KR20140111422A - Lighting apparatus - Google Patents

Abstract

The present invention discloses a lighting apparatus which realizes stable control of dimming a lamp comprising LEDs and the like. The lighting apparatus increases efficiency of electric power by driving electric power, supplied to the lamp, in an electric current regulating method; can perform constant electric current control to enable the lamp to maintain constant brightness; can perform dimming control for controlling the brightness of the lamp; can supply electric power to the lamp and peripheral circuit modules in common; and has a constant voltage control structure by which a level of driving voltages, supplied to a power source, is controlled to be maintained at a certain level or higher.

Description

LIGHTING APPARATUS

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting apparatus, and more particularly, to a lighting apparatus that realizes stable dimming control for a lamp composed of a light emitting diode or the like.

In recent years, a lighting apparatus has been replaced by a light emitting diode (hereinafter referred to as "LED") which can be realized to have a relatively long lifetime, low power consumption, and high brightness, instead of an incandescent lamp or a fluorescent lamp.

As an example of the above-mentioned lighting device, an indoor lamp, a crime prevention lamp, a street lamp, or the like can be exemplified, and the lighting device employing the LED illumination lamp is also developed and commercialized as the above-mentioned interior lamp, crime prevention lamp or street lamp.

Conventional LED lighting devices are generally implemented by using a commercial AC power supply using a SMPS (Switching Mode Power Supply: hereinafter referred to as "SMPS") module.

An example of a conventional LED lighting apparatus configured as described above is disclosed in Korean Patent No. 10-1164631, which has a configuration in which a commercial AC power source supplies power to an LED via an SMPS module and a driving circuit.

A conventional LED lighting apparatus may further include a sensor board including a sensor for illuminating or sensing a human body for dimming control or switching control. In this case, the LED lighting device is configured to supply power to the sensor board through the SMPS module.

However, the above-described conventional LED lighting apparatus has a disadvantage in that it has a complicated structure due to the constitution of the SMPS module for supplying power to the LED lighting lamp and the driving circuit for driving the LED by the current driving method.

Further, in the conventional LED lighting apparatus, the SMPS module is designed to have a power efficiency of about 90%, and the driving circuit is designed to have a power efficiency of about 90%. As a result, the overall power efficiency of conventional LED lighting devices is designed to be approximately 81%. Thus, the conventional LED lighting apparatus has a problem that the overall power efficiency is lowered due to the complicated configuration.

Further, a peripheral circuit module such as a sensor board may be additionally formed in the LED lighting device. Even in this case, most of the electric power is consumed in the driving circuit for driving the LED.

Therefore, the conventional LED lighting apparatus has a problem that the power efficiency is lowered, and the power efficiency is also lowered for the peripheral circuit modules that are additionally constructed.

In addition, the conventional LED lighting apparatus can realize dimming control in a constant current control system.

In this case, a dimming control processor may be configured for dimming control. The dimming control processor requires more than a certain level of operating voltage for constant current control.

The operating voltage may be provided using a driving voltage, which is an output voltage applied to an LED lamp configured by a lamp.

However, when the light output is controlled to be very low, such as the dimming off state, the driving voltage provided to the lamp for light output is difficult to maintain the level required to generate the operating voltage required by the dimming control processor.

As described above, when the driving voltage falls below the level required to generate the operating voltage required by the dimming control processor, the conventional lighting device is difficult to perform stable dimming control.

An object of the present invention is to provide a lighting device capable of supplying power while maintaining high power efficiency for driving a lamp composed of a light emitting diode or the like.

Another object of the present invention is to provide a lighting device having a simple structure and high power efficiency by supplying power to not only a lamp but also a peripheral circuit module configured for dimming control or the like in common.

Further, the present invention provides an operation voltage of a dimming control circuit using a driving voltage for driving a lamp, and can maintain a level at which a driving voltage can be used as an operating voltage even if a driving voltage level is lowered for dimming control And a lighting device provided with the lighting device.

A lighting device according to the present invention includes: a power conversion circuit for converting a rectified voltage into a driving voltage by using a transformer; A lamp provided with the driving voltage; A dimming control circuit for providing a dimming control signal corresponding to an external control signal and operating using the driving voltage; And a driving control circuit for controlling the power conversion in accordance with the result of monitoring the power conversion and the dimming control signal, wherein the driving voltage is sensed and the driving voltage is maintained at a predetermined voltage or higher .

According to the present invention, the lighting apparatus can have a high power efficiency, and power can be supplied to peripheral circuit modules such as a sensor board and a communication module while maintaining high power efficiency, even with a simple structure.

Further, the present invention can provide the operating voltage of the dimming control circuit using the driving voltage for driving the lamp, and even if the level of the driving voltage such as dimming off is low, the level of the driving voltage can provide the operating voltage The control is performed so as to maintain a predetermined level or more, so that stable dimming control is enabled.

1 is a circuit diagram showing a preferred embodiment of a lighting apparatus according to the present invention;
Fig. 2 is a waveform diagram of a primary side coil and a secondary side coil of a transformer; Fig.
3 is a timing diagram illustrating a method of performing current control in the embodiment of FIG.
4 is a timing diagram illustrating a method for the embodiment of FIG. 1 to perform dimming control by a control signal;
5 is a waveform diagram of output current versus output voltage by dimming control;
6 is a circuit diagram showing another embodiment according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood that the terminology used herein is for the purpose of description and should not be interpreted as limiting the scope of the present invention.

The embodiments described in the present specification and the configurations shown in the drawings are preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention and thus various equivalents and modifications Can be.

The embodiment according to the present invention has a structure in which power efficiency is improved by driving a power source supplied to the lamp 100 in a current regulating manner.

In addition, the embodiment of the present invention has an improved structure in which the lamp 100 can maintain a constant brightness by performing current control. The current control is preferably a constant current control.

In addition, the embodiment according to the present invention has a dimming controllable structure for controlling the brightness of the lamp 100.

In addition, the embodiment according to the present invention can supply the power supplied to the lamp 100 to the peripheral circuit module in common, and the level of the driving voltage supplied to the power supply can be controlled to a certain level Or more.

1, an embodiment according to the present invention includes a power supply circuit 10, a power conversion circuit 20 including a transformer T, a drive control circuit 30, a dimming control circuit 50, (60).

The power supply unit 10 has a configuration of full-wave rectifying the AC power and outputting it as a rectified voltage. That is, the power supply unit 10 has a structure in which the power supply 12 and the rectification circuit 14 are connected in parallel.

The power source 12 is preferably a commercial power source as the AC power source.

The rectifying circuit 14 has a configuration for full-wave rectifying an AC power source having a sinusoidal waveform supplied from the power source 12 and outputting it with a rectified voltage having a ripple component.

The rectified voltage output from the power supply unit 10 is provided to a power conversion circuit 20 for converting the rectified voltage to a driving voltage V using a transformer T. [

The power conversion circuit 20 performs power conversion corresponding to the rectified voltage supplied to the primary coil L1 of the transformer T and supplies the power to the secondary coil L2 via the diode D1 and the capacitor C1 And outputs a driving voltage (V).

The transformer T is configured to have a primary side coil L1, a secondary side coil L2 and an auxiliary coil L3 and a winding ratio of the primary side coil L1 and the secondary side coil L2 is N: 1 Can be set. Here, N can be set to any constant.

The auxiliary coil L3 is configured to sense a current induced in the secondary coil L2, and various winding ratios can be applied according to the manufacturer's intention. It is preferable that the auxiliary coil L3 is applied with a winding ratio to induce the current to a level that can provide the internal voltage Vcc of the drive control circuit 30. [

The transformer T outputs the induced current to the secondary coil L2 by the current flow of the primary coil L1 to which the rectified voltage is applied and the induced current of the secondary coil L2 is output to the diode Is rectified and smoothed by the capacitor (D1) and the capacitor (C2) and converted into a driving voltage (V) and output.

Further, current is also induced in the auxiliary coil L3 by the current flow of the primary coil L1 of the transformer T.

The rectified voltage is driven by the drive control circuit 30, which will be described later, on the primary coil L1 of the transformer T described above.

