Breaking the traditional structure of AC drive LED light-emitting technology matures

A new generation of LED driver IC design, we must break the traditional DC/DC topology design concept. Such as the use of constant power, do not use hysteresis control and the use of fixed frequency constant current control to solve the use of halogen lamp electronic transformer generated by the flashing light source and multi lamp parallel and so on.

LED as a green, energy saving, energy saving, long life of the fourth generation of lighting lamps, a widespread concern, is developing in full swing. Since the LED light source is a low voltage (VF=2-3.6V), high current (IF=200mA-1500mA) semiconductor device, it is necessary to provide the appropriate DC current to normal light. DC (DC) drive DCLED light source technology has become more and more mature.

Lighting drive IC voltage range is wider

Because we are using the daily lighting power supply high voltage alternating current (AC100V-220V), it is necessary to use a step-down technique to obtain lower voltage transformers or switch power supply, commonly used by buck, and alternating current (AC) transform into DC (DC), and then converted into DC constant current source, so as to make LED light source.

DC drive LED light source system application program must be: Transformer + rectifier or switching power supply + constant current source (see right). LED lamps must have a certain space to install the power module, but for the E27 standard screw mouth lamp is very limited space, it is difficult to place. The system will have a certain amount of loss through the transformer or rectifier or switching power supply. DCLED lamps in the AC, DC conversion between about 15% ~ 30% of the power consumption, the system efficiency is difficult to achieve more than 90%. So if you can use AC (AC) direct drive LED light source, the system will greatly simplify the application program, the system efficiency can easily reach more than 90%.

Seen in this light, LED driver IC (integrated circuit) is essential in LED lamps. At present, the domestic lighting LED driver IC R & D, manufacturers have more than and 10.

System application scheme of DC drive LED light source

The basic technical elements of LED light source applications are the need to satisfy its VF (forward voltage) and IF (forward current) requirements. VF is for the LED light source to establish a normal working state, IF is to promote the LED light source, LED brightness and current proportional to the size. With the development of LED technology, the LED driver IC input voltage (Vin) range will be wider (DC5V-45V), the output constant current accuracy is higher (1%) (IC). In view of the increasing number of LED lamps using multiple high-power LED series application technology, a new generation of LED drive IC output voltage increased to 60V-100V, which requires the use of high pressure technology to produce LED drive IC wafer. LED drive IC output voltage for its improvement in automotive electronics, automotive lighting, high brightness lighting applications such as high voltage requirements to open a new market.

Huarun powtech Co. Ltd. is a relatively early intervention LED driver IC design and production of domestic Integrated Circuit Design Company, its PT4115 is a typical Vin wide input voltage (DC6V-30V), constant current output (1.2A) DC/DC step-down LED driver IC, PT4115 is a continuous inductor, current mode buck the constant current source, it has a wide range of input voltage of DC 6V to 30V, the breakdown voltage of >45V, output 200mA - 1200mA constant DC, can meet the requirement of 1-7 series light driven high power LED or N a series parallel low power LED constant current drive, big can be set according to the application program.

The new design breaks the traditional topology

LED light source is a long life light source, the theoretical life of up to 50000 hours, but if the application of circuit design is not reasonable, improper selection of circuit components, LED light source is not good, will affect its service life. Especially in the application of the circuit, as the electrolytic capacitor AC/DC bridge rectifier output filter, its service life is less than 5000 hours, which became a manufacturing long life LED lighting technology in the way of. The only feasible solution is advanced design and production can be used in the circuit without electrolytic capacitor in the new generation of LED driver IC, a Japanese company's new LED driver ICTK5401 without the use of electrolytic capacitor used in circuit, life of up to 40 thousand -5 million hours, just match the LED life. The use of this IC can make the PCB board area reduced to 40% of the original, saving the space of the power module, which is the important aspect of the design of LED lamps to be preoccupied.

A new generation of LED driver IC design, we must break the traditional DC/DC topology design concept. Such as the use of constant power, do not use hysteresis control and the use of fixed frequency constant current control, to solve the use of halogen lamp electronic transformer generated by the flashing light source and multi lamp parallel does not light, etc.. In addition, we must make the LED drive IC in a variety of applications in the circuit through the EMC, security, CE, UL and other certification. The application of the circuit to simplify, reduce the use of components is also the cost of customer requirements. The application of isolation and non isolation has always been the focus of business security and efficiency of contention, PWM controller duty cycle is constantly improving.

0.5W-3W LED light source and LED driver IC integrated in a CMC package within the new generation of chips has been small batch production, indicating that the LED driver IC is highly integrated multi chip (CMC) packaging direction. The new generation of LED can be directly driven by the alternating current (AC), and the production technology of special topology ACLED light source is becoming more and more mature.

Turnkey program into a trend

IC manufacturers tend to provide end users with a solution that can be directly used for production,