12W LED downlight design with dimming and colour management over Bluetooth

August 02, 2017 // By Nick Flaherty
​Power Integrations has teamed up with Casambi Technologies of Finland to develop a reference design for a constant-voltage (CV), constant-current (CC) 12-watt isolated flyback power supply with power factor correction for Bluetooth smart lighting applications.

The design includes a 3.3 V power supply to drive a Casambi CBM-001 Bluetooth® wireless module, which provides dimming and colour management control of the four-string LED load from 0 mA to 400 mA. The power supply operates over a universal input voltage range of 90 VAC to 265 VAC and achieves greater than 0.8 power factor across all line conditions.

The design is based on Power Integrations’ InnoSwitch-CH power supply controller, which combines primary, secondary and feedback circuits in a single surface-mounted offline flyback switcher IC. The IC incorporates the primary FET, the primary-side controller and a secondary-side synchronous rectification controller. The device also includes Power Integrations’ magneto-coupling communications technology, FluxLink, which bridges the isolation barrier and eliminates the need for an optocoupler. Secondary-side control enables highly accurate constant-voltage regulation and an ultra-fast step load response while simple PWM control eliminates the need for a secondary DC/DC regulator.

The high efficiency and very low standby power of the IC eliminates the need for additional heatsinks and enables customers to create solutions that meet demanding DOE-6 regulations. A built-in secondary-side auxiliary power output supports RF and MCU control circuitry.

“The InnoSwitch-CH power supply controller has excellent efficiency, particularly at light load. This allows our module to operate continuously and effectively, resulting in a great user experience with high performance and scalability,” said Timo Pakkala, CEO and co-founder at Casambi.

he CBM-001 is a Class 2 embedded Bluetooth 4.0 module designed for LED lighting control applications, light fixtures and LED bulbs. It is pre-programmed with Casambi’s proprietary firmware, making it compatible with other Casambi enabled devices. The module is controlled wirelessly with Casambi smartphone and tablet applications using the Bluetooth 4.0 protocol. Devices automatically form a self-healing and self-organizing wireless mesh network so that a large number of fixtures can be controlled from any point. No external gateway module is needed.

“Smart lighting systems monitor and control sophisticated home and workplace lighting installations," said Hubie Notohamiprodjo,