Maxim MAX16816 high voltage programmable HB LED driver

Maxim launched MAX16816 high voltage, programmable, LED (HB) driver for automotive and general lighting applications. MAX16816 through the on-chip nonvolatile EEPROM registers can provide a lot of user programmable features, more generic than competitive devices. The program can be completed in the factory or the design site through the microcontroller and single wire interface.

MAX16816 integrates all modules required to implement a fixed frequency HB LED driver with wide range of brightness adjustment. The device can be configured as a buck (Buck), boost (boost) or L / Buck (buck-boost) type current regulator. The device also includes an integrated differential current amplifier and a dimming driver capable of driving N channel MOSFET.

MAX16816 is designed to meet the latest design of automobile headlights and configuration, such as a headlamp, headlight, adaptive headlight system, daytime running lights and fog lamps (DRL) etc.. The device can also be ideal for high-power floodlights, chandeliers, and LED systems requiring high current.

Advanced programmable features overcome traditional design / production problems

Due to its flexible programming capabilities, MAX16816 overcomes many of the problems and limitations of previous LED drives.

Designers have been working to ensure that multiple LED brightness is the same. Usually the user has to choose according to the brightness level (for example, distinguish) LED, this method takes a lot of time and cost. And now the MAX16816 LED current programming control capability eliminates the need to select the need to distinguish between LED. By LED current regulation, MAX16816 can compensate for changes in brightness during production.

The traditional LED driver does not provide free gate drive voltage selection function. The designer can only use the device requires expensive, high gate voltage MOSFET. It is now possible for the designer to program the gate drive output voltage to a voltage below the full-scale supply voltage, which means that the MOSFET can be used in the design of a low cost, low gate drive voltage.

The proposed scheme can not adjust the switching frequency of the controller. Because of the programmability of the MAX16816, the switching frequency can now be properly adjusted to reduce system level noise and EMI.

The previous scheme does not have the function of adjusting the blanking time. Since the MAX16816 allows setting up blanking time to device programming, this parameter can now be easily adjusted during the design phase. The adjustable function of blanking time improves the immunity of LED driver to the noise caused by high switching current.

Programmable features of MAX16816 include: soft start, LED current regulation, external MOSFET gate driver supply voltage, slope compensation, blanking time and enable / disable internal PWM oscillator. These advanced programmable features ensure efficiency, size, and low EMI design flexibility.

High power, high voltage advantage

The highly integrated MAX16816 HB LED driver operates from an input voltage range of 5.4V to 76V, ensuring compatibility with cold start and load rejection (up to 80V). The high power performance of the driver reaches the HB level. The driver has a high efficiency and can be controlled by analog or PWM to achieve a wide brightness adjustment range (1000:1). The analog control signal is compared with the internal 200Hz ramp signal, which can simplify the design of multi-level brightness adjustment. In the whole operating temperature range, the LED current control precision is 5%, which can achieve excellent brightness matching.

High voltage performance improves LED lamp / drive reliability. The rated voltage of the device 76V enables the automotive lighting manufacturer to provide a more reliable LED lighting system than ever before.

Other advantages of LED drives

MAX16816 can be flexibly designed for a variety of topologies: Buck, boost, buck-boost, and SEPIC. The peak current mode control is combined with the leading edge blanking to simplify the design of the control loop. Internal slope compensation to ensure the stability of the duty cycle of up to 50%.

The extremely low 100mV LED current reference and the internal gate driver with 1.4A/2A source / sink current capability achieve high efficiency operation, thus minimizing thermal dissipation. The integrated LED detector amplifier and brightness regulation MOSFET drive greatly reduces the number of components and ensures high reliability. The proprietary enable / shutdown input ensures that the current is less than 45 A in shutdown mode.

MAX16816 powerful LED driver also provides output overvoltage, overcurrent, overtemperature and LED short circuit protection.

MAX16816ATJ+ rated operating temperature range from -40 to +125 DEG C. Devices with bare pad, lead free, 32 lead TQFN package. Chip starts at $2.33 (1000 chips, us FOB).

Source: International Electronic Business