JP2012059422A - Led lighting device and luminaire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To light LED lamps with a plurality of rated voltages, and to prevent the LED lamp from getting out of order by suppressing a rush current flowing when the LED lamp is attached to and detached from a lamp socket.SOLUTION: An output control part 5 performs constant current control and then a plurality of LED lamps which has a constant current and different rated voltages, for example, LED lamps which have rated voltages of at least 35 to 70 V can be lighted by the same LED lighting device. Further, an output voltage determination part 4 changes an abnormality determination threshold according to the rated voltage of an LED lamp 110 connected to a lamp socket 120. An overvoltage when the LED lamp 110 is detached can, therefore, be suppressed low, and consequently a rush current flowing when the LED lamp 110 is attached to the lamp socket 120 is suppressed to prevent the LED lamp 110 from getting out of order.

Description

  The present invention relates to an LED lighting device for lighting an LED (light emitting diode), and a lighting fixture using the same.

  In recent years, LEDs have been used instead of fluorescent lamps as illumination light sources. For example, Patent Document 1 discloses an LED lamp having a shape close to a conventional straight tube fluorescent lamp. This LED lamp includes a light source block in which a large number of LEDs are mounted on a strip-shaped mounting board, a straight glass tube that houses the light source block, a base that closes both ends of the glass tube, and a base And a terminal pin for supplying power to the light source block. Such an LED lamp is detachably attached to a lamp socket provided in a dedicated lighting fixture, and electric power (DC power) is supplied from the LED lighting device mounted on the lighting fixture via the lamp socket. Lights up.

  Moreover, there exists a thing described in patent document 2 as a prior art example of an LED lighting device. In the conventional example described in Patent Document 2, a voltage (output voltage) applied to an LED lamp (lamp socket) and a current (output current) flowing through the LED lamp are detected, and the output current is a target value (for example, an LED lamp). Control (constant current control) is performed to adjust the output voltage so as to coincide with the rated current.

JP 2009-43447 A JP 2006-210271 A

  By the way, when the LED lamp is replaced, the LED lamp may be mounted in the lamp socket again after the LED lamp is removed from the lamp socket while the LED lighting device is operating. . In this case, immediately after the LED lamp is removed from the lamp socket, the power supplied to the LED lamp instantaneously becomes zero, so that the voltage supplied from the LED lighting device to the LED lamp is increased to a voltage higher than the steady voltage. End up. Therefore, immediately after the LED lamp is mounted again, an excessive current exceeding the rated value (rush current) may flow through the LED lamp. If such an excessive current flows, there is a possibility that the light emitting diode of the LED lamp may break down.

  In the conventional example described in Patent Document 2, by providing a standby mode in which the supply voltage from the LED lighting device is lower than the steady voltage when the LED lamp is removed, or a stop mode in which the LED lighting device stops. The inrush current described above is avoided. However, since the supply voltage is not sufficiently lowered immediately after the LED lamp is removed, there is a possibility that an inrush current flows when the LED lamp is instantaneously connected.

  Further consideration is that the efficiency of the light emitting diode mounted on the LED lamp is improved year by year. The rated voltage of the LED lamp is a value (= Vf × n) obtained by multiplying the forward voltage Vf of the used light emitting diode by the number n of the light emitting diodes. For example, in the current efficiency, if the forward voltage Vf is 3.5 volts and the number n of light-emitting diodes for obtaining a required light flux is 20, the rated voltage is 3.5 × 20 = 70 volts. However, if the number n of light emitting diodes for obtaining a required light flux can be reduced to 10 by improving efficiency in the future, 3.5 × 10 = 35 volts is the rated voltage. If the LED lighting device performs constant current control, a plurality of LED lamps having a rated voltage of 35 to 70 volts can be lit by a single LED lighting device. However, in order to reduce the inrush current described above, the LED lighting device is stopped at 80 volts, which is slightly higher than the rated voltage (70 volts) after the LED lamp is removed, and then the supply voltage is reduced to a sufficiently low voltage. Even if the configuration is adopted, immediately after the LED lamp with a rated voltage of 35 volts is removed, a supply voltage (80 volts) that is higher than the rated voltage of 35 volts will be generated. If connected, the inrush current mentioned above will flow.

