JP6273885B2 - LED power supply device and LED lighting device - Google Patents

Description

  The present invention relates to an LED power supply device and an LED lighting device.

  Patent Document 1 discloses a circuit device including voltage detection means for detecting the voltage of an output terminal to which an LED is connected. In this circuit device, a signal is generated when the voltage at the output terminal exceeds a predetermined value when there is no load or the like, and the current path in the circuit device is cut based on this signal, thereby obtaining a protective operation. In order to further simplify and reduce the cost of the circuit configuration from the power supply device having such an output voltage detection circuit, a configuration in which the voltage detection circuit is omitted has been proposed.

  Patent Document 2 discloses an LED driving device that determines the connection state of an LED light source from the detection result of the output current and adjusts the output to the LED. The LED driving device includes a converter that outputs a DC voltage to the LED light source, a current detection unit that detects a current flowing through the LED light source, and a drive control unit that controls the converter according to the result of current detection. The drive controller adjusts the output of the converter as if the LED light source is connected if the detected current exceeds the threshold, and reduces the output if the LED light source is not connected if the detected current is less than the threshold. Or stop.

JP-T-2001-501360 Japanese Patent No. 4169008

  However, according to the configuration of Patent Document 2, when a power failure occurs for a short time, there is a problem that the LED that is turned off when the power is stopped does not light up again when the power is restored. Specifically, when the LED current stop is detected by the current detection means, the LED current stop is caused by the input power supply stop (ie, power failure), or the LED is not connected to the output terminal. The control unit does not determine whether this is caused by the fact (that is, no load state). That is, the control unit stops the output of the converter even when a power failure occurs and when there is no load, and maintains the stopped state. If this power outage lasts for a long time, the supply of control power to the control unit is temporarily interrupted during the power outage, the control power is resupplied when the power is restored, and the control unit and the converter are restarted. On the other hand, when the power failure is short (for example, about several tens of milliseconds to 20 seconds), the control power supply to the control unit is not cut off during the power failure, and the control unit continues to stop the output of the converter. The output stop state of the converter, that is, the LED off state is maintained. In this case, in order to relight the LED, the input power must be turned on again to reset the circuit state. This is not preferable because it causes the user to turn on the power again in a dark room that is turned off, especially during a power outage at night.

  Therefore, in the LED power supply device, if the stop of the LED current is caused by a no-load state, the light-off state is maintained, and if it is caused by a short-time power failure, it can be automatically turned on again after the power is restored. desirable. Therefore, an object of the present invention is to provide an LED power supply apparatus that controls output based on the state of LED current, and that is re-lighted when input power is restored even when the input power supply is stopped for a short time. To do.

  The LED power supply device of the present invention includes a capacitor that charges a voltage from an input power supply, a current control circuit that supplies an output current to the LED using the voltage of the capacitor as a power supply, and a detection unit that detects the state of the LED current flowing through the LED. When the detection unit detects that the LED current has stopped operating with the control voltage generated from the capacitor voltage, the current control circuit stops the output operation and measures the elapsed time from the stop of the output operation And a control unit configured to restart the current control circuit according to the elapsed time.

  According to the LED power supply device, the control unit causes the current control circuit to stop the output operation in response to the stop of the LED current, and the elapsed time from the stop of the output operation as long as the control voltage is supplied. In response to this, the current control circuit is restarted. As a result, when the input power supply is stopped, the output operation of the current control circuit is stopped, and when the input power supply is restored in a short time, the LED can be turned on again without requiring the input power supply to be turned on again.

  Here, the detection unit may be a current detection resistor that detects the output current. In this case, the control unit causes the current control circuit to stop the output operation when the detected current detected by the current detection resistor becomes a predetermined value or less. Thereby, the LED power supply device with a simple configuration using the current detection resistor is realized.

  Moreover, it is preferable that a control part performs restart of a current control circuit in multiple times according to elapsed time. Thereby, the expected value of the time lag from the time of power return to LED relighting can be reduced.

