A few years ago, Philips launched a glass shell to Feifan LED lamp tube, as an upgrade of the Philips Economic 15W LED plastic lamp. Feifan’s brightness increased by 33%, and the light effect increased by 25%. It was a cost -effective LED lamp tube. Searching online, no driving circuit was seen. By destructive disassembly a lamp tube, look at the workmanship of this lamp and the true face of the driving circuit.
1. Basic situation
The picture below is the Philips Feifan LED lamp tube. It uses the T8 size structure and glass lamp tube widely used in public places. There are two specifications: 16W (1.2 meters) and 8W (0.6 meters):
Comparison of Feifan LED lamp pipes with several other products in Philips:
When Philips launched “Feifan”, we focused on promoting its advantages. Let’s take a look at the abstract (attached), mainly to compare the disassembly, see if it is truthful, not advertising it for it!
There is a store renovated and replaced all the lamps installed before. Pick up two discarded 1.2 meters 16W Philips Feifan LED lamps:
The tube of the label sign is the power of the power, and the LED drive is in the interior of this end:
The tube of the other end is not power -on, and only a fixed role:
Information on the label: 6500K, 1600LM
Power 16W, working current 135mA
Precautions for installation:
Crusted glass housing:
The lamp bar is glued to the inner wall of the glass tube with high temperature, and the thermal resistance is not low:
There are 56 Philips original LED chips (2015 lamp beads) on the lamp bar, glass fiber substrate (single -sided copper):
Looking at Philips 2015 lamp beads, dual -gold line lead, seemingly different from ordinary LED structures:
High -purity glass shell, thickness 0.6mm:
The lamp tube is controlled and color temperature control. The patented ECO water -based powder powder technology is used for molding powder. The knife can be scraped off the inner wall coating.
Delipple with the drive of the drive, first tear off the label:
Remove the remaining glass shell:
The driver’s circuit board is installed in a black plastic cylinder. This is “
Philips ’original split -driving power protective cover design of 360 degrees for the power supply to ensure personal safety.
Fine copper tube:
Use a knife to remove the aluminum end cover:
Remove the drive circuit board from the plastic cylinder:
The power supply lead is pressed in the foot of the copper tube, which is firm and well contact:
The component distribution on the circuit board, see the following icon:
In order to judge what F1 wrapped in the hot tube on the circuit board! Remove it, it is 10 ohm insurance resistance:
Back on the circuit board:
Drive “Family Portrait” picture:
3. Circuit diagram
According to the situation of PCB, draw the lamp -driven circuit diagram (see the figure below). This is the “
Optimized high -efficiency driving circuit
“. This circuit is very simple, non -isolation, useless IC, all of which are used in a small number of separation elements.
D2 ～ D5 and C1 are common bridge rectifier circuits; C2 and L1 are high -frequency filter circuits to prevent high -frequency harmonics generated by this circuit from entering the city’s power supply and interfere with nearby electrical appliances; T1, Q1, Z1 and related resistance capacitors It constitutes a single -tube self -forth switch circuit and has a certain constant flow function. C4 and R4 ～ R6 are the RC charging circuit components, that is, the self -coupled component, the stabilization diode Z1 starting the stabilization stabilization effect, R7 and R8 are current limiting resistors, C5 is a gifted capacitor by bypass, R1 and R2 are the starting resistance. R3, R9 is the function of starting auxiliary resistors and C3, and D1 is the diode of the continuity.
Fourth, simple measurement
Because there is no professional integral ball measuring instrument, a normal meter is used for simple measurement.
1. Connect the other intact lamp tube to measure the electricity measurement
City electric voltage 224 volts:
The input current is 120mA, which is lower than the nominal 135mA:
The input power is 15.6 watts, which is lower than the nominal 16 watts:
The power factor is 0.55, which is slightly lower than the nominal 0.58:
2. illustration measurement
The illumination meter is measured (dark room) from the light tube, and the illuminance is 157LUX. Follow Feifan’s own standard (distance of 1 meter, illuminance> 150lux):
3. Heating measurement (room temperature 28 ℃)
After 1 hour of boot, measure the front glass shell on the front of the lamp tube 35 ° C:
Behind the lamp (stickers) glass shell 50.7 ℃:
The lamp driver end is 46.3 ° C. The heat is not serious (the internal temperature is higher than this temperature), and it is guaranteed for a long time.
4. Flights Observation
From a distance, the average light effect of the glass tube is better, and you can’t see the flash:
The picture below is shot with a mobile phone, and the humble black horizontal lines are rolled up and down:
Use the oscilloscope to measure the voltage waveform at both ends of the polar R7 and R8 (note: 220V isolation transformers to light the lamp!), The frequency is 50Hz, only half of the work, so the power factor is low. The current flowing through the LED light bar is not so large due to the filter capacitor C3 and T1 transformers, D1 diode renewal.
5. Power fluctuation driver performance test
The power supply voltage was used to regulate the voltage with auto -coupled voltage, and then measured the working current, power, and power factor.
The voltage is 200 volts:
Input current 110mA:
Input power 13.17 watts:
Power factor 0.56
The rest of the pressure regulating work will not be above the picture one by one, the list is as follows:
The above chart shows that the nature of this circuit, above 220V, the current remains constant, has not changed, but the input power changes positively with the positive input voltage; below 220V, the voltage is reduced, the current decreases, and the power decreases.
In order to meet the market demand, Philips launched a civilian route, and launched the Feifan LED lamps around 20 yuan. In order to reduce costs and have high quality, design it with carefully, and the effect is still good. However, the power factor is low, and the large -scale use of enterprises and institutions should consider centralized compensation. Its closedness and disposable structure design, once it is broken, can only be thrown away and cannot be maintained. Even if the circuit is so simple, the maintenance technical requirements are not high. Of course, for electronic enthusiasts, the available elements of disassembly points are still available.
Thanks for watching!
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Source of this article: Digital Home