Features and Benefits
- 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 ≤ VOUT ≤ 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
- AEC-Q100 Qualified for Automotive Applications
The LT3795 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.
- High Power LED, High Voltage LED
- Battery Chargers
- Accurate Current Limited Voltage Regulators
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration Circuit 1827A features a 110V LED controller with spread spectrum frequency modulation - the LT3795. Unlike most boosts, the circuit disconnects the output to protect against shorts or other fault conditions when the input voltage exceeds the output. The input voltage range for normal operation is from 8V to 60V. OVLO becomes active for inputs above 63V and the maximum input voltage is 110V. The LED current is 400mA and the switching frequency is 250kHz. The efficiency is 92% when the input is 12V and the LED voltage is at 87V which is the maximum LED voltage.
Documentation & Resources
R518 Reliability Data3/26/2018
DC1827A - Demo Manual9/10/2013
Spread Spectrum Frequency Modulation Reduces EMI11/4/2015
One LED Driver Is All You Need for Automotive LED Headlight Clusters (LT3795)7/1/2015 LT Journal
LED Driver with Integrated Spread Spectrum Reduces EMI without Adding Flicker10/1/2013 LT Journal
Tools & Simulations
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Models for the following parts are available in LTspice:
LT3795 Companion Parts
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.