  Further, it is preferable that the time from when the output operation is stopped to when the last restart is performed is longer than the time from when the output operation is stopped until the control voltage becomes less than the operable voltage of the control unit. Thereby, the current control circuit can be reliably restarted and the LED can be lit again regardless of the relationship between the return timing of the input power supply and the timing at which the control unit stops operating.

  In addition, it is preferable that the control unit includes a microprocessor, and the time from when the output operation is stopped to when the last restart is performed is longer than the time from when the output operation is stopped until the reset voltage of the microprocessor is reached. . Accordingly, the current control circuit can be reliably restarted and the LED can be lit again regardless of the relationship between the recovery timing of the input power supply and the timing at which the microcomputer is reset.

  In addition, a capacitor voltage detection circuit that detects the voltage of the capacitor is further provided so that the control unit does not restart the current control circuit when the voltage of the capacitor at the time of stopping the output operation exceeds a predetermined value. May be. Thereby, unnecessary restart operation can be eliminated and power consumption during no-load protection can be reduced.

  The LED lighting device of the present invention includes the LED power supply device and an LED. Thereby, even if there is a power failure for a short time, it is possible to realize an LED lighting device in which an LED is relighted without requiring the input power to be turned on again when the input power is restored.

It is a circuit block diagram of the LED power supply device and illuminating device by embodiment of this invention. It is a figure explaining the operation | movement at the time of a power failure in the LED power supply device by embodiment of this invention. It is a figure explaining the operation | movement at the time of a power failure in the LED power supply device by embodiment of this invention. It is a figure explaining operation | movement at the time of no load in the LED power supply device by embodiment of this invention. 4 is a flowchart illustrating an operation of the LED power supply device according to the embodiment of the present invention. It is a circuit block diagram of the LED power supply device and illuminating device by the modification of this invention. It is a circuit block diagram of the LED power supply device and illuminating device by the modification of this invention.

  In FIG. 1, the circuit block diagram of the LED lighting apparatus 3 containing the LED power supply device 1 which concerns on embodiment of this invention is shown. The LED lighting device 3 includes an LED power supply device 1 and an LED 2. An AC power supply AC (for example, commercial power supply) is input to the LED power supply device 1 from the input terminals T1 and T2, and a DC output is supplied to the LED2 from the output terminals T3 and T4 of the LED power supply device 1. LED2 should just be an LED module etc. which consist of a plurality of LED elements 2a connected in series. In FIG. 1, four LED elements 2a are shown, but the number of LED elements 2a connected is arbitrary.

  The LED power supply device 1 includes an input circuit 10, a power factor correction circuit 20 (hereinafter referred to as “PFC 20”), a current control circuit 30, a current detection resistor 40 (detection unit), an auxiliary power supply circuit 50, and a control unit 60. In the description of the present specification, it is convenient for each circuit or component to belong to which block, and the present invention is not bound thereto. Moreover, the same code | symbol is attached | subjected to the same component and the overlapping description is abbreviate | omitted.

  The input circuit 10 includes current fuses 11 and 12, a full wave rectifier 13 and an input capacitor 14. Current fuses 11 and 12 are connected between input terminals T1 and T2 and the input terminal of full-wave rectifier 13, respectively. The input circuit 10 may further include a noise filter, a varistor, and the like as necessary. The input AC voltage is full-wave rectified by the full-wave rectifier 13 and the pulsating voltage generated at the input capacitor 14 is supplied to the PFC 20 at the subsequent stage.

  The PFC 20 includes an inductor 21, a switching element 22, a diode 23, a PWM control circuit 24, a smoothing capacitor 25, a capacitor voltage detection circuit 26, and a current detection resistor 27. The capacitor voltage detection circuit 26 includes components 26a, 26b, and 26c. Includes pressure circuit. In the following description, a node having the same potential as the negative electrode of the capacitor 25 is referred to as ground. Note that the PWM control circuit 24 is grounded by a wiring (not shown). The switching element 22 is PWM-controlled by high-frequency switching by the PWM control circuit 24, thereby improving the input power factor. During the period in which the switching element 22 is on, energy is stored in the inductor 21 by the pulsating voltage from the input circuit 10 flowing through the inductor 21 and the switching element 22. During the period when the switching element 22 is off, the energy stored in the inductor 21 is charged to the capacitor 25 via the diode 23. As a result, the capacitor 25 is charged with a voltage boosted from the input power supply voltage. The PWM control circuit 24 determines the ON width in the PWM control so that the voltage of the capacitor 25 detected by the capacitor voltage detection circuit 26 becomes a desired value, and refers to the current detected by the current detection resistor 27. The operating state of the switching element 22 is determined and controlled.

