Source: https://patents.google.com/patent/KR101275399B1/en
Timestamp: 2020-05-25 06:17:14
Document Index: 425539595

Matched Legal Cases: ['art 311', 'art 312', 'art 313', 'art 320', 'art 321', 'art 322', 'art 310', 'art 411', 'art 412', 'art 413', 'art 421', 'art 422', 'art 410', 'art 410', 'art\n112', 'art\n120']

KR101275399B1 - Light emitting diodes driver - Google Patents
Light emitting diodes driver Download PDF
KR101275399B1
KR101275399B1 KR1020100126900A KR20100126900A KR101275399B1 KR 101275399 B1 KR101275399 B1 KR 101275399B1 KR 1020100126900 A KR1020100126900 A KR 1020100126900A KR 20100126900 A KR20100126900 A KR 20100126900A KR 101275399 B1 KR101275399 B1 KR 101275399B1
KR1020100126900A
KR20120065655A (en
천정인
2010-12-13 Application filed by 삼성전기주식회사 filed Critical 삼성전기주식회사
2010-12-13 Priority to KR1020100126900A priority Critical patent/KR101275399B1/en
2012-06-21 Publication of KR20120065655A publication Critical patent/KR20120065655A/en
2013-06-17 Publication of KR101275399B1 publication Critical patent/KR101275399B1/en
The present invention relates to a light emitting diode driving apparatus for controlling power switching on a primary side by integrating a light emitting diode control function and a power switching control function on a secondary side insulated from a primary side in a power supply circuit without using a photo coupler. A power supply for switching input power to a driving power having a predetermined voltage level, and supplying the driving power to at least one light emitting diode (LED) channel, and the at least one LED channel from the power supply A driving unit controlling the supply and blocking of the driving power to drive the at least one LED channel, and controlling switching of the power supply unit according to a state of the driving power supplied to the at least one LED channel; A switching control signal for controlling switching of the power supply from the power supply It provides a light emitting diode driving device comprising a transfer unit for transmitting to the supply in a magnetic induction manner.
Light Emitting Diode Drive Device {LIGHT EMITTING DIODES DRIVER}
The present invention relates to a light emitting diode driving apparatus capable of driving a light emitting diode by converting a commercial power source into a driving power source.
Recently, the display industry is being replaced by a flat panel display (FPD) device reflecting user demands such as high resolution and large screen in a display device mainly using a cathode ray tube (CRT).
In particular, in the case of large display devices, liquid crystal display (LCD) devices are showing rapid growth due to light and small size, and are expected to play a leading role in terms of price and marketability.
Meanwhile, in the conventional liquid crystal display device, a cold cathode fluorescent lamp (CCFL) is mainly used as a backlight light source, but recently, due to various advantages such as power consumption, lifespan, and eco-friendliness, light emitting diodes are gradually used. Diode (LED) is being used.
In order to drive such a light emitting diode, a power supply circuit for converting commercial AC power into a DC power source and a driving circuit for controlling the supply of DC power to the light emitting diode are generally employed. The power supply circuit can be divided into the primary side and the secondary side based on the transformer to enhance the insulation function. The primary side is composed of a circuit for switching the power by rectifying and smoothing commercial AC power, and the secondary side by the transformer. It consists of a circuit that rectifies the transformed power supply and controls the supply to the load. That is, in general, a power switching control circuit is formed on the primary side, and the above-described driving circuit is formed on the secondary side. In order to achieve this, a plurality of photo couplers for providing feedback current with insulation functions are mainly used. However, since photo couplers are optical devices, the signal transmission characteristics are photon, time of use, and junction. ) It is not easy to design the circuit depending on the temperature, and there is a problem that the manufacturing cost is increased by employing a photo coupler.
SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting diode driving apparatus for controlling power switching on a primary side by integrating a light emitting diode control function and a power switching control function on a secondary side insulated from a primary side in a power supply circuit.
In order to achieve the above object, one technical aspect of the present invention has a primary side and a secondary side that are electrically insulated, and by switching the power input from the primary side, the pre-set voltage A power supply for converting to a driving power having a level and supplying the driving power to at least one light emitting diode (LED) channel, and controlling the supply and disconnection of the driving power to the at least one LED channel from the power supply; A driving unit for controlling the switching of the power supply unit according to a state of the driving power supplied to the at least one LED channel and switching the power supply unit from the driving unit It includes a transmission unit for transmitting a control signal from the secondary side of the drive unit to the primary side of the power supply unit. To provide a LED driving apparatus is characterized in that.
