Maxim Releases New LED Driver for Lighting Applications

Maxim Integrated Products Inc. introduced the MAX16806, a EEPROM-programmable, 350mA, high-voltage (40V) linear, high-brightness LED (HB LED) driver for automotive and other demanding lighting applications. This IC can be programmed through an I2C interface to fold back the LED current if input voltage or LED temperature rises above the programmed threshold. Although a traditional architecture requires switch-mode converters to reduce power dissipation, the unique design of the MAX16806 LED driver manages total power dissipation in a lighting system, and thus eliminates the need for a switch-mode converter. Consequently, the MAX16806 reduces both cost and EMI concerns for powering high-brightness LEDs. The product is intended for a broad range of lighting applications such as automotive interior and exterior lighting.

The architecture for the MAX16806 eliminates the need for a microcontroller's PWM signal, because an on-board 200Hz ramp generator allows analog control for PWM or theater dimming effect. The device's high-voltage (40V rated) DIM pin can also sync with up to a 2kHz external PWM signal. The fast turn-on/off times ensure a wide dimming range, while the wave-shaping circuitry minimizes EMI. The MAX16806 was also designed to simplify production and reduce manufacturing cost. This LED driver uses one value of a current-sense resistor in conjunction with EEPROM-programmable current-sense reference to set the LED current for all LED bins.

Integrated debounce circuitry supplies the necessary wetting current for a momentary switch. This feature makes the MAX16806 a suitable LED driver for automotive dome- or map-lighting applications. The device requires minimum external components to implement the LED driver circuit, making it a cost effective solution for many lighting applications. The MAX16805, a companion product, has many of the same features as the MAX16806, but is offered for applications that do not need LED current thermal foldback or wetting current and debounce circuitry for a momentary switch.

The MAX16806 driver combines a low-voltage (204mV) current-sense reference with differential LED current sensing to provide load accuracy of +/-3.5%. This current accuracy allows consistent brightness for all light assemblies. The device's low-dropout pass element (0.5V typical) and current-sense reference minimize power dissipation. Output voltage is rated to 39V and allows the MAX16806 to drive multiple LEDs in series. The driver has overtemperature and short-circuit protection, important safeguards for lighting applications.

The MAX16806/MAX16805 are rated for operation over the automotive temperature range (-40°C to +125°C). They are available in a thermally enhanced, surface-mount, 5mm x 5mm, 20-pin TQFN lead-free package rated at 2.67W power dissipation. Prices for the MAX16805 start at $1.42 and $1.49 for the MAX16806 (1000-up, FOB USA).