CN103945592A - Compatible with LED tubes with electronic ballasts with preheating current - Google Patents

Abstract

The invention is a LED lamp tube compatible with electronic ballast with preheating current, the LED lamp tube includes two buffer circuits, the input end of each buffer circuit is used for connecting to two electrodes of the lamp tube, and at least one resistor is connected in series between the two electrodes; a waveform conversion circuit, which comprises a plurality of rectifier diodes, wherein the input end of the waveform conversion circuit is connected to the output ends of the two buffer circuits; the recovery time of each rectifying diode is less than 2.5 μ s; at least one LED lamp string, wherein two ends of the LED lamp string are connected to the output end of the waveform conversion circuit; in addition, each LED lamp string is formed by connecting a plurality of LED elements in series. The resistance connected between the two electrodes in series enables impedance to be arranged between the two electrodes, so that short-circuit current cannot be generated between the two electrodes, and the electronic stabilizer and the electrode interface (or interface) of the LED lamp tube cannot be damaged.

Description

Compatible with LED tubes with electronic ballasts with preheating current

technical field

The invention relates to an LED lamp tube, in particular to an LED lamp tube compatible with an electronic ballast with preheating current.

Background technique

Please refer to the circuit block diagram of a traditional fluorescent tube 60 shown in FIG. 2 . The traditional fluorescent tube 60 is a gas discharge light source, so the filament 62 inside the tube 61 must be heated to ionize the gas inside the tube before emitting light.

Generally speaking, the traditional fluorescent tube 60 includes a first electrode terminal L and a second electrode terminal N, which are respectively arranged at the left and right ends of the traditional fluorescent tube 60, and are electrically connected to the AC power output terminal of the electronic ballast 70. The first electrode end L has two electrodes L1 and L2, and the second electrode end N has two electrodes N1 and N2; two filaments 62 are arranged in the lamp tube 61 and connected in series with the electrodes L1, L2 and the electrodes N1, N2 respectively. between; when the traditional fluorescent tube 60 works, if a rapid start type (Rapid start) or a program start type (Program Start) electronic ballast is used to provide the first electrode terminal L and a second electrode terminal N respectively A preheating current, the preheating current flows through the filament 62 arranged in the lamp tube 61 to heat the filament, ionize the gas in the tube, and the conventional fluorescent tube 60 can emit light.

In order to match the commonly used traditional lamp holders, the current LED lamp tubes mostly retain the design of the existing lamp tube 61, that is, retain the first electrode terminal L and a second electrode terminal N at both ends of the lamp tube 61, and use the first electrode terminal L and a second electrode end N are respectively connected to the two ends of the LED element of the LED lamp as the light source as a power supply, but the LED lamp does not have a filament 62, that is, the electrodes L1, L2 of the first electrode end L and the electrodes L1 and L2 of the first electrode end L. There is no impedance (filament 62) connection between the electrodes N1 and N2 of the second electrode terminal N. Therefore, if the LED lamp tube is directly plugged into a fast start type (Rapid start) or program start type (Program Start) electronic Ballast, after the power is turned on, the electronic ballast will provide a short-circuit current for the electrodes L1, L2 and the electrodes N1, N2 respectively, and the short-circuit current will damage the electronic ballast 70 and the electrode interface (or interface) of the LED lamp tube. , affecting the service life of the electronic ballast 70 and the electrode interface (or interface) of the LED lamp tube.

Contents of the invention

In view of the above-mentioned technical defect that the LED lamp tube cannot directly use an electronic ballast, the main purpose of the present invention is to provide an LED lamp tube that is compatible with an electronic ballast with a preheating current.

The main technical means used in order to achieve the above purpose is to make the LED lamp tube include: two buffer circuits, respectively connected to the two electrode terminals of the lamp tube, wherein the two input terminals of each buffer circuit are respectively connected to the corresponding electrode terminals. Two electrodes; In addition, each buffer circuit has at least one resistor, and the at least one resistor is connected in series between the two electrodes at the corresponding electrode end to prevent short circuit between the two electrodes due to lack of impedance; a waveform conversion circuit, which includes a plurality of Rectifier diodes, the input end of the waveform conversion circuit is connected to the output ends of the two buffer circuits; the recovery time of each rectifier diode is less than 2.5 μs; and at least one LED light string, the two ends of the LED lights are connected to the output end of the waveform conversion circuit; in addition, each LED light string is formed by a plurality of LED elements connected in series.

Preferably, the waveform conversion circuit is a full bridge circuit.

Preferably, in the buffer circuit, a resistor is connected in series between the two electrodes, and one end of the resistor is the output end of the buffer circuit.

Preferably, in the buffer circuit, two resistors are connected in series between the two electrodes, and the output terminal of the buffer circuit is between the two resistors.

Preferably, a capacitor is connected in parallel to both ends of the LED light string.

Preferably, a capacitor is connected in parallel to both ends of the LED light string.

Preferably, a capacitor is connected in parallel to both ends of the LED light string.

Preferably, the recovery time of each rectifier diode is less than 1 μs or 0.2 μs.

Preferably, the recovery time of each rectifier diode is less than 1 μs or 0.2 μs.

Preferably, in the buffer circuit, a resistor is connected in series between the two electrodes, and one end of the resistor is the output end of the buffer circuit.

The beneficial effects of the present invention are: when the user inserts the LED lamp tube of the present invention into a traditional lamp holder and starts the power supply, through the design of the above-mentioned buffer circuit, at least one resistor will be connected in series between the two electrodes of each electrode end of the lamp tube, so that The electronic ballast with preheating current regards the resistor as a filament, that is, the filament is simulated by the resistance, so that the preheating current of the electronic ballast flows through the series resistor at the electrode end; therefore, the current will be affected by the at least one resistor Limitation, so that there is impedance between the two electrodes without short circuit phenomenon, so as to avoid damage to the electronic ballast and the lamp tube caused by the excessive current.

Description of drawings

FIG. 1A is a circuit block diagram of a first preferred embodiment of an electrode interface (or interface) of an LED lamp compatible with an electronic ballast according to the present invention.

FIG. 1B is a circuit block diagram of a second preferred embodiment of an electrode interface (or interface) of an LED lamp tube compatible with an electronic ballast according to the present invention.

Fig. 2 is a circuit block diagram of an existing traditional fluorescent tube.

Description of main component symbols

10 electronic ballast 20 first buffer circuit

21 Resistor 21' Resistor

30 second buffer circuit 31 resistor

31'resistor 40 waveform conversion circuit

41 rectifier diodes 50LED light string

51 LED components 52 capacitors

60 fluorescent tubes 61 fluorescent tubes

62 lamps and 70 electronic ballasts.

Detailed ways

Please refer to Fig. 1A, which is the circuit block diagram of the first preferred embodiment of the electrode (or interface) of the LED lamp tube of the present invention, wherein the electronic ballast 10 is connected to the AC power supply (60Hz) of the commercial power at its input end, the electronic ballast 10 The ballast 10 has four AC output terminals which are respectively connected to the electrodes L1, L2, N1 and N2 of the two electrode terminals L and N of the lamp tube.

The first preferred embodiment of the LED lamp tube of the present invention includes a first buffer circuit 20 , a second buffer circuit 30 , a waveform conversion circuit 40 and an LED lamp string 50 .

The input end of the first buffer circuit 20 is connected to the two electrodes L1 and L2 of the first electrode end L of the lamp tube, and the output end is connected to the input end of the waveform conversion circuit 40 . In this embodiment, the first buffer circuit 20 includes a resistor 21, the resistance value of which is equivalent to the resistance value of the filament before preheating; wherein the two ends of the resistor 21 are respectively connected to the first electrode terminal L The two electrodes L1 and L2 , that is, the resistor 21 is connected in series between the two electrodes L1 and L2 of the first electrode terminal L to prevent short circuit between the two electrodes L1 and L2 due to lack of impedance.

In addition, either end of the input end of the resistor 21 is also the output end of the first buffer circuit 20; in addition, the circuit diagram of the second preferred embodiment of the electrode interface (or interface) of the LED lamp tube of the present invention can also be shown in FIG. 1B A block diagram, wherein the first buffer circuit 20 may include two serially connected resistors 21', the two ends of the two serially connected resistors 21' are the input terminals of the buffer circuit 20, and the serially connected node is the buffer circuit 20 The output end can also prevent short circuit between the two electrodes L1 and L2 due to lack of impedance; the resistance value of the two serially connected resistors 21 ′ is equivalent to the resistance value of the filament before preheating.

The input end of the second buffer circuit 30 is connected to the two electrodes N1 and N2 of the second electrode end N of the lamp tube, and the output end is connected to the input end of the waveform conversion circuit 40 . In this embodiment, the second buffer circuit 30 includes a resistor 31 whose resistance value is equivalent to the resistance value of the filament before preheating; wherein the two ends of the resistor 31 are respectively connected to the two ends of the second electrode terminal N The electrodes N1 and N2, that is, the resistor 31 is connected in series between the two electrodes N1 and N2 at the second electrode end, so as to prevent short circuit between the two electrodes N1 and N2 due to lack of impedance. In addition, either end of the input end of the resistor 31 is also the output end of the second buffer circuit 30; in addition, as shown in FIG. 1B, the second buffer circuit 30 may also include two resistors 31' connected in series, The two ends of the two serially connected resistors 31' are the input terminals of the buffer circuit 30, and the serially connected nodes are the output terminals of the buffer circuit 30, which can also prevent the short circuit between the two electrodes N1 and N2 due to the lack of impedance; The resistance value of the series resistor 31' is equivalent to the resistance value before the filament is preheated.