According to one technical aspect of the present invention, the driving unit is connected between the at least one LED channel and the ground switch unit for switching so that the driving power is supplied or cut off to the at least one LED channel, the at least one It may include a control unit for detecting the state of the driving power supplied to the LED channel to control the switching of the switch unit, and generates the switching control signal according to the detected state of the driving power to transmit to the transfer unit.
According to one technical aspect of the present invention, the control unit includes a current generator for generating a current set according to the detected state of the driving power supply, and a clock signal whose period is set in accordance with the current generated by the current generator A clock generator for generating a clock signal, a dead time generator for generating a dead time of a clock signal generated by the clock generator according to the current generated by the current generator, and a dead time generated by the dead time generator. The generated clock signal is processed for control of the switching of the power supply unit and transferred to the transfer unit, and the switching of the switch unit is controlled according to the detected state of the driving power to increase the brightness of the at least one LED channel. A dimming unit to control and the gate driver when the detected state of the driving power corresponds to a preset abnormal operation May include a protector that blocks an operation.
According to one technical aspect of the present invention, the dimming unit receives the state of the detected driving power as a detection signal when the PWM signal to switch on and off the pulse width modulation (PWM) signal is a high signal generation unit The calculator may include a calculator configured to calculate a current control signal transmitted to the controller, and a buffer unit configured to control a voltage level of the detection signal to a preset voltage level when the PWM signal is a low signal.
According to one technical aspect of the present invention, the transfer unit may include a first winding receiving a switching control signal from the gate driver, and a switching control signal electrically insulated from the first winding and input to the first winding. It may be a pulse transformer having a second winding that is induced and delivered to the power supply.
According to one technical aspect of the present invention, the driving device of the present invention may further include a rectifying unit for rectifying the driving power from the power supply to supply to the at least one LED channel.
According to one technical aspect of the present invention, the power supply may supply the driving power to the first and second LED channels of at least one LED channel block having first and second LED channels, respectively.
According to one technical aspect of the present invention, the drive device of the present invention further comprises a current balancer having at least one current balance unit which maintains the current balance of the drive power supplied to the first and second LED channels, respectively. It may include.
According to one technical aspect of the present invention, the at least one current balancing unit includes a current balancing capacitor for maintaining a current balance between driving power delivered to each of the first and second LED channels according to the charge balancing principle; First and second diodes connected in series with each other between the first LED channel and ground to rectify driving power, and third and fourth diodes connected in series with each other between the second LED channel and ground and rectifying driving power. And a first stabilizing capacitor connected in parallel with the first and second diodes to stabilize driving power supplied to the first LED channel, and connected in parallel with the third and fourth diodes to supply the second LED channel. A second stabilizing capacitor for stabilizing a driving power source, or connected to one end of the secondary winding in accordance with a charge balancing principle to the first and second LED channels, respectively. A current balancing capacitor that maintains current balance between the driving power supplies; a first diode connected between the other end of the secondary winding and the first LED channel to rectify the driving power; and the current balancing capacitor and the second LED. A second diode connected between channels to rectify driving power, a first stabilizing capacitor connected in parallel with the first LED channel to stabilize driving power, and a second connecting in parallel with the second LED channel to stabilize driving power A stabilizing capacitor, or the secondary winding is divided into a predetermined number of turns about a center tap, the first LED channel and the second LED channel are connected in series, and the at least one current balancing unit is Spheres connected to the center taps of the secondary windings and connected to the connection points of the first and second LED channels and transmitted to the first and second LED channels, respectively. A current balancing capacitor which maintains a current balance between power supplies, a first diode connected between one end of the secondary winding and the first LED channel to rectify a driving power supply, and a connection between the other end of the secondary winding and the second LED channel And a second diode for rectifying driving power, a first stabilizing capacitor connected in parallel with the first LED channel to stabilize driving power, and a second stabilizing capacitor connected in parallel with the second LED channel to stabilize driving power. It may include.
According to one technical aspect of the present invention, the power supply is a rectification smoothing unit for rectifying and smoothing commercial power, a power factor correction unit for adjusting the phase difference between the voltage and current of the rectified power from the rectifying smoothing unit; A switching unit for switching the power factor corrected power from the power factor correcting unit according to the switching control signal, at least one primary winding receiving the switched power from the switching unit, and electrically insulated from the at least one primary winding; The transformer may include a transformer having at least one secondary winding configured to form a predetermined winding ratio and receive power from the at least one primary winding.
According to one technical aspect of the present invention, the transformer includes a plurality of secondary windings connected to each of the plurality of LED channel blocks to supply driving power to a corresponding LED channel block, and the current balance unit comprises the plurality of secondary windings. A plurality of the current balancing unit for supplying the driving power from the winding to the first LED channel and the second LED channel of the corresponding LED channel block to maintain the current balance.
