MY-SEMI INC.

FAQ

• 1、What are the unique characteristics of MY-Semi’s LED drivers?

  • Considering the constant current control characteristics of LEDs, MY-Semi's LED drivers provide customers with high accuracy and stable constant current. Through these drivers, LEDs are driven with the best performance and lifetime.

• 2、What are the potential applications for these drivers?

  • Possible applications are everywhere. As you can see the decorating lighting for the building, bridge or events, commercial lighting, indoor and outdoor LED displays, LED message boards or LED moving signs for banks, airport, bus, hospitals, clinics, railways, highways,...etc.

• 3、What is the advantage of using MY-Semi's LED drivers?

  • With using the MY-Semi's LED drivers, the design and manufacturing of LED lighting product and LED displays become easier, lower cost, and more reliable, since very few external components are needed. More importantly, the maintenance is easy and would not cost a lot.

• 4、How to control the LED current while using the MY-SEMI's LED drivers? (compare
  with the voltage mode drivers)

  • Only need one or three external resistors for each LED drivers to set the current of all output channels. Pin #23 is for 16 channels LED driver to connect the external resistor. Compared with the way of attaching one resistor to each pin, this way can ease the manufacturing process, simplify the process of preparing and purchasing materials and thus decrease the cost.

• 5、Is there any difficulty in using MY-Semi's LED drivers if customer's original design
  is for constant voltage LED drivers?

  • Compared to the voltage mode LED driver like 74HC595, MY-Semi's LED driver provides constant current, and controls the LED current easily. Customers are encouraged to current mode controlled LED drivers for easy manufacturing and lower cost. Customers need to re-layout the PCB board while changing from the constant voltage mode LED driver. Customers may consult with MY-Semi's FAE team if customers have any difficulty in designing the PCB board.

• 6、Is there any difficulty in using MY-Semi's LED drivers if customer's original design
  is for Macroblock’s drivers or Toshiba's LED drivers?

  • MY-Semi's LED drivers are fully pins and pitch compatible with Macroblock’s or Toshiba's drivers. There is no need for PCB modifications. Customers can use the LED drivers very easily. Only external resistors may need to be changed.

• 7、What are the main characteristics of MY-Semi's LED constant current drivers?

  • 1.Constant output current invariant to load voltage changes (<±0.1 %).
  • 2.Excellent output current accuracy between channels: <±2% (max.) between ICs: <±3% (max.)
  • 3.Output current adjusted through an external resistor
  • 4.Fast response of output current
  • 5.25MHz clock frequency
  • 6.Schmitt trigger input for noise immunity 3-5.5V supply voltage

• 8、Will it be helpful to add a heat sink against the heat generated from power
  dissipation?

  • Yes. To add a heat sink is a solution to power dissipation. This method also applies to various brands of IC to solve the heat problem.

• 9、Do MY-Semi's LED drivers pass the reliability test?

  • Yes. MY-Semi’s LED Drivers process severe quality control tests.

  Reliability of device

  • 1.High Temperature Operating Life test (HTOLT) (125°C/5V/1000hrs)
  • 2.ESD test (human body mode/machine mode) (2KV/200V)
  • 3.Latch-up test (I>100mA)

  Reliability of package

  • 1.Pre-condition test (TCT/Bake/Moisture Soak/IR re-flow)
  • 2.Pressure cooker test (PCT) (121°C/100%RH/168hrs)
  • 3.Temperature cycle test (TCT) (-65°C~150°C/200cycles)
  • 4.Temperature & Humi Test (THST) (85°C/85%RH/1000hrs)
  • 5.High temperature storage (HTS) (150°C/1000hrs)
  • 6.Solderability

• 10、Can users adjust current only by Rtrim, not by Rext, when MY9161 are connected
    in parallel? If the answer is yes, can MY9161 still remain constant current?

  • We suggest users still attach one additional resistor, Rext, to each MY9161 can thus achieve excellent performance. When ICs are connected in this way, no companies would suggest users to use only one external resistor shared by all ICs to adjust current.