  The current control circuit 30 includes a switching element 31, an inductor 32, a diode 33, a capacitor 34, and a PWM control circuit 35, and constitutes a step-down chopper circuit. The PWM control circuit 35 is grounded by a wiring (not shown). The current control circuit 30 supplies a limited output current to the LED 2 using the voltage of the capacitor 25 as a power source. The switching element 31 is PWM controlled by the PWM control circuit 35. During the period when the switching element 31 is on, an output current flows through the PFC 20 (capacitor 25) → the switching element 31 → the inductor 32 → the LED 2 → the current detection resistor 40, and energy is stored in the inductor 32. During the period when the switching element 31 is off, the output current flows through the inductor 32 → LED 2 → current detection resistor 40 → diode 33 based on the energy stored in the inductor 32. Capacitor 34 smoothes the output voltage and current. Thereby, the limited direct current is supplied from the current control circuit 30 to the LED 2. In the present embodiment, since the output current of the current control circuit 30 and the LED current flowing through the LED 2 are substantially the same, the output current and the LED current are synonymous terms.

  As will be described in detail later, the PWM control circuit 35 enables or disables the output operation of the current control circuit 30 in accordance with a signal input from the control unit 60. Specifically, the PWM control circuit 35 executes the output operation of the current control circuit 30 by PWM controlling the switching element 31 as described above when the operation signal is input, and the switching element 31 when the stop signal is input. 31 is turned off to stop the output operation of the current control circuit 30.

  The current detection resistor 40 is composed of a low resistance element of about 0.1 to 1Ω. The voltage generated in the current detection resistor 40 is supplied to the control unit 60 as a current detection value. Further, as indicated by a broken line in the figure, a voltage generated in the current detection resistor 40 may be input to the PWM control circuit 35 as a current detection value. In this case, the PWM control circuit 35 determines the PWM width so that the detected current value matches the target value, and the output current (LED current) is subjected to constant current control.

  The auxiliary power supply circuit 50 includes, for example, a constant voltage output circuit such as a step-down chopper circuit, a ringing choke converter circuit, a three-terminal regulator, and the like, and a control power supply for the PWM control circuit 24, the PWM control circuit 35, and the control unit 60 from the voltage of the capacitor 25. Is generated. It is assumed that the auxiliary power supply circuit 50 is grounded by a wiring (not shown). The control power supply may be a low voltage of about 5 to 15 V, and the control power supplies supplied to the PWM control circuit 24, the PWM control circuit 35, and the control unit 60 may have the same voltage value or different voltage values. .

  The controller 60 operates by receiving control power from the auxiliary power circuit 50. The control unit 60 includes a microprocessor (hereinafter referred to as “microcomputer”), and is grounded by a wiring (not shown). The voltage generated in the current detection resistor 40 is input to the control unit 60 as a current detection value. When activated, the control unit 60 (microcomputer) outputs an operation signal (start signal) to the PWM control circuit 35. Thereafter, when the current detection value becomes equal to or less than a predetermined value (for example, zero), a stop signal is output to the PWM control circuit 35 to stop the output operation of the current control circuit 30 and the elapsed time from the stop of the output operation. Measure. As will be described in detail later, the control unit 60 outputs an operation signal (restart signal) to the PWM control circuit 35 at least once after a predetermined period has elapsed after outputting the stop signal. That is, after stopping the output operation of the current control circuit 30, the control unit 60 performs a retry operation for restarting the current control circuit 30 at least once according to the elapsed time from the stop of the output operation.