According to one technical aspect of the present invention, the transformer may include a plurality of primary windings each one-to-one corresponding to the plurality of secondary windings.
According to the present invention, the light emitting diode control function and the power switching control function are integrated on the secondary side to control the power supply switching on the primary side, thereby reducing manufacturing cost and facilitating circuit design, preventing current rise delay, and spike current component. There is an effect that can be suppressed.
1 is a schematic configuration diagram of a first embodiment of a light emitting diode driving apparatus of the present invention.
2 is a schematic structural diagram of a second embodiment of a light emitting diode driving apparatus of the present invention;
3 is a schematic structural diagram of a third embodiment of a light emitting diode driving apparatus of the present invention;
4 is a schematic structural diagram of a fourth embodiment of a light emitting diode driving apparatus of the present invention;
5A to 5C are schematic configuration diagrams of embodiments of a switching unit employed in the LED driving apparatus of the present invention.
6 is a schematic configuration diagram of a control unit employed in the LED driving apparatus of the present invention.
7 is an enlarged view of a part of a control unit employed in the LED driving apparatus of the present invention;
8A and 9A are graphs showing electrical characteristics of a general LED driving apparatus, and FIGS. 8B and 9B are graphs showing electrical characteristics of the LED driving apparatus of the present invention.
10 is a signal waveform graph of a main configuration of a light emitting diode driving apparatus of the present invention.
11A and 11B are schematic configuration diagrams of embodiments of the current balancer employed in the LED driving apparatus of the present invention.
12A and 12B are current flow charts illustrating an operation of a current balancer in the LED driving apparatus of the present invention.
Referring to FIG. 1, the first embodiment 100 of the LED driving apparatus of the present invention may include a power supply 110, a driver 120, and a transmitter 130, and further includes a rectifier 140. It may include.
The power supply unit 110 receives a commercial AC power and adjusts the phase difference between the rectified smoothing unit 111 and the rectified smoothing unit 111 and the rectified smoothing unit 111. The power factor correction unit 112, a switching unit 113 for switching the power factor corrected from the power factor correction unit 113, and a transformer unit 114 for varying the voltage level of the power source switched by the switching unit 113. can do. Although not shown, an EMI filter may be further included to eliminate electromagnetic interference (EMI).
The switching unit 113 may be configured as an LLC resonant inverter having two switches connected in series to alternately change the power factor corrected power from the power factor correcting unit 113 and having a leakage inductance L lkg and a resonance capacitor C. As shown in FIGS. 5A to 5C, embodiments of the switching unit 113 employed in the first embodiment 100 of the LED driving apparatus of the present invention may be a half bridge inverter (FIG. 5A), a full- And a bridge inverter (FIG. 5B) or a push-pull inverter (FIG. 5C).
The transformer unit 114 may include at least one primary winding Np and at least one secondary winding Ns, and the primary winding Np receives the power switched by the switching unit 113, and the secondary winding. The winding Ns may be electrically insulated from the primary winding Np, and may receive a power input to the primary winding Np according to a preset winding ratio with the primary winding Np to transform the voltage level. The transformed power may be delivered to at least one light emitting diode channel (LED) in which a plurality of light emitting diodes are connected in series.
The driving unit 120 may include a switch unit 121 and a control unit 122.
The switch unit 121 is connected to the light emitting diode channel (LED) to turn on or off according to the dimming signal so that driving power is supplied or cut off to the light emitting diode channel (LED).
The control unit 122 controls the turn-on and turn-off of the switch unit 121 according to the state of the power supplied to the light-emitting diode channel (LED), and controls the switching of the switching unit 113 to the light-emitting diode channel (LED). It can control the voltage level or current level of the power supplied to.
The transmission unit 130 transmits the switching control signal from the control unit 122 to the switching unit 113 in a magnetic induction manner. For this purpose, the transmission unit 130 may include the first winding N1 and the second winding N2. It may include a pulse transformer having a). The first winding N1 and the second winding N2 are electrically insulated from each other, the first winding N1 receives the switching control signal from the controller 122, and the second winding N2 is electrically The switching control signal S magnetically induced from the insulated first winding N1 may be transmitted to the switching unit 113.
