Four Problems of Designing LED Driver Power Supply

- Aug 28, 2018-

The quality of LED driver power supply directly influences LED lifespan. So it is significant for designers to achieve a good LED driver power supply.

In the present market, LED lighting is a new light source, which takes advantage of the energy saving, power saving, no-pollution and long lifetime. However, LED needs a good driver power supply,

Firstly, driving circuit directly influences LED lifetime

As we all know, LED driver includes digital driver and analog driver. Digital circuit driver includes digital dimming controller, RGB full color transformation, etc. Analog circuit driver includes AC constant current switching power supply, DC constant current control circuit. The driving circuit is made of electronic components, including semiconductor components, electrical resistance, capacitance, DC constant current control circuit, etc. These components influence the working life. Any component losing efficacy directly affects the whole circuit or partial function failure. LED working life is about 50,000 ~ 100,000 hours. The warranty of common switching power supply is just about 2 ~ 3 years. The warranty of the top switching power supply is about 6 years. However, the cost is higher than the common switching power supply. Some manufacturers can’t accept the price to buy good power supply, so the driving circuit often occurs failure.

Secondly, heat dissipation

LED is the cold light illuminator, the working junction temperature couldn’t exceed the limiting value. We should think about the nice appearance, easy installation, timing and heat dissipation problems to design the whole lighting. To seek the balance point in many factors, the whole light will be good. The development time of LED light is so short, and the designers’ experience is not rich. Some manufacturers often buy power supply from other companies. The lighting designers know little about the power supply. They often give large space to LED heat dissipation and small space to power supply heat dissipation. It is so difficult for designers to find decent power supply after finishing designing LED lighting. So we should comprehensively consider LED heat dissipation, power supply heat dissipation, controlling high internal temperature problems to design excellent lighting.

Thirdly, power supply’s design problems

Power design

Although, LED lighting effect is so high, it has 80~85% thermal energy loss, which results in the internal lighting temperature rising 20~30℃. If the indoor temperature is 25℃, the internal lighting temperature is about 45~55℃. The power supply works in high temperature for a long time. To assure the lifetime, we should increase the power.

Component selection

If the internal lighting temperature is about 45~55℃, the internal power supply is about 20℃, the temperature near the components is about 65~75℃. Some components’ technical parameter will be changed in high temperature and its working life will be short.

Electrical property design

The constant current parameters are more significant for designing LED. The current determines LED brightness. If the current error is large, the brightness will be uneven. If the error is controlled less than ±5%, the lighting brightness will not change.

Fourthly, using parameters

Some manufacturers choose the power supply according to the range of constant current and voltage. The constant current is lower than LED technical standard. So we should choose moderate voltage to avoid power losing.