High Power Mini LED Driver is Easy to Use

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Requiring a single external resistor to very accurately set its output current, the ZXLD1350 from Zetex Semiconductors dramatically simplifies high power LED driving. Operating from an input supply of between 7V and 30V, the driver can produce an adjustable output current of up to 350mA, to support an LED chain of up to eight 1 Watt LEDs.

Its use of the 2.9mm x 2.8mm footprint TSOT23 5-pin package and its high level of component integration means this switching regulator will fit even the most space starved application. By integrating a 30V NDMOS switch, and a high side current sensing circuit yielding a typical +/-4% precision current control, the ZXLD1350 needs the support of a total of just four external circuit components.

Through careful selection of external components, a very high efficiency LED driving solution can be created. Using Zetex's ZLLS1000 high temperature, low leakage Schottky diode for example, the whole system can achieve efficiency as high as 95%, depending on input voltage and load conditions. This combined with the ZXLD1350's very low typical shutdown current of only 15µA, ensures the device offers good power economy and extended battery life.

With an operating temperature range from –40°C to +105°C, the ZXLD1350 can also tolerate temperatures more than 20% higher than alternative solutions. In addition, its ability to support a continuous supply voltage of 30V and surge voltages of 40V makes its suitable for even the most demanding industrial and automotive applications.

Where LED lighting applications require dimming and more complex control attributes, the ZXLD1350 also offers designers a wealth of alternative control strategies. The high side current setting resistor can be varied to dim the LED. The device's multifunction control pin provides the ability to finely regulate the output current in a number of ways: by applying a resistor; a DC voltage; a low frequency PWM or a high frequency PWM. The high frequency PWM filter components are onchip.

The ZXLD1350 has a versatile adjust pin that can be used in many ways to adjust the brightness of the LED by controlling the current in the LED.

 

 

Features Simple low parts count Internal 30V NDMOS switch 350mA output current Single pin off/on and brightness control using DC voltage or PWM Internal PWM filter

Applications Low voltage halogen replacement LEDs Automotive lighting Low voltage industrial lighting LED back-up lighting Illuminated signs

 

 

Schematic for the evaluation board ZXLD1350EV2
The ZXLD1350EV2 is an evaluation board for the ZLD1350 350mA LED driver with internal switch. The board can be used to drive 1, 2 or 3 one-watt LEDs, or an external choice of LEDs. The number of external LEDs which can be connected depends on their combined forward voltage drop.

The operating voltage is nominally 24V. For three 1W series connected LEDs, the voltage can be from 12V minimum to 30V maximum. The 100uH inductor used in the circuit is based on a nominal 24V supply, which should be connected across the +VIN and GND pins. Note: The board does not have reverse battery protection. The nominal current through the LEDs is set at 300mA with a 0.33Ω sense resistor, Rs.

 

 

Mathematical Simulations
ZXLD1350 Performance Evaluation Calculator (link to document)
The above calculator is in MS Excel. To avoid problems whilst saving, we recommend selecting the "Save" option at the prompt to save the file to your local PC then opening it, rather than opening the file directly in your browser.

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
ZXLD1350ET5TA		7V-30V Input, 350mA LED Driver with Internal Switch

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