TW595265B - The device for driving multi-lamps - Google Patents

Abstract

Disclose a device for driving multi-lamps mainly including a low frequency burst mode duty ratio controller that serial connects each lamp, the lighting output on lamp balancing adjustment is determined by the detection and feedback on the specific lamp current when in comparison with the preset brightness signal of the desired level, with the coordination of the synchronized and evenly deployed phase switch, it ensures the overall steadiness of the light output without interlace or blinking, furthermore, it detects any abnormality and reports, additionally, the soft start and keep alive topology having been considered to prolong the lamp life-span, also to provide better quality on lighting output.

Description

595265 5. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a lamp driving system, especially a multi-lamp driving system for a backlight module of a liquid crystal display (LCD). . [Previous technology] According to a general LCD panel, a discharge lamp (such as a cold cathode fluorescent lamp (CCFL) is passed through a discharge lamp (CCFL) as the backlight of the panel. These discharge lamps are It is driven by an inverter circuit. In a large enough bright transformer or discharge lamp, the brightness of each parallel lamp is insufficient, which shortens the error of the lamp and the lamp grip. Therefore, the current effect of the custom circuit is quite high and it is like our own. In LCD panels, it is often necessary to use multiple lamps to provide. Therefore, for the above-mentioned lamp power supply, if a single other power conversion system is used to drive more than two parallel connections, 'due to the impedance difference between the lamps, It will seriously affect the uniform distribution of the tube current of the flow tube. If the current is too small, it will affect the uniformity of the light source of the LCD panel. If the current is too large, it will use the life of the entire system and the tube's favorite tube characteristics. Changes over time and other conditions can not be refined. The known technologies can still be achieved through multiple sets of power conversion systems and relative control applications. Although this can achieve a balance between the lamps, μ, it is necessary to increase the use of components. Quantity, while paying volume and cost. „Case No. 90 1 0 5249“ The multi-lamp driving system must be based on the output load end of the early-converter and use the impedance 595265. V. Description of the invention (2) The principle of matching to achieve the lamp thunder iiΛ Q ^ w Box news ,, a book 柃 μ * = thousands of purposes, but the above system still needs two and two & ,,, and ground level, and then other auxiliary lamps to match the balance current;; Γ: 二;: Interval: fi has some deviations of the internal resistance characteristic curve of the tube current that cannot be calculated from the micro-L, so it is tired and still looks pretty ^ Considerable, # Unable to keep each—the tubes are kept in the best state m 〇 ▲ 荣 trong—generally, it will bring strong interference, noise, and dog wave 4 problems at the moment of lighting, so it is necessary to pay more attention to the direct impact of the product or its peripheral equipment, because this kind of light tube belongs to A combination of high-voltage and low-voltage digital voice and video products, so when the power wattage == P Gongu u · ππ) will be larger. In addition to this situation at the moment of startup, it will also be The working pressure or frequency of the lamp is within the same operating range ', so the EM I produced at this time will be A large source of interference, so in order to reduce the damage of instant startup noise and interference sources, it needs to be isolated with other wave devices, which increases the cost in vain. In low-frequency control dimming, it is common practice to synchronize the same phase The mode operation controls the turning on and off of each lamp, that is, the lamps are turned on at the same time, and the lights are turned off at the same time, resulting in low light output quality. In the eyes of the human, although the visual retention effect, the lamp will not be detected. Flickering, but the eyes are still tense due to the low-frequency flicker, so that the eyes are easily tired.

595265 V. Description of the invention (3) The main purpose of the present invention is to provide a multi-lamp, which mainly uses a converter or main ^ = group (P .... dule) whose operating frequency is lower than the system. Low frequency: The Burst Mode Controller is individually connected in series to each output tube, = to detect the effective tube current of each tube, and to feedback each tube current to the input end of the controller, and the preset light The comparison of the tube luminance signal is used to adjust the turn-on period of the :: tube, so that each tube will pass the effective tube current equal to the expected, to achieve the light output balance requirement. Another object of the present invention is to provide a multi-lamp lighting device, which is combined with a synchronous out-of-phase cycle lighting control function, so that the overall lighting output is balanced, without flicker, and because the lamps are staggered from each other. The lamp can be used to avoid ills such as the obvious fluctuation of output power caused by lighting at the same time as the total lamp, the false increase in power demand and the increase in electromagnetic interference.危 # ^ Another purpose of the invention is to provide a multi-lamp lighting device, which can provide abnormal detection and indication functions when any one of the lamps fails to light normally. Another object of the invention is to provide a multi-lamp lighting device, which is a slow start and non-extinguishing lighting topology (Keep Alive Topology): You Tian: indeed improve the light output quality of the lamp, and then effectively extend the lamp The use of brother's life. In order to achieve the above-mentioned object, the main architecture of the present invention includes: the last several lamps; the 徂 Γ Ϊ current converter circuit 'is used to convert the DC power to the AC power and supply the plurality of lamps;