The driving voltage V output from the power conversion circuit 20 including the transformer T is supplied to the lamp 100 and the dimming control circuit 50 as a common power.

The driving voltage V provided to the lamp 100 and the level of the operating voltage required for the operation of the dimming control circuit 50 are different from each other. Generally, the driving voltage V of the lamp 100 is higher than the operating voltage required for the operation of the dimming control circuit 50.

Therefore, the output of the power conversion circuit 20, that is, the driving voltage V, is voltage regulated in the dimming control processor 52 of the dimming control circuit 50 to be converted into a working voltage at a level lower than the driving voltage V And then used. According to the manufacturer's intention, the voltage regulation may be configured within the dimming control processor 52 as described above, or may be configured by a separate voltage regulator.

The embodiment according to the present invention will be described with reference to FIG. 1, in which voltage regulation is performed in the dimming control processor 52. Voltage regulation is performed by a separate voltage regulator 54, Will be described later.

Meanwhile, the lamp 100 receives the output of the power conversion circuit 20, that is, the driving voltage V, to perform the light emission.

The lamp 100 according to an embodiment of the present invention includes one or more light emitting diodes, and more preferably, the plurality of light emitting diodes may be configured as an array. In addition, the lamp 100 may be realized by various light sources that emit light by application of an electrical physical quantity such as a fluorescent lamp other than a light emitting diode.

The lamp 100 may be an indoor lamp, a crime prevention lamp, or a street lamp. The lamp 100 may be a sub-illuminating lamp installed on a crosswalk and illuminating a crosswalk.

The dimming control circuit 50 configured by the embodiment of the present invention may be included in the peripheral circuit module supplied with power. The dimming control circuit 50 and the lamp 100 are configured to receive power supply in common.

The peripheral circuit module may include various devices that require power supply, such as a configurable communication module to control dimming or on / off of the lamp 100.

The dimming control circuit 50 is configured to provide a dimming control signal corresponding to an external control signal and to operate using the driving voltage V. [

The dimming control circuit 50 is configured to generate and output a dimming control signal by performing current control corresponding to the control signal.

The dimming control circuit 50 can receive an on / off signal for controlling the output of the visible light sensor CDS or the infrared sensor PIR or the dimming on / off, as an external control signal Din. The visible light sensor (CDS) is a sensor that senses the ambient brightness (illuminance), and the infrared sensor (PIR) is a sensor that senses the motion of the human body.

The control signal Din is input to the dimming control processor 52 included in the dimming control circuit 50.

The control signal Din may be provided as a pulse signal or a DC voltage. The dimming control circuit 50 converts the control signal Din provided as an external pulse signal or a DC voltage into a pulse to generate a dimming-out signal Do, And a dimming control processor 52 for outputting the dimming control signal.

Here, the dimming control processor 52 may perform dimming control by varying the pulse width of the dimming-out signal Do. For example, the dimming-out signal Do may be defined as to turn off the lamp 100 if it is output to have a duty ratio of less than 10%.

The dimming control processor 52 operates using the operating voltage whose level of the driving voltage V is converted.

The dimming control processor 52 outputs a dimming-out signal Do corresponding to a control signal Din inputted as a pulse signal or a DC voltage, and the dimming-out signal Do is outputted as a pulse .

The dimming control circuit 50 may be configured to include the dimming control processor 52 and the transfer circuit described above.

The transfer circuit includes an inverter IV for inverting the dimming out signal Do output from the dimming control processor 52, a transistor Q2 switched by the output of the inverter IV, a light emitting diode A resistor RD1 connected to the light emitting diode PD1 and a resistor R1 connected to the emitter of the light receiving transistor PT1 and the light receiving transistor PT1 switched by receiving light from the light emitting diode PD1 . Here, the resistor RD1 has a configuration in which the drive voltage V is applied to one end, and the drain of the transistor Q2 is grounded. The light emitting diode PD1 and the light receiving transistor PT1 constitute a photocoupler.

The transfer circuit configured as described above performs the operation of providing the driving control circuit 30 with a dimming control signal corresponding to the dimming-out signal Do.