  Note that the PWM control circuit 35 is input such that any signal is always output from the control unit 60 for processing of the operation signal (start signal, restart signal) and stop signal in the PWM control circuit 35. The operating state of the switching element 31 can be determined based on the signal. Alternatively, any signal may be pulsed from the control unit 60, and the PWM control circuit 35 may determine the operating state of the switching element 31 based on the last received signal. In the examples described below, the former is adopted, but it is clear that the same effect can be obtained by appropriately modifying the processing even if the latter is used.

  Next, the operation of the LED power supply device 1 according to the present embodiment will be described. In addition, in this specification, a short time shall mean any time width of about several tens of milliseconds to 20 seconds.

  With reference to FIG.2 and FIG.3, the operation | movement at the time of a power failure in the LED power supply device 1 is demonstrated. In this example, the output timing of the restart signal from the control unit 60, that is, the retry timing is assumed to be 3 seconds, 6 seconds, and 17 seconds after the output operation of the current control circuit 30 is stopped. .

  FIG. 2 is a diagram for explaining the operation in the case of a relatively short power failure (when the microcomputer of the control unit 60 is not reset during a power failure). For example, it is assumed that the AC power is cut off for 5 seconds due to a lightning strike. To do. 2 shows, from the top, the AC power supply voltage, the LED current, the voltage of the capacitor 25 (hereinafter referred to as “capacitor voltage Vdc”), the operating state of the switching element 31, and the control voltage of the control circuit 60 (hereinafter referred to as “control voltage Vcc”). The horizontal axis represents time. In addition, drawing is a schematic diagram and is not necessarily true to scale.

  It is assumed that normal lighting has been performed until time t1 when a power failure occurs. That is, the AC power is input, the PFC 20 operates so that the capacitor voltage Vdc is constant at 420 V, and the current control circuit 30 operates so that the LED current is constant at 600 mA. As a premise, the forward voltage drop of the LED 2 is 200V, and the voltage drop in the current control circuit 30 is 10V. Further, it is assumed that the control voltage Vcc is 5 V, and the auxiliary power supply circuit 50 can output the control voltage Vcc (5 V) when the capacitor voltage Vdc is 100 V or more. It is assumed that the maximum on-duty in the PWM control of the switching element 31 is 70%.

After the occurrence of a power failure at time t1, the capacitor voltage Vdc decreases.
At time t2, the capacitor voltage Vdc becomes 285V. After the time t2, when the capacitor voltage Vdc falls below 285 V, the switching element 31 operates at the maximum duty (70%), and the LED current decreases.

  At time t3, the capacitor voltage Vdc becomes 210V. After the time t3, when the capacitor voltage Vdc falls below 210V, the voltage drop (200V + 10V = 210V) of the LED2 and the current control circuit 30 is not held even if the switching element 31 operates at the maximum duty (70%), and the LED current Stops (becomes zero). In response to the LED current becoming zero, the control unit 60 outputs a stop signal, and the PWM control circuit 35 stops the operation of the switching element 31. After that, since the capacitor voltage Vdc is equal to or higher than the threshold value 100V, the auxiliary power supply circuit 50 maintains the output of the control voltage Vcc (5V).

  The first retry is performed at time t4 (4 seconds after time t1 and 3 seconds after time t3). However, even if the control unit 60 outputs a restart signal and restarts the current control circuit 30, the LED current does not flow. Since the LED current is not detected by the current detection resistor 40, the control unit 60 outputs the stop signal again. Therefore, the operation state of the entire LED lighting device 3 does not change around time t4.

  At time t5 (5 seconds after time t1 and 4 seconds after time t3), the AC power supply recovers from the power failure, and then the capacitor voltage Vdc is restored to 420 V by the operation of the PFC 20.

  A second retry is performed at time t6 (7 seconds after time t1 and 6 seconds after time t3). That is, the control unit 60 outputs a restart signal to restart the current control circuit 30. As a result, the LED current flows, and the operation state in which the LED current is controlled at a constant current of 600 mA is resumed as before the power failure.

