JP2016085950A - Power supply device for illumination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device for illumination capable of stably detecting the turning-off of a light source without malfunction, and easily achieving fadeout at the time of turning-off.SOLUTION: Voltage level generation means 15 generates a voltage level DCOUT corresponding to a lighting control signal. Lighting control means 16 varies a constant current value flowing to a light source in accordance with the voltage level DCOUT. Turning-off detection means 17 detects the turning-off of the light source after the lapse of a preset time since a timing in which it is detected that the voltage level DCOUT becomes not more than a preset reference voltage Vth2. Stop means 18 stops the operation of the lighting control means 16 when the turning-off of the light source is detected by the turning-off detection means 17.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an illumination power supply device that varies a constant current value flowing through a light source in accordance with a voltage level generated in response to a dimming signal.

  2. Description of the Related Art Conventionally, there is an illumination device that performs light control by changing a constant current control value of a light source current according to a duty ratio of a light control signal that is a PWM signal. Further, there is an illumination device that turns off the light source or gradually turns off (fade out) the light control level according to the light control signal before the light is turned off according to the level of the light control signal.

  As for the duty ratio of the PWM signal sent from the dimmer to the lighting device, when a signal with a deep dimming degree is sent, the light output becomes a low level, and when a signal with a shallow dimming degree is sent, the light output becomes a high level. Be controlled. Further, when the dimming signal is maintained at a high level, the light is turned off.

  However, if turning off is detected only under the condition that the dimming signal maintains a high level, when turning off the lighting device that is turned on with a light output of a predetermined dimming degree, the light output is gradually lowered and turned off ( It is not easy to realize the effect lighting (fade out). Further, the control for directly detecting the pulse signal of the dimming signal and turning off the light may cause malfunction.

JP 2002-190398 A JP 2014-89844 A

  The problem to be solved by the present invention is to provide a lighting power supply device that can stably detect the turning-off of a light source without malfunction and can easily realize a fade-out at the time of turning off.

  The illumination power supply device according to the embodiment includes a voltage level generation unit, a dimming unit, a turn-off detection unit, and a stop unit. The voltage level generation means generates a voltage level corresponding to the dimming signal. The dimming means varies the constant current value flowing through the light source corresponding to the voltage level. The extinguishing detection means detects that the light source is extinguished when a preset time has elapsed from the timing at which the voltage level is detected to be equal to or lower than the preset first setting voltage. The stop means stops the operation of the light control means when the light extinction detection means detects the light extinction of the light source.

  According to the present invention, when the preset time elapses from the timing when it is detected that the voltage level generated by the voltage level generation means is equal to or lower than the preset first set voltage, the extinction detection means is Since the light source is detected to be turned off, the light source is stably turned off without malfunction, and the voltage level generated by the voltage level generation means is supported until the voltage level falls below the first set voltage. Since the constant current value flowing through the light source is gradually reduced by the light control means, it can be expected that fading out at the time of extinguishing can be easily realized.

It is a circuit diagram which shows the power supply device for illumination of one Embodiment. 3 is a timing chart showing the operation of the illumination power supply apparatus according to the embodiment (a) to (f).

  The configuration of one embodiment will be described below with reference to the drawings.

  In FIG. 1, reference numeral 11 denotes an illumination power supply device. The illumination power supply device 11 is a light source corresponding to a duty ratio of a pulse signal (PWM signal) DIMIN that receives a dimming signal input from a dimmer (not shown). The power is supplied to the lighting device that performs light control by varying the constant current control value of the current.

  The illumination power supply device 11 includes a voltage level generation unit 15 that generates a voltage level DCOUT corresponding to the pulse signal DIMIN, and a constant current flowing to the light source corresponding to the voltage level DCOUT generated by the voltage level generation unit 15. Dimming means 16 for changing the current value, extinction detection means 17 for detecting the extinction of the light source, stop means 18 for stopping the operation of the dimming means 16 when the extinction detection means 17 detects the extinction of the light source, and the light source Protection means 19 for stopping the output when the output voltage of the light source becomes equal to or lower than a predetermined voltage, and mask means 20 for masking detection of the output voltage of the light source by the protection means 19.

  The voltage level generation means 15 includes a comparator 22, a switching element Q1 having a gate terminal as a control terminal connected to the output terminal of the comparator 22, and a resistor R1 connected to a drain terminal being an output terminal of the switching element Q1. ˜R3, and the capacitor C1 is connected to the drain terminal of the switching element Q1.

  The comparator 22 has the non-inverting input terminal connected to the reference voltage Vth1, the inverting input terminal receives the pulse signal DIMIN, compares the pulse signal DIMIN with the reference voltage Vth1, and compares the comparison result with the gate terminal of the switching element Q1. Is output. Therefore, the comparator 22 outputs a high level signal when the pulse signal DIMIN is at a low level equal to or lower than the reference voltage Vth1 to turn on the switching element Q1, and when the pulse signal DIMIN is at a high level higher than the reference voltage Vth1. In addition, a low level signal is output to turn off the switching element Q1.

  The switching element Q1 has a pull-up resistor R1 and a grounding resistor R2 connected to the source terminal of the ground and a drain terminal connected to the voltage V (FIG. 2 (a)). A series circuit with the capacitor C1 is connected. The voltage level DCOUT corresponding to the pulse signal DIMIN is generated by the capacitor C1 at the connection point between the resistor R3 and the capacitor C1.

  The light control means 16 is, for example, an inverter circuit, and is connected to a connection point between the resistor R3 and the capacitor C1, and supplies a constant current corresponding to the voltage level DCOUT to the light source.

  The extinction detection means 17 includes a comparator 25, a NOT gate 26, an OR gate 27, a switching element Q2, a constant current source 28 for supplying a constant current I, and an output comparator 29, and a timer. Capacitor C2 is connected.

  The comparator 25 has a non-inverting input terminal connected to the connection point between the resistor R3 of the voltage level generating means 15 and the capacitor C1, an inverting input terminal connected to the reference voltage Vth2 that sets the first set voltage, and an output terminal ORed Connected to gate 27. Therefore, the comparator 25 outputs a high level signal to the OR gate 27 when the voltage level DCOUT is higher than the reference voltage Vth2, and to the OR gate 27 when the voltage level DCOUT is equal to or lower than the reference voltage Vth2. A low level signal is output.

  The NOT gate 26 is connected between the output terminal of the comparator 22 and the OR gate 27. Therefore, the NOT gate 26 outputs a high level signal to the OR gate 27 when the pulse signal DIMIN is at a high level, and outputs a low level signal to the OR gate 27 when the pulse signal DIMIN is at a low level. Is output.

  The OR gate 27 has an output terminal connected to a gate terminal that is a control terminal of the switching element Q2. Accordingly, the OR gate 27 turns on the switching element Q2 when a high level signal is input from at least one of the comparator 25 and the NOT gate 26.

  The switching element Q2 has a source terminal grounded and a drain terminal connected to the non-inverting input terminal of the comparator 29.

  The constant current source 28 is connected to the non-inverting input terminal of the comparator 29.

  The capacitor C2 is connected in parallel to the switching element Q2 with respect to the constant current source 28, and is connected to the non-inverting input terminal of the comparator 29. Therefore, the capacitor C2 is discharged with the switching element Q2 turned on, and is charged by the constant current source 28 with the switching element Q2 turned off (FIG. 2 (e)).

