Design scheme of replacement LED tube

With the technological innovation of LED products, LED lighting has gradually been widely used in lighting fields such as home, office, and public facilities. Straight tube type tubes, as a major product in the traditional lighting field, have a high market share. Under the large-scale development trend of LED lighting products, the development and promotion of straight tube type LED tubes are also in full swing. This article introduces a design scheme of LED tubes that can replace traditional tubes. Through mass production verification, the process is simple and reliable, and can be promoted and applied. This product can replace traditional straight tubes. The market prospect of fluorescent lamps is very broad.

1, Classification and characteristics of straight tube LED products

1.1. Classification of product structure characteristics

From the perspective of the tube structure, the more common straight tube LED products on the market are the following: ①Half-aluminum and semi-plastic; ②Clad aluminum; ③Full plastic; ④All glass.

1.2  Characteristics of all glass LED straight tube light

With its own characteristics: all-glass straight tube LED has the same shape as traditional T8 (T5) light source, soft light color, high light efficiency, easy replacement and other advantages. It has been increasingly accepted in the market and has a market share. It is also rising steadily. At present, although glass straight tube LEDs have a certain market share, they can really directly replace traditional fluorescent lamps, and there are not many products that directly point to the original fluorescent lamps. Based on the consideration of convenient replacement, we have designed and manufactured a kind of appearance that tubes are consistent with LED tubes.

2. Design scheme of LED tube

Combined with the shape of traditional fluorescent lamps, the parts of the replacement type LED tube are divided into: drive design, shell glass selection, plug head, light emitting devices, etc.

2.1  Drive circuit design

The driving circuit is the key to the design of the replacement type LED tube. The circuit is connected to simulate the filament of a traditional fluorescent lamp. The driving power supply consists of a main circuit for step-down current limiting, rectification and filtering, and an analog filament resistance circuit with the function of normally lighting the LED tube and protecting the LED tube from transient high-voltage shock. The design solution includes an overvoltage and overcurrent protection circuit to prevent the lamp from being damaged due to excessive current and / or excessive voltage, a frequency detection circuit that generates an induced voltage only when a high-frequency current is input, and a low-frequency alternating current or high-frequency A rectifying and filtering circuit in which alternating current is converted into a direct current without clutter, a buck step-down circuit for stepping down the direct current output from the rectifying and filtering circuit to obtain the working voltage of the LED lamp bead group in the LED fluorescent tube, and used for shielding the the PWM switching circuit in the BUCK step-down circuit directly controls the high-frequency pass-through circuit of the operation of the BUCK step-down circuit; the input end of the over-voltage and over-current protection circuit is connected to the low-frequency AC power or the output of the electronic ballast. High frequency alternating current, the output end of the over-voltage and over-current protection circuit is connected to the input end of the frequency detection circuit, and one output end of the frequency detection circuit is connected to the input end of the rectification filter circuit. The other output end of the frequency detection circuit is connected to the input end of the high-frequency pass-through circuit, and the output terminal of the rectification filter circuit is connected to the input terminal of the BUCK step-down circuit, the output terminal of the high-frequency pass-through circuit is connected to the control terminal of the BUCK step-down circuit, and the BUCK step The output end of the voltage circuit is connected with the LED lamp bead group in the LED fluorescent tube.