  The present invention has been made in view of the above-described problems, and is capable of lighting LED lamps having a plurality of rated voltages and suppressing an inrush current that flows when the LED lamp is detached from the lamp socket. The purpose is to prevent lamp failure.

  The LED lighting device of the present invention includes a power conversion unit having a variable output voltage, a current detection unit that detects an output current supplied from the power conversion unit to the LED lamp through the lamp socket, and the lamp socket. An output voltage determination unit that detects the output voltage applied to the LED lamp and determines whether or not it is a normal lighting operation voltage, and an output current detected by the current detection unit is made to coincide with a target value. An output control unit that controls the power conversion unit to increase or decrease the output voltage; a connection determination unit that determines whether or not the lamp socket and the LED lamp are connected; and the output voltage determination unit and the connection determination unit. A sequence control unit that determines a period during which the determination operation is prohibited, and the output control unit includes a determination result of the connection determination unit that there is no connection and a determination result of the output voltage determination unit In the case of normal voltage, the power conversion unit is controlled to limit the output voltage to a predetermined lower limit value or less, and when the determination result of the connection determination unit is connected, and the determination result of the output voltage determination unit is normal In the case of voltage, the output voltage is not limited to the lower limit value or less, and the output voltage determination unit is determined by the sequence control unit and during a predetermined period set immediately after the power conversion unit starts operation. The determination level of the abnormal voltage is set according to the lighting voltage of the LED lamp connected to the lamp socket.

  In this LED lighting device, a constant voltage source for applying a constant voltage via the lamp socket, and a detection resistor connected in parallel via the lamp socket to a resistor connected in parallel to the light emitting diode in the LED lamp The connection determination unit determines that there is a connection when a voltage drop in the detection resistor is less than a predetermined threshold, and determines that there is no connection when the voltage drop is equal to or greater than the threshold, It is preferable that the determination operation is stopped at least while a current is supplied from the power conversion unit to the LED lamp.

  In this LED lighting device, the output voltage determination unit sets the abnormal voltage determination level during the predetermined period immediately after the power conversion unit starts operation, and prohibits the setting operation after the setting. Is preferred.

  The lighting fixture of this invention was equipped with the LED lighting device in any one of Claims 1-3, the said lamp socket, the said LED lighting device, and the fixture main body holding the said lamp socket.

  The LED lighting device and the lighting fixture of the present invention can turn on LED lamps having a plurality of rated voltages, and prevent a failure of the LED lamp by suppressing an inrush current that flows when the LED lamp is attached to and detached from the lamp socket. There is an effect that can be done.

It is a circuit block diagram which shows embodiment of the LED lighting device which concerns on this invention. It is a timing chart figure for operation | movement description same as the above. It is operation | movement explanatory drawing of the output voltage determination part in the same as the above. It is a perspective view which shows embodiment of the lighting fixture which concerns on this invention.

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

  FIG. 1 is a circuit block diagram showing an embodiment of an LED lighting device according to the present invention.

  The LED lamp 110 that is turned on by the LED lighting device of the present embodiment has a configuration similar to the LED lamp described in Patent Document 1. That is, this LED lamp 110 closes both ends of a series circuit of a large number of light emitting diodes 111, a resistor R110 connected in parallel to the series circuit, a straight glass tube (see FIG. 4), and the glass tube. And a base (not shown). In addition, a pair of terminal pins (not shown) connected to the output end of the LED lighting device via the lamp socket 120 are projected from the base. Then, a direct current (output current Io) is supplied from the lamp socket 120 to the light emitting diode 111 via the terminal pin. Since the rectifier DB1 is connected between the lamp socket 120 and the series circuit of the light emitting diode 111, there are no restrictions on the combination of the receptacles A1 and A2 of the lamp socket 120 and the terminal pins, and either combination is used. Even in this case, the forward output current Io is supplied to the series circuit of the light emitting diodes 111.

