Datasheet LT3796, LT3796-1 (Analog Devices)

LT3796/LT3796-1 100V Constant-Current and Constant-Voltage Controller with Dual Current Sense
FeaTures DescripTion
n
3000:1 True Color PWM™ Dimming
The LT®3796/LT3796-1 are DC/DC controllers designed to n
Wide Input Voltage Range: 6V to 100V
regulate a constant-current or constant-voltage and are n
Current Monitoring Up to 100V
ideal for driving LEDs. The fixed frequency and current n
High Side PMOS Disconnect and PWM Switch Driver
mode architecture result in stable operation over a wide n Constant-Current and Constant-Voltage Regulation range of supply and output voltages. Two ground referred n Dual Current Sense Amplifiers with Reporting voltage FB pins serve as the input for several LED protec- n C/10 Detection for Battery and SuperCap Charging tion features, and also allow the converter to operate as a n Linear Current Sense Threshold Programming constant-voltage source. The LT3796/LT3796-1 feature a n Short-Circuit Protection programmable threshold output current sense amplifier n Adjustable Frequency: 100kHz to 1MHz with rail-to-rail common mode range. A separate high n Frequency Synchronization (LT3796) side amplifier is gain configurable with two resistors and n Independent Top Gate Enable Pin (LT3796-1) can be used to regulate a second current or a voltage n Programmable Open LED Protection with VMODE Flag in combination with one of the FB pins. The PWM input n Programmable Undervoltage Lockout with Hysteresis provides LED dimming ratios of up to 3000:1. n Soft-Start with Programmable Fault Restart Timer n The LT3796-1 is optimized for a second output current Available in 28-Lead TSSOP Package regulation loop that can be enabled/disabled with a PMOS switch, either to drive a second LED string or to extend
applicaTions
analog dimming range. n High Power LED, High Voltage LED, Dual String L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and True n Battery and SuperCap Chargers Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7199560, 7321203, n Accurate Current Limited Voltage Regulators 7746300.
Typical applicaTion Boost LED Driver with Input Current Monitor Efficiency vs VIN
V 50mΩ 22µH IN 9V TO 60V 100 100V (TRANSIENT) 2.2µF 2k ×4 95 2.2µF 1M 499k 1M ×3 VIN VS CSP CSN 90 118k EN/UVLO GATE 13.7k 85 97.6k VREF SENSE CTRL 15mΩ EFFICIENCY (%) 80 LT3796 CSOUT CSOUT GND 75 10nF 40.2k PWM PWM FB1 ISP 70 ISMON 0 10 20 30 40 50 60 0.1µF 620mΩ INTVCC SYNC VIN (V) ISN 37961 TA01b 100k 100k FAULT FAULT TG VMODE VMODE INTVCC INTVCC VC RT FB2 SS 4.7µF 85V LED 31.6k 400mA 10k 10nF 250kHz 0.1µF 37961 TA01a 3796fb For more information www.linear.com/3796 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts