CN201114946Y - Double straight tube electronic ballast - Google Patents

Abstract

The utility model relates to a double straight-tube electronic ballast, which comprises an EMI electromagnetic interference circuit, a rectifier circuit, a power factor compensation circuit, a self excited oscillation circuit, an inverter or a booster circuit and a protection circuit. 220V alternating current input eliminates EMI electromagnetic interference and RFI high frequency interference by the EMI electromagnetic interference circuit firstly, direct current is output after rectification, then the power factor compensation circuit is used for correcting the power factor, and the inverter or booster circuit is used for outputting high-frequency voltage to drive two parallel connected fluorescent tubes under the control of the self excited oscillation circuit. The utility model provides an electronic ballast which can drive two solid mercury tricolor fluorescent lamps, and has the advantages of saving energy, environmental protection, long service life and being convenient for replacement.

Description

Double straight tube electronic ballast

technical field

The utility model relates to an electronic ballast.

Background technique

At present, traditional inductive ballasts and ordinary electronic ballasts are used for lighting fluorescent lamps in large-scale businesses, enterprises, offices, and homes. Inductive ballasts and ordinary electronic ballasts have been used in the fluorescent lamp market because of their relatively cheap prices, but they have many defects and disadvantages. Such as large volume and weight, high power consumption, low power factor, noise, which will cause the fluorescent tube to flicker, the end of the tube will turn black after long-term use, and the starter is easily damaged; for the lamps with the original double-tube structure, it must be used Two magnetic ballasts or electronic ballasts, this not only wastes the rectifier equipment, but also wastes electric energy due to the increased power consumption of the ballasts.

At present, the new lamps launched on the market are required to have the characteristics of energy saving and environmental protection. The luminous efficiency of traditional fluorescent lamps is affected by the color rendering of halogen powder luminescent materials and the luminous efficiency is not high. At present, rare earth tricolor phosphor luminescent materials are used and protective films are applied. , the light efficiency is significantly improved. For example, the luminous efficiency of a 28-watt T5 fluorescent lamp is about 40% higher than that of a T12 fluorescent lamp, and 18% higher than that of a T8 fluorescent lamp. This material also solves the problems caused by the increase in load, lamp temperature, and mercury vapor pressure when the tube diameter becomes thinner; at the same time, the narrower tube diameter also greatly reduces the use of materials such as phosphor powder, mercury, and glass tubes. Therefore, solid mercury tricolor fluorescent tubes will gradually replace the original T8 and T12 fluorescent tube products. The emergence of new lamps and lamps requires electronic ballasts adapted to them.

Therefore, the market needs a kind of electronic ballast for supporting the use of double-tube lamps using solid mercury tricolor fluorescent tubes.

Utility model content

The technical problem to be solved by the utility model is to provide an electronic ballast capable of driving two solid mercury tricolor fluorescent tubes.

The technical solution adopted by the utility model is: the double straight tube type electronic ballast is composed of EMI filter circuit, rectifier circuit, power factor compensation circuit, self-excited oscillation circuit, inverter/boost circuit, protection circuit, 220V AC input First remove EMI electromagnetic interference and RFI high-frequency interference by EMI filter circuit, then rectify to DC output, then correct power factor through power factor compensation circuit, under the control of self-excited oscillation circuit, output high voltage through inverter/boost circuit A frequency voltage drives two parallel fluorescent tubes.

The EMI filter circuit is composed of capacitors CA1, CA2, CY1, CY2, and inductance T1 to form a double Π-type filter circuit, wherein the two windings of the inductance T1 are symmetrically wound on the same magnetic core, and the inductance values on both sides are the same. Together with capacitors CA1 and CA2, two groups of mutually symmetrical Π-type EMI filters are formed.

The power factor compensation circuit adopts the active power factor correction special chip S6500P, and the input alternating current is rectified into direct current by the rectifier bridge D1, which is used as the input of the APFC active power factor compensation circuit; the capacitor C1 filters out the high-frequency part in the inductor current; the resistor R1, R2, and R3 form a resistor divider network to determine the waveform and phase of the input voltage. Capacitor C3 and resistor R3 form an RC filter to remove high-frequency interference signals from pin 3. The secondary winding of inductor T2 passes through resistor R4 on the one hand. Pass the zero-crossing signal of the inductor current to pin 5 of the chip, and on the other hand, it is used as the power supply for the chip to work normally; the chip drive signal is connected to the gate of the MOS tube through the resistor R5, and the resistor R7 is connected in parallel as the inductor current detection resistor. One end of the resistor is connected to the system ground, and the other end is connected to the source of the MOS tube. After being divided by R6 and filtered by C4, the signal is fed back to pin 4 of the chip; resistors R8, R9, R11, and R12 form a resistor divider network. Form a negative feedback loop of the output voltage; capacitor C5 is connected between pins 1 and 2 of the chip to form a compensation network for the voltage loop; capacitor C2, diodes D12, D13, and regulator ZD1 provide the startup voltage of the chip when the system is powered on .