Page 7 595265 V. Description of the invention (4) A low-frequency control unit 'sets the effective average value of the lamp current at the output end and controls the voltage cycle of the drive converter circuit; the current sampling unit individually captures each of the aforementioned lamps The effective average current of the tube is fed back to the low-frequency control unit; and the adjustment switch is 'controlled by the control unit to individually control the current cover of each tube' so that the effective average current of each tube can reach the Set effective current average. [Embodiment] The present invention provides a multi-lamp driving lighting device (as shown in the first figure), which mainly includes: a plurality of lamp tubes 1 (lampl, lamp2, lamp3, Ump4); a converter Circuit 2 includes a transformer T1, and the secondary side of the transformer n is respectively connected to a plurality of lamp tubes lampl, lamp2, la_3, and lamP4, and is used for converting a DC power source into an AC power source and supplying each of the AC power sources to the complex number A lamp; a low-frequency control unit 3, which sets the average value of the effective current of the lamp i at the output end, and controls the voltage cycle of the drive converter circuit 2; the current sampling unit 4, which individually captures each of the foregoing lamps The average current amount is fed back to the low-frequency control unit 3; and > The adjustment switch 5 is controlled by the low-frequency control unit 3 to "effectively average the amount of current flowing through the lamp tube 2 by the current amount of the lamp tube 1" Reached the set average value of effective current. L 里 月 b will be described in detail later.

Page 8 595265 V. Description of the invention (5) The load output of the secondary side of transformer T1 of converter circuit 2 detects the current flow of each branch through lamp 1 and then controls the lamp current in a low frequency manner. The operating time of the adjusting switch 5 is adjusted to adjust the average value of the effective current of each lamp 1 to the same set value, so that the effective average current amount flowing through each lamp 1 can be the same, which means that For each lamp the current has reached equilibrium. As shown in the second figure, it is a preferred implementation circuit based on the above-mentioned block structure. The lamp 1 is provided on the secondary side of the transformer τ 1 of the inverter circuit 2, and the secondary of the transformer T 1 The side supplies AC power to each lamp iampi, iamp2, iamp3, lamp4 through the coupling capacitors C4, C5, C6, and C7, and the output of each lamp lampl, lamp2, lamp3, lamp4 has an independent output terminal. A set of current sampling unit 4 and adjustment switch 5, and then the on-period of each adjustment switch 5 is modulated by the low-frequency control unit 3, where: / ', each adjustment switch 5 may each include: a first transistor Q4, The bases of Q6, Q8, and Q10 consume the resistors R10, R16, R2i, and R27 respectively through the trigger wheel output terminals SW1 to SW4 of the low-frequency control unit 3, and the collectors consume power through the resistors R9, R15, R22, and R28 ( Vcc) and the emitter is connected to the ground (Ground) to form a conductive circuit; a second transistor q5, q7, Q9, Q11, the base of which is coupled to the collector of the first transistor, and the emitter and The collectors are connected to the ends of a first impedance r13, R19, R25, and r31, respectively. The second impedance R14, r20, R26, r32 is connected to the ground potential (Ground), wherein the first impedance is high impedance to provide a normal level, and the second impedance is low impedance to provide a conduction level Bit.

Page 9 595265 V. Description of the invention (6) Each current sampling unit 4 may each include: a first diode!) 2, D4, D7, D9 and second diodes D3, D5, D6, D8 Connect the emitters of each of the second transistors Q5, Q7, Q9, and Q11 in the forward and reverse directions, respectively, and divide the voltage through the resistors R12, R18, R24, and R30, and then pass through the resistor to work, R17, Integrating circuits composed of R23, R29, and electric valley C8, C9, C10, and C11 are respectively coupled to the current signal input terminals of the low-frequency control unit 3 丨 0 —; [~ j 〇-4 ° Control signals of the low-frequency control unit 3 The output terminal is first divided by the resistors R5 and R6, and then coupled to the gate of a slow-start transistor Q3. The source of the slow-start transistor Q3 is input through the inductor 11 and the inverter circuit 2. The terminal is coupled, and its non-pole is coupled to the gate to the ground potential (Ground). In addition, the inverter circuit 2 is used to convert DC power to AC power and supply it to the plurality of lamps, which is not limited to the implementation type, and its common composition may include: transistor, Q2, The resistor R7, R8, and capacitor 谐振 resonate with a push-pull (push_pul i) formed by the primary side of the transformer I§T1 to generate an oscillating source, which is then boosted by the secondary side of the transformer 71 to light up the lamp. Its input terminal is a current feed buck regulator composed of transistor q3, inductor u and diode D1.