The waveform conversion circuit 40 includes multiple rectifier diodes 41 to form a half-bridge circuit or a full-bridge circuit; the input terminals of the waveform conversion circuit 40 are connected to the output terminals of the first buffer circuit 20 and the second buffer circuit respectively. The output terminal of the circuit 30; the recovery time of each rectifier diode 41 is less than 2.5 μs, that is, based on the electronic ballast 10 being 40 KHz, and taking 1/10 of its period to prevent overheating, preferably less than 1 μs or 0.2 μs.

Both ends of the LED light string 50 are connected to the output end of the waveform conversion circuit 40; the LED light string 50 is formed by a plurality of LED elements 51 connected in series; and a capacitor 52 can be connected in parallel at both ends of the LED light string 50 , the capacitor 52 is charged when the AC power rises from the low voltage to the peak voltage, and when the AC power drops from the peak voltage to the low voltage, it releases its accumulated power to the LED light string 50 to solve the problem of when the LED light string 50 is lit. Generally speaking, the frequency of this strobe is very high (20KHZ-40KHz), if the capacitor 52 is added, the strobe can be completely eliminated; the best capacitance of the capacitor 52 is between 1uF-20uF , because the frequency of the electronic ballast 10 is very high, the capacitance value does not need to be too large.

Through the above design, the user inserts the LED lamp tube of the present invention into a conventional lamp holder and starts the power supply. Through the design of the above-mentioned buffer circuits 20 and 30, the two electrodes L1, L2 and N of the two electrode ends L of the lamp tube At least one resistor 21, 21', 31, and 31' are connected in series between N1 and N2, so that the electronic ballast 10 with preheating current regards the resistors 21, 21', 31, and 31' as filaments, that is, Resistors 21, 21', 31 and 31' simulate filaments, allowing the preheating current of the electronic ballast 10 to flow through the series connected resistors 21, 21', 31 and 31' of the electrode terminals L and N; therefore, the current will Restricted by the at least one resistor 21, 21', 31, and 31', there is an impedance between the two electrodes L1, L2 and N1, N2 without short-circuiting, thereby avoiding damage to the electrode due to excessive current. Electronic ballast 10 and the lamp tube.

To sum up, the principle of the second embodiment of the LED lamp tube of the present invention is substantially the same as that of the first embodiment, and both can effectively prevent short-circuit currents from being generated between the electrodes L1, L2, N1, and N2 of the lamp tube to damage the electronic stability. device 10 and the LED lamp tube of the present invention, and also has a rectifying effect.

Claims (10)

1. a LED fluorescent tube for the compatible electric stabilizer in tool preheat curent, includes:

Two buffer circuits, are connected to respectively two electrode tips of described fluorescent tube, and wherein two outputs of each buffer circuit are connected to respectively two electrodes of counter electrode end; Each buffer circuit has at least one resistance in addition, and described at least one resistance is connected between described two electrodes of counter electrode end;

One waveform changing circuit, described waveform changing circuit comprises multiple rectification diodes, and the input of described waveform changing circuit is connected to the output of described two buffer circuits; Be less than the recovery time of each rectification diode below 2.5 μ s; And

At least one LED lamp string, described LED lamp string two ends are connected to the output of described waveform changing circuit; Each LED lamp string is to be formed by multiple LED element serial connections in addition.

2. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 1, described waveform changing circuit is a full-bridge circuit.

3. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 1 and 2, described buffer circuit makes the resistance of connecting between described two electrodes, the output that one end of described resistance is described buffer circuit.

4. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 1 and 2, described buffer circuit makes two resistance of connecting between two electrodes, between described two resistance, is the output of described buffer circuit.

5. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 1 and 2, a described LED lamp string two ends electric capacity in parallel.

6. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 3, a described LED lamp string two ends electric capacity in parallel.

7. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 4, a described LED lamp string two ends electric capacity in parallel.

8. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 1 and 2, is less than 1 μ s the recovery time of each rectification diode or is 0.2 μ s.

9. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 6, is less than 1 μ s the recovery time of each rectification diode or is 0.2 μ s.

10. the LED fluorescent tube of the compatible electric stabilizer in tool preheat curent according to claim 7, described buffer circuit makes the resistance of connecting between described two electrodes, the output that one end of described resistance is described buffer circuit.