In the self-excited oscillating circuit and the inverter/boost circuit, the resistor R18 and the capacitor C10 form a series resonant circuit, and the resonant signal generated is coupled to each other by the three windings of the oscillating pulse transformer T3 to generate two high frequencies with opposite polarity phases The square wave pulse makes the bipolar transistors Q2 and Q3 cycle on and off, and then makes the fluorescent lamp work normally through the choke inductors T4 and T5.

In the protection circuit, the capacitors C14 and C15 sample the no-load and overload signals of the fluorescent tubes, and after being ballasted and divided by R22, D11, R21, R20 and D15, they feed back and drive the Q4SCR element to stop the resonant circuit from working.

The positive effect of the utility model is:

Energy saving: 1. Compared with the general magnetic ballast, it can achieve a power factor of 0.99, while the general T8 magnetic ballast can only achieve a power factor of 0.50. This saves a lot of waste of resources for the current power energy shortage problem; 2. High luminous efficiency, driving a T6 type 36W solid mercury trichromatic fluorescent tube can reach 3145LM, while a 40W ordinary T8 tube can only achieve 1818LM, and one T6 tube can achieve the effect of almost two T8 tubes. Can save 4W of energy.

Environmental protection: The traditional inductive ballast uses a working frequency of 50Hz, and the light flickers 100 times per second. When working and studying under this kind of light source, the eyeball, retina and optic nerve are prone to fatigue due to the stroboscopic effect of the light source, which is harmful to human vision. Cause serious injury. Using this frequency conversion electronic ballast, the working frequency is above 30KHz, and it flickers more than 30,000 times per second. The light source is stable, which can reduce visual fatigue caused by stroboscopic flicker. In addition, the solid mercury trichromatic fluorescent lamp uses mercury, bismuth, and indium alloys, and if the discarded lamp is broken, it will not cause environmental pollution, which is in line with environmental protection.

Long service life: Ordinary inductive ballasts start for a long time during use, and the life of the lamp cathode and starter is easily damaged by multiple starts; the utility model has a preheating function, which can extend the life of the lamp tube after one start Bright device, and the average life of the lamp itself is 16,000 hours, more than three times that of ordinary lamps.

Easy to replace: the length of this T6 solid mercury tricolor fluorescent tube is the same as that of the traditional T8, and the replacement cost for customers who originally used the T8 tube can also be used with the practical new ballast, which is easy to install and saves costs.

In addition, the utility model has the function of automatic compensation for input voltage fluctuations, high power factor, and low power consumption; and has better ability to suppress electromagnetic interference and radio frequency interference; Protection functions such as overvoltage and undervoltage.

Description of drawings

Fig. 1 is a schematic diagram of the utility model

Figure 2 is the EMI filter circuit diagram

Figure 3 is a power factor compensation circuit diagram

Figure 4 is a diagram of self-excited oscillation circuit and inverter/boost circuit

Figure 5 is a protection circuit diagram

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

As shown in Figure 1, the double straight tube electronic ballast is composed of EMI filter circuit, rectifier circuit, power factor compensation circuit, self-excited oscillation circuit, inverter/boost circuit, and protection circuit. The 220V AC input is first filtered by EMI The circuit removes EMI (Electro Magnetic Interference) electromagnetic interference and RFI (Radio Frequency Interference) high-frequency interference, and then rectifies it into a DC output, and then corrects the power factor through the power factor compensation circuit. Under the control of the self-excited oscillation circuit, the inverter The /boost circuit outputs a high-frequency voltage to drive two parallel fluorescent tubes.

The EMI filter circuit is shown in Figure 2. The double ∏ filter design is adopted in the design. The double ∏ EMI filter circuit composed of CA1, CA2, CY1, CY2, and T1 components can effectively suppress EMI electromagnetic waves by using the differential mode-common mode method. Interference and RFI high frequency interference. The two windings of the inductance T1 are symmetrically wound on the same magnetic core, and the inductance values on both sides are the same, forming two sets of mutually symmetrical Π-type EMI filters with the capacitors CA1 and CA2, which are characterized in that: the winding of T1 The magnetic field generated by the magnetic material wound on the same magnetic core compensates each other. For asymmetric interference signals, the magnetic fields generated by the two coils are mutually strengthened, and the inductance appearing on the outer layer increases, and the symmetrical interference information is suppressed. suppressed. Similarly, for the interference signal between the live wire AC (W) and the ground wire, it is attenuated by the filter composed of CA1, T1, and CY1 and then introduced into the earth; for the interference signal between the neutral wire AC (B) and the ground wire, it is passed through the capacitor CA1, The filter composed of T1 and CY2 is attenuated and introduced into the earth.

