IL9910DT-B

TECHNICAL DATA UNIVERSAL HIGH-VOLTAGE LED DRIVER IL9910-A/B/C DESCRIPTION The IL9910 is a PWM high-efficiency LED driver control IC. The IC is purposed for control of LED lighting as source of constant current FEATURES  8V to 450V input range  Maximum external consumption current on VDD pin IDD(ext) 1 mA  Operating temperature range -40°C ~ +85°C applications from a few mA to more than 1A Output  Brightness control for LED string from one to hundreds of diodes  PWM Low-Frequency LED Dimming TA = -40 to 85 C for all packages. APPLICATION  DC/DC or AC/DC LED Driver application  RGB Backlighting LED Driver  Back Lighting or Flat Panel Display  General purpose constant current source  Signage and Decorative LED Lighting  Automotive  Chargers ORDERING INFORMATIOIN Device Vcs Package IL9910N-A DIP-8 225~242mV IL9910DT-A SOP-8 IL9910N-B DIP-8 242~257mV IL9910DT-B SOP-8 IL9910N-C DIP-8 257~275mV IL9910DT-C SOP-8 1 2014, April Ver. 05 IL9910A/B/C PIN DIAGRAM IL9910N, IL9910D PIN DESCRIPTION Pin number IL9910N IL9910D 1) 2) Symbol Function 01 VIN Supply voltage input 02 CS LED control current input 03 GND Common pin 04 GATE Output of control of external MOSFET 05 PWM_D 06 VDD Pin of internally adjusted supply voltage 2) 07 LD Linear Dimming input 08 ROSC Input of PWM Low-Frequency LED Dimming 1) Input of internal oscillator control Can be used as enable input. Can be used as supply voltage output for external circuit . 2 2014, April Ver. 05 IL9910A/B/C BLOCK DIAGRAM AND TYPICAL APPLICATION CIRCUIT ABSOLUTE MAXIMUM RATINGS (Unless otherwise stated, Ta=25°C, GND=0V) Symbol VIN VDDMAX Value Parameter Input voltage Maximum voltage applied to VDD pin Unit Min Max -0.5 470 V - 13.5 V VCS CS pin voltage -0.3 VDD + 0.3 V VLD LD pin voltage -0.3 VDD – 0.3 V PWM_D -0.3 VDD – 0.3 V GATE pin voltage -0.3 VDD + 0.3 VPWM_D VGATE ТJ Junction temperature 125 V o C * Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. RECOMMENDED OPERATING RANGE (Unless otherwise stated, Ta= -40 to +85°C, GND=0V) Symbol VIN ТA Value Parameter Input voltage Ambient operating temperature Max 8 450 -40 3 Unit Min 85 V o C 2014, April Ver. 05 IL9910A/B/C ELECTRICAL CHARACTERISTICS (Т A =-40 ~ 85°C) Internally regulated voltage VIN = 8 V VIN = 450 V 7.0 8.0 Ambient temperature, Unit °С V 25  10 VDD pin current available for external circuit VIN = 8 V VIN = 100 V - 1.0 mA IDD(ext) UVLO Under voltage lockout VIN rise threshold from 5 to 8 V 6.20 6.95 V VEN(hi) Enable high level output voltage 2.4 - V PWM_D pin pull-down VEN = 5 V resistance 50 150 kOhm VIN = 8 V 225 275 mV 225 242 257 242 257 275 VIN = 8 V ROSC = 1 MOhm 20 30 VIN = 8 V ROSC = 226 kOhm 80 120 - 1.0 mA 6.7 - V - 0.3 V 150 280 ns 300 ns 50 ns 50 ns Symbol VDD REN VCS(hi) Parameter Test Condition VIN = 8 V VIN = 450 V Current sense pull-in threshold Voltage fOSC Internal oscillator frequency IINsd Shutdown mode consumption current A B C PWM_D pin is connected to GND, VIN = 8 V VGATE(hi) PWM_D pin is Gate high level output connected to VDD, voltage VIN = 8 V VIN = 450 V VGATE(lo) PWM_D pin is Gate low level output connected to GND, voltage VIN = 8 V VIN = 450 V TBLANK Current sense blanking interval TDELAY Delay from CS trip to GATE lo TRISE GATE output rise time TFALL GATE output fall time VCS = 0.55VLD, VLD = VDD Vin = 12V, VLD = 0.15, VCS = 0 to 0.22V after TBLANK CGATE = 500pF CGATE = 500pF 4 Value Min Max kHz 2014, April Ver. 05 IL9910A/B/C APPLICATION INFORMATION AC/DC Off-Line Applications The IL9910 is a low-cost off-line buck, boost or buck- boost converter control IC specifically designed or driving multi-LED stings or arrays. It can be operated from either universal AC line or any DC voltage between 8-450V. Optionally, a passive power factor correction circuit can be used in order to pass the AC harmonic limits set by EN6100-3-2 Class C for lighting equipment having input power less than 25W. The IL9910 can drive up to hundreds of High-Brightness (HB) LEDs or multiple strings of HB LEDs. The LED arrays can be configured as a series or series/parallel connection. The IL9910 regulates constant current that ensures controlled brightness and spectrum of the LEDs, and extends their lifetime. The IL9910 features an enable pin (PWM_D) that allows PWM control of brightness. The IL9910 can also control brightness of LEDs by programming continuous output current of the LED driver (so-called linear dimming) when a control voltage is applied to the LD pin. The IL9910 is