SN8500D Semiconductor Switching Type (Buck) LED Driver IC http:// www.auk.co.kr ◈ Description The SN8500D is a high power PWM LED driver IC using a buck converter topology that is capable of driving up to 1.5A of output current. it operates from an input voltage range of 3Vdc to 40Vdc and generates a regulated programmable constant output current for high power LEDs. external resistor controlled the maximum output current to single LED or a LED string. ◈ Features • Operation from 3.0V to 40V input. • Low Standby Current • High efficiency • Output Switch Current to 1.5A • Halogen-Free Package is Available ◈ Application • Automotive and Marine Lighting • High Power LED Driver • Constant Current Source ◈ Pin Assignment & Description (Top View) OSC 5 Pin Symbol Description OUT 4 1 VCC Input Voltage 2 CS Peak Current Sense Pin GND 3 3 GND Ground CS 2 4 OUT Output Pin VCC 1 5 OSC Oscillator Timing pin Package : TO-252-5L ◈ Ordering Information Package Type Device Name Marking TO-252-5L SN8500D SN8500---(1) YYWW---(2) (1) Device Code, (2) Year & Week Code KSD-I6T002-000 1 SN8500D ◈ Absolute maximum ratings [Ta=25℃] Characteristic Symbol Rating Unit Power Supply Voltage VCC(MAX) 40 V Output Current IOUT(MAX) 1.5 A Thermal Resistance Junction-Ambient Rth(j-a)* 96.1 ℃/W Power Dissipation PD* 1.3 W Operating Temperature Range Topr -40 ~ +85 ℃ Storage Temperature Range Tstg -55 ~ +150 ℃ * Mounted on a glass epoxy circuit board of 30x30mm Pad dimension of 50mm2 ◈ Recommended operating conditions Characteristic Symbol Power Supply Voltage Rating Unit Min Max VCC 7 40 V Output Current IOUT - 1.5 A Dimming Frequency FDIM - 10 kHz ◈ Electrical Characteristics (Ta=25℃, unless otherwise noted.) Characteristic Symbol Condition Min. Typ. Max. Unit Supply Current 1 ICC1 VCC=4V, Out=open - 2.0 4.0 mA Supply Current 2 ICC2 VCC=40V, Out=open - 2.0 4.0 mA Dropout Voltage Vdrop VCC=10V, Iout=1A - 1 1.3 V 270 300 330 mV Current Sense Voltage VCS VCC=10V, Rout=820kΩ Maximum duty cycle TDC - - 85 - % VCC=40V, VOSC=1.5V - 200 1000 µA Current Sense Off Current ICS(OFF) OSC ON Voltage VOSC(on) VCC=4V~40V - - 0.5 V OSC OFF Voltage VOSC(off) VCC=4V~40V 1.5 - - V OSC Charge Current ICH Vcc=5V, VOSC=0.5V 24 35 42 µA OSC Discharge Current IDCH Vcc=5V, VOSC=1.5V 140 180 260 µA KSD-I6T002-000 2 S8500D ◈ Functional block diagram OUT CS + 0.3V CONTROL VCC Driver OSC OSC SN8500 GND ◈ Typical Application L CS RSENSE OUT SN8500 Supply Voltage 7~40V VCC DF Power LED OSC CIN GND + CT KSD-I6T002-000 3 SN8500D ◈ Application Information 1) Input Capacitor The input capacitor (CIN) reduces the ripple of the input current drawn from the input supply and reduces noise injection into the IC. The reflected ripple voltage will be smaller when an input capacitor with larger capacitance is used. The capacitors should be placed close to the VCC and GND. 2) Current-Sense Resistor The snese resistor Rsense can be obtained as follows Rsense = 300mV / (IAVG + 0.5 x IRIPPLE) Thus target average LED current 700mA and ripple current 100mA then the result Rsense= 300mV/ (700mA + 0.5 x 100mA) = 0.4Ω When selecting the sense resistor, low–inductance resistors, such as surface–mount metal film resistors, are preferred. 