  In the comparator 29, the non-inverting input terminal is connected to the capacitor C2, the constant current source 28, and the drain terminal of the switching element Q2, the inverting input terminal is connected to the reference voltage Vth3 / Vth4, and the output terminal is the stopping means 18. It is connected to the. Vth3 / Vth4 is smaller than Vth3 (Vth4 <Vth3). When comparator 29 is high level output, Vth4 potential is biased to the inverting input terminal of comparator 29 and low level output In this case, the potential of Vth3 is biased to the inverting input terminal of the comparator 29. That is, the comparator 29 operates as a hysteresis comparator. Therefore, when the output is low and the potential CDIM of the capacitor C2 becomes larger than the reference voltage Vth3, the comparator 29 inverts the signal output to the stopping means 18 to the high level signal (extinguishing signal SO) and the output is high. In this state, when the potential CDIM of the capacitor C2 becomes equal to or lower than the reference voltage Vth4, the signal output to the stopping means 18 is inverted to a low level signal.

  The stop means 18 is connected to the light control means 16 and stops the operation of the light control means 16 when a signal is input from the extinction detection means 17 (comparator 29).

  The protection means 19 is connected to the dimming means 16 and detects the output voltage of the light source.When the detected output voltage falls below a predetermined voltage, the protection means 19 determines that the light source is short-circuited. The operation of the light control means 16 is forcibly stopped.

  The mask means 20 is, for example, a comparator, the non-inverting input terminal is connected to the connection point between the resistor R3 of the voltage level generating means 15 and the capacitor C1, and the inverting input terminal sets a reference voltage Vth5 (> Vth2) and the output terminal is connected to the protection means 19. Therefore, the mask means 20 makes the output signal SM high level (FIG. 2 (d)) when the voltage level DCOUT is higher than the reference voltage Vth5, and the operation of the protection means 19 is made effective, and the voltage level DCOUT becomes the reference voltage. When Vth5 or less, the output signal SM becomes low level (FIG. 2 (d)), and the operation of the protection means 19, that is, the detection of the output voltage of the light source is masked by the protection means 19. .

  Next, the operation of the one embodiment will be described.

  In the illumination power supply device 11, the voltage level generation means 15 receives the dimming signal from the dimmer as the pulse signal DIMIN (FIG. 2 (b)), converts it to a voltage corresponding to the pulse signal DIMIN, and converts the signal into a signal ( Voltage level DCOUT) is generated (FIG. 2 (c)). Based on the voltage level DCOUT, the light source is dimmed by controlling the constant current value to the light source by the dimming means 16.

  When the light source is turned off, when the pulse signal DIMIN stops, the voltage level DCOUT gradually decreases according to the capacitance of the capacitor C1. The decrease in the voltage level DCOUT, that is, the discharge speed of the capacitor C1, can be controlled by the capacitance of the capacitor C1. When the comparator 25 detects that the voltage level DCOUT has dropped to a predetermined reference voltage Vth2 or less, the switching-off element Q2 is turned off in the extinction detection means 17, and charging of the capacitor C2 is started by the constant current source 28 ( FIG. 2 (e)). That is, charging of the capacitor C2 is masked until the voltage level DCOUT becomes equal to or lower than the reference voltage Vth2 (charging mask). The charging speed of the capacitor C2 can be controlled by the constant current I of the constant current source 28 and the capacity of the capacitor C2. Then, the extinction detecting means 17 (comparator 29) detects that the potential CDIM of the capacitor C2 exceeds the reference voltage Vth3, that is, when a predetermined time elapses after the voltage level DCOUT drops to a predetermined reference voltage Vth2 or less. The light source is detected to be turned off (determined that the light source is turned off), the comparator 29 outputs a high-level signal (light-off signal SO) to the stop means 18, and the stop means 18 stops the operation of the light control means 16. The extinguishing mode is set. Therefore, the voltage level DCOUT gradually decreases from when the pulse signal DIMIN stops and the voltage level DCOUT starts decreasing until the light source is detected to be extinguished. The light source fade-out is turned off by the dimming means 16 for controlling the constant current value, and a light-off period in which the light source is turned off is entered.