  FIG. 3 is a diagram for explaining the operation in the case of a relatively long short-time power outage (when the microcomputer of the control unit 60 is reset during a power outage). For example, the case where the AC power is cut off for 17 seconds due to a lightning strike. Show. FIG. 3 shows, from the top, the AC power supply voltage, the LED current, the capacitor voltage Vdc, the operating state of the switching element 31, and the control voltage Vcc, and the horizontal axis represents time. In addition, drawing is a schematic diagram and is not necessarily true to scale.

  In FIG. 3, before time t1 and from time t1 to time t4 are the same as in FIG. That is, a power failure occurs at time t1, and the capacitor voltage Vdc starts decreasing, the LED current starts decreasing at time t2, the LED current becomes zero at time t3, and the first retry is performed at time t4. LED2 is not lit again. At the time t6, the second retry is performed. In this example, the LED current does not flow even in the second retry, and therefore the LED current is not detected. Therefore, as in the first retry at the time t4, The operation state of the LED lighting device 3 as a whole does not change before and after.

  At time t7 (15 seconds after time t1 and 14 seconds after time t3), the capacitor Vdc is less than 100 V, and the control voltage Vcc is less than the operable voltage of the control unit 60, that is, the microcomputer reset voltage. Thereby, the microcomputer is shut down.

  At time t8 (17 seconds after time t1 and 16 seconds after time t3), the AC power supply recovers from the power failure, and then the capacitor voltage Vdc recovers to 420 V by the operation of the PFC 20. Immediately after time t8, the capacitor voltage Vdc exceeds 100V, and the output of the control voltage Vcc (5V) is resumed. Thereby, the microcomputer of the control unit 60 is restarted, and a start signal is output to the PWM control circuit 35 to start the current control circuit 30. Thereby, LED2 is lighted.

  A third retry is scheduled at time t9 (18 seconds after time t1 and 17 seconds after time t3), but in this example, this retry is not executed. Here, in the following description, the time (17 seconds in this example) from the operation stop time (t3) of the current control circuit 30 to the time (t9) at which the last retry is scheduled is referred to as a retry period. In addition, the time from the operation stop time (t3) of the current control circuit 30 to the time (t7) when the control voltage Vcc becomes less than the operable voltage of the control unit 60, that is, the time to reach the reset voltage of the microcomputer (in this example, 14 seconds) is referred to as a reset period. If the power failure recovers between the last retry and the reset of the microcomputer if the retry period is shorter than the reset period (although in rare cases), the last retry will not occur and the microcomputer will not be reset. Thus, the stop signal is maintained even after the input power supply is restored. In such a case, the LED lighting does not return even though the input power is restored. Therefore, it is desirable that the retry period be set longer than the reset period.

  As a result, the operation of the current control circuit 30 is resumed by either retry or reset regardless of when the input power supply recovers from the occurrence of a power failure. The reset period is determined by the capacitor voltage Vdc, the capacitance of the capacitor 25, the specifications of the auxiliary power supply circuit 50, and the like. The retry period may be set longer by several seconds (about 1 to 5 seconds) than the reset period in consideration of variations in the reset period.

  As a reference, FIG. 4 shows the operation of the LED power supply device 1 when there is no load. 4 also shows the AC power supply voltage, the LED current, the capacitor voltage Vdc, the operating state of the switching element 31, and the control voltage Vcc from the top, as in FIGS. 2 and 3, and the horizontal axis represents time. In addition, drawing is a schematic diagram and is not necessarily true to scale.

  It is assumed that an unloaded state (for example, disconnection of the LED 2) occurs at time t11, and the LED current stops. In response to the LED current becoming zero, the control unit 60 outputs a stop signal, and the PWM control circuit 35 stops the operation of the switching element 31. Since the AC power supply voltage is input after that, the capacitor voltage Vdc is maintained at 420 V by the operation of the PFC 20, and the control voltage Vcc (5 V) from the auxiliary power supply circuit 50 is also maintained. The no-load state will continue after that.