That is, the inverter INV inverts the dimming-out signal Do to the gate of the transistor Q2, the transistor Q2 is controlled to be switched by the dimming-out signal Do, and the light-emitting diode PD1 Light emission and extinction are performed in synchronization with the turn-on and turn-off of the transistor Q2, and the light-receiving transistor PT1 performs turn-on at the time of light emission of the light-emitting diode PD1.

That is, a pulse signal is generated in accordance with a state in which the light-receiving transistor PT1 is turned on and off, and the pulse signal is supplied to the drive control circuit 30 as the dimming control signal.

On the other hand, the drive control circuit 30 controls the power conversion of the power conversion circuit 20 in accordance with the result of monitoring the power conversion of the power conversion circuit 20 and the dimming control signal of the dimming control circuit 50.

More specifically, the drive control circuit 30 has a configuration for performing current regulating to the power conversion circuit 20. [

To this end, the drive control circuit 30 includes a voltage regulator 32, a current monitor 34, a comparator COM1, a ramp signal generator 36, a comparator COM2, a pulse controller 38, a smoothing circuit 40 And a driving circuit. Here, the driving circuit may be configured to include the switching element Q1 and the buffer BF, and the buffer BF may be configured to transfer the output of the pulse controller 38 to the gate of the switching element Q1 have.

The voltage regulator 32 generates the internal voltage Vcc using the sensing current obtained by sensing the current of the secondary coil L2 of the transformer T and supplies the internal voltage Vcc to the ramp signal generator 36, To the controller 38, the dimming control circuit 50, and the drive voltage holding circuit 60. [0060]

The voltage regulator 32 may be configured to receive a sensing current obtained by sensing the current of the secondary coil L2 of the transformer T from the auxiliary coil L3. That is, the current of the auxiliary coil L3 is supplied to the voltage regulator 32 via the diode D2, and the voltage regulator 32 uses the current flowing through the diode D2 to generate the internal voltage Vcc And outputs it.

The current monitor 34 senses the current of the primary coil L1 of the transformer T and the current of the secondary coil L2.

The current monitor 34 senses the current of the secondary coil L2 by using the current flowing in the secondary coil L3 and detects the zero current point Z of the current induced in the secondary coil L2 And to output a set signal (S) synchronized with the zero current point (Z).

Further, the current monitor 34 outputs a monitoring voltage corresponding to the result of sensing the current of the primary coil L1. The current of the primary coil L1 of the transformer T may be configured to be supplied from the resistor R1 connected to the switching element Q1.

The current monitor 34 is configured to apply the monitoring voltage to the negative terminal (-) of the comparison section COM1. The monitoring voltage may be output as a DC voltage corresponding to the current flowing in the resistor R1.

The comparator COM1 receives the reference voltage REF_Cc for the constant current control at the negative terminal of the comparator COM2 and the negative terminal of the comparator COM2, -).

The ramp signal generator 36 outputs a ramp signal RP and the ramp signal RP can be provided as a sawtooth pulse or a triangle wave pulse.

The smoothing circuit 40 is configured to smooth the dimming control signal of the pulse waveform provided by the dimming control circuit 50 and to apply the smoothing control signal to the negative terminal (-) of the comparing part COM2. The smoothing circuit 40 can convert the dimming control signal of the pulse waveform into a DC voltage.

The comparator COM2 receives the signal obtained by mixing the smoothed dimming control signal from the smoothing circuit 40 and the comparison signal COMP output from the comparator COM1 in a negative stage and receives the ramp signal from the ramp signal generator 36, To the positive terminal (+). The comparator COM2 compares the signal obtained by mixing the dimming control signal and the comparison signal COMP with the ramp signal RP and outputs the reset signal R.

The pulse controller 38 is configured to receive the reset signal R of the comparator COM2 and the set signal S of the current monitor 34 and output the drive pulse Q. [ The pulse controller 38 performs an RS flip-flop operation for outputting a pulse signal that maintains the enable state from the time when the set signal S is enabled to the time when the reset signal R is enabled as the drive pulse Q It is preferable to configure it to perform.

The drive pulse Q is transferred to the gate of the switching element Q1 via the buffer BF.

The buffer BF is a part configured to compensate the level of the drive pulse.

