MBI1816 6 Constant-Current LED Driver Preliminary Datasheet Macroblock All-Ways-OnTM Features l 16 constant-current output channels l Constant output current invariant to load voltage change l Excellent output current accuracy: between channels: <±3% (max.), and between ICs: <±6% (max.) l Output current adjusted through an external resistor l Constant output current range: 5-90 mA l Fast response of output current, OE (min.): 10μs l Schmitt trigger input l 5V supply voltage l Package Type: TSSOP20 with thermal pad Current Accuracy Between Channels Between ICs < ±3% < ±6% CT: TSSOP20-173-0.65 Conditions IOUT = 10 ~ 60 mA Product Description MBI1816 is an instant On/Off LED driver for lighting applications and exploits PrecisionDrive™ technology to enhance its output characteristics. At MBI1816 output stage, sixteen regulated current ports are designed to provide uniform and constant current sinks for driving LEDs within a large range of VF variations. MBI1816 provides users 16-channel constant current ports to match LEDs with equal current. Users may adjust the output current from 5 mA to 90 mA through an external resistor, Rext, which gives users flexibility in controlling the light intensity of LEDs. In addition, users can adjust device brightness via OE pin. The duty cycle of OE can decide the brightness intensity from 0% to 100%. MBI1816 guarantees to endure maximum 17V at the output ports. Additionally, to ensure the system reliability, MBI1816 is provided in the TSSOP20 with thermal pad for dramatically increased power dissipation capability. As a result, a large amount of current can be handled safely in one package. Applications l Automotive Interior Lighting l Channel Letter l Decoration Lighting Macroblock, Inc. 2004 Floor 6-4, No.18, Pu-Ting Rd., Hsinchu, Taiwan 30077, ROC. TEL: +886-3-579-0068, FAX: +886-3-579-7534 E-mail: [email protected] -1November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver Typical Application Circuit Figure 1 Block Diagram OUT0 OUT1 OUT14 OUT15 IO Regulator R-EXT VDD 16 switches OE Terminal Description Pin Configuration Pin Name Function GND Ground terminal for control logic and current sink OUT0 ~ OUT15 Constant current output terminals OE R-EXT VDD Output enable terminal When OE (active) low, the output drivers are enabled; when OE high, all output drivers are turned OFF (blanked). Terminal used to connect an external resistor (Rext) for setting up output current for all output channels MBI1816 5V supply voltage terminal -2- November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver Maximum Ratings Characteristic Symbol Rating Unit Supply Voltage VDD 0~7.0 V Input Voltage VIN -0.4~VDD + 0.4 V Output Current IOUT 90 Output Voltage VDS -0.5~+17.0 GND Terminal Current IGND 1440 mA Power Dissipation* (On PCB, Ta=25°C) PD 0.85 W Thermal Resistance* (Under good thermal system) mA V 31.99** TSSOP20 °C/W Rth(j-a) Thermal Resistance* (On PCB, Ta=25°C) 117 Operating Temperature Topr -40~+85 °C Storage Temperature Tstg -55~+150 °C *Users must notice that the power dissipation (almost equaling to IOUT x VDS) should be within the Safe Operation Area shown in Figure 6. ** Good thermal system design can ensure that the heat management of the total system (storage temperature and operating temperature) maintains MBI1804 within the defined temperature limits (Rth(j-a)= 31.99°C/W). -3- November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver Electrical Characteristics Characteristic Symbol Condition Min. Typ. Max. Unit Supply Voltage VDD - 4.5 5.0 5.5 V Output Voltage VDS OUT0 ~ OUT15 - - 17.0 V IOUT DC Test Circuit 5 - 90 mA “H” level VIH Ta= -40~85ºC 0.7*VDD - VDD V “L” level VIL Ta= -40~85ºC GND - 0.3*VDD V Output Leakage Current IOH VOH= 17.0V - - 0.5 μA Output Current 1 IOUT1 VDS= 0.6V Rext= 720 Ω - 25 - mA Current Skew dIOUT1 IOL= 25mA VDS= 0.6V Rext= 720 Ω - ±1 ±3 % Output Current 2 IOUT2 VDS= 0.8V Rext= 360 Ω - 50 - mA Current Skew dIOUT2 IOL= 50mA VDS= 0.8V Rext= 360 Ω - ±1 ±3 % Output Current Input Voltage Output Current vs. Output Voltage Regulation Output Current vs. Supply Voltage Regulation %/dVDS VDS within 1.0V and 3.0V - ±0.1 - %/V %/dVDD VDD within 4.5V and 5.5V - ±1 - %/V Pull-up Resistor RIN(up) 250 500 800 KΩ = Off - 6 8 “OFF” Supply Current “ON” OE IDD(off) 1 Rext= Open, IDD(off) 