Programmable Switch-Mode LED Driver with Analog-Controlled PWM Dimming

The MAX16816 is a current-mode, high-brightness LED (HB LED) driver designed to control two external n-channel MOSFETs for single-string LED current regulation. The MAX16816 integrates all the building blocks necessary to implement fixed-frequency HB LED drivers with wide-range dimming control and EEPROM-programmable LED current binning with a factor of up to 1.6. This device is configurable to operate as a stepdown (buck), step-up (boost), or step-up/step-down (buck-boost) current regulator.

Current-mode control with adjustable leading-edge blanking simplifies control-loop design. Adjustable slope compensation stabilizes the current loop when operating at duty cycles above 50%. The MAX16816 operates over a wide input voltage range and is capable of withstanding load-dump events. Multiple MAX16816 devices can be synchronized to each other or to an external clock. The MAX16816 includes a floating dimming driver for brightness control with an external n-channel MOSFET in series with the LED string.

HB LEDs using the MAX16816 can achieve efficiencies of over 90%. The MAX16816 also includes a 1.4A source and 2A sink gate driver for driving switching MOSFETs in high-power LED driver applications, such as front light assemblies. Dimming control allows for wide PWM dimming range at frequencies up to 5kHz. Higher dimming ratios (up to 1000:1) are achievable at lower dimming frequencies.

The MAX16816 provides user-programmable features through on-chip nonvolatile EEPROM registers. Adjustable features include a programmable soft-start, LED current (binning), external MOSFET gate driver supply voltage, slope compensation, leading-edge blanking time, and disabling/enabling of the RT oscillator.

The MAX16816 is available in a 32-pin TQFN package with exposed pad and operates over the -40°C to +125°C automotive temperature range.

Applications

* General Illumination * Navigation and Marine Indicators * Neon Replacement, Emergency Lighting * Signage and Beacons

* EEPROM-Programmable LED Current Binning

* Wide Input Range: 5.9V to 76V with Cold Start Operation to 5.4V

* Integrated Floating Differential LED Current-Sense Amplifier

* Floating Dimming Driver Capable of Driving an n-Channel MOSFET

* 5% or Better LED Current Accuracy

* Multiple Topologies: Buck, Boost, Buck-Boost, SEPIC

* Resistor-Programmable Switching Frequency (125kHz to 500kHz) and Synchronization Capability

* 200Hz On-Board Ramp Allows Analog-Controlled PWM Dimming and External PWM Dimming

* Output Overvoltage, Overcurrent, and LED Short Protection

* Enable/Shutdown Input with Shutdown Current Below 45µA