The switching element Q1 may be a power transistor and the FET may be configured and connected to the primary coil L1 of the transformer T and the drive pulse Q applied to the gate thereof and switched by the drive pulse Q.

That is, the switching element Q1 is operated to repeatedly turn on and off by the driving pulse Q transmitted through the buffer BF. As a result, a rectified voltage is driven in the primary coil L1 of the transformer T in conjunction with the switching of the switching element Q1, and a current is driven in the primary coil L1 of the transformer T.

On the other hand, the driving voltage holding circuit 60 is configured to sense the driving voltage V and to control the dimming control signal so that the driving voltage V is maintained at a predetermined voltage or higher.

That is, the driving voltage holding circuit 60 controls the level of the output signal of the smoothing circuit 40 by controlling the level of the dimming control signal in response to the level of the driving voltage V falling below the predetermined voltage. As a result, the level of the driving voltage V can be controlled by controlling the dimming control signal.

The driving voltage holding circuit 60 includes a comparator COM3 for comparing the driving voltage V with a reference voltage REF_Cv set for constant voltage control, The photodiode PD2 performs light emission or extinction according to the ON / OFF state of the transistor Q3. The photodiode PD2 emits light corresponding to light emission and extinction of the photodiode PD. And a light receiving transistor PT2 for controlling the level of the dimming control signal.

Here, the source of the transistor Q3 is commonly connected to the negative terminal (-) of the comparator COM3 via the resistor R3, and the collector of the light-receiving transistor PT2 is connected to the internal voltage Vcc And the emitter is configured to be connected to the node to which the dimming control signal of the smoothing circuit 40 is applied.

The comparator COM3 is configured such that the driving voltage V is applied to the negative terminal thereof and the reference voltage REF_Cv is applied to the positive terminal thereof.

As described above, the embodiment according to the present invention is constituted, and the power conversion of the transformer T is performed in accordance with the operation of the switching element Q1.

Referring to FIG. 2, when the switching element Q1 is turned on, the current of the primary coil L1 of the transformer T gradually increases. At this time, a large induction current is not formed in the secondary coil L2.

When the switching element Q1 is turned off, the current flow in the primary coil L1 of the transformer T is abruptly cut off, and a large induced current is formed in the secondary coil L2 and then gradually decreased.

The zero current point Z means a time point when the induced current of the secondary coil L2 of the transformer T disappears, that is, a time point when the zero point is reached.

When the zero current point Z is reached, the flow of the current increases to the turn-on of the switching element Q1 in the primary coil L1 of the transformer T again.

That is, the current flow of the primary coil L1 of the transformer T is started in synchronization with the zero current point Z, thereby reducing the switching loss, thereby increasing the overall conversion efficiency.

The current I induced in the secondary coil L2 is rectified by the diode D1 by the operation of the transformer T as described above and the voltage due to the rectified current is smoothed in the capacitor C1, And is output as a voltage (V).

The lamp 100 emits light by the driving voltage V described above. The light emitting state of the lamp 100 can be determined according to the level of the driving voltage V. [ That is, the dimming control can be performed by controlling the level of the driving voltage (V).

In the above process, the current induced in the secondary coil L2 is sensed in the auxiliary coil L3, and the sensed current can be provided to the voltage regulator 32 and the current monitor 34, respectively.

The voltage regulator 32 generates the internal voltage Vcc by using the sensing current of the auxiliary coil L3 and supplies the internal voltage Vcc to the ramp signal generator 36, the pulse generator 38, the drive voltage holding circuit 60, ) At a constant voltage.

The current monitor 34 senses the zero current point Z using the sensing current of the auxiliary coil L3 and outputs the set signal S synchronized to the zero current point Z. [

The current monitor 34 senses the current flowing through the resistor Rs and applies the DC voltage corresponding to the amount of the current flowing in the resistor Rs, that is, the monitoring voltage, to the negative terminal (-) of the comparator COM1.

The comparator COM1 compares the monitoring voltage with the reference voltage REF_Cc. If the monitoring voltage is lower than the reference voltage REF_Cc, the comparator COM1 outputs a positive comparison signal. If the monitoring voltage is higher than the reference voltage REF_Cc, And outputs a comparison signal.