  Retry is performed at time t12 (after 3 seconds from time t11), time t13 (after 6 seconds from time t11), and time t14 (after 17 seconds from time t11). In each retry operation, the control unit 60 outputs a restart signal and outputs a stop signal again because no LED current is generated even if the current control circuit 30 is operated. Therefore, the operation state of the LED lighting device 3 as a whole does not change before and after each retry operation. Thus, when there is no load, the protection state due to the operation stop of the current control circuit 30 is maintained. Note that for relighting, it is necessary to eliminate the no-load state and to turn on the input power again.

FIG. 5 is a flowchart showing the operation of the LED lighting device 1.
If the control voltage Vcc generated by the auxiliary power supply circuit 50 exceeds the reset level Vth of the microcomputer in step S100, the microcomputer is activated in step S105. In step S105, the number of restarts (retry number n), which will be described later, is set to zero.

  In step S110, the control unit 60 determines whether or not the LED current Iout detected by the current detection resistor 40 is equal to or less than the threshold value Ith (for example, whether or not the LED current Iout is 0A). When the LED current Iout is less than or equal to the threshold value Ith (step S110, YES), in step S115, the control unit 60 outputs a stop signal to the PWM control circuit 35 to stop the output operation of the current control circuit 30.

  In step S120, the control unit 60 determines whether or not the number of retries n is less than the set value N. In this example, N = 3. If the number of retries n has reached the set value N (step S120, NO), the process ends and the output stop state is maintained. If the number of retries is less than the set value N (step S120, YES), the process proceeds to step S125.

  In step S125, the length of the timer, that is, the timing of the next retry is set according to the number of retries n. In this example, when the number of retries n is 0, the length of the timer is 3 seconds (t3 to t4 in FIGS. 2 and 3), and when the number of retries n is 1, the length of the timer is 3 seconds. (T4 to t6 in FIGS. 2 and 3), and when the number of retries n is 2, the length of the timer is 11 seconds (t6 to t9 in FIGS. 2 and 3).

  In step S130, the control unit 60 determines whether or not the timer set in step S125 has expired. If the timer has not expired (step S130, NO), the process proceeds to step S135. If the timer has expired (step S130, YES), the process proceeds to step S145.

  In step S135, when the control voltage Vcc is equal to or lower than the reset level Vth of the microcomputer (step S135, YES), the operation of the microcomputer is stopped in step S140, and the process returns to step S100. Thereby, when the control voltage Vcc next exceeds the reset level Vth (step S100, YES), the current control circuit 30 is started. When the control voltage Vcc exceeds the microcomputer reset level Vth (step S135, NO), the timer continues counting. Thereby, the process according to the elapsed time from the output operation stop by step S115 is performed.

  In step S145, the control unit 60 outputs a restart signal to the PWM control circuit 35 to restart the output operation of the current control circuit 30, and in step S150, increments the number of retries n. The process returns to step S110. Here, when the LED current Iout is zero (step S110, YES), the output operation of the current control circuit 30 is stopped again (step S115), and the subsequent retry processing is performed.

  As described above, according to the LED power supply device 1 of the present embodiment, when the stop of the LED current is detected, the control unit 60 causes the current control circuit 30 to stop the output operation and the elapsed time from the output stop. The current control circuit 30 is restarted according to the elapsed time as long as the measured control voltage supplied from the capacitor 25 is equal to or higher than a predetermined value. As a result, in an LED power supply device that controls output based on the LED current state (that is, does not detect the output voltage or LED voltage), even when the input power supply is stopped for a short time, the input power supply is restored when the input power supply is restored. It becomes possible to light up the LED again without requiring it to be turned on.

  Although preferred embodiments of the present invention have been described above, the present invention can be modified into various modes as shown below, for example.

(1) Modification of the detection unit that detects the state of the LED current In the above embodiment, as the detection unit that can be realized most simply, the current detection that detects the output current of the current control circuit 30 (current substantially equal to the LED current). Although the resistor 40 is shown, the detection unit may be an illuminance sensor that detects illuminance substantially proportional to the LED current, as shown in FIG. The LED power supply device 1 in FIG. 6 is the same as the LED power supply device 1 in FIG. 1 except that an illuminance sensor 45 is provided as a detection unit. The illuminance sensor 45 is provided in the vicinity of the LED 2 and detects illuminance proportional to the LED current. The voltage conversion value of the illuminance detected by the illuminance sensor 45 is input to the control unit 60. The present invention is implemented by processing this voltage conversion value in the same manner as the current detection value of the above embodiment.

