This reference circuit powers an LED light bulb using power-over-ethernet (PoE) and control through a Bluetooth® module. The bulb can be wirelessly turned on/off and dimmed with 9 levels of brightness using Bluetooth. The circuit comprises a MAX5969A powered device (PD) controller, a MAX16832 LED driver with an integrated MOSFET, a MAX15062 synchronous step-down DC-DC converter, an 8-bit microcontroller, and a Bluetooth module. This reference design includes a schematic, PCB files, and a bill of materials.
The MAX5969A receives power from the power-sourcing equipment (PSE) and provides 48V (nominal) of DC power to the MAX16832 LED driver and the MAX15062 DC-DC converter. The DC-DC converter powers the 8-bit microcontroller and the Bluetooth module. The microcontroller takes user input through the Bluetooth module and converts it to a PWM-dimming signal and feeds it to the LED driver.
The board accommodates footprints for an HM-12 BT module, a BL-600 BT module, and an ESP8266 Wi-Fi module. HM-12 control software for both Android and iOS is available. Search for “PoE LED” in the appropriate app store.