The comparator COM2 controls the pulse width of the driving pulse output from the pulse controller 38 by comparing the comparison signal COMP with the ramp signal RP and outputting the reset signal R as shown in FIG.

The embodiment of the present invention has a feedback function for constant current control that keeps the level of the current output from the transformer T constant so that the lamp 100 can emit light while maintaining a constant brightness by the monitoring voltage.

That is, when the current induced in the primary coil L1 of the transformer T increases, the monitoring voltage output from the current monitor 34 rises and the comparator COM1 compares the negative low voltage with the comparison signal COMP, (For example, Vb level in Fig. 3), and the comparator COM2 outputs a reset signal R having a large pulse width. The pulse controller 38 outputs a drive pulse Q (Qb) having a pulse width maintaining the high level until the reset signal R is input (enabled) after the set signal is enabled. That is, the pulse controller 38 outputs a drive pulse Qb having a small pulse width, and the turn-on time of the switching element Q1 is reduced by the decrease in the pulse width of the drive pulse Qb. As a result, the current induced in the primary coil L1 of the transformer T is reduced.

On the other hand, when the current induced in the primary coil L1 of the transformer T decreases, the monitoring voltage output from the current monitor 34 falls and the comparator COM1 outputs a positive high voltage as the comparison signal COMP (For example, Va level in FIG. 3), and the comparator COM2 outputs a reset signal R having a small pulse width. The pulse controller 38 outputs a drive pulse Q (Qa) having a pulse width maintaining the high level until the reset signal R is input after the set signal S is enabled. That is, the pulse controller 38 outputs the drive pulse Qa having a large pulse width, and the turn-on time of the switching element Q1 is increased by the increase in the pulse width of the drive pulse Qa. As a result, the current induced in the primary coil L1 of the transformer T increases.

As described above, according to the embodiment of the present invention, since the current of the primary coil L1 of the transformer T is controlled based on the reference voltage REF_Cc for constant current control, the amount of current supplied to the lamp 100 A constant current control that keeps constant can be performed. That is, the brightness of the lamp 100 can be kept constant by the above-described constant current control.

Meanwhile, the embodiment of the present invention can perform dimming control for adjusting the brightness of the lamp 100 by an external control signal.

The dimming control processor 52 controls an external control signal Din for dimming control to brighten or darken the lamp 100 or an external control signal Din for controlling the turn- And outputs a dimming-out signal Do having a pulse signal form corresponding to the dimming-out signal Do.

Here, the turn-off (dimming off) of the lamp 100 may be set based on when the width of the pulse output from the dimming control processor 52 is less than a predetermined level. For example, if the pulse width or duty ratio is less than 10%, the lamp 100 may be set to be turned off. In this case, when the duty ratio of the pulse output from the dimming control processor 52 is less than 10%, the lamp 100 is not turned on by the power outputted from the transformer T.

When the lamp 100 is not turned on, the transformer T may output a driving voltage V of a level lower than the level at which the lamp 100 is turned on. In this case as well, the operating voltage necessary for the operation of the dimming control circuit 50 can be continuously supplied by the driving voltage V. [

The above-described dimming control function will be described with reference to FIG.

The dimming control processor 52 of the dimming control circuit outputs a dimming-out signal Do in response to an external control signal Din as a pulse signal.

In order to lighten the lamp 100, a pulse signal having a small duty ratio as shown in 'Do1' of FIG. 4 may be output as the dimming out signal Do from the dimming control processor 52, and in order to darken the lamp 100 A pulse signal having a large duty ratio such as 'Do2' of 4 may be output as the dimming out signal Do in the dimming control processor 52. [

The dimming-out signal Do output from the dimming control processor 52 is inverted by the inverter IV and transmitted to the gate of the transistor Q2.

As a result, the light-receiving transistor PT1 of the photocoupler is turned on for a long time corresponding to the pulse Do1 for brightening the lamp 100 and is turned on for a short time corresponding to the pulse Do1 for darkening the lamp 100 do.

The smoothing circuit 40 outputs a low level DC voltage V2 when the turn-on time of the light-receiving transistor PT1 is long and a DC voltage V1 of high level when the turn-on time of the light-receiving transistor PT1 is short.

