to be constant by monitoring the divided voltage values of the resistors 24-25.

  The smoothing capacitor 9 smoothes the chopper output voltage output from the power factor correction circuit 70.

  The lighting circuit 2 is a circuit that causes a direct current to flow through the LEDs 10 to 13 of the LED module 200. For example, a buck converter system or a half bridge system is used. The LED module 200 is detachably connected to the lighting circuit 2. That is, the LED circuit 200 can be connected to various LED modules with different numbers of LED connections, such as 10 or 20 LEDs connected in series. For example, it is assumed that the LED module 200 with 10 LEDs is replaced with the LED module 200 with 20 LEDs.

  The LED module 200 connected to the LED lighting device 110 includes LEDs 10 to 13 connected in series, and is lit by a direct current output from the lighting circuit 2. In FIG. 1, the number of LEDs in series is four as an example, but it is obvious that any number of LEDs may be connected in series.

  The connection number discrimination circuit 3 detects the number of connected LEDs.

  The connection number discrimination circuit 3 according to the first embodiment includes a resistor 40 and a resistor 41. The resistor 40 and the resistor 41 detect the sum of forward voltages of the connected LEDs. More specifically, the resistors 40 and 41 detect a divided voltage (a value corresponding to the number of connections) obtained by dividing the sum of forward voltages of the LEDs to be connected. The table 410 of the output setting unit 4-1 is created based on the detected divided voltage.

  The output setting unit 4-1 sets the output voltage of the boost chopper of the power factor correction circuit 70.

Next, the circuit operation of the LED lighting device 110 will be described.
FIG. 2 is a graph showing the relationship between the number of LEDs connected in series in the LED module 200 and the output voltage output from the power factor correction circuit 70.

  When the AC power supply AC is input to the LED lighting device 110, power is supplied to the LED module 200 via the input filter circuit 1, the rectifier circuit 60, the power factor correction circuit 70, the smoothing capacitor 9, and the lighting circuit 2.

  First, the operation of the power factor correction circuit 70 is started, and the power factor correction circuit 70 outputs a predetermined output voltage (for example, 400 V), and this output voltage is smoothed by the smoothing capacitor 9.

  Next, the smoothed voltage smoothed by the smoothing capacitor 9 is input to the lighting circuit 2, and the lighting circuit 2 supplies power to the LED module 200 (LEDs 10 to 13) based on the smoothed voltage. At this time, the lighting circuit 2 is controlled so that a constant current flows through the LED module 200 (LEDs 10 to 13), and the LED module 200 (LED) is lit.

  When the LED module 200 (LED) is lit, the voltage output from the lighting circuit 2 is a voltage depending on the forward voltage (Vf) of the LEDs 10 to 13 constituting the LED module 200.

  Therefore, when the forward voltage of the LEDs constituting the LED module 200 is 3.5 V, for example, and 10 LEDs are connected in series, the voltage output from the lighting circuit 2 is 35 V.

  The connection number determination circuit 3 detects the output voltage of the lighting circuit 2 at this time, determines that there are ten LEDs, and outputs the determination result to the output setting unit 4-1.

  The output setting unit 4-1 receives the determination result output from the connection number determination circuit 3, compares it with the table 410 (having the contents of the graph shown in FIG. 2), and outputs the power factor improvement circuit 70. A control signal is output to the power factor correction circuit 70 (control IC 23) so that the chopper output voltage becomes a voltage corresponding to the number of LEDs. For example, when the number of LEDs is 10, the output setting unit 4-1 outputs a control signal that causes the output voltage of the power factor correction circuit 70 to be 260V.

  The power factor correction circuit 70 (control IC 23) changes the internal reference value of the control IC 23 based on the input control signal, controls the switching frequency of the MOS-FET 22, and corresponds the chopper output voltage to the control signal. To control the voltage.

  The output voltage output from the power factor correction circuit 70 is gradually decreased from 400V to 260V. Thus, since the output voltage of the power factor correction circuit 70 is slowly (gradually) lowered, the lighting circuit 2 can maintain the constant current supplied to the LED module 200 to be constant, and the LED module 200 emits light. The light does not fluctuate.

  Thus, since the output voltage of the power factor correction circuit 70 is changed in accordance with the number of LEDs constituting the LED module 200, the voltage difference borne by the lighting circuit 2 is reduced as will be described later. It is possible to reduce the switching loss and improve the circuit conversion efficiency.

  For example, when the forward voltage drop of the LED is 3.5 V, the total number of LEDs to be connected is 10, 20, 30, 40, 50, and the total sum is 35V, 70V, 105V, 140V, 175V. When the chopper output voltage output from the power factor correction circuit 70 is constant, for example, 400V, the difference between the boosted chopper output voltage and the forward voltage of the LED is 365V, 330V, 295V, 260V, 225V. Since these voltages are handled by the lighting circuit 2, the smaller the number of connections, the greater the switching loss and the lower the circuit conversion efficiency.

