Features

• 3000:1 True Color PWM™ Dimming
• Wide Input Voltage Range: 4.5V to 110V
• Input and Output Current Reporting
• PMOS Switch Driver for PWM and Output Disconnect
• Internal Spread Spectrum Frequency Modulation
• ±2% Constant Voltage Regulation
• ±3% Constant Current Regulation: 0V ≤ V_OUT ≤ 110V
• Programmable Input Current limit
• CTRL Inputs Linearly Adjust LED Current
• Adjustable Frequency: 100kHz to 1MHz
• Programmable Open LED Protection with OPENLED Flag
• Short-Circuit Protection and SHORTLED Flag
• Programmable Undervoltage Lockout with Hysteresis
• Soft-Start with Programmable Fault Restart Timer
• C/10 Detection for Battery Charging
• Available in 28-Lead TSSOP Package

Typical Application

Description

The LT®3795 is a DC/DC controller designed to regulate a constant-current or constant-voltage and is ideal for driving LEDs. It drives a low side external N-channel power MOSFET from an internal regulated 7.7V supply. The fixed frequency and current mode architecture result in stable operation over a wide range of supply and output voltages. Spread spectrum frequency modulation (SSFM) can be activated for improved electromagnetic compatibility (EMC) performance. The ground referred voltage FB pin serves as the input for several LED protection features, and also allows the converter to operate as a constant-voltage source. The maximum output current is set by an external resistor, and the output current amplifier has a rail-to-rail common mode range. The LT3795 also includes a separate input current sensing amplifier that is used to limit input current. The TG pin inverts and level shifts the PWM signal to drive the gate of the external PMOS. The PWM input provides LED dimming ratios of up to 3000:1, and the CTRL inputs provide additional analog dimming capability.