  Further, during lighting of the light source of the lighting device, the protection means 19 detects the output voltage of the light source, and determines that the light source is in a short-circuited state when this output voltage is equal to or lower than a preset voltage. Although the operation is stopped, when the mask means 20 detects that the voltage level DCOUT has become equal to or lower than the reference voltage Vth5, the mask means 20 outputs a low level signal (output signal SM) to the protection means 19. Then, detection of the output voltage of the light source by the protection means 19 is stopped (protection means mask). That is, when turning off is detected, the operation of the protection unit 19 is masked to prevent the protection unit 19 from erroneously detecting a short circuit of the light source due to a decrease in the current of the light source.

  When canceling the extinguishing mode, if the pulse signal DIMIN that received the dimming signal from the dimmer is a high level signal that is equal to or higher than the reference voltage Vth1, the comparator 22 of the extinguishing detection means 17 outputs a low level signal. This low level signal is inverted by the NOT gate 26 and converted into a high level signal and input to the OR gate 27, so that the switching element Q2 is turned on and the capacitor C2 is discharged. When it is detected that the potential CDIM of the capacitor C2 has become equal to or lower than the reference voltage Vth4, the extinguishing signal SO is input to the stop means 18, and the stop of the operation of the dimming means 16 by the stop means 18 is released. In other words, the extinction period is from the timing when the extinction is detected (timing when the potential CDIM of the capacitor C2 exceeds the reference voltage Vth3) to the timing when the extinction mode is released (timing when the potential CDIM of the capacitor C2 becomes equal to or lower than the reference voltage Vth4). (FIG. 2 (f)).

  According to the embodiment described above, when the pulse signal DIMIN that maintains the high level for a preset time is input, or the voltage level DCOUT generated by the voltage level generating means 15 is the preset reference voltage. When a preset time elapses from the timing when it has been detected that Vth2 or less, the light extinguishing detection means 17 detects the extinction of the light source, so that the extinction of the light source can be detected stably without malfunction. In addition, until the voltage level DCOUT generated by the voltage level generation unit 15 becomes equal to or lower than the reference voltage Vth2, the constant current value flowing to the light source by the dimming unit 16 is gradually decreased corresponding to the decrease of the voltage level DCOUT. Therefore, fading out at the time of light extinction can be easily realized.

  Moreover, by adjusting the capacitances of capacitors C1 and C2 and setting the time constant, the time required for the voltage level DCOUT to decrease and the potential CDIM to rise can be easily changed, so the light source fade-out can be easily controlled. .

  Further, the output voltage of the light source is detected by the protection means 19 that detects the output voltage of the light source and stops the operation of the dimming means 16 when the detected output voltage is equal to or lower than a preset voltage. Is masked by the mask means 20 when the voltage level DCOUT generated by the reference voltage Vth5 which is higher than the reference voltage Vth2 is lower than the preset reference voltage Vth5. It is possible to prevent erroneous detection of a short circuit.

  In the above embodiment, the extinguishing detection means 17 may be configured to detect the extinction of the light source when the pulse signal DIMIN detects a high level signal for a preset time or more.

  The capacitors C1 and C2 may be externally attached to the illumination power supply device 11, respectively.

  Although one embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

11 Lighting power supply
15 Voltage level generation means
16 Light control means
17 Light-off detection method
18 Stopping means
19 Protection measures
20 Mask means
DCOUT voltage level

Claims (2)

Voltage level generating means for generating a voltage level corresponding to the dimming signal;
Dimming means for varying a constant current value flowing through the light source corresponding to the voltage level;
An extinction detecting means for detecting extinction of the light source when a preset time has elapsed from a timing when it is detected that the voltage level is equal to or lower than a preset first set voltage;
Stop means for stopping the operation of the dimming means when the turn-off detection means detects that the light source is turned off;
An illumination power supply device comprising: Protection means for detecting the output voltage of the light source, and stopping the operation of the dimming means when the detected output voltage is equal to or lower than a preset voltage;
Mask means for masking detection of the output voltage of the light source by the protection means when the voltage level is equal to or lower than a preset second set voltage higher than the first set voltage;
The illumination power supply device according to claim 1, comprising:

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