The output signal of the smoothing circuit 40 is mixed with the comparison signal COMP and applied to the negative terminal (-) of the comparator COM2.

In order to brighten the lamp 100, a high level signal is applied to the negative terminal (-) of the comparator COM2 as shown by V1 in FIG. Conversely, to darken the lamp 100, a low level signal is applied to the negative terminal (-) of the comparator COM2 as shown by V2 in FIG.

The positive ramp signal (+) of the comparator COM2 is supplied with the ramp signal RP as shown in Fig. 4, which is output from the ramp signal generator 32. [

The comparator COM2 compares the voltage of the negative terminal (-) with the ramp pulse RP of the positive terminal (+) and outputs the reset signal R.

At this time, the comparator COM2 outputs a reset signal R having a narrow pulse width corresponding to the case where the lamp 100 is to be brightened. On the contrary, the comparator COM2 outputs a reset signal R having a wide pulse width corresponding to the case where the lamp 100 is to be dimmed.

As a result, the pulse controller 38 outputs the drive pulse Q having a pulse width maintaining the high level until the reset signal R is input after the set signal S is enabled. That is, the pulse controller 38 outputs a drive pulse Qa having a large pulse width corresponding to the case where the lamp 100 is intended to be brightened, and the turn-on time of the switching element Q1 is a pulse of the drive pulse Q The width increases by an increase. As a result, the current induced in the primary coil L1 of the transformer T increases, and the lamp 100 is illuminated by receiving the increased driving voltage V.

On the contrary, the pulse controller 38 outputs a drive pulse Qb having a narrow pulse width corresponding to the case where the lamp 100 is to be dimmed, and the turn-on time of the switching element Q1 is a pulse of the drive pulse Qb As the width decreases, it decreases. As a result, the current induced in the primary coil L1 of the transformer T decreases, and the lamp 100 becomes darker by receiving the lowered driving voltage V.

As described above, the embodiment of the present invention can perform dimming control in response to an external control signal.

The embodiment according to the present invention can implement dimming control in the constant current control method as described above.

At this time, the dimming control processor 52 requires an operation voltage of a certain level or more to perform a stable operation.

The dimming control processor 52 is driven by an operating voltage that varies the level of the driving voltage V by voltage regulation.

The driving voltage V provided to the lamp for light output must be maintained at a level capable of generating the operating voltage required by the dimming control processor 52 even if the light output is controlled to be very low such as the dimming off state .

The level control of the driving voltage V may be performed by the driving voltage holding circuit 60. [

The driving voltage V in the comparator COM3 of the driving voltage holding circuit 60 is compared with the reference voltage REF_Cv for constant voltage control.

When the driving voltage V falls below the reference voltage REF_Cv, the comparator COM3 outputs a high level signal, and as a result, the transistor Q3 is turned on.

The photodiode PD2 is lighted by the light emission of the transistor Q3 and the light receiving transistor PT2 is turned on by light reception to bias the internal voltage Vcc to the dimming control signal. As a result, the output of the smoothing circuit 40 can be raised.

When the output of the smoothing circuit 40 is increased, the pulse width of the driving pulse Q output from the pulse controller 38 is increased as described in the dimming control of FIG. Therefore, the current induced in the transformer T increases and the drive voltage V rises.

The rise of the driving voltage V may be continued until the driving voltage V becomes higher than the reference voltage REF_Cv for constant voltage control.

The drive voltage V can always be kept higher than the reference voltage REF_Cv for constant voltage control by the operation of the drive voltage holding circuit 60 described above.

At this time, it is preferable that the level is set so that the reference voltage REF_Cv can maintain a driving voltage V sufficient to generate the operating voltage required by the dimming control processor.

Therefore, in the embodiment of the present invention, the dimming control processor 52 can stably receive the operating voltage by the driving voltage V which is stably maintained at the level, so that the stable constant current control can be performed.

5, the constant current control and the constant voltage control may be performed by the reference voltage REF_Cc for constant current control, and the constant voltage control may be performed using the reference voltage for constant voltage control And the voltage REF_Cv. The curve for dimming control can be formed by varying the driving voltage V, which is the output voltage, and the output current is also reduced when the driving voltage V is reduced.

