Off-line LED drivers AL9910
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AL9910/ AL9910A/ AL9910-5 UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER The AL9910/A high voltage PWM LED driver-controller provides an efficient solution for offline high brightness LED lamps from rectified line voltages ranging from 85VAC up to 277VAC. The AL9910 drives external MOSFETs at switching frequencies up to 300kHz, with the switching frequency determined by a single resistor. The AL9910 topology creates a constant current through the LEDs providing constant light output. The output current is programmed by one external resistor and is ultimately determined by the external MOSFET chosen and therefore allows many low current LEDs to be driven as well as a few high current LEDs. The LED brightness can be varied by both Linear and PWM dimming using the AL9910’s LD and PWM_D pins respectively. The PWM_D input operates with duty ratio of 0-100% and frequency of up to several kHz. The AL9910 can withstand input voltages up to 500V which makes it very resilient to transients at standard mains voltages. As well as standard SO-8 package the AL9910 is available in the thermally enhanced SO-8EP package. Signage and Decorative LED Lighting Back Lighting of Flat Panel Displays High Voltage DC-DC LED Driver Internal Voltage Regulator Removes Start-Up Resistor >90% Efficiency Universal Rectified 85 to 277VAC Input Range General Purpose Constant Current Source Tighter current sense tolerance: 5% AL9910-5 Drives LED Lamps with Both High and Low Current LEDs LED Brightness Control with Linear and PWM Dimming Internal Thermal Protection (OTP) Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3) 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. December 2012 © Diodes Incorporated

Typical Ap pplications Circuit s Pin Descri iptions Pin Name Senses LE string and ex ED xternal MOSFET switch current Device Gr round Drives the gate of the exte e ernal MOSFET switch. Low Frequ uency PWM Dim mming pin, also E Enable input. Inte ernal 200kΩ pull-down to GND. y Internally regulated supply voltage. 7.5V nominal for AL9910 and AL L9910-5 10V nominal for AL9910A. r Can supply up to 1 mA for external circuitr A sufficient sto r ry. orage capacitor i used to provide storage when is the rectifie AC input is ne the zero cros ed ear ssing. Linear Dim mming Input. Cha anges the...

AL9910/ AL9910A/ AL9910-5 Absolute Maximum Ratings (Note 4) (@TA = +25°C, unless otherwise specified.) Symbol VIN(MAX) Maximum input voltage, VIN, to GND Maximum CS input pin voltage relative to GND Maximum LD input pin voltage relative to GND Maximum PWM_D input pin voltage relative to GND Maximum GATE pin voltage relative to GND VPWM_D VGATE VDD(MAX) Maximum VDD pin voltage relative to GND Continuous Power Dissipation (TA = +25°C) Junction Temperature Range Storage Temperature Range Human Body Model ESD Protection (Note 5) Machine Model ESD Protection (Note 5) 4. Stresses above those...

AL9910/ AL9910A/ AL9910-5 Electrical Characteristics (@TA = +25°C, unless otherwise specified.) Symbol Parameter Shut-Down Mode Supply Current Internally Regulated Voltage Conditions Pin PWM_D to GND, VIN = VIN(MIN) (Note 6) VIN = VIN(MIN) ~500V, (Note 8) lDD(ext) = 0, Gate pin open VDD Current Available for External Circuitry VDD Under Voltage Lockout Threshold VDD rising RPWM_D VCS(HI) PWM_D Pull-Down Resistance Current Sense Threshold Voltage VPWM_D = 5V Full ambient temperature range (Note 10) VDD Under Voltage Lockout Hysteresis VGATE(HI) GATE High Output Voltage VGATE(LO) GATE Low...

CURRENT SENSE THRESHOLD (mV) -15 10 35 60 85 AMBIENT TEMPERATURE (°C) Change in Current Sense Threshold vs. Ambient Temperature 450 SHORT CIRCUIT OUTPUT CURRENT (mA) Input Current vs. Ambient Temperature 100 150 200 250 V LD DIMMING CONTROL (mV) I OUT MAX vs. V LD Dimming Control 150 85 105 125 145 165 185 205 225 245 265 INPUT VOLTAGE (VRMS ) 180mA LED Driver Short Circuit Output Current vs. Input Voltage -15 10 35 60 85 AMBIENT TEMPERATURE (°C) Change in Oscillation Frequency vs. Ambient Temperature December 2012 © Diodes Incorporated

AL9910/ AL9910A/ AL9910-5 Typical Characteristics (cont.) measured using AL9910EV4 200 105 125 145 165 185 205 225 245 265 INPUT VOLTAGE (VRMS ) 180mA LED Driver Output Current vs. Input Voltage POWER FACTOR 105 125 145 165 185 205 225 245 265 INPUT VOLTAGE (VRMS ) 180mA LED Driver Power Factor vs. Input Voltage 105 125 145 165 185 205 225 245 265 INPUT VOLTAGE (VRMS ) 180mA LED Driver Input Power Dissipation vs. Input Voltage December 2012 © Diodes Incorporated

Application Information The AL9910 is very versatile and is capable of operating in isolated or non-isolated topologies. It can also be made to operate in continuous as well as discontinuous conduction mode. VIN Figure 1. Functional Block Diagram The AL9910 contains a high voltage LDO (see Figure 1) the output of the LDO provides a power rail to the internal circuitry including the gate driver. A UVLO on the output of the LDO prevents incorrect operation at low input voltage to the VIN pin. In a non-isolated Buck LED driver when the gate pin goes high the external power MOSFET Q1 is turned...

Applications Information (cont.) Setting Operating Frequency The AL9910 is capable of operating over a 25 and 300 kHz switching frequency range. The switching frequency is programmed by connecting an external resistor between ROSC pin and ground. The corresponding oscillator period is: tOSC = The switching frequency is the reciprocal of the oscillator period. Typical values for ROSC vary from 75kΩ to 1MΩ When driving smaller numbers of LEDs, care should be taken to ensure that tON > tBLANK. The simplest way to do this is to reduce/limit the switching frequency by increasing the ROSC value....