Regulator), on the one hand, stabilizes the input power and doubles as a converter switch, and at the same time, it can further provide a slow start function; the following describes the operation of the above embodiment in detail, where: When the standby power supply (Vcc) is turned on (please refer to the third figure) (Shown), that is, controlling the on-period (Duty) and frequency (frequency) of the slow-start transistor q3, so that the output voltage gradually increases with the size of the on-period

Page 10 595265 V. Description of the invention (7) 'Slow start of the low-frequency control unit 3 output terminal and the adjustment switch 5' at the same time, so that you can slowly start each lamp lighting the output terminal to the preset Effective average current value to reduce the adverse effects of EM I noise caused by high-frequency high-voltage voltages that are instantaneously activated. Take the lamp tube 1 amp 1 as an example (please refer to Figure 4). When you want to light the lamp tube 1 amp 1, the low-frequency control unit 3 will be turned on by the pin output of the trigger output terminal SW1 first. The signal potential (which is not limited to low level or south level trigger), causes the first transistor Q4 in the adjustment switch 5 to be turned on to trigger the second transistor Q5, and the tube current Ibl flowing through the lamp lampl is controlled by the second electrode Sun-body Q 5 —The second impedance R1 4 flows to the ground potential ((jr 0 und). At this time, the conduction level voltage generated by the emitter of the second transistor Q5 by the second impedance r14 is obtained by After the current sampling unit 4 rectifies the first diode D2, the second diode D3, and the resistor R12, an integrating circuit composed of the resistor r17 and the capacitor C4 is integrated into a valid average current amount, and then passed through the current signal input terminal "Μ The low-frequency control unit 3 is compared with the preset average value of the starting effective current; 俟 When the starting current set value is reached, the pin of the trigger output terminal swi outputs a cut-off signal potential, making the first of the adjusting switches 5 Transistor Q4 and the second transistor Q5 are cut off, and flow through the lamp The tube current of l_ is from the first impedance R13-the second impedance is short-circuited to the ground potential) b1 to restore the normal level. At this time, the cutoff due to the high impedance of the first impedance R1 3 and the second impedance R14 Level voltage so that current does not / thunder

The sampling unit 4 flows to the low-frequency control unit 3; ^ ", L In the same way, the lamp tubes lamp2, lamp3, and lamp4 can also pass through the flow of j. Crystal ^ 595265 V. Description of the invention (8), Q9, Q11 cooperate with the current sampling unit 4 to capture the required starting current setting value '俟 When each lamp current has reached the average value of the effective current set by the starting current' then It indicates that each lamp is in a normal state. At this time, the power of the slow-start transistor Q3 is adjusted so that the lamp current at the output end of the transformer T1 in the converter circuit 2 can gradually reach the preset effective current average value of the tube current. In addition (as shown in the fifth figure), because the internal resistance of each lamp tube is often not the same, the current value of each lamp tube at the output end is still quite different, whether it is due to the difference in the original process of the lamp tube, the excessive use Aging or due to the different lengths of the lamps, the amount of current flowing through each lamp tube will be significantly different, so individually control the working time of the second transistor Q5, Q7, Q9, Ql 1 The tube current of the f tube 1 μ, I μ, I w, I μ can pass through the low frequency control unit f 1 to the same effective average current amount, so as to ensure that each lamp tube can be maintained, and maintain the brightness of 疋, and To achieve the purpose of effectively controlling the lamp current. $ < For the flashing and power 3 trigger, that is to achieve the cyclical flashing effect, the electromagnetic stem has another output terminal SW1-that is, the lamp tube avoids the false increase in the same rate of the lamp tube and the electric output terminal SW1, the so-called phase point The lamp control function effectively smoothes the disturbance. It is worth mentioning that the wheel of SW4 is troubled by the sudden increase of magnetic interference caused by the lights being turned on and off at the same time when the switch is adjusted. The low-SW 4 'can be planned to be controlled by a synchronized phase (Deployed Phase) to allow the overall lighting output to The power consumption of the inverter is evenly distributed and it is' whether the low-frequency control unit is the conducting signal potential or the wear-stop 5 is on or off.) The frequency control unit triggers the mode wheel mode. 3 trigger round signal potential (will pass through the second