In FIG. 5, the solid curve represents an ideal state according to a design value, and the broken curve represents a state formed when an error occurs.

In the embodiment of the present invention, the driving voltage V can always be maintained at a constant level or higher by the constant voltage control as shown in FIG. 5, so that the malfunction of the dimming control processor 52 can be prevented as described above.

Further, the present invention can be configured such that the voltage regulator 54 is separated from the dimming control processor 52 as shown in Fig.

The embodiment of FIG. 6 illustrates that the voltage regulator 54 regulates the voltage of the driving voltage V into a working voltage and provides it to the dimming control processor 52, Voltage is supplied from the voltage regulator 54 and operated.

The embodiment of FIG. 6 differs from FIG. 1 only in that the voltage regulator 54 is separated and the remaining components are the same, so that redundant configuration and operation description thereof are omitted.

The embodiment of the present invention described above is a structure in which the AC power is regulated by the drive control circuit 30 and the operation voltage is simultaneously supplied to the peripheral circuit module such as the lamp 100 and the dimming control circuit 50 .

Accordingly, the embodiment according to the present invention can be easily designed to supply power to the lamp 100 and the peripheral circuit module.

Further, the embodiment according to the present invention can have a power efficiency of 90% as a whole without changing the power efficiency of the lamp 100 and the peripheral circuit module when the power efficiency of the drive control circuit 30 is designed to be 90%.

In other words, the present invention has improved power efficiency according to the design level of the current regulator since the power source is converted only in the current regulating step without going through several steps and then supplied to the lamp 100 and the peripheral circuit module.

The embodiment of the present invention has a characteristic in which the feedback operation for the constant current control and the dimming control operation are stably overlapped.

10: power supply unit 20: power conversion circuit
30: drive control circuit 32: voltage regulator
34: current monitor 36: lamp signal generator
38: Pulse controller 40: Smoothing circuit
50: dimming control circuit 52: dimming control processor
54: voltage regulator 60: driving voltage holding circuit
100: lamp

Claims (9)

A power conversion circuit for converting a rectified voltage into a driving voltage by using a transformer;
A lamp provided with the driving voltage;
A dimming control circuit for providing a dimming control signal corresponding to an external control signal and operating using the driving voltage; And
A driving control circuit for controlling the power conversion in accordance with a result of monitoring the power conversion and the dimming control signal;
Including,
Wherein the driving voltage is sensed and the driving voltage is maintained at a predetermined voltage or higher. The method according to claim 1,
And a driving voltage holding circuit for controlling the dimming control signal,
Wherein the driving voltage holding circuit performs voltage control corresponding to the driving voltage by controlling a level of the dimming control signal corresponding to a level of the driving voltage falling below the predetermined voltage. The method according to claim 1,
Wherein the dimming control circuit includes a voltage regulator and the voltage regulator converts the drive voltage to a level of operation voltage required for internal operation. The method according to claim 1,
And a voltage regulator for converting the driving voltage into an operating voltage of a level necessary for operation of the dimming control circuit and providing the driving voltage. The method according to claim 1,
Wherein the lamp comprises a light emitting diode lamp including a plurality of light emitting diodes or a light source emitting light by application of an electric physical quantity. The method according to claim 1,
Wherein the dimming control circuit generates the dimming control signal corresponding to the control signal to perform current control. The driving circuit according to claim 1, wherein the dimming control circuit comprises:
A dimming control processor which operates using a voltage at which the level of the driving voltage is converted, and outputs a dimming-out signal corresponding to the control signal after receiving the control signal; And
And a transfer circuit having a photocoupler for transferring the dimming control signal corresponding to the dimming-out signal to the drive control circuit. The method according to claim 1,
Wherein the drive control circuit performs current regulating for the power conversion circuit. The driving voltage holding circuit according to claim 2,
A comparing unit comparing the driving voltage with a reference voltage for controlling the constant voltage;
A switching element for switching transmission of the driving voltage according to an output of the comparator; And
And an optocoupler for controlling the level of the dimming control signal in accordance with the ON / OFF state of the switching element.

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