Common Problems and Analysis of LED Lighting Design

LED (Light Emitting Diode) is a solid-state semiconductor device that can directly convert electricity into light. The heart of an LED is a semiconductor chip. When current acts on this chip through a wire, electrons and holes are pushed into a quantum well, where they recombine and then emit energy in the form of photons. They can do dozens of different jobs and can be found in a variety of devices. For example, they can form the numbers on the dial of an electronic clock, transmit information from a remote control, illuminate the dial of a watch and notify you when the device is turned on. If they are gathered together, they can form an image on a very large TV screen or be used to light up traffic lights.

Key issues and analysis in the lighting design process.

1. Problems in semiconductor lighting applications

Heat dissipation

● Lack of standards, uneven product quality

● Price and design quality issues, consumers ultimately lack confidence in choosing LED lighting

● Semiconductor lighting is very different from traditional lighting in terms of electrical design. Traditional lighting companies need to accumulate experience/skills.

● Everyone is optimistic about this market, but it has not yet reached a large scale

Features:

By adjusting the high-precision constant current chip, the consistency of LED brightness and color is ensured, and standard, customized, reliable and high-quality products are provided to downstream customers at the module level;

New and old lighting design manufacturers, do not overly complicate the electrical design, just add a traditional constant voltage power supply externally power supply

The simple circuit design that works immediately is the fastest and most reliable way;

Solve the technical and quality issues of large-scale LED lighting market.

2. Heat dissipation design

● The shortest heat transfer path, reducing heat conduction resistance;

● Increase the mutual conduction area and increase the heat transfer speed;

● Reasonable calculation and design of heat dissipation area;

● Effectively utilize the heat capacity effect.

● Output drive voltage selection:

● When driven by mains power within 20W, 48V is more suitable;

● The most suitable output voltage for a larger power AC drive is about 36V;

● Most of the offline lighting is 12V and 24V voltage.

Features:

Consider the appropriate driving voltage value for the load based on series and parallel safety, and try to unify the voltage value to reduce the power supply design specification cost;

Based on safety regulations, product design must meet certification requirements, with a peak current exceeding 42.4Vac or a DC voltage exceeding 60Vdc;

Considering the technical and quality issues in solving the large-scale LED lighting market.

3. Highest Efficiency Back-end Drive Mode

When the output voltage is around 48V, the constant current efficiency of the low-voltage difference linear constant current device is as high as 99%, the constant current accuracy is within ±3%, and it is not affected by any peripheral devices; when the output voltage is around 36V, the constant current efficiency of the low-voltage difference linear constant current device is as high as 98.6%, the constant current accuracy is within ±3%, and it is not affected by any peripheral devices; even in the offline lighting part, the lower voltages of 12V and 24V have efficiencies of 96% and 98% respectively; the power size and efficiency are equal.

Features: The most efficient driving constant current architecture; the highest precision constant current method, with minimal impact from peripheral devices; simple, convenient and practical.

4. The power consumption of constant current has reached a negligible level

In the Shenzhen CYT laboratory, we have verified that the back-end constant current efficiency has reached 99.99375%, which is completely negligible.

In the future, we will complete this design achievement in one year. With the cooperation of an IC design team of more than ten people and a strong power supply manufacturer, we will achieve this goal as soon as possible.

5. AC-DC Design

switch switch

The development of power supply to today is the result of many years of accumulation. In the short term, AC-DC direct constant current cannot be broken through; constant voltage and constant current are like a spear and a shield, and must be considered separately; the load adjustment rate of constant current source is 1% (mA)/V, which cannot achieve the constant current effect; the more ideas there are, the higher the cost, which is proportional to the risk. Constant current source

A constant current source is a power source that can output a constant current. It is mainly used to detect thermal relays, molded case circuit breakers, small circuit breakers, and production occasions where the rated current, operating current, short-circuit protection current, etc. need to be set.

Features:

Reasonable use of existing switching power supplies Switching Power Supply

Resources are the most economical;

The combination of constant voltage and constant current technology is inevitable;

Creativity is only effective when it comes to stable product technology.