The rectifier 140 may include a capacitor Cb1, first to fourth diodes D1 to D4, and a stabilization capacitor Co1. The rectifier 140 rectifies and supplies power from the secondary winding Ns of the transformer 114. By stabilizing, driving power may be supplied to the light emitting diode channel (LED). As shown, one end of the capacitor Cb1 is connected to one end of the secondary winding Ns, the first and second diodes D1 and D2 are connected in series with each other, and the other end of the capacitor Cb1 is connected to the first and second ends. It may be connected to the connection point of the second diode (D1, D2). The third and fourth diodes D3 and D4 are connected in series with each other and are connected in parallel with the first and second diodes D1 and D2, and the other end of the secondary winding Ns is connected to the third and fourth diodes D3 and D4. ) And the stabilizing capacitor Co1 may be connected in parallel with the third and fourth diodes D3 and D4.
As described above, the primary winding Np of the rectifying smoothing unit 111, the power factor correcting unit 112, the switching unit 113, and the transformer unit 114 and the second winding N2 of the transfer unit 130 are The first winding Ns of the driving unit 120, the rectifying unit 140, the transformer unit 114, and the transmission unit 130 may be formed on the secondary side. Accordingly, the function of controlling the switching on the primary side and the function of driving the light emitting diode on the secondary side may be integrally formed on the secondary side.
2 is a schematic structural diagram of a second embodiment of a light emitting diode driving apparatus of the present invention.
Referring to FIG. 2 together with FIG. 1, the second embodiment 200 of the LED driving apparatus of the present invention can supply driving power to at least two LED channels LED1 and LED2. Accordingly, the second embodiment 200 of the LED driving apparatus of the present invention may include a current balancer 240, unlike the rectifier 140 of FIG. 1.
The current balancing unit 240 may include a current balancing capacitor Cb1, first to fourth diodes D1 to D4, and first and second stabilizing capacitors Co1 and Co2. As shown, one end of the current balancing capacitor Cb1 is connected to one end of the secondary winding Ns, the first and second diodes D1 and D2 are connected in series with each other, and the other end of the capacitor Cb1 is It may be connected to the connection point of the first and second diodes (D1, D2), the second stabilizing capacitor (Co2) may be connected in parallel to the first and second diodes (D1, D2). The third and fourth diodes D3 and D4 are connected in series to each other, the other end of the secondary winding Ns is connected to the connection point of the third and fourth diodes D3 and D4, and the first stabilizing capacitor Co1 is formed to It may be connected in parallel with the third and fourth diodes (D3, D4).
The current balancing capacitor Cb1 may maintain the current balance between the driving power supplied to the first light emitting diode channel LED1 and the second light emitting diode channel LED2 according to the principle of charge averaging. Detailed description thereof will be described later with reference to FIGS. 12A and 12B.
Other than the rectifier smoothing unit 211, power factor correction unit 212, the switching unit 213 and the transformer 214, the drive unit 220 having a switch unit 221 and the control unit 222 ) And the configuration and function of the delivery unit 230 is the same as the description in Figure 1 will be omitted.
3 is a schematic configuration diagram of a third embodiment of the LED driving apparatus of the present invention.
Referring to FIG. 3, in a third embodiment 300 of the LED driving apparatus of the present invention, the transformer 314 includes a plurality of secondary windings N S1 to N SN , and accordingly, the current balance unit 340. ) Includes a plurality of current balancing units 341 to 34N, and the plurality of current balancing units 341 to 34N may be electrically connected to correspond to the plurality of secondary windings N S1 to N SN , respectively. Each of the plurality of current balancing units 341 to 34N may have the same configuration as that of the current balancing unit 240 illustrated in FIG. 2, and a detailed description thereof will be omitted. In addition, the resonant capacitor C may be different from the positions in FIGS. 1 and 2, but there is no influence on the LLC resonance, and the leakage inductance L lkg is omitted.
Other than the rectifier smoothing part 311, the power factor correcting part 312, the switching part 313, the driving part 320 having the switch part 321 and the control part 322, and the transmission part of the power supply part 310. The configuration and function of 330 are the same as those in FIG. 1, and thus detailed descriptions thereof will be omitted.
4 is a schematic configuration diagram of a fourth embodiment of the LED driving apparatus of the present invention.
Referring to FIG. 4, in a fourth embodiment 400 of the LED driving apparatus of the present invention, the transformer 414 may include a plurality of primary windings N P1 to N PN and a plurality of secondary windings N S1 to N SN. ), And the plurality of primary windings N P1 to N PN and the plurality of secondary windings N S1 to N SN may correspond to each other one-to-one. The current balance unit 440 includes a plurality of current balance units 441 to 44N, and the plurality of current balance units 441 to 44N respectively correspond to the plurality of secondary windings N S1 to N SN to be electrically connected to each other. Can be. Each of the plurality of current balancing units 441 to 44N may have the same configuration as that of the current balancing unit 240 illustrated in FIG. 2, and a detailed description thereof will be omitted.
