Smallest, High-Efficiency, High-Brightness LED Drivers Save Space and Cost
SUNNYVALE, CA—February 8, 2007—Maxim Integrated Products (NASDAQ: MXIM) introduces the MAX16819/MAX16820, high-efficiency LED drivers for architectural, industrial, and automotive lighting applications that utilize high-brightness light-emitting diodes (HB LEDs). The MAX16819/MAX16820 HB LED drivers require just one external MOSFET and only a few passive components to power LEDs that need up to 3A of current. Each device is capable of delivering from 1W to over 25W of output power with up to 94% efficiency, while driving as many as six white LEDs connected in series. Packaged in a tiny 3mm x 3mm TDFN, these devices are the smallest LED drivers to provide LED-driver designs with such a wide power range. Moreover, a high-voltage current-sense amplifier and up to 2MHz switching frequency further reduce space and component-count requirements. These highly integrated devices minimize power dissipation, increase reliability, and reduce manufacturing costs, making them ideal for light sources such as the energy-efficient LED MR16 (an alternative to the traditional halogen MR16) and front and rear automotive lighting (RCL, DRL, and fog/low-beam lights).
Unlike the general-purpose buck controllers most commonly used to power HB LEDs, the MAX16819/MAX16820 LED drivers employ hysteretic control. With this control technique, the drivers ensure rapid transient response and turn-on/-off times during PWM dimming, which translates into a wide dimming range (up to 5000:1) or the ability to dim at very high switching frequencies (up to 20kHz) using a dedicated DIM input. Hysteretic control also offers a high level of input-supply rejection, as well as rapid response during LED dimming. There is no control-loop compensation, which simplifies the design and further minimizes component count.
High-side current sensing further differentiates these drivers from standard buck PWM controllers. Because the voltage drop across the external sense resistor is only 200mV, the MAX16819/MAX16820 reduce power dissipation. In addition, the high-side current sensing and integrated current-setting circuitry minimize the number of external components while delivering an LED current with ±5% accuracy. The MAX16819 and MAX16820 offer 30% and 10% LED current ripple, respectively, without the use of an output capacitor.
A wide input-voltage range (4.5V to 28V) allows the MAX16819/MAX16820 to be optimized for different input-voltage standards in architectural and ambient lighting, and ensures cold-start and load dump compliance in automotive applications. These LED drivers are specified for the automotive temperature range (-40°C to +125°C) and are available in a lead-free, tiny, 3mm x 3mm, 6-pin TDFN package with exposed pad. Prices start at $0.58 (1000-up, FOB USA).
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