Menu Close

On the crossing of the trends in the LED lighting industry

Two attractive trends we can see now on the nowadays landscape of LED Lighting. First is tendency to place various electronics circuitry directly on PCB of LED engine itself for providing its functionality. Tesla ACOB TRC57-30W-120 COB LED Module from Lynk Labs demonstrates this tendency clearly: on COB AS powering circuitry is combined with thermal shutdown function.

Second is impressive penetration of Active Cooling System in Thermal Management for LED Lighting, in LED Headlight for cars particularly. [picture] A lot of manufacturers entered already in this segment of market with LED fixtures integrated with Active Cooling Modules based on combination of fan with heat sink (Fan Sink). On the crossing of these trends MP Lighting may offer its innovative patented technology for active cooling including of control of the FAN (as FAN Driver) [2].

The original active cooling system was developed on the base new concept using of thermistors for thermal management of LED lamp. The NTC thermistor array has been connected directly in the power line between DC power supply (the same which powering LED lamp) and fan. Being thermally coupled to heat sink of LED lamp and electrically coupled to fan the NTC thermistor array capable to perform double function in the cooling system in the same time: changing its resistance by means of changing of temperature of heat sink (acting as temperature sensor) and changing of current through fan by means of changing its resistance (acting as current regulator).

As result of this negative feedback in the control loop the configuration of active cooling system is simplified significantly because of any amplifier, comparator, microprocessor and auxiliary power supply is excluded from the circuitry. This active cooling system was realized as “cooling module” which integrates heat sink, fan and intermediate plate – thermo conductor (with NTC thermistor array inside) for LED’s PCB attaching.

MingfaTech Manufacturing Limited, a LED thermal solution-leading provider, established the cooperation with MP Lighting – the developer and owner of innovated concept of ACS, which has been protected by family of US patents. [3]

Our common experimental works and comparable testing (between passive and active cooling) showed clearly that efficiency of ACS can be 4 – 6 times greater than passive cooling (given the same constructions and conditions).

As high-grade professionals, MingfaTech engineers understand the attractiveness of Active Cooling for application in Thermal Management of SSL, for high-wattage LED fixtures particularly. Active Cooling System (ACS) is the best solution to avoid extra size and weight of aluminum heat sinks. It saves materials and eliminates the need to hang those “bobs” under ceilings.

New perspective application of innovative ACS may be considered now: thanking to small size of SMD thermistor matrix and very limited BOM of circuitry for Fan Driver all electronic components can be placed directly on PCB of COB for example. Therefore the excellent thermal coupling of temperature sensitive components is reached and electrical signaling for Fan control loop will be provided. Thus all Thermal Management functionality can be realized in the frame of COB structure itself. On Fig.1 is presented the prototype of “built-in” ACS components directly into Edison-Opto 35W COB.

Fig.1

The results of the testing of prototype show evidently that standard non expensive heat sink dia. 90×45 mm in combination with regular FAN 60x60x15mm was able to provide Ts < 37*C at nominal (around 35Wt) input power for Edison-Opto COB and Tamb. = 25*C, with total thermo resistance Rt=0.34 *C/Wt.
The FAN consumed about 1, 1 W which is just 3% relatively to input electrical power.
ACS is able to provide also through connector the electrical signal about 5 Vdc in the case of overheating of COB which could be used for remote monitoring. MP lighting is inviting for cooperation any parties who will be interested for developing and design of ACS for various application in LED lighting industry.

  1. 120VAC Direct Dimmable
  2. MP Lighting introduces thermistor-based active cooling system for LED lamps
  3. The next step in LED Thermal Management had been accomplished

 

Leave a Reply

%d bloggers like this: