IL9910-A IKSEMICON | Alldatasheet
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Technical content
1 2014, April Ver. 05 UNIVERSAL HIGH-VOLTAGE LED DRIVER
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 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 225~242mV DIP-8 IL9910DT-A SOP-8 IL9910N-B 242~257mV DIP-8 IL9910DT-B SOP-8 IL9910N-C 257~275mV DIP-8 IL9910DT-C SOP-8 IL9910-A/B/C TA = -40 to 85 C for all packages.
2014, April Ver. 05 PIN DIAGRAM IL9910N, IL9910D PIN DESCRIPTION Pin number Symbol Function IL9910N IL9910D
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 Input of PWM Low-Frequency LED Dimming 1)
06 VDD Pin of internally adjusted supply voltage 2)
07 LD Linear Dimming input
08 ROSC Input of internal oscillator control
1) Can be used as enable input. 2) Can be used as supply voltage output for external circuit .
2014, April Ver. 05 BLOCK DIAGRAM AND TYPICAL APPLICATION CIRCUIT ABSOLUTE MAXIMUM RATINGS (Unless otherwise stated, Ta=25°C, GND=0V) Symbol Parameter Value Unit Min Max VIN Input voltage -0.5 470 V VDDMAX Maximum voltage applied to VDD pin - 13.5 V VCS CS pin voltage -0.3 VDD + 0.3 V VLD LD pin voltage -0.3 VDD – 0.3 V VPWM_D PWM_D -0.3 VDD – 0.3 V VGATE GATE pin voltage -0.3 VDD + 0.3 V ТJ Junction temperature 125 oC * 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 Parameter Value Unit Min Max VIN Input voltage 8 450 V Т A Ambient operating temperature -40 85 oC
2014, April Ver. 05
ELECTRICAL CHARACTERISTICS
(Т A =-40 ~ 85°C) Symbol Parameter Test Condition Value Ambient temperature, Unit Min Max VDD Internally regulated voltage VIN = 8 V VIN = 450 V 7.0 8.0 25 10 V IDD(ext) VDD pin current available for external circuit VIN = 8 V VIN = 100 V - 1.0 mA UVLO Under voltage lockout threshold VIN rise from 5 to 8 V 6.20 6.95 V VEN(hi) Enable high level output voltage VIN = 8 V VIN = 450 V 2.4 - V REN PWM_D pin pull-down resistance VEN = 5 V 50 150 kOhm VCS(hi) Current sense pull-in threshold Voltage VIN = 8 V A B C 225 225 242 257 275 242 257 275 mV fOSC Internal oscillator frequency VIN = 8 V ROSC = 1 MOhm 20 30 kHz VIN = 8 V ROSC = 226 kOhm 80 120 IINsd Shutdown mode consumption current PWM_D pin is connected to GND, VIN = 8 V - 1.0 mA VGATE(hi) Gate high level output voltage PWM_D pin is connected to VDD, VIN = 8 V VIN = 450 V 6.7 - V VGATE(lo) Gate low level output voltage PWM_D pin is connected to GND, VIN = 8 V VIN = 450 V - 0.3 V TBLANK Current sense blanking interval VCS = 0.55VLD, VLD = VDD 150 280 ns TDELAY Delay from CS trip to GATE lo Vin = 12V, VLD = 0.15, VCS = 0 to 0.22V after TBLANK 300 ns TRISE GATE output rise time CGATE = 500pF 50 ns TFALL GATE output fall time CGATE = 500pF 50 ns
2014, April Ver. 05
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 stin gs 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 havi ng 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 d river (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 c onverter 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 term inal 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 p assive 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 i s 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 t opology 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 curr ent 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 no t 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
achieve a power factor greater than 0.85. Figure 1. PFC quiescent current of less than 1mA.
2014, April Ver. 05 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 l ower 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 oscillatio n 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 e xample, 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 ener gy 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 switchin g 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 R OUT=3 Ohm in our example, in order to attenuate the switching rippl e 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.
Figure 4. IL9910 Buck Driver for a single 900mA HB LED (VIN = 8 ~ 30V)
2014, April Ver. 05 Package Dimension N SUFFIX PLASTIC DIP (MS – 001BA) Symbol MIN MAX A 8.51 10.16 B 6.1 7.11 C 5.33 D 0.36 0.56 F 1.14 1.78 G H J 0° 10° K 2.92 3.81 NOTE S: L 7.62 8.26 1. Dimensions “A”, “B” do not include mold flash or protrusions. M 0.2 0.36 Maximum mold flash or protrusions 0.25 mm (0.010) per side. N 0.38 D SUFFIX SOIC (MS - 012AA) Symbol 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 G H J 0° 8° NOTE S: K 0.1 0.25 1. Dimensions A and B do not include mold flash or protrusion. M 0.19 0.25 1.27 5.72 Dimension, mm Dimension, mm 2.54 7.62 A BH C K C M J F M P G D R x 45 SEA TING PLANE 0.25 (0.010) M T -T- L H M J A B F G D SEATING PLANE N K 0.25 (0.010) M T -T- C