Bluetooth low energy dimmable smart lighting solution

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The Internet of Things is growing rapidly. In its sub-segment, smart home and building automation applications, smart lighting plays a pivotal role in achieving energy saving and power saving, reducing electricity costs, and making people's lives more convenient. To design a competitive smart lighting solution, it is necessary to consider LED driving, communication, energy efficiency and other aspects. ON Semiconductor provides a smart lighting solution based on Bluetooth low energy, integrating the scalable power linear LED AC direct driver NCL30170, the industry's lowest power Bluetooth 5 system-on-chip (SoC) RSL10 and the high-voltage linear regulator NCP786A, eliminating the switching power supply (SMPS), the analog dimming range from 5% to 100%, the power factor (PF) of 0.99, the total harmonic distortion (THDi) of only 11% under full load conditions, and the standby power consumption of less than 200 mW, which helps designers to achieve ultra-low power Bluetooth controlled dimmable smart lighting solutions with high cost performance.

Figure 1: Bluetooth low energy smart lighting solution demonstration NCL30170 + RSL10 + NCP786A

How to drive smart dimming?

An obvious advantage of the AC direct drive topology is that it eliminates the traditional switching power supply, reduces bill of materials (BoM) cost, reduces board space, improves EMI performance, and extends LED life.

ON Semiconductor's NCL30170 AC direct-drive LED driver integrates a high-voltage startup current source for fast startup and is used in smart lighting and phase-cut dimming applications. The controller manages the current of multiple LEDs in series and uses ON Semiconductor's proprietary auto-commutation topology to generate a smooth sinusoidal current, making the LED constant current accuracy reach ±1% and the THD less than 10%, thereby ensuring that the LED brightness remains unchanged and providing an industry-leading power factor (0.99).

Figure 2: NCL30170 achieves high-precision constant current

Figure 3: NCL30170 provides excellent PF and THD

The NCL30170 is also the first product on the market capable of driving multiple external MOSFET switches to support the connection of multiple LED strings, with power scalable from 5 W to 300 W. The total number of connected LED strings and external switches is limited only by the highest power level.

The NCL30170 can achieve analog dimming from 5% to 100% and maintain voltage regulation throughout the dimming range, ensuring that the LED brightness remains constant even at low power. For phase-cut dimming using TRIAC, the NCL30170 can achieve good thyristor compatibility.

In addition, NCL30170 also integrates protection features such as input overvoltage protection, Rcs short-circuit protection, and thermal shutdown to ensure high reliability.

Control smart lighting with Bluetooth Low Energy

RSL10 is a Bluetooth 5 certified radio system-on-chip that supports Bluetooth low energy and 2.4 GHz proprietary/custom protocols, with a data rate of 2 Mbps. It uses different packages to provide the industry's lowest Bluetooth power consumption for multi-field IoT applications, with a power consumption of only 62.5 nW in deep sleep mode and a peak reception power consumption of only 7 mW. Its high energy efficiency has received the industry's highest EEMBC? ULPMark? score, and supports a wide power supply voltage range of 1.1 V to 3.3 V. It uses 384 kB flash memory, a dual-core processor (ARM Cortex-M3 processor, 32-bit Dual-Harvard DSP system), and supports the CEVA Bluetooth stack. When there is no high-voltage power supply, RSL10 has a connection interval of 50 ms, providing fast response when interacting with the user, with a peak current of 8 mA and an average current of only 42 ?A.

Figure 4: RSL10 block diagram

Adjustable Output Buck Regulator

NCP786A is a high-performance high-voltage linear regulator with an input voltage range of 55 V to 450 VDC and an output current of 10 mA. The output voltage can be set by a resistor divider in the range of 1.27V to 15V, making it extremely suitable for high input voltage applications. It provides ultra-low quiescent current (typical value 10 ?A), ultra-high power supply rejection ratio (PSRR: 70 dB@60 Hz, 90 dB@100kHz), self-consumption of no more than 25 ?A, and power consumption of only 8 mW, which is much lower than the commonly used switching power supply buck regulator.

Power consumption of RSL10 + NCP786A for dimming application

At 300 VDC input, we measured the RSL10 + NCP786A dimmer to draw an average current of 38 A when unconnected and 57 A to 67 A when connected, while dissipating only 22 mW.

Figure 5: Dimmer power consumption – Vin 300 VDC

Standby power consumption

The measured standby power consumption (NCL30170 + RSL10) at 230 V AC input is about 140 mW to 150 mW, of which NCL30170 consumes about 125 mW. The standby power consumption of the whole solution is less than 200 mW.

Summarize

This Bluetooth low-power dimmable smart lighting solution adopts an innovative AC direct drive topology, which does not require a traditional SMPS. It has advantages in cost, size, service life and reliability, and can flexibly expand the power range as needed. It is based on ON Semiconductor's proprietary active constant power dimming control technology. The dimming range is from 5% to 100%, the power factor is 0.99, and the THDi at full power is only 11%. Even when dimming, the lighting brightness can be maintained uniformly. It integrates the industry's lowest power Bluetooth 5 SoC RSL10, providing advanced wireless functions without affecting the system size. The high-voltage linear regulator NCP786A provides ultra-high PSRR, improves the performance of wireless applications, and realizes high-performance, ultra-low power Bluetooth controlled dimmable smart lighting solutions with high cost performance.

lele_liu

Thanks for sharing, thank you................