  The LED lighting device of this embodiment includes a boost chopper unit 1, a power conversion unit 2, a current detection unit 3, an output voltage determination unit 4, an output control unit 5, a connection determination unit 6, a constant voltage source 7, a sequence control unit 8, and the like. It has.

  The step-up chopper unit 1 converts the AC voltage supplied from the commercial AC power supply 100 into a desired DC voltage to improve the power factor. Here, if the output voltage of the step-up chopper unit 1 is set to a little over 400 volts, the power supply voltage value can correspond to a wide range of commercial AC power supply 100 with a voltage of 100 volts to 242 volts.

  The power conversion unit 2 includes a conventionally known step-down chopper circuit including a semiconductor switching element (hereinafter abbreviated as a switching element) Q1, such as a bipolar transistor and a field effect transistor, an inductor L1, a diode D1, and a capacitor C1.

  The output voltage determination unit 4 includes a series circuit of voltage dividing resistors R1 and R2 connected between output terminals of the power conversion unit 2 (between both ends of the capacitor C1), two comparators CP101 and CP102, and an abnormality determination unit 40. It comprises. The detection voltage (voltage proportional to the output voltage Vo of the power conversion unit 2) divided by the voltage dividing resistors R1 and R2 and the output voltage of the comparators CP101 and CP102 are input to the abnormality determination unit 40. Is output to the sequence control unit 8. The detection voltage divided by the voltage dividing resistors R1 and R2 is compared with an abnormality determination threshold value set according to the output voltages of the comparators CP101 and CP102 in the abnormality determination unit 40, and the detection voltage is determined to be abnormal. If it exceeds the value, it is determined to be abnormal. Each of the abnormality determination unit 40 and the sequence control unit 8 includes a microcontroller, and performs a clocking operation, a determination operation, reading of data stored in a memory, storage of a set state, etc. set in advance by a program.

  The current detection unit 3 includes a detection resistor R3 inserted between the output terminal on the negative potential side of the power conversion unit 2 and the negative side (A2) of the lamp socket 120. The voltage drop of the detection resistor R3 due to the output current Io is output from the current detection unit 3 to the output control unit 5 as a detection voltage.

  The output control unit 5 includes a drive circuit 50 for driving the switching element Q1 of the power conversion unit 2, a feedback circuit 51 for causing the drive circuit 50 to perform feedback control, a chopper control circuit 52 for controlling the step-up chopper circuit 1, and the like. is doing. The output control unit 5 controls the power conversion unit 2 to increase or decrease the output voltage Vo so that the output current Io detected by the current detection unit 3 matches the target value. When the feedback circuit 51 is configured by an integrating circuit using the operational amplifier OP100, the rated current value data of the LED lamp 110 is stored in advance in the memory of the sequence control unit 8, and the data read from the memory and the current detection unit 3 The detected voltage is compared and calculated, and the output voltage Vo is increased or decreased by adjusting the on-duty ratio of the switching element Q1 so that the detected voltage matches the rated current value (target value) stored in the memory. . That is, the output control unit 5 performs constant current control in which a constant current (rated current) flows through the LED lamp 110.

  As described in the prior art, the rated voltage of the LED lamp 110 is a value (= Vf × n) obtained by multiplying the forward voltage Vf of the used light emitting diode 111 by the number n of the light emitting diodes 111. For example, if the forward voltage Vf is 3.5 volts and the number n of light emitting diodes 111 is 20, the rated voltage is 3.5 × 20 = 70 volts, and if the number n of light emitting diodes 111 is 10, 3.5 × 20 10 = 35 volts is the rated voltage. When the output control unit 5 performs constant current control, a plurality of LED lamps having a constant rated current and different rated voltages, for example, LED lamps having a rated voltage of at least 35 volts to 7 O volts are provided with the same LED lighting device. It becomes possible to light up.

  The output control unit 5 is supplied with control power from the control power supply unit 130. In order to generate a drive signal supplied to the switching element Q1 of the power conversion unit 2, the capacitor C101 is charged from the control power supply unit 130 via the diode D101. However, since the control power supply unit 130 can be configured by a conventionally known circuit, detailed illustration and description of the configuration are omitted.

