The EV1528DQ-00A evaluation board is designed for driving up to nine (9) series WLEDs from a single cell Lithium Ion battery. The board is set up to obtain 20mA LED current. The current can be adjusted by varying the resistor R1.
The MP1528 uses current limited, variable frequency architecture to regulate the LED current while maintaining high efficiency. The BIAS pin measures the output voltage and turns off the converter if an over voltage condition is present to prevent damage due to an open circuit condition. The LED current is measured with an external current sense resistor. The low 0.4V full-scale regulation threshold and 0.4Ω power switch minimize power loss to improve efficiency. Either a DC voltage or a PWM signal at the BRT input can control the LED brightness.