Based on BP2808 achieve highly efficient LED lighting power supply design

LED lighting, with its high energy saving, long life, the characteristics of the environmental protection has become the focus of people widely. High brightness LED light source in recent years because of its manufacturing technology by leaps and bounds, and its production cost and decreasing, now use LED light source as high brightness, high efficiency and energy saving lighting source to save electricity, no carbon has become the world's voracious demand, to create a LED lighting lamps and lanterns is on the rise of new industry, the industrial chain is increasingly perfect, the technology is updated day by day. Basic working principle

BP2808 BP2808 is specifically to drive the LED light source of constant current control chip. BP2808 work in continuous current mode step-down system chip of LED light source control through the peak current and ripple current, so as to realize the LED light source of constant average current. Chips use very few external components to realize constant current control, analog dimming and PWM dimming, and other functions. System applied voltage range from 12 VDC to 600 VDC, the duty ratio up to 100%; Suitable for ac 85 v - Wide input voltage 265 v, is mainly used in the isolation of the LED lamps and lanterns of the power drive system. BP2808 adopts the patent technology of the source driver and constant current compensation technology, makes constant current drive LED light source, the ac 85 v - 265 v range change is less than + / - 3%. Combining BP2808 patent technology application circuit of driving system, makes the 18 w LED fluorescent lamp and practical solutions, the ac 85 v - Within the scope of the 265 v system efficiency is higher than 90%. In ac 85 v - 265 v input range, BP2808 can drive from 3 w to the 36 w LED light source array, so widely used in E14 / E27 / PAR30 PAR38 / GU10 lamp cup and LED fluorescent lamp, etc.

BP2808 with multiple leds protection function including LED open-circuit protection, LED a short circuit protection, over temperature protection. Once the system failure occurs, the power system automatic into protection state, until the fault lifted, system to automatically back into the normal working mode. Reuse DIM pin LED simulation system of the lamps and lanterns that move light, PWM dimming, and the dynamic temperature protection. BP2808 using SOP8 encapsulation.

the LED fluorescent lamp used typical design

article LED fluorescent lamp, LED light source lamp power drive plan, there are many current unfenced solution because of its high efficiency, small volume, low cost and dominant, and use PWMLED drive controller for the LED fluorescent lamp and the vast majority of drive power supply. In fact the traditional fluorescent fluorescent lamp are isolation scheme.

to AC176V - Full voltage 264 v input, for example, mainly BP2808 chip is used to design load for small power of the LED light source series, and the LED fluorescent lamp, the whole design of the system block diagram is shown in figure 1. The whole circuit by anti surge/lightning protection, EMI filter, full bridge rectifier, passive power factor correction ( PPFC) , starting voltage ( Including feedforward compensation, boot after feed flow of power supply and drive to soften) , constant current compensation, PWM control, the source drive, LED light source array, and the sampling resistor, Toff time setting, energy storage inductors, the fly-wheel diode and so on various parts.

the LED light source array design is 0. 06 w white LED ( SMT or straw hat lamp) 24 series, 12 series parallel scheme, drive 288 small power WLED, total power 18 w. Full voltage 18 w LED fluorescent lamp switch constant-current source circuit design as shown in figure 2, the function of each part as the scarlet letter. Figure in the resistance to lightning of EMC and EMI filter circuit, power supply is the use of feed flow has been in the inside of the chip rectifier diode.

from AC220V, ac mains inlet with 1 a fuse F1 and anti surge pressure sensitive resistance Vz1 / lightning; After is the EMI filter, composed of Ld1, Lc1 and Cx1, Cx2; DB1 is full bridge rectifier, interior is four high voltage silicon diode; CE1 and CE2, R10 and D2 and D4 passive power factor correction circuit; BP2808 chips by R15, step-down the R17 R16 starting resistance, C3, feedforward compensation and the Dz1, C2, R18 and internal circuit of patent of BP2808 BP2808 after compensation circuit voltage regulator control circuit with constant current power supply, the system starts due to the small static current control circuit, and the chip within the OUT to VCC feed flow diode can offer BP2808 work power, resistance R15 - at this time 17 on current will be greatly reduced, thus the total system power consumption is greatly reduced, system efficiency is improved obviously. Patent the source driver circuit consists of MOS tube Q1, D6, Rg, Rt, Rcs and BP2808 internal circuit composition, its distinguishing feature is effectively reduce the power consumption, improve the precision of constant current. Drive system, the source of drive circuit reduce consumption of system current, especially in the traditional high pressure differential power supply path similar to R15 - The current on the 17th, which, in turn, reduces the power consumption, improve the efficiency. D6, Rg can make the switch opening drive soft, shut off the drive to keep strong, both improve EMI, and as far as possible without sacrificing efficiency. With LED light source parallel output filter capacitor C0 to reduce the current ripple on the LED light source.

BP2808 CS side to collect current sampling resistance Rs1 ~ Rs2 peak current, controlled by the internal logic in a single cycle OUT feet signal pulse duty ratio of constant current control, constant current output and D5, LM1 fly-wheel circuit merge to LED light source, constant current power supply. LED light source array combination changes, the resistance of Rs1 ~ Rs2 resistance also want to change, make the output current of the circuit to meet the requirements of the LED light source array combination.

PCB arrangement is the key to getting the product, so the PCB to get the line to design according to the requirements of power electronic safety codes. This circuit can be universal in T10, T8 fluorescent tubes, because of two different pipe size, the width of the two pieces of PCB will be different, to reduce the height of all parts, so that in the T10, T8 tubes. Figure 3 is T10 constant-current source board pictures, 30 component installation 0. 8 mm thick epoxy single-sided PCB.

so AC85V - design - Full voltage 264 v input, but also want to consider PFC, LED light source array can be designed to be 0. 06 w white LED 12 series, 24 series parallel scheme. BP2808 do LED fluorescent lamp power supply drive power supply design, suggested that the output voltage