  The constant voltage source 7 has a resistor R4 having one end connected to the output terminal on the high potential side of the boost chopper unit 1, a cathode connected to the other end of the resistor R4, and an anode connected to the low potential side (A2 of the lamp socket 120). ) And a Zener diode 70 connected to each other. Then, a constant voltage (zener voltage Vz) generated at both ends (between the cathode and anode) of the Zener diode 70 is applied to the lamp socket 120 and the connection determination unit 6 via the resistor R5. Note that the constant voltage (zener voltage Vz) applied from the constant voltage source 7 needs to be lower than the rated voltage of the LED lamp 110. Further, in order to be able to use a plurality of types of LED lamps having different rated voltages, a constant voltage (zener voltage Vz) may be set to be lower than the rated voltage with reference to the LED lamp having the lowest rated voltage.

  Furthermore, when the rated voltage of the LED lamp 110 exceeds the dangerous voltage and the voltage divided by the resistors R5, R6, and R7 exceeds the dangerous voltage, a constant voltage (zener voltage Vz) applied from the constant voltage source 7 Must be lower than the dangerous voltage. The voltage value of the dangerous voltage varies slightly depending on public standards, but is generally a voltage exceeding 50 volts for direct current.

  The connection determination unit 6 includes a series circuit of three resistors R5, R6, and R7 connected between the cathode of the Zener diode 70 and the low potential side (A2) of the lamp socket 120, and a voltage at the resistor (detection resistor) R7. A comparator CP100 is provided for comparing the drop with the threshold voltage Vref1. The connection point between the two resistors R5 and R6 is connected to the high potential side of the lamp socket 120. When the LED lamp 110 is not connected to the lamp socket 120 (no load state), a voltage obtained by dividing the Zener voltage Vz by the three resistors R5, R6, and R7 (resistor R7) at the positive terminal of the comparator CP100. Voltage drop) is input. On the other hand, when the LED lamp 110 is connected to the lamp socket 120 (loaded state), the resistor R110 of the LED lamp 110 is connected in parallel with the two resistors R6 and R7. Therefore, the voltage drop across the resistor R7 in the loaded state is lower than in the no-load state. Here, the threshold voltage Vref1 input to the negative terminal of the comparator CP100 is set between the voltage drop at the resistor R7 in the loaded state and the voltage drop at the resistor R7 in the unloaded state. . Accordingly, the output of the comparator CP100 is H level when there is no load, and L level when there is a load. The output of the comparator CP100 (the determination result of the connection determination unit 6) is input to the sequence control unit 8, and the output control unit 5 is activated or deactivated according to the output of the sequence control unit 8, and the power conversion unit 2 and the step-up chopper unit 1 are activated or deactivated.

  Next, the operation of the LED lighting device of this embodiment will be described in detail with reference to the timing chart of FIG. First, a power switch (not shown) is turned on at time t0, and power supply from the commercial AC power supply 100 is started. The output voltage of the step-up chopper unit 1 before the step-up chopper unit 1 starts operation (from time t0 to t1) is a voltage obtained by full-wave rectifying and smoothing the power source voltage of the commercial AC power source 100 as shown in FIG. It becomes. At this time, the output voltage of the constant voltage source 7 is a constant voltage determined by the Zener voltage Vz as shown in FIG. 2B, and the positive side input voltage of the comparator CP100 constituting the connection determination unit 6 is the LED lamp 110. When connected to the lamp socket 120, the voltage is lower than the threshold value Vref1. The determination result of the presence / absence of connection in the connection determination unit 6 is input to the sequence control unit 8.

  The sequence control unit 8 has a timer function, and the output control unit 5 is not operated until time t1. In addition, when the determination result of the connection determination unit 6 is determined to be connected until time t1, the sequence control unit 8 outputs an operation signal to start the operation of the output control unit 5, and determines connection after time t1. When the connection determination unit 6 determines that there is no connection, the timer function is stopped and the state at time t0 is always maintained.