Other than the rectifier smoothing part 411, the power factor correcting part 412, the switching part 413, the switch part 421 and the control part 422 of the power supply part 410 other than the power supply part 410, and the transmission part ( Since the configuration and function of 430 are the same as those in FIG. 1, detailed descriptions thereof will be omitted.
6 is a schematic configuration diagram of a controller employed in the LED driving apparatus of the present invention, and FIG. 7 is an enlarged view of a part of the controller employed in the LED driving apparatus of the present invention.
Referring to FIG. 6, the control unit employed in the LED driving apparatus of the present invention may be commonly employed in the embodiments 100, 200, 300, and 400 of the LED driving apparatus illustrated in FIGS. 1 to 4, and accordingly, the control unit of FIG. 1. It will be described based on (122).
The controller 122 may include a current generator 122a, a clock generator 122b, a dead time generator 122c, a gate driver 122d, a dimming unit 122e, and a protection unit 122f.
The current generator 122a generates a current having a level set according to the state of the driving power supplied to the light emitting diode channel LED1, and the clock generator 122b generates the current generated by the current generator 122a. It is possible to generate a clock signal having a period set according to.
The dead time generator 122c may perform a dead time for controlling switching of the switching unit 113 based on the current level generated by the current generator 122a and the clock signal generated by the clock generator 122b. dead time), and the gate driver 122d generates a switching control signal based on a pulse width modulation (PWM) signal from the outside and has a dead time generated by the dead time generator 122c, which is transmitted The switch 130 may be transferred to the switching unit 113.
The dimming unit 122e controls the switching signal SW to supply or cut off driving power to the LED channel LED1 based on a PWM signal supplied to the gate driver 122d or an analog dimming signal ADM from the outside. Can be provided. To this end, the dimming unit 122e detects the driving power supplied to the light emitting diode channel LED1 by the detection resistor R SEN and the first and second feedback signals FB1 and FB2 through the resistors R1 and R2. Can be delivered.
In addition, the dimming unit 122e may receive the driving power supplied to the LED channel LED1 as an error signal ERO by the resistor R2 and the RC network. The above-described error signal ERO may be transmitted to the current generator 122a to be involved in current generation.
The protection unit 122f determines whether or not an abnormal operation is performed according to the voltage and current states SLP and OLP of the power supplied to the LED channel LED1, and during the abnormal operation, the current generator 122a and the gate driver 122d. Can stop the operation.
Meanwhile, referring to FIG. 7, the dimming unit 122e may include an operation unit 122e-1 and a buffer unit 122e-2, and the operation unit 122e-1 may be detected by the detection resistor R SEN . The current level FB1 of the driving power supplied to the LED channel LED1 may be input by the voltage level V SEN of the driving power supplied to the LED channel LED1.
The calculation unit 122e-1 may control PFM (Pulse Frequency Modulation) by varying the frequency according to the level of the feedback signal FB1 described above.
Referring to the operation, when the PWM signal from the outside is high, the switch M1 of the switch unit 121 is turned on and the feedback signal FB1 is transmitted to the operation unit 122e-1 to generate the current generator ( The generation of the current RT of 122a can be controlled. At this time, the switch Q1 of the buffer unit 122e-2 is turned off and does not operate.
When the PWM signal is low, the switch M1 of the switch unit 121 is turned off and the switch Q1 of the buffer unit 122e-2 is turned on to adjust the voltage level of the error signal ERO. By maintaining the voltage level of the analog dimming signal ADM, even when the PWM signal is low, the voltage level of the error signal ERO can be adjusted through the analog dimming signal ADM like the level of the feedback signal FB1.
On the other hand, when the feedback level signal is transmitted, a phenomenon occurs in which the current level rises as indicated by identification A of FIG. 8A due to the external resistance and the capacitor component of the calculator 122e-1. However, in the dimming unit 122e of the present invention, even when the PWM signal is a low signal, the voltage level of the error signal ERO is kept constant as the period of the high signal of the PWM signal, so that the dimming-off where the PWM signal is low level. Even when dimming on, the rise time of the current I LED flowing through the LED channel LED1 can be shortened as shown in 8b.
In the LLC power conversion method, the switching control signal S operates at a low frequency at no load to increase the gain of the output voltage. Thus, the output voltage V OUT increases when the PWM signal is low. An increase of may cause a problem in which the current (LED current) flowing through the light emitting diode channel LED1 instantaneously rises as shown by the identification code B of FIG. 9A when the PWM signal is high. Accordingly, in the present invention, when the PWM signal is low, the output of the switching control signal is turned off to maintain the output voltage V OUT to stably maintain the current level flowing in the LED channel LED1 as shown in FIG. 9B. Can be.
