IS32BL3554 BOOST TYPE LED DRIVER WITH 4-CHANNEL CURRENT SOURCE QUICK START DESCRIPTION The IS32BL3554 is a white LED driver for backlight applications based on a highly efficient boost controller operating over a wide input voltage range of 4.5V to 33V. The IS32BL3554 contains four regulated current sources with 1.5% (Typ.) current matching between strings for a uniform LED brightness. Each current source can be programmed via an external resistor to drive from 20mA to 180mA. A fast slew rate current source allows high frequency and narrow pulse width dimming signals to achieve a very high contrast ratio. The device operating frequency can be adjusted from 0.1MHz to 1MHz. The IS32BL3554 has safety protection features to prevent damage during fault conditions. Protection features include an internal soft-start circuit to prevent a high inrush current during start up, open/short LED protection to automatically disable a faulty current source, over temperature protection (OTP), cycle-by-cycle current limit, under voltage lockout (UVLO), programmable OVP, VOUT short / Schottky diode open protection and Schottky Diode short-circuit protection. FEATURES Input voltage range: 4.5V to 33V 4-Channel LED current sinks, 180mA per string LED current adjustable from 20mA to 180mA String-to-string current matching accuracy: 1.5% Adjustable operating frequency: 100kHz to 1MHz External PWM dimming High contrast ratio Less than 3µA shutdown current Programmable soft-start Built-in protection features - OCP, OTP, UVLO - Open/short LED protection - Programmable OVP - Schottky Diode/inductor short-circuit protection Automotive AEC-Q100 Qualified Figure 1: Photo of IS32BL3554 Evaluation Board RECOMMENDED EQUIPMENT 12V, 3A power supply LED load board Excel Calculator download from the ISSI website www.issi.com/US/product-analog-backlight-driver.shtml ABSOLUTE MAXIMUM RATINGS ≤ 33V power supply All LED channels must be connected to an LED load. Caution: Do not exceed the conditions listed above, otherwise the board will be damaged. PROCEDURE The IS32BL3554 evaluation board is fully assembled and tested. Follow the steps listed below to verify board operation. Caution: Do not turn on the power supply until all connections are completed. 1) 2) Connect the ground terminal of the power supply to the GND and the positive terminal to the VCC. Or connect the DC power to the connector (DC IN). Turn on the power supply and pay attention to the supply current. If the current exceeds 2A, please check for circuit fault. ORDERING INFORMATION Part No. Temperature Range Package IS32BL3554-ZLA3-EB -40°C ~ +125°C (Automotive) eTSSOP-16, Lead-free Table 1: Ordering Information For pricing, delivery, and ordering information, please contacts ISSI’s analog marketing team at [email protected] or (408) 969-6600. Integrated Silicon Solution, Inc. – www.issi.com Rev. C, 07/24/2015 1 IS32BL3554 BOOST TYPE LED DRIVER WITH 4-CHANNEL CURRENT SOURCE 2. W2 Overvoltage Protection – VOVP can be adjusted from 10.6V to 50V by W2. VOVP should be set to 1.2 times VOUT to ensure OVP function. The IS32BL3554 operation is unstable if VOVP is set to less than VOUT. EVALUATION BOARD OPERATION IS32BL3554 evaluation board drives four strings of WLEDs. There are three variable resistors used for adjusting the operating frequency (W1), OVP voltage (W2) and LED current (W3). A clockwise rotation will increase the resistance resulting in a lower operating frequency, lower OVP and lower LED current. Use an ohmmeter to measure the adjusted resistance value. 3. W3 LED Current – The LED channel current (ICH) can be adjusted from 45mA to 180mA by W3. RCS = 0.135Ω is calculated by setting VIN = 12V, VOUT = 32V, ICH = 180mA, L1/L2 = 10µH, fOSC = 1MHz. RCS should be reduced when ICH = 180mA and fOSC is less than 1MHz or the IC will enter into the power limit mode. The default parameters of the evaluation board are: VIN = 12V, VOUT = 32V, fOSC = 1MHz (W1= 9kΩ), VOVP = 39V (W2 = 13kΩ), ICH = 120mA (W3 = 3.2kΩ), RCS = 0.135Ω, L1/L2 =10µH. Note that W1, W2 and W3 are set at the factory. The operating temperature is from -40°C to +125°C. 4. Excel Calculator – W1, W2 and W3 cannot be randomly changed. Please use the IS32BL3554 Excel Calculator to define the system parameters. It is recommended to maintain the switching duty cycle less than 70% when ICH > 150mA and fOSC > 0.8MHz. Otherwise the switching MOSFET and Diode will have large power losses, will heat up resulting in reduced power conversion efficiency. Please follow the suggested procedures below when modifying the DEMO board parameters. 