  After time t1, when an operation signal is output from the sequence control unit 8, the chopper control circuit 52 and the drive circuit 50 of the output control unit 5 output drive signals as shown in FIGS. 2 (f) and 2 (g), respectively. To start. The chopper control circuit 52 is well known in the art and detects the output voltage of the step-up chopper unit 1 and inputs it to the error amplifier. The control (PWM) determines the conduction period of the switching element according to the output signal of the error amplifier. Control). Further, the drive circuit 50 has, for example, a constant voltage buffer function, and the conduction period of the switching element Q1 is increased in accordance with an increase in the current flowing through the resistor R109 connected between the output terminal Pls of the constant voltage buffer function and the ground. It is only necessary to be configured to shorten the length.

  Further, the output terminal of the operational amplifier OP100 of the feedback circuit 51 is connected to the output terminal Pls of the drive circuit 50 through a series circuit of a resistor R100 and a diode D102. Therefore, when the detection voltage input from the current detection unit 3 is low, the output voltage of the operational amplifier OP100 decreases and the amount of current sunk from the output terminal Pls to the operational amplifier OP100 increases and is input from the current detection unit 3. When the detection voltage is high, the output voltage of the operational amplifier OP100 increases and the amount of current sunk from the output terminal Pls to the operational amplifier OP100 decreases. Thus, the on-duty ratio of the switching element Q1 can be adjusted so that the detected voltage matches the rated current value (target value) stored in the memory of the sequence control unit 8. The target value stored in the memory of the sequence control unit 8 is a voltage value lower than the target value corresponding to the rated current value at time t1, as shown in FIG. 2 (e), and the timer function of the sequence control unit 8 Is changed to a voltage value corresponding to the rated current value after time t2 determined by. The reason for performing such control is that the output voltage of the step-up chopper unit 1 rises more gradually as the output power increases, and it takes a relatively long time to reach a predetermined voltage. When the operations of the unit 1 and the power conversion unit 2 are started simultaneously, the power supplied from the power conversion unit 2 to the LED lamp 110 immediately after the operation is started is made as small as possible, and the output voltage of the boost chopper unit 1 is rapidly increased. This is because it is desirable to reach the desired voltage in a short time.

  From time t1 to t2, the output voltage of the step-up chopper unit 1 rises as shown in FIG. At this time, as the output terminal voltage of the power converter 2 (see FIG. 2 (i)) increases, the positive input voltage (see FIG. 2 (b)) of the comparator CP100 constituting the connection determination unit 6; In addition, the positive input voltages of the comparators CP101 and CP101 constituting the output voltage determination unit 4 also increase (see FIG. 2C). Here, as described above, the sequence control unit 8 prohibits the connection determination after time t1, so that no erroneous determination is made even if the positive side input voltage of the comparator CP100 becomes larger than the threshold value Vref1. .

  As shown in FIG. 2 (d), the output voltage determination unit 4 detects an abnormality and a detection voltage determined by the voltage dividing ratio of the resistors R1 and R2 from time t1 to time t3 determined by the timer function of the sequence control unit 8. Abnormality determination is performed by comparing with the value Vth1, and during time t3 to t4 determined by the timer function of the sequence control unit 8, abnormality determination is performed according to the output voltages of the comparators CP101 and CP101 constituting the output voltage determination unit 4 Reset the threshold. Here, the threshold values Vref3 and Vref4 input to the comparator CP101 and the comparator CP102 have a relationship of Vref3> Vref4, and detection is determined by the voltage dividing ratio between the resistors R1 and R2 as shown in FIG. When the voltage is lower than the threshold value Vref4 of the comparator CP102, the abnormality determination unit 40 determines that an LED lamp with a low rated voltage is connected, and changes the abnormality determination threshold value from Vth1 to Vth3 (however, at time t4) Reset to Vth1> Vth3). Although not shown, when the detection voltage determined by the voltage dividing ratio of the resistors R1 and R2 is lower than the threshold value Vref3 and equal to or higher than the threshold value Vref4, the abnormality determination threshold value is set to Vth2, and the threshold value Vref3 If this is the case, the abnormality determination threshold value may be set to Vth1.