  However, the connection number determination circuit 3 detects the number of connected LEDs, and the output setting unit 4-1 sets the chopper output voltage according to the table 410 as shown in FIG. Since the voltage handled by the lighting circuit 2 can be made constant, an effect that the switching loss does not increase can be obtained even if the number of connected LEDs decreases.

  In the first embodiment, the case where the internal reference value of the control IC 23 is changed to control the chopper output voltage output from the power factor correction circuit 70 has been described. However, the resistance value of the output voltage detection resistor 25 is changed. Even if this method is adopted, the chopper output voltage of the power factor correction circuit 70 can be controlled, so that the same effect can be obtained.

  In the first embodiment, the connection number determination circuit 3 is configured by the resistors 40 and 41, and the output setting unit 4-1 reads the voltage divided by the resistors 40 and 41, and the power factor correction circuit 70 is read. However, the connection number determination circuit 3 may be configured by a comparator such as a comparator, an A / D converter, or the like.

Embodiment 2. FIG.
Parts having the same functions and circuits as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
FIG. 3 is a circuit diagram of the LED lighting device 120 according to the second embodiment, and FIG. 4 shows the contents of the table 420 held by the output setting unit 4-2 of the LED lighting device 120.

  The LED lighting device 120 is further connected to the rectifier circuit 60 with respect to the LED lighting device 110 of the first embodiment, and determines whether the input AC power supply AC voltage is 100V or 200V. A voltage determination unit 30 (AC voltage detection unit) is provided. Although FIG. 3 shows the number-of-connections determination circuit 3, the configuration is, for example, the voltage dividing circuit of the resistors 40 and 41 shown in FIG.

  The input voltage determination unit 30 determines whether the AC power supply AC is 100V or 200V by detecting the output voltage (AC voltage equivalent value) of the rectifier circuit 60.

  FIG. 4 is a diagram showing the contents of the table 420 held by the output setting unit 4-2. The output setting unit 4-2 receives the chopper output voltage output from the power factor correction circuit 70 in accordance with the table 420 having the contents shown in FIG. Set. Specifically, the output setting unit 4-2 determines the type 1 characteristic (100V) among the characteristics of FIG. 4 according to the determination result of the “100V” power supply or the “200V” power supply by the input voltage determination unit 30. Know which type 2 characteristic (200V) should be used. When the characteristics of FIG. 4 are determined, the output setting unit 4-2 controls the output of the power factor correction circuit 70 in accordance with the determination result of the connection number determination circuit 3 (value on the horizontal axis in FIG. 4).

  The table 420 shown in FIG. 4 reduces the chopper output voltage output from the power factor correction circuit 70 when the number of connected LEDs decreases, and also outputs the chopper output from the power factor improvement circuit 70 in accordance with the power supply voltage of the AC power supply AC. It is a characteristic that changes the voltage.

  Since the chopper circuit constituting the power factor correction circuit 70 boosts the power supply voltage of the AC power supply AC, the chopper output voltage must be set to be equal to or higher than the peak value of the power supply voltage of the AC power supply AC. However, when the input power supply range is widened, if the chopper output voltage is set to 100 V with the chopper output voltage set at the power supply voltage 200 V (type 2 in FIG. 4), the chopper output voltage is too large and the efficiency becomes poor. Further, when 200 V is lit with the chopper output voltage set at 100 V (type 1 in FIG. 4), the chopper output voltage becomes lower than the peak value of the power source, and the power factor deteriorates.

  In order to avoid this deterioration in efficiency and power factor, the second embodiment adds the input voltage determination unit 30 to the configuration of the first embodiment, thereby providing “the power supply voltage to be used” and “the number of connected LEDs”. Under any of the conditions, it is possible to obtain the effect of operating the circuit with the optimum circuit conversion efficiency.

Embodiment 3 FIG.
In the third embodiment, the connection number determination circuit 3 is connected to the LEDs 10 to 10 connected by a voltage dividing circuit of the resistor 51 (device-side resistance element) and the resistor 50 (module-side resistance element) provided in the LED module 200. In this configuration, the sum of the 13 forward voltages is detected.

  FIG. 5 is a circuit diagram of the LED lighting device 130 according to the third embodiment.

  The LED module 200 includes a type specifying circuit (an example of resistance 50 and number information) for specifying the type (number of LEDs) of the LED module 200.

  In the third embodiment, the value of the resistor 50 of the LED module 200 is different depending on the number of LEDs mounted. When the LED module 200 is connected, the LED lighting device 130 (output setting unit 4-2) knows the number of LEDs (connection number equivalent value) by the resistor 50.

  The connection number determination circuit 3 detects a value (number information, connection number equivalent value) obtained by dividing the output voltage of the boost chopper by the resistor 51 and the resistor 50. The table 420 of the output setting unit 4-2 is created based on this divided voltage. That is, the horizontal axis of the table 420 is created based on the detected voltage.