2 Rext= 720 Ω, OUT0 ~ OUT15 = Off - 6 8 IDD(off) 3 Rext= 360 Ω, OUT0 ~ OUT15 = Off - 6 8 IDD(on) 1 Rext= 720 Ω, OUT0 ~ OUT15 = On - 9 11 IDD(on) 2 Rext= 360 Ω, OUT0 ~ OUT15 = On - 10 12 OUT0 ~ OUT15 mA Test Circuit for Electrical Characteristics Figure 2 -4- November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver Switching Characteristics Characteristic Propagation Delay Time (“L” to “H”) Propagation Delay Time (“H” to “L”) Symbol Condition Min. Typ. Max. Unit OE - OUTn tpLH 0.08 - 8.2 μs OE - OUTn tpHL VDD= 5.0 V VDS= 0.8 V- 1.0V VIH= VDD VIL= GND Rext= 300 Ω VL= 4.0 V RL= 52 Ω CL= 10 pF 0.08 - 8.2 μs 10 - - μs - 190 250 ns - 50 150 ns Pulse Width tw(OE) OE Output Rise Time of Vout (turn off) tor Output Fall Time of Vout (turn on) tof Test Circuit for Switching Characteristics Figure 3 Application Information Constant Current In LED lighting applications, MBI1816 provides nearly no variations in current from channel to channel and from IC to IC. This can be achieved by: 1) The maximum current variation between channels is less than ±3%, and that between ICs is less than ±6%. 2) In addition, the current characteristic of output stage is flat and users can refer to the figure as shown below. The output current can be kept constant regardless of the variations of LED forward voltages (VF). This performs as a perfection of load regulation. IOUT(mA) 100 90 80 70 60 50 40 30 20 10 0 0.0 I OUT vs. VDS @ Various Rext Rext=200Ω Rext=298Ω Rext=360Ω Rext=725Ω Rext=1829Ω Rext=3694Ω 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 VDS(V) Figure 4 -5- November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver Adjusting Output Current The output current of each channel (IOUT) is set by an external resistor, Rext. The relationship between Iout and Rext is shown in the following figure. Relationship between IOUT and Rext IOUT(mA) 100 90 80 70 60 50 40 30 20 10 0 0 500 1000 1500 2000 2500 3000 3500 4000 Rext (Ω) Figure 5 Also, the output current can be calculated from the equation: VR-EXT = 1.25V；IOUT = (VR-EXT / Rext ) x 14.4= (1.25V / Rext ) x 14.4 where Rext is the resistance of the external resistor connected to R-EXT terminal and VR-EXT is the voltage of R-EXT terminal. The magnitude of current (as a function of Rext) is around 50mA at 360Ω and 25mA at 720Ω. Package Power Dissipation (PD) The maximum power dissipation, PD(max) = (Tj – Ta) / Rth(j-a), decreases as the ambient temperature increases. Max. Power Dissipation at Various Ambient Temperature Power Dissipation (W) 1 0.8 Type: TSSOP20(CT); Rth(j-a)=117(°C/W)* 0.6 0.4 Safe Operation Area 0.2 0 0 25 50 Ambient Temperature (°C) 75 100 Figure 6 -6- November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver The maximum allowable package power dissipation is determined as PD(max) = (Tj – Ta) / Rth(j-a). When 16 output channels are turned on simultaneously, the actual package power dissipation is PD(act) = (IDD x VDD) + (IOUT x Duty x VDS x 16). Therefore, to keep PD(act) ≤ PD(max), the allowable maximum output current as a function of duty cycle is: IOUT = { [ (Tj – Ta) / Rth(j-a) ] – (IDD x VDD) } / VDS / Duty / 16, where Tj = 125°C; Duty= tON / T; tON: the time of LEDs turning on; T: OE signal period *Note 1: The thermal resistor Rth(j-a) =117 °C/W; it is based on the following structure. Copper foil The PCB area L2xW2 is 4 times to the L2 IC’s area L1xW1. L1 The thickness of the PCB is 1.6 mm, copper foil 1 OZ. The thermal pad on the W1 IC’s bottom has to be mounted on the copper foil. W2 -7- November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver Load Supply Voltage (VLED) MBI1816 are designed to operate with VDS ranging from 0.4V to 1.0V considering the package power dissipating limits. VDS may be higher enough to make PD(act) > PD(max) when VLED = 5V and VDS = VLED – VF, in which VLED is the load supply voltage. In this case, it is recommended to use the lowest possible supply voltage or to set an external voltage reducer, VDROP. A voltage reducer lets VDS = (VLED –VF) – VDROP. Resistors or Zener diode can be used in the applications as shown in the following figures. Voltage Supply Voltage Supply VDrop VDrop VLED VLED VF VF VDS VDS MBI1816 MBI1816 -8- November 2004, V1.00 MBI1816 16-Channel Constant-Current LED Driver Outline Drawing -9- November 2004, V1.00