  Here, when the LED lamp 110 is removed from the lamp socket 120 at time t5, the current Io flowing through the LED lamp 110 becomes zero as shown in FIG. 2 (j), and the output terminal voltage of the power converter 2 (FIG. 2). (See (i)) starts to rise. When the detection voltage determined by the voltage dividing ratio of the resistors R1 and R2 exceeds the abnormality determination threshold Vth3 at time t5, the abnormality determination unit 40 determines that a load abnormality (no load) has occurred and stops to the sequence control unit 8. Outputs a signal and stops determining subsequent load abnormality. The sequence control unit 8 changes the output of the operation signal so as to stop the operation of the output control unit 5 in response to the stop signal, and the boost chopper unit 1 and the power conversion unit 2 stop the operation.

  When the power conversion unit 2 stops operating, the output voltage Vo of the power conversion unit 2 decreases as shown in FIG. 2 (i), but the time until the capacitor C1 of the power conversion unit 2 is discharged is the connection determination unit 6. The connection determination prohibition by the connection determination unit 6 is resumed when the time determined by the timer function of the sequence control unit 8 (time from time t6 to time t7) elapses. At this time, the timer function of the sequence control unit 8 is reset and returns to the initial state.

  Here, when a voltage higher than the rated voltage of the LED lamp 110 is output from the power conversion unit 2 in the no-load state, an excessive current exceeding the rated value immediately after the LED lamp 110 is connected to the lamp socket 120. May flow. However, in the LED lighting device of this embodiment, the output control unit 5 stops the operation of the power conversion unit 2 until the connection determination unit 6 determines whether the LED lamp 110 is connected, and the connection determination unit 6 is connected ( Since the output control unit 5 starts the operation of the power conversion unit 2 after determining that there is a load state, a voltage higher than the rated voltage is not applied to the LED lamp 110. Further, in the abnormality determination unit 40 of the output voltage determination unit 4, the abnormality determination threshold is changed according to the rated voltage of the LED lamp 110 connected to the lamp socket 120. Therefore, when the LED lamp 110 is removed. Overvoltage can be kept low. As a result, since the inrush current that flows when the LED lamp 110 is mounted in the lamp socket 120 is suppressed, the failure of the LED lamp 110 can be prevented.

  Further, immediately after the LED lamp 110 is removed from the lamp socket 120 and the power conversion unit 2 is stopped, a high voltage is generated in the lamp socket 120. However, if the resistance value of the resistor R5 is set to a relatively small value, the current can flow sharply through the resistor R5 and the Zener diode 70, so that the voltage can be sharply reduced. can do.

  The case where the LED lamp 110 is removed from the lamp socket 120 has been described above. However, when a failure occurs in the LED lamp 110 while the power conversion unit 2 is operating, as described above, the lamp socket 120 is disconnected. The situation is substantially the same as when the LED lamp 110 is removed. Therefore, when a failure such as disconnection occurs in the LED lamp 110, the output control unit 5 stops the operation of the power conversion unit 2, so that the failed LED lamp 110 can be prevented from being used continuously. Here, in the case of a failure in which the line in the LED lamp 110 is short-circuited, the substantial number of the light-emitting diodes 111 is reduced. Therefore, the output controller 5 performs constant current control so that the output of the power converter 2 is output. Since the voltage Vo is lowered, it is not an unsafe failure. However, control is added so that the output control unit 5 stops the constant current control and stops the power conversion unit 2 when the output voltage detected by the output voltage determination unit 4 falls below a predetermined value (<rated voltage). It doesn't matter.

  In the present embodiment, the output control unit 5 stops the power conversion unit 2 at the time of no load or failure, but it is not always necessary to stop it. For example, at the time of no load or failure, the output control unit 5 may control the power conversion unit 2 to limit the output voltage Vo to a lower limit value sufficiently lower than the rated voltage of the LED lamp 110. Moreover, although the LED lighting device of this embodiment lights one LED lamp 110, it is of course possible to light a plurality of LED lamps 110 connected in series simultaneously.