(2) Change in the number of retry settings In the above embodiment, the number of retry settings is three as an example, but the number of retry settings may be smaller or larger. By reducing the number of retry settings, the control configuration can be simplified, and conversely, by increasing the number of retry settings, the expected value of the time lag from input power recovery to LED relighting can be reduced.

(3) Modification of no-load operation In the above embodiment, a configuration is shown in which a retry is performed even when a power failure is detected or when no load is detected. However, a configuration may be adopted in which no retry is performed when no load is detected. For example, as shown in FIG. 7, when the detection voltage of the capacitor voltage detection circuit 26 is input to the control unit 60 and it is detected that the LED current has stopped (t3 in FIGS. 2 and 3). When the capacitor voltage Vdc at t11) of 4 is equal to or greater than a predetermined value, the control unit 60 may not restart the current control circuit 30 on the assumption that no load is detected instead of a power failure. As a result, unnecessary retry operations can be eliminated, and power consumption during no-load standby can be reduced.

(4) Modification of PFC 20 In the above embodiment, the PFC is adopted as the preceding circuit of the current control circuit 30, but the capacitor 25 and the full-wave rectifier 13 are premised on the assumption that the power factor, power supply harmonics, and the like become desired values. A so-called capacitor input type circuit in which no switching circuit is provided may be employed. Furthermore, although the case where the input power source is an AC power source has been described in the above embodiment, the present invention can also be applied when the input power source is a DC power source. In this case, the full-wave rectifier 13 is not necessary.

(5) Modification of Current Control Circuit 30 In the above embodiment, the current control circuit 30 is configured by a step-down chopper circuit, but may be a circuit of another system such as a flyback converter or a bridge type converter.

1 LED power supply 2 LED
3 LED lighting device 25 Capacitor 30 Current control circuit 40 Current detection resistor (detection unit)
45 Illuminance sensor (detection unit)
60 Control unit

Claims (7)

An LED power supply,
A capacitor for charging the voltage from the input power supply;
A current control circuit for supplying an output current to the LED using the voltage of the capacitor as a power source;
A detection unit for detecting a state of an LED current flowing through the LED;
When the detection unit detects that the LED current is stopped by operating with a control voltage generated from the voltage of the capacitor, the current control circuit stops the output operation and the output operation is stopped. the elapsed time is measured, the control voltage supplied from the capacitor as long as a predetermined value or more, and a configured controlled unit so as to restart the current control circuit in accordance with the elapsed time LED power supply.   The LED power supply device according to claim 1, wherein the detection unit includes a current detection resistor that detects the output current, and the control unit detects that the detection current detected by the current detection resistor is equal to or less than a predetermined value. An LED power supply device configured to cause the current control circuit to stop the output operation.   3. The LED power supply device according to claim 1, wherein the control unit is configured to restart the current control circuit a plurality of times according to the elapsed time.   4. The LED power supply device according to claim 1, wherein the time from when the output operation is stopped to when the last restart is performed is determined by the control voltage from the time when the output operation is stopped until the control is performed. LED power supply device, which is longer than the time until it becomes less than the operable voltage of the part.   The LED power supply device according to any one of claims 1 to 3, wherein the control unit includes a microprocessor, and a time from when the output operation is stopped until the last restart is performed. An LED power supply unit that is longer than the time from when it is stopped until it reaches the reset voltage of the microprocessor. The LED power supply device according to any one of claims 1 to 5, further comprising a capacitor voltage detection circuit that detects a voltage of the capacitor.
When the voltage of the capacitor in the stop-time of the output operation is above a predetermined value, configured to pre-Symbol controller as no load is detected rather than the power failure does not perform restart of the current control circuit LED power supply. An LED lighting device comprising: the LED power supply device according to any one of claims 1 to 6; and the LED.

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