IS31BL3555-ZLS4

IS31BL3555 2 CHANNELS, 200MA BOOST LED BACKLIGHT DRIVER Preliminary Information September 2017 GENERAL DESCRIPTION FEATURES The IS31BL3555 is a step-up controller with an integrated switching FET for driving white LED arrays in LCD panel backlight applications. The boost controller is a current mode, fixed frequency architecture with the switching frequency set by an external resistor. The integrated boost controller generates the minimum output voltage to keep all LEDs illuminated at the set current. The current in each of the 2 channels is programmed to a specific value with an external current set resistor and matched to within 1%.    LED dimming is achieved using an external digital PWM signal to either adjust the internal ISET current or pulse-width-modulate the LED intensity. The LED sinks have a fast response to a PWM input making it possible to achieve a high contrast ratio of 10,000:1.          A synchronization pin can be used to synchronize multiple IS31BL3555 devices or to synchronize with the external PWM source in the range of 580kHz to 1MHz. The IS31BL3555 integrates protection features including output overvoltage, open or shorted diode, open or shorted LED, shorted FSET or ISET resistor, and IC over temperature. A dual level cycle-by-cycle current limit function provides soft start and protects the internal current switch against high current overloads. The IS31BL3555 is available in a thermally enhanced eTSSOP-16 package. Integrated Silicon Solution, Inc. – www.issi.com Rev. 0A, 09/08/2017 Input voltage range is 4.75V to 40V Excellent input voltage transient response Sync function to synchronize boost converter switching frequency up to 1MHz Single resistor primary OVP minimizes VOUT leakage Fully integrated LED current sinks and boost converter up to 55V LED current of 200mA per channel 1% LED to LED matching accuracy Internal secondary OVP for redundant protection Drives up to 12 series LEDs in 2 parallel strings 10000:1 PWM dimming at 100Hz PWM and analog dimming inputs Built-in protection features: - Shorted FSET or ISET resistor - Open or shorted LED - Open boost Schottky - Overtemperature (OTP) APPLICATIONS      LCD monitor LCD display module LCD TV Car infotainment Cluster 1 IS31BL3555 TYPICAL APPLICATION CIRCUIT L1 10 H VCC D1 2A/60V COUT 4.7 F * Note 1 VOUT 16 CVCC 4.7 F 1 SW VCC VIO 100k Micro Controller OVP VDD 2 4 5 11 12 ROVP 137k CVDD 1 F IS31BL3555 FAULTB APWM CH1 EN/PWM CH2 10 9 * Note 1 * Note 1 7 RISET RFSET 10k 15k 6 8 COMP ISET 3 CP 120pF FR/SYNC PGND AGND Figure 1 13 RZ 150 CZ 0.47 F 14, 15 Typical Application Circuit Note 1: Value of those devices need to adjust according different applications. Integrated Silicon Solution, Inc. – www.issi.com Rev. 0A, 09/08/2017 2 IS31BL3555 PIN CONFIGURATION Package eTSSOP-16 Pin Configuration (Top View) VCC 1 16 SW FAULTB 2 15 PGND COMP 3 14 PGND APWM 4 13 PGND EN/PWM 5 12 VDD FR/SYNC 6 11 OVP ISET 7 10 CH1 AGND 8 9 CH2 Integrated Silicon Solution, Inc. – www.issi.com Rev. 0A, 09/08/2017 3 IS31BL3555 PIN DESCRIPTION No. Pin Description 1 VCC Power supply input. Bypass VCC to GND with a capacitor to keep the DC input voltage constant. 2 FAULTB Open drain fault flag to indicate a fault condition. Connect a 100kΩ resistor between this pin and the required logic level voltage. 3 COMP Soft-start and control loop compensation. Connect a series RZ-CZ network from this pin to ground for control loop compensation. 4 APWM Analog trimming option for dimming. Applying a digital PWM signal to this pin adjusts the internal ISET current. 5 EN/PWM PWM signal input for LED dimming, used to control the LED intensity by using pulse width modulation. Also used to enable the IS31BL3555. 6 FR/SYNC Frequency and synchronization pin. A resistor RFR from this pin to ground sets the switching frequency. This pin can also be used to synchronize two or more IS31BL3555s in the system. The maximum synchronization frequency is 1MHz. 7 ISET LED current adjust input. Connect a resistor RISET between ISET pin and GND to set the reference current through each LED string. 8 AGND LED signal ground. 9,10 CH2,CH1 Connect the cathodes of the LED strings to these pins. All unused pins should be connected with a 1.54kΩ resistor to ground. 11 OVP Over voltage protection pin; connect the ROVP resistor from VOUT to this pin to adjust the overvoltage protection. 12 VDD Output of internal LDO; connect a 1μF decoupling capacitor between this pin and ground. 13~15 PGND Power ground for internal NMOS. 16 SW The drain of the internal NMOS switch of the boost converter. Thermal Pad Connect to GND. Integrated Silicon Solution, Inc. – www.issi.com Rev. 0A, 09/08/2017 4 IS31BL3555 ORDERING INFORMATION Industrial Range: -40°C to +125°C Order Part No. Package QTY IS31BL3555-ZLS4-TR IS31BL3555-ZLS4 eTSSOP-16, Lead-free 2500/Reel 96/Tube Copyright © 2017 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. 0A, 09/08/2017 5 IS31BL3555 ABSOLUTE MAXIMUM RATINGS Voltage in CHx, OVP pins Voltage in VCC, FAULTB pins Voltage in ISET, FR/SYNC, APWM, COMP pins Voltage in SW pin, continuous Voltage in SW pin, t