offered in standard 8-pin SOIC and DIP packages. It is also available in a high voltage rated SO-16 package for applications that require VIN greater than 250V. The IL9910 includes an internal high-voltage linear regulator that powers all internal circuits and can also serve as a bias supply for low voltage external circuitry. LED Driver operation The IL9910 can control all basic types of converters, isolated or non-isolated, operating in continuous or discontinuous conduction mode. When the gate signal enhances the external power MOSFET, the LED driver stores the input energy in an inductor or in the primary inductance of a transformer and, depending on the converter type, may partially deliver the energy directly to LEDs. The energy stored in the magnetic component is further delivered to the output during the off-cycle of the power MOSFET producing current through the string of LEDs (Flyback mode of operation). When the voltage at the VDD pin exceeds the UVLO threshold the gate drive is enabled. The output current is controlled by means of limiting peak current in the external power MOSFET. A current sense resistor is connected in series with the source terminal of the MOSFET. The voltage from the sense resistor is applied to the CS pin of the IL9910. When the voltage threshold, the gate drive signal terminates, and the power MOSFET turns off. The threshold is internally set to 250mV, or it can be programmed externally by applying voltage to the LD pin. When soft start is required a capacitor can be connected to the LD pin to allow this voltage to ramp at a desired rate, therefore, assuring that output current of the LED ramps gradually. Optionally, a simple passive power factor correction circuit, consisting of 3 diodes and 2 capacitors, can be added as shown in the application circuit diagram of Figure 2. Supply Current A current of 1mA is needed to start the IL9910. As shown in block diagram, this current is internally generated in IL9910 without using bulky startup resistors typically required in the offline application. Moreover, in many applications the IL9910 can be continuously powered using its internal linear regulator that provides a regulated voltage of 7.5V for al internal circuits. Setting Light Output When the buck converter topology of Figure 2 is selected, the peak CS voltage is a good representation of the average current in the LED. However, there is a certain error associated with this current sensing method that needs to be accounted for. This error is introduced by the difference between the peak and the average current in the inductor. For example if the peak-to-peak ripple current in the inductor is 150mA, to get a 500mA LED current, the sense resistor should be *Vcs/(500mA+0.5*150mA)= “Vcs/575mA”Ω. (*Vcs  A : 225~242mV / B : 242~257mV / C : 257~275mV) Dimming By input 0V to 250mV DC voltage to ADJ pin to change the current or switching the current on and off while maintaining the constant current drive. When Voltage is higher than 250mV will not change the output current. Or control the LED brightness by varying the duty of the output drive current through a PWM signal input to the PWM pin 5 2014, April Ver. 05 IL9910A/B/C Programming Operating Frequency The operating frequency of the oscillator is programmed between 25 and 300kHz using an external resistor connected to the Rosc Pin: Fosc = 25000/(Rosc[KΩ] + 22 ) [kHz] Power Factor Correction When the input power to the LED driver does not exceed 25W, a simple passive power factor correction circuit can be added to the IL9910 application circuit of Figure 1 in order to pass the AC line harmonic limits of the EN61000-3-2 standard for Class C equipment. The typical application circuit diagram shows how this can be done without affecting the rest of the circuit significantly. A simple circuit consisting of 3 diodes and 2 capacitors is added across the rectified AC line input to improve the line current harmonic distortion and to achieve a power factor greater than 0.85. Figure 1. PFC Enable The IL9910 can be turned off by pulling the PWM_D pin to ground. When disabled, the IL9910 draws quiescent current of less than 1mA. Output Open Circuit Protection When the buck topology is used, and the LED is connected in series with the inductor, there is no need for any protection against an open circuit condition in the LED string. Open LED connection means no switching and can be continuous. However, in the case of the buck-boost or the Flyback topology the IL9910 may cause excessive voltage stress of the switching transistor and the rectified diode and potential failure. In this case, the IL9910 can be disabled by pulling the PMW_D pin to ground when the over voltage condition is detected. 