  Furthermore, the abnormality determination unit 40 of the output voltage determination unit 4 may set the abnormality determination threshold value from the relational expression between the output voltage of the power conversion unit 2 and the abnormality determination threshold value as shown in FIG. Further, the abnormality determination unit 40, the two comparators CP101 and CP102, and the sequence control unit 8 may be configured by one microcomputer.

  By the way, the LED lighting device of this embodiment is mounted in the lighting fixture shown in FIG. 4, for example. The lighting fixture includes a fixture main body 130 that is directly attached to the ceiling, and a pair of lamp sockets 120 and 120 provided on the fixture main body 130. The instrument main body 130 is formed in a long rectangular tube shape having a trapezoidal side surface as viewed from the longitudinal direction, and an LED lighting device is accommodated therein. Then, lamp sockets 120 and 120 are disposed at both ends in the longitudinal direction on the lower surface of the instrument main body 130, respectively. The lamp sockets 120 and 120 have the same structure as that of a conventionally known lamp socket for a straight tube fluorescent lamp.

  Here, in the case where a direct current is supplied from one of the two lamp sockets 120, 120 to the LED lamp 110, a direct current may be supplied to the filament portion when the fluorescent lamp is erroneously mounted. . However, since the power conversion unit 2 stops when the output voltage determination unit 4 determines that the output voltage Vo falls below a predetermined value (<rated voltage) as described above, the fluorescent lamp is erroneously attached to the lamp socket 120. There is no risk of an unsafe phenomenon or failure of the LED lighting device.

  Here, since the user cannot tell whether it is safe even if the fluorescent lamp is mistakenly attached to the lamp sockets 120, 120, the electrode shape of the base portion of the LED lamp 110 is different from that of the fluorescent lamp. Therefore, the structure of the lamp sockets 120, 120 may be a structure that matches the electrode shape of the base portion of the LED lamp 110.

2 Power conversion unit 3 Current detection unit 4 Output voltage determination unit 5 Output control unit 6 Connection determination unit 8 Sequence control unit
110 LED lamp
120 Lamp socket

Claims (4)

A power conversion unit having a variable output voltage, a current detection unit for detecting an output current supplied from the power conversion unit to the LED lamp through the lamp socket, and the LED applied to the LED lamp through the lamp socket An output voltage determination unit that detects an output voltage and determines whether or not it is a normal lighting operation voltage, and controls the power conversion unit so that the output current detected by the current detection unit matches a target value. An output control unit that increases or decreases the output voltage, a connection determination unit that determines whether or not the lamp socket and the LED lamp are connected, and a period during which determination operations of the output voltage determination unit and the connection determination unit are prohibited are determined. A sequence control unit,
The output control unit controls the power conversion unit when the determination result of the connection determination unit is not connected and when the determination result of the output voltage determination unit is an abnormal voltage so that the output voltage is set to a predetermined lower limit value. When the determination result of the connection determination unit is connected and when the determination result of the output voltage determination unit is a normal voltage, the output voltage is not limited to the lower limit value or less.
The output voltage determination unit is determined by the sequence control unit and according to a lighting voltage of the LED lamp connected to the lamp socket during a predetermined period set immediately after the power conversion unit starts operation. An LED lighting device, wherein a determination level of the abnormal voltage is set.   A constant voltage source for applying a constant voltage via the lamp socket; and a detection resistor connected in parallel via the lamp socket to a resistor connected in parallel with a light emitting diode in the LED lamp, the connection The determination unit determines that there is a connection when a voltage drop in the detection resistor is less than a predetermined threshold, determines that there is no connection when the voltage drop is equal to or greater than the threshold, and at least from the power conversion unit 2. The LED lighting device according to claim 1, wherein the determination operation is stopped while a current is supplied to the LED lamp.   The output voltage determination unit sets the abnormal voltage determination level during the predetermined period immediately after the power converter starts operation, and prohibits the setting operation after the setting. The LED lighting device according to 1 or 2.   A lighting fixture comprising: the LED lighting device according to any one of claims 1 to 3, the lamp socket, and a fixture main body that holds the LED lighting device and the lamp socket.

Images