3) Output inductor The value of the inductor is not fixed and can be adjusted freely in order to make tradeoffs among size, cost, and efficiency. Although lower inductor values will minimize size and cost, they will also reduce efficiency due to higher peak currents. On the other hand, higher inductor values will increase efficiency, but at some point the resistive losses due to the extra turns of wire will exceed the benefit gained from lower AC current levels. Also, high inductor values can affect the load–transient response of the converter. 4) Freewheeling diode The schottky barrier diode SDB30A40(40V, 3A) was recommended for freewheeling diode KSD-I6T002-000 4 SN8500D ◈ Application Guide L=220uH CS RSENSE OUT SN8500 Supply Voltage 7~40V Power LED x n VCC OSC CIN=47uF GND DF (SDB30A40) + CT=470pF <Application 1. Constant Current Power LED Driver Circuit in Series> L=220uH CS RSENSE OUT Power LED x n SN8500 Supply Voltage 7~40V VCC OSC CIN=47uF GND DF (SDB30A40) + CT=470pF <Application 2. Constant Current Power LED Driver Circuit in Parallel> KSD-I6T002-000 5 SN8500D ◈ Application Guide L=220uH CS RSENSE OUT Supply Voltage 7~40V SN8500 VCC Power LED ENABLE SDS511 OSC GND DF (SDB30A40) + CT=470pF CIN=47uF <Application 3. LED Driver Circuit with PWM Dimming Function > IPK SDB30A40 OUT RSENSE Supply Voltage 12Vac SN8500 L=220uH VCC DF (SDB30A40) CIN=47uF + Power LED (MR16) CT GND CT=470pF <Application 4. Constant Current LED Driver Circuit for MR16> KSD-I6T002-000 6 SN8500D ◈ Electrical Characteristic Curves Fig.2 ICC vs TA 5 20 16 12 8 4 0 -4 -8 -12 -16 -20 V C C =10V Supply Current – ICC [mA] Current Sense Voltage Change – VCS [%] Fig.1 VCS vs TA V C C =5V 4 3 2 1 0 -50 -25 0 25 50 75 100 125 150 -50 -25 25 50 75 100 125 150 Ambient Temperature - TA [℃] Ambient Temperature - TA [℃] Fig.4 LED Current vs PWM Duty Fig.3 Dropout Voltage vs TA 3.0 350 V C C =10V I O U T =1A 2.5 2.0 1.5 1.0 0.5 LED Current- ILED[mA] Dropout Voltage- VDROP[V] 0 0.0 300 Vc c =1 5 V fD I M =1 KH z 250 CT=4 7 0 pF L= 2 2 0 u H R s = 0 .9 9 Ω 200 150 100 50 0 -50 -25 0 25 50 75 100 125 150 Ambient Temperature - TA [℃] 0 20 40 60 80 100 PWM Duty Cycle [%] KSD-I6T002-000 7 SN8500D ◈ Electrical Characteristic Curves Fig.5 Start-up Waveform Fig.6 Normal Operating Waveform VCC=15V VCC=15V Ch1► Ch1► Ch2► Ch2► Ch3► Ch3► Ch4► Ch4► Ch1 : OSC, 2V/Div Ch1 : OSC, 2V/Div Ch2 : IIN, 80mA/Div Ch2 : IIN, 50mA/Div Ch3 : VOUT, 10V/Div Ch3 : VOUT, 10V/Div Ch4 : IOUT, 200mA/Div Ch4 : IOUT, 200mA/Div Fig.7 Dimming Waveform fosc=100Hz Ch1► Ch2► Ch3► Ch4► Ch1 : OSC, 5V/Div Ch2 : IIN, 80mA/Div Ch3 : VLED, 3V/Div Ch4 : ILED, 200mA/Div KSD-I6T002-000 8 SN8500D ◈ TO-252-5L Outline Dimension (Unit : mm) θ θ ※ Recommend PCB solder land [Unit: mm] 2.00 7.20 11.00 5.60 5.60 1.27 KSD-I6T002-000 0.60 9 SN8500D The AUK Corp. products are intended for the use as components in general electronic equipment (Office and communication equipment, measuring equipment, home appliance, etc.). Please make sure that you consult with us before you use these AUK Corp. products in equipments which require high quality and / or reliability, and in equipments which could have major impact to the welfare of human life(atomic energy control, airplane, spaceship, transportation, combustion control, all types of safety device, etc.). AUK Corp. cannot accept liability to any damage which may occur in case these AUK Corp. products were used in the mentioned equipments without prior consultation with AUK Corp.. Specifications mentioned in this publication are subject to change without notice. KSD-I6T002-000 10