1. W1 Set Switch Frequency – Clockwise rotation of W1 will adjust the switching frequency (fOSC) from 1MHz to 100kHz and the inductor L1/L2 peak current (IPEAK) will increase from 1.8A to 5.17A. For operation with TA > 85°C, the MOSFET should be thermally protected with the addition of a heat sink. Also the temperature stability of magnetic saturation current for inductor and the temperature stability of compensation capacitor for COMP should be selected for elevated temperature operation. Caution: An IPEAK of 5.17A is too high for the installed 10µH inductor L1/L2. A higher IPEAK current will affect other component selections such as inductor L1/L2 and current sense resistor RCS (R1||R2). We recommend a lower fOSC by using a 47µH inductor instead of 10µH to keep IPEAK below 2.22A. Note: A higher inductor value will reduce the PWM dimming contrast. For the default L1/L2 value, the contrast is 1000:1. Choosing a smaller inductor like 4.7µH will increase the contrast to 2000:1(Max.). Notice that the inductor should be higher than LCCM(Min.). VCC L1/L2 2 1 VIN GND U1 R4 0R 6 C1 22uF/50V 2 1 Vo GND 2 1 DIM EN STATUS VCC VIN 0R OUT CS C6 VCC 5 DIM R7 10k 2 9 R5 300k R8 300k R12 C7 220nF C9 220nF C3 EN 22uF/100V 22uF/100V C10 220nF 0R R1 0.27R R2 0.27R C8 OVP CH1 CH2 NC 1 RT COM 4X10 Iset GND W2 16 10 CH1 13 CH2 11 CH3 14 CH4 R9' NC 15 R9 6.8k 0--20K 8 R11 43K 820pF DIM C11 R10 1M C4 0--200K 43k R15 Q1 13N06 STATUS CH4 0-500K Vo SS310 R3 C2 NC CH3 W1 R13 D1 IS32BL3554 7 10k 3 VCC R14 100k STATUS EN R6 4 2R C5 NC 2.2uF 2 1 FB 10uH 12 W3 1k V0 CH1 CH2 CH3 CH4 1 2 3 4 5 IS32BL3554 Figure 2: IS32BL3554 Application Schematic Integrated Silicon Solution, Inc. – www.issi.com Rev. C, 07/24/2015 2 IS32BL3554 BOOST TYPE LED DRIVER WITH 4-CHANNEL CURRENT SOURCE BILL OF MATERIALS Name Symbol LED Driver U1 Inductor L1/L2 Diode Description Qty Supplier Part No. Boost backlight LED driver 1 ISSI IS32BL3554 IND,10µH±20%,SMD 1 Würth Elektronik 7447709100 D1 Schottky Diode, SS310 SMD 1 Ferrite Bead FB 600R@100M SMD 1 NMOS Q1 100V N-Channel MOSFET SMD 1 Fairchild FQD19N10L Resistor R1,R2 RES,0.27Ω,1/10W,±1%,SMD 2 Yageo RL0805FR-070R27L Resistor R3,R4 RES,0Ω,1/10W,±1%,SMD 2 Yageo RL0805FR-0700RL Resistor R5,R8 RES,300k,1/10W,±5%,SMD 2 Yageo RC0603JR-07300KL Resistor R6,R7 RES,10k,1/10W,±5%,SMD 2 Yageo RC0603JR-0710KL Resistor R9 RES,6.8k,1/10W,±1%,SMD 1 Yageo RC0805FR-076K8L Resistor R10 RES,1M,1/10W,±1%,SMD 1 Yageo RC0805FR-071ML Resistor R11 RES,43k,1/10W,±1%,SMD 1 Yageo RC0805FR-0743KL Resistor R12 RES,43k,1/10W,±1%,SMD 1 Yageo RC0805FR-0743KL Resistor R13 RES,2Ω,1/10W,±5%,SMD 1 Yageo RC0805JR-072RL Resistor R14 RES,100k,1/10W,±5%,SMD 1 Yageo RC0805JR-07100KL Resistor R15 RES,1k,1/10W,±1%,SMD 1 Yageo RC0805FR-071KL Capacitor C1 CAP,22µF,50V,±20%,SMD 1 Capacitor C3,C4 CAP,22µF,100V,±20%,SMD 2 Capacitor C6 CAP, 2.2µF,16V,±10%,SMD 1 Yageo CC0805JKX7R7BB225 Capacitor C7,C9,C10 CAP,0.22µF,16V,±10%,SMD 3 Yageo CC0805JKX7R7BB224 Capacitor C8 CAP,820pF,16V,±10%,SMD 1 Yageo CC0805JKX7R7BB821 Variable Resistor W1 RES,0~500k 1 Variable Resistor W2 RES,0~200k 1 Variable Resistor W3 RES,0~20k 1 R9’,C2,C5,C11 Not Connect 4 SS310 Bill of materials, refer to Figure 2 above. Integrated Silicon Solution, Inc. – www.issi.com Rev. C, 07/24/2015 3 IS32BL3554 BOOST TYPE LED DRIVER WITH 4-CHANNEL CURRENT SOURCE 10 10 4 2 1 2 1 4 5 8 8 4 4 5 8 2 1 1 4 2 3 2 4 1 3 8 4 5 3 2 1 3 2 1 10 10 Figure 3: Board Component Placement Guide - Top Layer Figure 4: Board PCB Layout - Top Layer Integrated Silicon Solution, Inc. – www.issi.com Rev. C, 07/24/2015 4 IS32BL3554 BOOST TYPE LED DRIVER WITH 4-CHANNEL CURRENT SOURCE 10 10 4 2 1 2 1 4 5 8 8 4 4 5 8 2 1 1 4 2 3 2 4 1 3 8 4 5 3 2 1 3 2 1 10 10 Figure 5: Board Component Placement Guide - Bottom Layer Figure 6: Board PCB Layout - Bottom Layer Copyright © 2015 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances Integrated Silicon Solution, Inc. – www.issi.com Rev. C, 07/24/2015 5