High Power Non-Isolated LED Drivers

Solution – Non-isolated LED Driver

More and more grow lights and sports lights companies are evaluating the possibility of utilizing non-isolated LED drivers on their new products. With the new design, the cost can be reduced by about 20% to 30%.

Non-isolated LED Driver Applications

Benefits

Non-isolated LED Drivers

FAQ

What should be paid attention to when designing my non-isolated lamps?

It is not easy to find a right non-isolated driver for high-power design, the following has to be considered carefully:

• Efficiency and thermal. Non-isolated drivers have the advantage of efficiency compared with conventional isolated drivers. But it does not mean efficiency is not important. Better efficiency means lower power loss and less heat generation thus the LED driver can have a longer life and higher reliability with a better thermal situation. Checking the case temperature at Tc point is mandatory for a good luminaire design.
• Dimming performance. Using a lower-cost driver does not mean we have to sacrifice performance. Smooth dimming with either 0-10V or DALI or DMX control compatibility is important for stadium lights, especially the fast dimming response.
• Find the right input voltage range for different countries.
• Try to use the high LED voltage to achieve the best efficiency. 
• Utilize the LED board with higher insulation. 3kV insulation voltage is suggested.
• Do adequate insulation for the whole luminaire to make sure that all the points that can be touched by the human body are safe and able to pass the insulation test.

How do you solve the glow issue when dimming off?

1. Do NOT use the way of lowering output voltage to dim off because different LED behaves differently and we don’t know by how much voltage, the LED may conduct. So the eliminate the possibility, we need to totally shut down the LED driver rather than just lowering down the output voltage. Also, there is another benefit that the standby power is much lower because the driver is in “sleep mode”. But the other result is that the cost of the driver is higher by adding such kind of circuitry inside the driver.
2. To avoid the common mode leakage current through the parasitic capacitors, we have two ways, either disconnect the earth or disconnect the input/output during the dim-off status. Obviously, we are not allowed to disconnect the earth by safety standards with AC line connected. So the only way to have to do is to disconnect the input or output to LED by an internal relay. Also, the drawback is the higher cost.

Making sure of the darkness for cannabis and vegetable grow is so important that the LED driver manufacturers like uPowerTek is paying great efforts to the designs to avoid “glow” in off status. For the luminaire designers, you have to make sure that the luminaire is fully tested in the dark room before finalizing the product. Please feel free to let us know if you have any questions.