Comprehensive analysis of key design issues of LED lamps

1. Problems in semiconductor lighting applications

1. Heat dissipation

2. Lack of standards, uneven product quality

3. There are price and design quality issues, and consumers ultimately lack confidence in choosing LED lighting

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

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

Features:

1. 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;

2. For new and old lamp design manufacturers, do not overly complicate the electrical design. A simple circuit design that only requires a traditional constant voltage power supply is the fastest and most reliable way.

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

2. Heat dissipation design

1. The shortest heat transfer path reduces heat conduction resistance;

2. Increase the mutual conduction area and increase the heat transfer speed;

3. Reasonably calculate and design the heat dissipation area;

4. Effectively utilize the heat capacity effect.

Output drive voltage selection:

When the AC power is within 20W, 48V is more suitable;

The most suitable output voltage for 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 peak current exceeding 42.4Vac or 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%, to the point where it can be completely ignored;

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

The development of switching power supplies is the result of many years of accumulation. In the short term, direct AC-DC 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 the constant current source is 1% (mA)/V, which cannot achieve a constant current effect; the more ideas there are, the higher the cost, which is proportional to the risk.

Features:

It is most economical to make reasonable use of existing switching power supply resources;

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

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

Comparison with switch constant current method

6. LED combined packaging is the future development trend

The combined design of the 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. !

7. The packaging structure 'kidnaps' our optical effect design

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 packaging at the PCB board level is easy and low-cost; everyone can brainstorm and develop different types of packaging forms; integrate constant current technology and power LEDs with light distribution parameters to design products; effectively respond to the ever-changing needs of LED lamps; for the power supply part, only the existing traditional switch constant voltage power supply is used; improve the speed of product launch, the lamp design is simple and practical, and the cost is greatly reduced; it can also avoid the blockade of cutting-edge LED packaging 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 is based on LED packaging technology and directly integrates low voltage difference linear high-precision constant current technology. In the future, LED 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 no longer need to consider any LED constant current issues, and can use the existing standard constant voltage power supply. This technology will declare the end of the "LED constant current power supply"!

10. Design the light source according to the product

Break the original design of products according to the light source, and customize the LED light source packaging form according to the product; maximize the creative display of the product; design the optical packaging structure according to the product; low cost; design the heat dissipation structure in combination with the product, reduce the thermal resistance; high constant current accuracy; integrated protection function. Shenzhen CYT company LED laboratory can quickly help you complete the product design.

11. Advantages of modular light sources ① Effectively reduce costs

Reduce the number of packaging times and save packaging costs;

improve consistency and improve yield rate 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

The light source is directly combined with the housing heat sink;

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 road

This is the first step of stability; strong selectivity; the cost is the most favorable; the indicators that switching power supplies cannot achieve are also difficult to achieve with LED power supplies, so there are fewer detours; even if a powerful company designs, 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 supplies? Constant voltage first, then linear constant current, must be the future market mainstream of LED lighting drive mode!