ALT80802: Wide Input Voltage, Adjustable Frequency, Buck-Boost or Buck 2 Amp LED Driver

The ALT80802 is a high-frequency switching regulator that provides constant output current to drive high-power LEDs. It integrates a power MOSFET for step-down or inverting buck boost conversion. The wide input range of 3.8 to 50 V makes the ALT80802 suitable for a wide range of lighting applications, including those in an automotive input environment. The device rating also enables a simple solution for driving 3 to 4 WLEDs in buck boost configuration—a very common application requirement for automotive lighting applications.

ALT80802旨在通过频率抖动，软速行电二极管关闭和良好控制的开关节点转换速率帮助EMC / EMI设计。可编程振荡器允许ALT80802在EMI敏感频带（如AM频段）中切换。

With current-mode control and simple external compensation, the ALT80802 can achieve fast transient response. The control loop of the ALT80802 is designed for PWM dimming operation to achieve low dimming on-time and low turn-on overshoot. In buck-boost operation, the ALT80802 reduces the current overshoot normally caused by right half plane zero effect during a PWM diming turn-off transient. Extensive protection features of the ALT80802 include pulse-by pulse current limit, hiccup mode short-circuit protection, open/ short freewheeling diode protection, BOOT open/short voltage protection, VIN under voltage lockout, and thermal shutdown. Also, it includes internal clamp to prevent output voltage runaway if output LED string is opened in buck-boost operation.

The ALT80802 is available in a small 10 pin DFN package with thermal pad and wettable flank (automotive qualified).

• AEC-Q100 qualified—Automotive-Grade; Facilitates system level certification
  

• Simple operation—Same PN can be in buck-boost or buck mode

• Supply voltage from 3.8 to 50 V

• Handles automotive load dump and cold crank
• Can be run in buck mode from a pre-boost supply

• Supports up to 16 V output in buck-boost mode

• Addresses automotive market need for 3-4 WLED solution

• 150Ω集成MOSFET开关

• Supports up to ~2A in buck mode and ~750mA in buck-boost (Vinmin dependent)

• Programmable switching frequency up to 2.5 MHz, with frequency dithering

• Designed for low EMC
• Operation can be above AM band
• Small solution size

• Integrated level shifting

• Allows ground-referenced enable and fault flag in buck-boost mode

• PWM dimming via direct logic input or power supply voltage

• Supports all automotive PWM techniques including “single-wire”

• Extensive protection and fault table

• Robust, does not require extra protection components

• 3x3mm DFN-10 wettable flank exposed pad package

• Small yet thermally efficient
• Wettable flank eliminates need for x-ray inspection