6. LED combined packaging is the future development trend

The combined design of modules can effectively reduce the one-time packaging cost; the dispersed packaging form is conducive to reducing the cost of heat dissipation design; the selection of domestic aluminum-based PCB panels is convenient for optical design; the power supply design is simplified; the packaging form is diverse; it is conducive to enhancing the competitiveness of domestic LEDs.

These are some representative packages from Cree, Nichia, Lumileds, and OSRAM. To design a product, we must first determine whose LED package structure to use; then consider how to adapt to these packages; we have few options, and the optical structure is built on these packages; many of our creative ideas cannot be fully utilized.

Lighting design is ever-changing, how can we get rid of this situation?

8. Combination of modular packaging and constant current technology

Designing LED packages at the PCB level is easy and low-cost. By brainstorming, everyone can develop different types of packages. Products can be designed based on power LEDs that integrate constant current technology and light distribution parameters. This effectively responds to the ever-changing needs of LED lamps. For the power supply, only the existing traditional switching constant voltage power supply is used. This increases the speed of product launch, makes the lamp design simple and practical, and significantly reduces costs. It can also avoid the blockade of cutting-edge LED package patents.

9. Packaging according to voltage nominal value

The innovative technology of LED constant current driving was born in Shenzhen CYT. I named it "Power LED Constant Current Integrated Packaging" technology, or "Module Packaging" for short. This technology directly integrates low voltage difference linear high-precision constant current technology on the basis of LED packaging technology. In the future, LEDs can directly appear in nominal voltage value specifications, such as: 12V/1W, 24V/1W, 36V/1W, 48V/1W, 12V/3W, 24V/2W...36V/10W, etc. In the future, customers who use CYT technology in product design will no longer need to consider any issues about LED constant current, and can use the existing standard constant voltage power supply. This technology will declare "LED constant current power supply Constant current power supply

"It's the end!"

10. Design the light source according to the product

Break the original design of products based on light sources and customize LED light sources based on products

Packaging form; maximum coordination with product creativity; optical packaging structure due to product design; low cost; heat dissipation structure combined with product design, reduced thermal resistance; high constant current accuracy; integrated protection function. Shenzhen CYT company LED laboratory can help you quickly complete product design.

11. Advantages of modular light sources ① Effectively reduce costs

Reduce packaging times and save packaging costs;

Improve consistency and yield rate by producing under the same environment and conditions;

Reduce optical design costs;

Reduce heat dissipation design costs;

Batch mixed packaging to reduce binning costs;

Simplified product design reduces overall costs;

Low-cost packaging architecture. This technology will guide the LED lighting industry to develop in a healthy direction.

12. Advantages of modular light sources ② Reduced thermal resistance

Light source and housing radiator

Direct binding;

Avoid PCB as a heat medium;

Reduce the heat dissipation path from chip to housing;

Adopt the latest heat transfer technology; most effectively reduce the heat dissipation thermal resistance and solve the heat dissipation design problem.

13. Advantages of modular light sources ③ High constant current accuracy

The Vf value is uniformly considered within the module;

Constant current source is less affected by external factors;

The linear technology is mature and there are no peripheral devices that affect the accuracy;

No EMI interference issues affecting accuracy;

Multiple parallel connections are not independent of each other, which affects the accuracy;

The load constant current accuracy is not affected by power supply fluctuations. The highest constant current accuracy architecture, the design architecture that optimizes LED brightness consistency and lifespan.

14. Advantages of modular light source ④ Integrated protection design

Built-in temperature protection;

Internal power supply and protection technology;

Built-in high grayscale interface;

Short circuit and open circuit protection;

Linkage protection function can be set;

ESD protection.

Any other built-in functions and protection requirements can be discussed.

15. Advantages of modular light sources ⑤ Take the traditional power supply route

This is the first step of stability: strong selectivity; the most favorable cost; indicators that switching power supplies cannot achieve, LED power supplies

It is also difficult to achieve, and there are no detours; even if a powerful company designs it, the LED part also needs time to verify; there is no electromagnetic compatibility problem at all. It takes time for the power supply to mature. Do you believe some of the propaganda about LED power supply? Constant voltage first, then linear constant current, must be the mainstream of LED lighting driving method in the future market!