The new high voltage 350mA LED drive letter for automotive lighting applications

The on-chip 200Hz ramp generator allows the use of analog or PWM control to achieve PWM or theater lighting effects, and therefore does not require a microcontroller to generate a PWM signal. High voltage (rated 40V) DIM pin can also be synchronized to an external PWM signal, the frequency can be as high as 2kHz. Fast turn-on / turn off time to ensure a wide range of brightness control, and waveform shaping circuit can minimize EMI.

The 5V provides a fixed output voltage regulator that can provide up to 2mA load current for the low power applications over the entire 5.5V to 40V input voltage range. In order to make the design more flexible, the regulator can also supply power to the microcontroller or other external devices. The regulator remains in operation even when the DIM is pulled low.

The MAX16804 regulator combines a low voltage (204mV) current detection benchmark and differential LED current detection to provide + 3.5% load accuracy. Such a current accuracy allows the brightness of all lamp groups to be uniform. Low dropout voltage regulator (0.5V), and low voltage current sense reference to minimize power loss in the system. They can drive up to 39V multiple serial LED.

The circuit requires only two small ceramic capacitors and a small detection resistor to minimize board size and drive cost. MAX16804 provide short circuit and thermal protection, rated in the automotive temperature range (-40 to +125 DEG C). Devices to provide heat enhanced, surface mount, 5mm x 5mm, 20 lead TQFN lead-free package, power dissipation rating of 2.67W (MAX16804). The price of the device is $1.31 (1000 chips, us FOB).