In addition, since the above-described control unit 122 is formed on the secondary side, a power supply control circuit is generally formed on the primary side, thereby eliminating the use of a photo coupler for transferring the state of the power generated from the secondary side to the primary side.
10 is a signal waveform graph of the main configuration of the LED driving apparatus of the present invention.
Referring to FIG. 10, it can be seen that the protection operation is easily performed when any abnormal operation signal is applied in the normal operation as in identification codes (1), (2) and (3). That is, when the voltage of the source of the switch M1 of the switch unit 121 falls below a predetermined voltage as shown by the identification code 1 and the OLP voltage level becomes low, the capacitor of the SDT is charged and charged. It can be seen that the protection function is activated when the level exceeds 0.7V. In the identification code (2), if the drain voltage of the SLP (Short LED Protection) switch M1 is higher than a predetermined voltage of about 4V, as in the case where the LED channel is shorted, a latch-shutdown is immediately performed. If the drain voltage of M1) is 3V or more, the protection function is activated when the shutdown-down time (SDT) capacitor is charged and exceeds the predetermined voltage (SLP (Short LED Protection)). ), When the overcurrent occurs on the primary side, when the OCP (Over Current Protection) voltage exceeds a certain voltage level of about 2V, the output of the switching control signal (S) is stopped and the protection function operates.
11A and 11B are schematic diagrams of embodiments of the current balancer employed in the LED driving apparatus of the present invention.
Referring to FIG. 11A, the first current balancing unit includes a first diode D1 and a second diode D2, and the first current balancing capacitor Cb1 includes one end and a first end of the first secondary winding N S1 . Is electrically connected in series between the anodes of the second diode D2, the anode of the first diode D1 is electrically connected to the other end of the first secondary winding N S1 , and the cathode of the first diode D1 is One end of the first stabilization capacitor Co1 and one end of the first light emitting diode channel LED1 are electrically connected to each other, and the anode of the second diode D2 is together with the first current balancing capacitor Cb1 and the first stabilization capacitor Co1. Is electrically connected to the other end of the second light emitting diode channel LED1 and the cathode of the second diode D2 is connected to one end of the second stabilizing capacitor Co2 and one end of the second light emitting diode channel LED2. Electrically connected, the other end of the second stabilizing capacitor (Co2) and the second light emitting diode The other end of the lamp LED2 may be electrically connected to the other end of the first secondary winding N S1 . As described above, only the first current balancing unit has been described, but the second current balancing capacitor Cb2, the third and fourth diodes D3 and D4, and the third and fourth stabilizing capacitors Co3 and Co4 are described. The second current balancing unit having may also have the same configuration as the above-described first current balancing unit, and a plurality of such current balancing units may be provided.
Referring to FIG. 11B, the first current balancing unit has the first secondary winding N S1 dividedly wound and has a center tap, and the first current balancing capacitor Cb1 has the center tap of the first secondary winding N S1 . It is connected in series between the ground and the ground, having a first diode (D1) and a second diode (D2), the anode of the first diode (D1) is electrically connected to one end of the first secondary winding (N S1 ), The cathode of the first diode D1 is electrically connected to one end of the first stabilization capacitor Co1 and one end of the first light emitting diode channel LED1, and the anode of the second diode D2 is connected to the first secondary winding N. Is electrically connected to the other end of S1 ), and the cathode of the second diode D2 is electrically connected to one end of the second stabilizing capacitor Co2 and one end of the second light emitting diode channel LED2, and the first and second electrodes. The other ends of the stabilization capacitors Co1 and Co2 and the other ends of the first and second light emitting diode channels LED1 and LED2 are grounded. Can. Similarly, although only the first current balancing unit has been described as described above, the second current balancing capacitor Cb2, the third and fourth diodes D3 and D4, and the third and fourth stabilizing capacitors Co3 and Co4 are described. The second current balance unit having a) may also have the same configuration as the above-described first current balance unit, and a plurality of such current balance units may be provided.
As the switching unit 113 switches, the current flowing in the primary winding N P alternates in the forward direction (FIG. 12A) and the reverse direction (FIG. 12B). At this time, the number of turns of the first and second secondary windings N S1 and N S2 is equal to each other so as to equalize electromagnetic coupling between the first and second secondary windings N S1 and N S2 and the primary winding N P. In this case, in the forward direction, the currents Isec1_P and Isec2_P of the positive power of the first and second secondary windings N S1 and N S2 may be substantially the same as in Equation 1 below.
