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Macroblock Features l l l 16 constant-current output channels Preliminary Datasheet All-Ways-OnTM MBI1816 6 Constant-Current LED Driver Constant output current invariant to load voltage change Excellent output current accuracy: between channels: <3% (max.), and between ICs: <6% (max.) l l l l l l Output current adjusted through an external resistor Constant output current range: 5-90 mA Fast response of output current, OE (min.): 10s Schmitt trigger input 5V supply voltage Package Type: TSSOP20 with thermal pad Current Accuracy Between Channels < 3% Between ICs < 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 PrecisionDriveTM 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 l l Automotive Interior Lighting Channel Letter Decoration Lighting (c)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: info@mblock.com.tw -1November 2004, V1.00 MBI1816 Typical Application Circuit 16-Channel Constant-Current LED Driver Figure 1 Block Diagram OUT0 OUT1 OUT14 OUT15 R-EXT VDD IO Regulator OE 16 switches Terminal Description Pin Name GND Function Ground terminal for control logic and current sink Pin Configuration OUT0 ~ OUT15 Constant current output terminals 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 5V supply voltage terminal OE R-EXT VDD MBI1816 -2- November 2004, V1.00 MBI1816 Maximum Ratings Characteristic Supply Voltage Input Voltage Output Current Output Voltage GND Terminal Current Power Dissipation* (On PCB, Ta=25C) Thermal Resistance* (Under good thermal system) Thermal Resistance* (On PCB, Ta=25C) Operating Temperature Storage Temperature TSSOP20 16-Channel Constant-Current LED Driver Symbol VDD VIN IOUT VDS IGND PD Rating 0~7.0 -0.4~VDD + 0.4 90 -0.5~+17.0 1440 0.85 31.99** Unit V V mA V mA W Rth(j-a) 117 Topr Tstg -40~+85 -55~+150 C/W C 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)= 31.99C/W). -3- November 2004, V1.00 MBI1816 Electrical Characteristics Characteristic Supply Voltage Output Voltage Output Current Input Voltage "H" level "L" level Symbol VDD VDS IOUT VIH VIL IOH IOUT1 dIOUT1 IOUT2 dIOUT2 %/dVDS %/dVDD RIN(up) IDD(off) 1 "OFF" Supply Current "ON" IDD(off) 2 IDD(off) 3 IDD(on) 1 IDD(on) 2 16-Channel Constant-Current LED Driver Condition OUT0 ~ OUT15 DC Test Circuit Ta= -40~85C Ta= -40~85C VOH= 17.0V VDS= 0.6V IOL= 25mA VDS= 0.6V VDS= 0.8V IOL= 50mA VDS= 0.8V Rext= 720 Rext= 720 Rext= 360 Rext= 360 Min. 4.5 5 0.7*VDD GND 250 = Off = Off = Off = On = On - Typ. 5.0 25 1 50 1 0.1 1 500 6 6 6 9 10 Max. 5.5 17.0 90 VDD 0.3*VDD 0.5 3 3 800 8 8 8 11 12 Unit V V mA V V A mA % mA % %/V %/V K Output Leakage Current Output Current 1 Current Skew Output Current 2 Current Skew Output Current vs. Output Voltage Regulation Output Current vs. Supply Voltage Regulation Pull-up Resistor VDS within 1.0V and 3.0V VDD within 4.5V and 5.5V OE Rext= Open, Rext= 720 , Rext= 360 , Rext= 720 , Rext= 360 , OUT0 ~ OUT15 OUT0 ~ OUT15 OUT0 ~ OUT15 OUT0 ~ OUT15 OUT0 ~ OUT15 mA Test Circuit for Electrical Characteristics Figure 2 -4- November 2004, V1.00 MBI1816 Switching Characteristics Characteristic Propagation Delay Time ("L" to "H") Propagation Delay Time ("H" to "L") Pulse Width OE - OUTn OE - OUTn OE 16-Channel Constant-Current LED Driver Symbol tpLH tpHL tw(OE) tor tof Condition VDD= 5.0 V VDS= 0.8 V- 1.0V VIH= VDD VIL= GND Rext= 300 VL= 4.0 V RL= 52 CL= 10 pF Min. 0.08 0.08 10 - Typ. 190 50 Max. 8.2 8.2 250 150 Unit s s s ns ns Output Rise Time of Vout (turn off) Output Fall Time of Vout (turn on) 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=200 Rext=298 Rext=360 Rext=725 Rext=1829 Rext=3694 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 -5November 2004, V1.00 MBI1816 Adjusting Output Current 16-Channel Constant-Current LED Driver 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. IOUT(mA) 100 90 80 70 60 50 40 30 20 10 0 0 500 Relationship between IOUT and Rext 1000 1500 2000 2500 3000 3500 4000 Rext () Figure 5 Also, the output current can be calculated from the equation: VR-EXT = 1.25VIOUT = (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 360 and 25mA at 720. 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 1 Power Dissipation (W) 0.8 Type: TSSOP20(CT); Rth(j-a)=117(C/W)* 0.6 0.4 Safe Operation Area 0.2 0 0 25 Ambient Temperature (C) 50 75 100 Figure 6 -6November 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 = 125C; 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 L1 IC's area L1xW1. 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 Load Supply Voltage (VLED) 16-Channel Constant-Current LED Driver 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 VLED VF VDrop VDrop VLED VDS VF VDS MBI1816 MBI1816 -8- November 2004, V1.00 MBI1816 Outline Drawing 16-Channel Constant-Current LED Driver -9- November 2004, V1.00 |
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