100V Constant-Current and Constant-Voltage Controller with Dual Current Sense

The LT3796/LT3796-1 are DC/DC controllers designed to regulate a constant-current or constant-voltage and are ideal for driving LEDs. The fixed frequency and current mode architecture result in stable operation over a wide range of supply and output voltages. Two ground referred voltage FB pins serve as the input for several LED protection features, and also allow the converter to operate as a constant-voltage source. The LT3796/LT3796-1 feature a programmable threshold output current sense amplifier with rail-to-rail common mode range. A separate high side amplifier is gain configurable with two resistors and can be used to regulate a second current or a voltage in combination with one of the FB pins. The PWM input provides LED dimming ratios of up to 3000:1.

The LT3796-1 is optimized for a second output current regulation loop that can be enabled/disabled with a PMOS switch, either to drive a second LED string or to extend analog dimming range.

Applications

* High Power LED, High Voltage LED, Dual String

* Battery and SuperCap Chargers

* Accurate Current Limited Voltage Regulators

* 3000:1 True Color PWM™ Dimming

* Wide Input Voltage Range: 6V to 100V

* Current Monitoring Up to 100V

* High Side PMOS Disconnect and PWM Switch Driver

* Constant-Current and Constant-Voltage Regulation

* Dual Current Sense Amplifiers with Reporting

* C/10 Detection for Battery and SuperCap Charging

* Linear Current Sense Threshold Programming

* Short-Circuit Protection

* Adjustable Frequency: 100kHz to 1MHz

* Frequency Synchronization (LT3796)

* Independent Top Gate Enable Pin (LT3796-1)

* Programmable Open LED Protection with VMODE Flag

* Programmable Undervoltage Lockout with Hysteresis

* Soft-Start with Programmable Fault Restart Timer

* Available in 28-Lead TSSOP Package