Similarly, in the reverse direction, the currents Isec1_N and Isec2_N of the negative power of the first and second secondary windings N S1 and N S2 may be substantially the same as in Equation 2 below.
At this time, each rectifier may include one current balancing capacitor Cb1 and Cb2, and as shown in FIGS. 12A and 12B, current conduction paths in the forward and reverse directions are formed, and current balancing capacitors Cb1 and Cb2. The power supplied to the first and third light emitting diode channels (LED1, LED3) and the second and fourth light emitting diode channels (LED2, LED4) according to the charge balance law of Equation 4 may be approximately the same as each other (charge balance principle is a well-known conventional technique, so a detailed description thereof will be omitted).
That is, the current of the driving power supplied to the first to fourth LED groups LED1 to LED4 may be kept constant.
According to various embodiments of the above-described configuration, when one transformer has N secondary windings having the same number of windings, the transformer is supplied to at least 2N light emitting diode lamps according to the charge balancing principle of the N current balancing capacitors provided corresponding to each secondary winding. The current balance of the driving power supply is maintained so that a constant current flows in each LED lamp (where N is a positive even number).
As described above, according to the present invention, it is possible to reduce the manufacturing cost without using a photo coupler by integrating the switching control circuit formed on the primary side and the light emitting diode control circuit formed on the secondary side generally. have.
100,200,300,400 ... LED driving device
110,210,310,410 ... Power Supply
111,211,311,411 ... Commutation Smoothing Part
112,212,312,412 ... power factor correction unit
113,213,313,413 ... Switching Part
120,220,320,420 ... Driver
121,221,321,421 ... switch
122,222,322,422 ... control unit
130,230,330,430 ... delivery
140.Rectifier
240,340,440 ... Current Balance
Having a primary side and a secondary side that are electrically insulated, and switching power input from the primary side to convert the power switched on the secondary side into a driving power source having a predetermined voltage level, and converting the driving power source into at least one LED. (Light Emitting Diode) a power supply for supplying a channel;
Controlling the supply and blocking of the driving power to the at least one LED channel from the power supply to drive the at least one LED channel and the power supply according to the state of the driving power supplied to the at least one LED channel Driving unit for controlling the switching of; And
A transfer unit for transferring a switching control signal for controlling switching of the power supply unit from the driver to the primary side of the power supply unit from the secondary side of the drive unit;
Light emitting diode driving apparatus comprising a.
2. The apparatus of claim 1, wherein the driving unit
A switch unit connected between the at least one LED channel and ground to switch the driving power to be supplied or cut off to the at least one LED channel; And
A control unit which detects a state of driving power supplied to the at least one LED channel to control switching of the switch unit, and generates and transmits the switching control signal according to the detected state of the driving power and transmits it to the transfer unit.
A current generator for generating a current set according to the detected state of the driving power supply;
A clock generator for generating a clock signal whose period is set according to the current generated by the current generator;
A dead time generator for generating a dead time of a clock signal generated by the clock generator according to the current generated by the current generator;
A gate driver for processing a clock signal in which a dead time is generated by the dead time generator to control the switching of the power supply and transferring the clock signal to the transfer unit;
A dimming unit controlling the brightness of the at least one LED channel by controlling the switching of the switch unit according to the detected driving power state; And
A protection unit which blocks the operation of the gate driver when the detected driving power corresponds to a preset abnormal operation
The method of claim 3, wherein the dimming unit
A calculation unit configured to calculate a current control signal transmitted to the current generation unit by receiving a state of the detected driving power as a detection signal when a PWM signal for switching on and off the switching unit is a high signal; And
The buffer unit for controlling the voltage level of the detection signal to a predetermined voltage level when the PWM signal is a low signal
The transfer unit may include a first winding receiving a switching control signal from the gate driver and a second winding electrically insulated from the first winding and receiving a switching control signal input to the first winding, and transferring the switching control signal to the power supply. A light emitting diode drive device, characterized in that the pulse transformer.
And a rectifying unit rectifying driving power from the power supply unit and supplying the rectified power to the at least one LED channel.
And the power supply unit supplies the driving power to the first and second LED channels of at least one LED channel block having first and second LED channels, respectively.
And a current balancer having at least one current balance unit which maintains current balance of the driving power supplied to the first and second LED channels, respectively.
9. The apparatus of claim 8, wherein the at least one current balancing unit
A current balancing capacitor which maintains a current balance between driving powers delivered to the first and second LED channels, respectively, according to a charge balancing principle;
First and second diodes connected in series with each other between the first LED channel and ground to rectify a driving power source;
Third and fourth diodes connected in series between the second LED channel and ground to rectify driving power;
A first stabilizing capacitor connected in parallel with the first and second diodes to stabilize driving power supplied to the first LED channel;
A second stabilizing capacitor connected in parallel with the third and fourth diodes to stabilize driving power supplied to the second LED channel;
The method of claim 9, wherein the power supply unit
Rectification smoothing unit for rectifying and smoothing the commercial power;
A power factor correction unit for adjusting a phase difference between the voltage and the current of the rectified power supply from the rectifying smoothing unit;
A switching unit for switching the power factor corrected power from the power factor correcting unit according to the switching control signal; And
At least one primary winding receiving the switched power from the switching unit, at least one primary winding electrically insulated from the at least one primary winding, and configured to form a predetermined turns ratio to receive power from the at least one primary winding Transformers with secondary windings
Light emitting diode driving apparatus comprising a
The transformer includes a plurality of secondary windings connected to each of the plurality of LED channel blocks to supply driving power to a corresponding LED channel block.
The current balancing unit includes a plurality of the current balancing unit for supplying the driving power from the plurality of secondary windings to maintain the current balance to the first LED channel and the second LED channel of the corresponding LED channel block Diode drive.
The transformer includes a plurality of primary windings each one-to-one corresponding to the plurality of secondary windings.
The power supply unit supplies the driving power to the first and second LED channels of at least one LED channel block having first and second LED channels, respectively,
A switching unit for switching the power factor corrected power from the power factor correcting unit according to the switching control signal;
At least one primary winding receiving the switched power from the switching unit, at least one primary winding electrically insulated from the at least one primary winding, and configured to form a predetermined turns ratio to receive power from the at least one primary winding A transformer having a secondary winding; And
The method of claim 13, wherein the at least one current balance unit
A current balancing capacitor connected to one end of the secondary winding in accordance with a charge balancing principle to maintain a current balance between driving power delivered to the first and second LED channels, respectively;
A first diode connected between the other end of the secondary winding and the first LED channel to rectify driving power;
A second diode connected between the current balancing capacitor and the second LED channel to rectify a driving power source;
A first stabilizing capacitor connected in parallel with the first LED channel to stabilize driving power; And
A second stabilizing capacitor connected in parallel with the second LED channel to stabilize driving power;
The secondary winding is divided into a predetermined number of turns around the center tap,
The first LED channel and the second LED channel are connected in series,
The at least one current balancing unit
A current balancing capacitor connected to a center tap of the secondary winding and connected to a connection point of the first and second LED channels to maintain current balance between driving power delivered to the first and second LED channels, respectively;
A first diode connected between one end of the secondary winding and the first LED channel to rectify a driving power source;
A second diode connected between the other end of the secondary winding and the second LED channel to rectify a driving power source;
The method according to any one of claims 14 to 15,
A switching unit for switching the power factor corrected power from the power factor correcting unit according to a switching control signal;
At least one primary winding receiving the switched power from the switching unit, at least one primary winding electrically insulated from the at least one primary winding, and configured to form a predetermined turns ratio to receive power from the at least one primary winding A transformer having a secondary winding;
A current balancer having at least one current balance unit that maintains current balance of drive power supplied to the first and second LED channels of the at least one LED channel block having first and second LED channels, respectively;
A switch unit connected between the at least one LED channel block and ground to switch the driving power to be supplied or cut off to the at least one LED channel;
A control unit which detects a state of driving power supplied to the at least one LED channel block to control switching of the switch unit, and generates and transmits the switching control signal according to the detected state of the driving power to a transfer unit;
A switching control signal for controlling switching of the power supply unit from the controller, a first winding receiving a switching control signal, and a switching control signal electrically insulated from the first winding and input to the first winding; A transmission part having a pulse transformer having a second winding for transmitting to the part
The method of claim 19, wherein the dimming unit
21. The apparatus of claim 20, wherein the at least one current balance unit is
KR1020100126900A 2010-12-13 2010-12-13 Light emitting diodes driver KR101275399B1 (en)
KR1020100126900A KR101275399B1 (en) 2010-12-13 2010-12-13 Light emitting diodes driver
US13/117,691 US8581515B2 (en) 2010-12-13 2011-05-27 Light emitting diode driver
JP2011232164A JP5743845B2 (en) 2010-12-13 2011-10-21 Light emitting diode drive device
KR20120065655A KR20120065655A (en) 2012-06-21
KR101275399B1 true KR101275399B1 (en) 2013-06-17
ID=46198661
US (1) US8581515B2 (en)
JP (1) JP5743845B2 (en)
KR (1) KR101275399B1 (en)
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