Integrated, 2-Channel, High-Brightness LED Driver with High-Voltage Boost and SEPIC Controller

The MAX16838 is a dual-channel LED driver that integrates both the DC-DC switching boost regulator and two 150mA current sinks. A current-mode switching DC-DC controller provides the necessary voltage to both strings of HB LEDs. The MAX16838 accepts a wide 4.75V to 40V input voltage range and directly withstands automotive load-dump events. For a 5V ±10% input voltage, connect VIN to VCC. The wide input range allows powering HB LEDs for small-to-medium-sized LCD displays in automotive and display backlight applications.

An internal current-mode switching DC-DC controller supports the boost or SEPIC topologies and operates in an adjustable frequency range between 200kHz and 2MHz. The current-mode control provides fast response and simplifies loop compensation. The MAX16838 also features an adaptive output-voltage adjustment scheme that minimizes the power dissipation in the LED current sink paths. The MAX16838 can be combined with the MAX15054 to achieve a buck-boost LED driver with two integrated current sinks.

The channel current is adjustable from 20mA to 150mA using an external resistor. The external resistor sets both channel currents to the same value. The device allows connecting both strings in parallel to achieve a maximum current of 300mA in a single channel. The MAX16838 also features pulsed dimming control with minimum pulse widths as low as 1µs, on both channels through a logic input (DIM).

The MAX16838 includes an output overvoltage protection, open LED, shorted LED detection, and overtemperature protection. The device operates over the -40°C to +125°C automotive temperature range. The MAX16838 is available in the 20-pin TSSOP and 4mm x 4mm, 20-pin TQFN packages.

Applications

* Automotive Display Backlights * Automotive Lighting Applications * LCD Display Backlights

* Integrated, 2-Channel, 20mA to 150mA Linear LED Current Sinks

* Boost or SEPIC Power Topologies for Maximum Flexibility

* Adaptive Voltage Optimization to Minimize Power Dissipation in Linear Current Sinks

* 4.75V to 40V or 5V ±10% Input Operating Voltage Range

* 5000:1 PWM Dimming at 200Hz

* Open-Drain Fault Indicator Output

* LED Open/Short Detection and Protection

* Output Overvoltage and Overtemperature Protection

* Programmable LED Current Foldback at Lower Input Voltages

* 200kHz to 2MHz Resistor Programmable Switching Frequency with External Synchronization

* Current-Mode Control Switching Stage with Internal Slope Compensation

* Enable Input

* Thermally Enhanced, 20-Pin TQFN (4mm x 4mm) and 20-Pin TSSOP Packages