Maxim Introduces New 350mA, 40V LED Driver

Maxim Integrated Products Inc. introduced the MAX16806 EEPROM-programmable, 350mA, high-voltage (40V) linear, high-brightness LED driver. 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 products are intended for use in a broad range of lighting applications such as automotive interior and exterior lighting.

The novel 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 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 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).