595265 V. Description of the invention (9): Two: find the conduction level, or obtain the constant output through the first impedance to maintain the power-on state, that is, in a certain cycle: two switch to the minimum value, and then to the quasi-reliance :: sheep You know that the quasi-standard value is gradually taken to the private standard value, but the lamp is not reduced to the sudden and the operation is performed at this point. This is also called the non-extinguishing lighting topology; The action F ^ j fork-style questions. "Cut & Health, and increase the number of interference question 1 again (as shown in the sixth figure) 'The low-frequency control unit 3 can also _ by ^^^ tness). Or R3, R4 and then through a parallel Lei Xuan Cha and Shi w (PWM) ^, Λ ring is Gutian 4 μ, and W is a dimming mode that is restricted by the pull-up type, and is stable and stable. The invention is mainly to improve the phenomenon of cost and complexity of customary Nannan, enabling it to be converted into a more cost-effective = and purified structure, and has more space for operating scope, which is beneficial; this detection & 'In order to control the length of the operation time, it can greatly reduce the converter and transformer ^ The circuit structure tends to be simplified, and it is within the required brightness value in the length of the lamp. 『J 捋 捋 在 · Features and Effects】 The multi-lamp lighting equipment provided by the present invention is compared with other conventional technologies 595265 V. Description of the invention (10) When compared with each other, it has the following advantages ·· 1 , Can greatly reduce the number of converter and transformer costs. In order to effectively save the 2 3 4 5 circuit structure, it is more simplistic. Have more space for operation. It can also be used when the length of the lamp is inconsistent. It can generate a double value at a fixed frequency. It is evenly spread over a wide range of points to achieve the purpose of information. Biting N to reduce the side noise is clear. The detailed description is based on one of the feasible solutions of the present invention and is not intended to limit the patent scope of the present invention. Cathode fluorescent lamps (CCFL) can also be applied to other types of loads.糸, first, such as fluorescent lamp electronic ballasts, battery chargers, to improve the light output quality or load balance, advance & special 'to achieve the ten balance of Panxi eclipse field car man Bei Feizhen halberd and then effectively extend the lamp or Loss of 5 hits, and all equivalents that do not depart from the technical spirit of the present invention: The application or change shall be included in the scope of the patent of this case; " For its customary use 312 3, this case is not only technically innovative And can be compared with the above-mentioned multiple effects, which should have fully met the novelty and progress criteria; Feng 2: the patent elements, apply in accordance with the law, and earnestly approve the application for this invention patent towel to encourage invention, to Deben

Page 14 595265

The first figure is a block diagram of the system architecture of the present invention. A preferred implementation circuit diagram is provided for the present invention. The first picture is the slow start of the low frequency control unit of the present invention. The fourth picture is the current sampling unit and adjustment of the present invention: = diagram. Illustration. The fifth part is a schematic diagram of the current flow of the balance control of the present invention. The sixth diagram is a further embodiment of the brightness control of the present invention. [Representative symbols of main parts] 1 · · • Lu tube (1 amp 1, 1 amp2, lamp3 ', 1 amp4) 2 ·· Inverter circuit 3 · · Low frequency control unit 4 · · Current sampling unit 5. · Adjustment Switch T1 · · Transformer L1 .. · · · Inductor Q3 · · · · Slow-start transistors Q4, Q6 Q8, Q10 ····, the first-transistor Q5, Q7, Q9, Q11 ···, the second two Transistors R13, R19, R25, R31 First impedance R14, R20 R26, R32 »# Second impedance D2, D4 D7, D9 ... First diode D3 > D5 > D6, D8 ... · · Second Diode

Claims (1)

595265 VI. Patent application scope Multi-lamp lighting lamp; Circuit for one lamp; Control unit, set inverter electric unit, individual to low frequency control, controlled by the front volume, so that each effective current averages the scope of patent The control unit controls the slow-start electrical crystal connection, and its drain is patented. Each switch includes a crystal, its base is supplied to the value, and the amount of current is adjusted from the lamp to the set output circuit of the gate of the body. The electric captures the front unit; the low frequency flows through the lamp value. The source of the first signal output body is connected to the power supply device of the first item of the gate. The main components include: Converting DC power to AC power, and planting a plurality of lamps, a converter, and a plurality of low-frequency control devices. The drive current is sampled and the current of the feedback section switch is determined, such as the low-frequency control electrode, and the input terminal is coupled. 3, each of which adjusts the first electric wheel output terminal, and the collector passes through the resistance coupling circuit; and a second The base-emitter and collector of the transistor are respectively coupled to the over-coupled second impedance ground. 4. If the effective current average voltage period of the lamps at the end of the scope of the patent application; the effective average electricity and control unit of each lamp, to individually control the effective average current of each official can reach the multi-lamp lighting The output terminal of the device is coupled to a slow-starting transistor which is coupled to the ground potential through the inductor and the inverter electrode. The multi-lamp lighting device is coupled to the trigger of the low-frequency control unit and is grounded to the emitter to form a conductive pole surface connected to the collector of the first transistor. The two ends of the first impedance are transmitted by the emitter. Multi-lamp lighting device as described in item 1, page 595265 Page 17