Offline and DC-DC PWM Controllers for High-Brightness LED Drivers

The MAX16801A/B/MAX16802A/B high-brightness (HB) LED driver-control ICs contain all the circuitry required for the design of wide-input-voltage-range LED drivers for general lighting and display applications. The MAX16801 is well suited for universal input (rectified 85VAC to 265VAC) LED drivers, while the MAX16802 is intended for low-input-voltage (10.8VDC to 24VDC) LED drivers.

When the LED current needs to be tightly regulated, an additional on-board error amplifier with 1% accurate reference can be utilized. A wide dimming range can be implemented by using low-frequency PWM dimming.

The MAX16801/MAX16802 feature an input undervoltage lockout (UVLO) for programming the input-supply start voltage, and to ensure proper operation during brownout conditions. The MAX16801 has an internal-bootstrap undervoltage lockout circuit with a large hysteresis that simplifies offline LED driver designs. The MAX16802 does not have this internal bootstrap circuit and can be biased directly from a +12V rail.

The 262kHz fixed switching frequency is internally trimmed, allowing for optimization of the magnetic and filter components, resulting in a compact, cost-effective LED driver. The MAX16801A/MAX16802A are offered with 50% maximum duty cycle.The MAX16801B/MAX16802B are offered with 75% maximum duty cycle. These devices are available in an 8-pin µMAX® package and operate over the -40°C to +85°C temperature range.

Applications

* Commercial and Industrial Lighting * Decorative and Architectural Lighting * Offline and DC-DC LED Drivers * RGB Back Light for LCD TVs and Monitors

* Suitable for Buck, Boost, Flyback, SEPIC, and Other Topologies

* Up to 50W or Higher Output Power

* Universal Offline Input Voltage Range: Rectified 85VAC to 265VAC (MAX16801)

* IN Pin Directly Driven From 10.8VDC to 24VDC Input (MAX16802)

* Internal Error Amplifier with 1% Accurate Reference for Precise LED Current Regulation

* PWM or Linear Dimming

* Fixed Switching Frequency of 262kHz ±12%

* Thermal Shutdown

* Digital Soft-Start

* Programmable Input Startup Voltage

* Internal Bootstrap UVLO with Large Hysteresis (MAX16801)

* 45µA (typ) Startup Supply Current, 1.4mA (typ) Operating Supply Current

* 50% (MAX16801A/MAX16802A) or 75% (MAX16801B/MAX16802B) Maximum Duty Cycle

* Available in a Tiny 8-Pin µMAX Package