100V/120V LED Controller with Exponential PWM and Scalable Dimming

The LT8356-1 is a DC/DC controller designed to drive high current LEDs. The fixed frequency, current mode architecture results in stable operation over a wide range of supply and output voltages. A voltage feedback pin serves as the input for several LED protection features and makes it possible for the converter to operate as a constant-voltage source. The LT8356-1 can implement boost, boost-to-battery, buck-mode, SEPIC, and flyback LED drivers.

The LT8356-1 senses output current at the high or low side of the load. The product of CTRL and IADJ inputs provides analog programming of the output current. The PWM input and PWMTG high side PMOS driver provides precision time-based LED dimming capability. When driven by an external digital signal, the PWM input provides LED dimming ratios of up to 20,000:1 at 100Hz. When driven by a constant voltage, the PWM input selects from one of 128 internally generated, precision, exponentially spaced dimming ratios ranging from 0.78% up to 100%.

APPLICATIONS

* High Voltage LED Applications

* Automotive Head Lamps/Running Lamps

* Accurate Current Limited Voltage Regulator

* 128:1 Internal Exponential PWM Dimming

* Two-Pin Multiplying Analog Dimming

* Internal Spread Spectrum Frequency Modulation

* 20,000:1 External PWM Dimming at 100Hz

* Rail-to-Rail LED Current Sensing: 0V to 120V

* ±2% LED Current Regulation

* ±2% Output Voltage Regulation

* LED Short/Open Protection and Indication

* Wide Input Voltage Range (5V to 100V)