At the end of 2019, the product development of W40 0-10V version was started. L3,L6 and L12 could not guarantee the complete consistency of component parameters due to the power supply, and there were problems of inconsistent minimum brightness and inconsistent lighting time between products of the same length or different lengths. Through many tests and program adjustments, the minimum brightness of L3 and L12 has been adjusted to the difference is not obvious, but there is still a big difference in the lighting time; At present, the delivery time of the power supply is very long, there are 3 kinds of power supply specifications, it is difficult to make inventory plan, and the inspection of the power supply incoming materials is difficult (the same power, different power, before and after the batch should be compared).        

    Product design and features:

  1. 24V constant voltage power supply +0-10V control driver integration; The power supply uses Jinshengyang 15W module power supply, L12 adopts dual power supply scheme; Dimming parameters and consistency are decouple from the power supply, which can be stored in bulk

  2. The common single chip microcomputer model of the lamps: 0-10V control driver board uses the new Tang single chip microcomputer N76E003

  3. the MBI6655 driver chip is also made of modular integration, the consistency of the dimming current is determined by the accuracy of the driver chip and the dimming resistance, error <5%

       

    Product design points:

    1.dimming consistency solution theory and method:

The voltage of 0-10V dimming signal is detected by AD pin of MCU, and 15 groups of voltage data are continuously detected by rolling, and the influence of voltage fluctuation is eliminated by means of arithmetic average value.

  The dimming starting voltage of Ming Weft is 0.6V, Ochese and the dimming starting voltage is 0.35V(nominal 0.3V), because of the weak pull-up resistance built into the 0-10V voltage signal, the dimmer starting voltage is between 0.35-0.75V (related to the internal resistance of the power supply signal, and the more the number of connected power supplies, the higher the starting voltage). Therefore, when the starting voltage is set to less than 0.35V, the problem of uneven dimming lighting can be avoided.

  Based on this situation, the program has set the dimming signal voltage > 0.31V, the lamp starts to light, the initial brightness ratio of 0.4%.

  In order to prevent the lamp from repeatedly turning on and off when the dimming threshold (critical value) is 0.31V, the program adds signal voltage hysteresis comparison processing, when the dimming voltage is <  0.19V, the lamp will be turned off, maintain the voltage width of 0.12V, and prevent the lamp from turning on and off due to signal voltage fluctuations at 0.31V.  Solve stroboscopic and out-of-sync problems at the dimming threshold (critical value).

 2.the principle of hysteresis explanation:

  Hysteresis voltage is to ensure that the system work more stable and put forward, you can understand, for example, we set the circuit overvoltage protection of 100V, then it is impossible to let the system at 100.1V off, and 99.9V start again, so the fluctuation is too large, if we set the hysteresis voltage of 90V, which is lower than 90V to restart can avoid the above problems, You can refer to the hysteresis comparator to understand.

  Generally, the hysteresis voltage is set in the protection and enable of these pins to enhance the reliability of the system.  For example, set 0.31V as the dimming starting voltage, at this time when the input voltage is 0.31V, and there are +-100mV fluctuations, we certainly do not want the lamp to start and turn off at this time, the existence of hysteresis voltage makes the input voltage must fall to 0.19V before the lamp is extinguished.  The influence of hysteresis voltage should be considered when calculating circuit protection and enabling parameters.

  

  Product performance comparison:

Product model	power	Dimming signal	Lamp bead	Bead brightness	Temperature	PC cover	Lens Angle	Whole light effect
LLS-COVE2-W40-8W-277V-016(MCU solution)	8W	0-10V	Osram3030	120-130LM	3500K	Opal arch cover	15°	74
LLS-COVE2-W40-30W-277V-016(MCU solution)	30W	0-10V	Osram3030	120-130LM	3500K	Opal arch cover	15°	83.5
LLS-COVE2-W40-8W-277V-016	8W	0-10V	Philips3030	160LM	4000K	Opal arch cover	15°	80

  Product process optimization:
  1. New process plan:
  Constant voltage power supply + control drive integrated solution, the use of modular design, the use of Jinshengyang module power supply and self-produced low-voltage LED constant current driver board, through the pin welding on the control board, the heat shrink sleeve will be integrated into a whole.

  The welding work can be completed in the electronics workshop, and the input and output lines use 3.96 5P terminals to simplify the assembly process.

         

  2.Old process scheme:
  Constant current power supply scheme, power supply high voltage input, low voltage output plus light modulation a total of 6 lines, the use of nylon wire cap wire, wiring operation is complicated, and easy to connect the wrong line.
  After the wire is connected, it is also time-consuming to arrange the wire and plug the power supply, and there is a hidden danger of breaking the wire.