This evaluation board demonstrates the high power efficiency and outstanding output current accuracy of the LM3464A typical application circuit. With four LED strings connected, the total output power is about 50W. The schematic, bill of material and PCB layout drawing of the LM3464A evaluation board are provided in this document.
This evaluation board is designed around an L6902D-based DC-DC converter with dimming interface. The board implements both of two well known dimming methods: - Analog current control - Average current control by PWM
This evaluation board showcases the LM3409HV PFET controller for a buck current regulator. It is designed to drive 12 LEDs (VO = 42V) at a maximum average LED current (ILED = 1.5A) from a DC input voltage (VIN = 48V). The switching frequency (fSW = 400 kHz) is targeted for the nominal operating point, however fSW varies across the entire operating range.
This design was developed to minimize the current spikes coming out of an electronic transformer to less than 5A, which is a typical transformer rating, when driving an LED MR16 circuit. The off the shelf LED MR16 solutions exhibit spikes that significantly exceed a transformers maximum rated output current which will degrade the reliability of the transformer and reduce its operating lifetime. T…
The L6920D is used in this flashlight application as it is a high efficiency step-up controller that realizes the conversion from battery voltage to the selected output voltage with only three external components.
Whenever a lighting application, such as street lighting for example, requires an elevated number of LEDs, there are basically two solutions: the first is to connect all the diodes in series in a single "string"; the second is to place several strings in parallel with fewer elements in each one.
The LM3404HV circuit and BOM have been designed to provide a constant forward current of 1.0A to a single LED with a forward voltage of approximately 3.7V from an input of 48V ±10%. Over the input voltage range of 6V to 75V the average LED current, IF, is 1.0A ±10%, the ripple current, ΔiF, will not exceed 400 mAP-P, and the switching frequency is 200 kHz ± 10%.
The ZXSC400 is voltage mode boost converter in SOT23-6 package. Its low feedback voltage allows the current in a chain of LEDs to be set and accurately monitored with a single resistor with minimal losses. The ZXSC400EV4 is configured as a boost converter to drive a 1W LED from two NiCd / NiMH batteries.
The ZXSC400, although designed for small LEDs in LCD backlighting, is sufficiently flexible to provide an efficient 1W solution producing a nominal 350mA constant current source from 2 NiMH or NiCd cells.