  When the AC power supply AC is turned on, the power factor correction circuit 70 operates and outputs, for example, 400 V as an output voltage. At this time, the operation of the lighting circuit 2 is stopped.

  The output voltage of the power factor correction circuit 70 is divided by the resistors 51 and 50, and this divided voltage is input to the connection number determination circuit 3.

  Since the resistance value of the resistor 50 is different depending on the number of LEDs constituting the LED module 200, the divided voltage divided by the resistor 51 and the resistor 50 is a voltage corresponding to the number of LEDs.

  Note that the both-end voltage (divided voltage) of the resistor 50 is lower than the forward voltage Vf of the LEDs 10 to 13, and the LEDs 10 to 13 are not lit.

  Therefore, the connection number determination circuit 3 can determine the number of LEDs before the LED module 200 (LED) is lit.

  After the number-of-connections determination circuit 3 determines the number of LEDs, the output setting unit 4-2 refers to the table 420 held by itself to the power factor improvement circuit 70 so as to obtain an output corresponding to the number of LEDs. A control signal is output, and the power factor correction circuit 70 sets the output voltage to a voltage value corresponding to the number of LEDs.

  Next, the lighting circuit 2 operates to supply a constant current to the LED module 200 to light the LEDs 10 to 13.

  Therefore, since the number of LEDs constituting the LED module 200 can be grasped before the lighting circuit 2 starts to operate, the output voltage of the power factor correction circuit 70 is set to a voltage value corresponding to the number of LEDs, and then the LED Can be turned on, and the circuit efficiency can be improved.

  AC AC power supply, 1 input filter circuit, 2 lighting circuit, 3 connection number discrimination circuit, 4-1, 4-2 output setting unit, 5-8 diode, 9 smoothing capacitor, 10-13 LED, 20 inductor, 21 diode, 22 FET, 23 control IC, 24, 25 resistance, 30 input voltage discrimination unit, 410, 420 table, 50, 51 resistance, 60 rectifier circuit, 70 power factor correction circuit, 110, 120, 130 LED lighting device, 200 LED module .

Claims (4)

In an LED lighting device in which an LED module having a plurality of LED elements connected in series is detachably connected,
A DC voltage is input, the magnitude of the input DC voltage is converted, and the DC voltage after the magnitude conversion is applied to a plurality of LED elements connected in series of the connected LED modules to light them. A lighting circuit;
The DC voltage rectified from a rectifier circuit that rectifies an AC voltage supplied from an AC power source into a DC voltage is input, the magnitude of the input DC voltage is converted, and the DC voltage after the magnitude conversion is converted to the lighting circuit. A rectified voltage conversion circuit that outputs to the lighting circuit as the DC voltage that is input,
When the LED module is connected, a connection number detection unit that detects a connection number equivalent value corresponding to the number of connections of the plurality of LED elements connected in series;
A control unit that controls the magnitude of the DC voltage that the rectified voltage conversion circuit outputs to the lighting circuit based on the connection number equivalent value detected by the connection number detection unit;
An input voltage determination unit for determining the AC power supply,
The controller is
A first characteristic in which the output voltage of the rectified voltage conversion circuit is associated with each number of connected LED elements, and a second characteristic in which the output voltage of the rectified voltage conversion circuit is associated with each number of connected LED elements And the output voltage of the same number of connections as the first characteristic stores the second characteristic higher than the output voltage of the first characteristic,
When the determination result of the AC power supply by the input voltage determination unit is a second AC power supply that supplies an AC voltage having a peak value larger than the peak value of the AC voltage supplied by the first AC power supply, The rectified voltage conversion circuit controls the magnitude of the DC voltage output to the lighting circuit based on the second characteristic and the connection number equivalent value detected by the connection number detection unit, and the input voltage determination unit When the determination result of the AC power source is the first AC power source, the rectified voltage conversion circuit is based on the first characteristic and the connection number equivalent value detected by the connection number detection unit. LE that controls the magnitude of the DC voltage output to the
D lighting device. The connection number detection unit
The LED lighting device according to claim 1, wherein a voltage corresponding to a sum of forward voltages of the LED elements of the plurality of LED elements connected in series is detected as the connection number equivalent value. The LED module
Having unique number information according to the number of the plurality of LED elements,
The connection number detection unit
The LED lighting device according to claim 1, wherein the number information is acquired, and the acquired number information is detected as the connection number equivalent value. The LED module
A module-side resistance element having a resistance value corresponding to the number of the plurality of LED elements;
The LED lighting device is
When the LED module is connected, a device-side resistance element that forms a series connection with the module-side resistance element and is a resistance element that divides the DC voltage that the rectified voltage conversion circuit outputs to the lighting circuit. Prepared,
The connection number detection unit
The LED lighting device according to claim 3, wherein the DC voltage of the rectified voltage conversion circuit divided by the module-side resistance element and the device-side resistance element is acquired as the number information.

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