6 2014, April Ver. 05 IL9910A/B/C DC/DC LOW VOLTAGE APPLICATIONS Buck Converter Operation The buck power conversion topology can be used when the LED string voltage is needed to be lower than the input supply voltage. The design procedure for a buck LED driver outlined in the previous chapters can be applied to the low voltage LED drivers as well. However, the designer must keep in mind that the input voltage must be maintained higher than 2 times the forward voltage drop across the LEDs. This limitation is related to the output current instability that may develop when the IL9910 buck converter operates at a duty cycle greater than 0.5. This instability reveals itself as an oscillation of the output current at a sub-harmonic of the switching frequency. Flyback (Buck-Boost) Operation This power conversion topology can be used when the forward voltage drop of the LED string is higher, equal or lower than the input supply voltage. For example, the buck-boost topology can be appropriate when input voltage is supplied by an automotive battery (12V) and output string consists of three to six HB LEDs, as the case may be for tail and break signal lights. In the buck-boost converter, the energy from the input source is first stored in the inductor or a Flyback transformer when the switching transistor is ON. The energy is then delivered to the output during the OFF time of the transistor. When the energy stored in the Flyback inductor is not fully depleted by the next switching cycle (continuous conduction mode) the DC conversion between input and output voltage is given by: VOUT = - VIN*D/(1-D) The output voltage can be either higher or lower than the input voltage, depending on duty ratio. Let us discuss the above example of an automotive LED driver that needs to drive three HB LEDs at 350mA. Knowing the nominal input voltage VIN=12V, the nominal duty ratio can be determined, as D=VLEDs/(VIN+VLEDs)=9/(12+9)=0.43 Then, given the switching frequency, in this example Fosc=50KHz, the required on-time of the MOSFET transistor can be calculated: Ton=D/Fosc=8.6 microsecond The required value of the inductor is given by: L = VIN*Ton/(0.3*ILED)= 0.98mH, use 1mH Output Capacitor Unlike the buck topology, the buck-boost converter requires an output filter capacitor to deliver power to the LED string during the ON time of switching the transistor, When the Flyback inductor current is diverted from the output of the converter. In order to average the current in the LED, this capacitor must present impedance to the switching output AC ripple current that is much lower than the dynamic impedance R OUT of the LED string. If we assume ROUT=3 Ohm in our example, in order to attenuate the switching ripple by a factor of 10, a capacitor with equivalent series resistance(ESR)of 0.3 Ohm is needed. A chip SMT tantalum capacitor can be selected for this purpose. 7 2014, April Ver. 05 IL9910A/B/C Figure 2. Typical Application Circuit (Buck Driver) IL9910 1k 200pF Figure 3. Typical Linear Dimming Application Circuit 8 2014, April Ver. 05 IL9910A/B/C Figure 4. IL9910 Buck Driver for a single 900mA HB LED (VIN = 8 ~ 30V) 9 2014, April Ver. 05 IL9910A/B/C IL9910 Figure 5. IL9910 Buck-Boost driver powering 3 to 8, 350mA HB LEDs (VIN =8 ~ 30 V) Figure 6. IL9910 Universal, Off-Line, HB, 350mA LED Driver Application 10 2014, April Ver. 05 IL9910A/B/C Package Dimension N SUFFIX PLASTIC DIP (MS – 001BA) A Dimension, mm 5 8 B 1 4 MIN MAX A 8.51 10.16 B 6.1 7.11 C L F Symbol C 5.33 D 0.36 0.56 F 1.14 1.78 -T- SEATING PLANE N G M K 0.25 (0.010) M J H D T NOTES: 1. Dimensions “A”, “B” do not include mold flash or protrusions. Maximum mold flash or protrusions 0.25 mm (0.010) per side. G 2.54 H 7.62 J 0° 10° K 2.92 3.81 L 7.62 8.26 M 0.2 0.36 N 0.38 D SUFFIX SOIC (MS - 012AA) Dimension, mm A 8 5 B H 1 G P 4 D K MIN MAX A 4.8 5 B 3.8 4 C 1.35 1.75 D 0.33 0.51 F 0.4 1.27 R x 45 C -T- Symbol SEATING PLANE J F 0.25 (0.010) M T C M NOTES: 1. Dimensions A and B do not include mold flash or protrusion. 2. Maximum mold flash or protrusion 0.15 mm (0.006) per side for A; for B ‑ 0.25 mm (0.010) per side. 11 M G 1.27 H 5.72 J 0° 8° K 0.1 0.25 M 0.19 0.25 P 5.8 6.2 R 0.25 0.5 2014, April Ver. 05