The design of this circuit presents high impedance to common-mode interference signals and low impedance to differential-mode signals and power supply current, which can greatly attenuate current noise signals in the power supply. In fact, the design of this circuit is also a low-pass filter. Since the T1 inductance blocks the flow of radio frequency, it can also effectively suppress the interference of radio frequency signals. The EMI filter adopted by the utility model can effectively suppress the electromagnetic interference from the power grid, and at the same time attenuate the electromagnetic interference generated by the electronic ballast itself, which can ensure that the power grid is not polluted.

The power factor compensation circuit is shown in Figure 3. The circuit uses the active power factor correction chip S6500P produced by AUK Company. It can easily form an APFC power supply with wide voltage input (AC85V-265V) and low harmonic content; it can directly drive MOS tubes, and integrates various protection functions; Components reduce losses and improve efficiency. Its principle is to rectify the input alternating current to direct current through the rectifier bridge D1, which is used as the input of the APFC active power factor compensation circuit; the capacitor C1 is used to filter out the high frequency part of the inductor current, and reduce the harmonic content of the input current; the resistor R1, R2 and R3 form a resistor divider network to determine the waveform and phase of the input voltage. Capacitor C3 and resistor R3 form an RC filter to remove high-frequency interference signals from pin 3. Inductor T2 has a secondary winding. On the one hand, the winding transmits the inductor current zero-crossing signal to pin 5 of the chip through the resistor R4, and on the other hand, it is used as the power supply for the chip to work normally; the chip drive signal is connected to the gate of the MOS tube through the resistor R5, and the resistor R7 is connected in parallel As an inductor current detection resistor, it is used to sample the rising edge of the inductor current (MOS tube current). One end of the resistor is connected to the system ground, and the other end is connected to the source of the MOS tube at the same time. The signal is fed back after being divided by R6 and filtered by C4. Pin 4 of the chip; resistors R8, R9, R11, and R12 form a resistor divider network to form a negative feedback loop for the output voltage; capacitor C5 is connected between pins 1 and 2 of the chip to form a voltage loop compensation Network; Capacitor C2, diodes D12, D13, voltage regulator ZD1 provide the starting voltage of the chip when the system is powered on. The APFC circuit designed by using this chip can input voltage 85VAC-265VAC to ensure that the output voltage is stable at 400V, the power factor of the power supply system is increased to above 0.99, and the total harmonic content is lower than 10%, providing an inverter for the ballast. Excellent power supply.

The self-excited oscillation circuit and the inverter/boost circuit are shown in Figure 4. In the inverter design, the "self-excited" oscillation working mode driven by the magnetic core is adopted, and the principle of voltage feedback resonance is used. Resistor R18 and capacitor C10 form a series resonant circuit to generate a 38KHz resonant signal, and then couple each other through the three windings of the oscillating pulse transformer T3 to generate two high-frequency square wave pulses with opposite polarity phases, so that ordinary bipolar transistors Q2, Q3 circulates the switch to work, and then makes the fluorescent lamp work normally through the choke inductors T4 and T5.

The protection circuit is shown in Figure 5. When the lamp holder is no-load or overloaded, the circuit samples the signal through C14 and C15 components, after being ballasted and divided by R22, D11, R21, R20 and D15, the feedback drives the Q4SCR component to act, so that the resonant circuit stops working, which can effectively achieve Protect lamp and ballast function.

Claims (5)

1. two straight pipe type electric ballasts; form by EMI filter circuit, rectification circuit, power factor compensation circuit, self-maintained circuit, inversion/booster circuit, protective circuit; it is characterized in that: 220V exchanges input and removes EMI electromagnetic interference and RFI High-frequency Interference through the EMI filter circuit earlier; be direct current output through rectification again; pass through power factor compensation circuit corrected power factor then; under the control of self-maintained circuit, drive the fluorescent tube of two parallel connections through inversion/booster circuit output high voltage.

2. as claimed in claim 1 pair of straight pipe type electric ballast, it is characterized in that: described EMI filter circuit, form two ∏ type filter circuits by capacitor C A1, CA2, CY1, CY2, inductance T1, wherein two of inductance T1 windings are that symmetry is on same magnetic core, its both sides inductance value is identical, constitutes two groups of symmetrical ∏ type electromagnetic interface filters with capacitor C A1, CA2.

3. as claimed in claim 1 pair of straight pipe type electric ballast, it is characterized in that: described power factor compensation circuit adopts Active Power Factor Correction special chip S6500P, the input AC electricity is a direct current through rectifier bridge D1 rectification, as the input of APFC active power factor compensating circuit; HFS in the capacitor C 1 filtering inductive current; Resistance R 1, R2 and R3 constitute resistance pressure-dividing network, determine the waveform and the phase place of input voltage, and capacitor C 3 constitutes the RC filter with resistance R 3, removes the high-frequency interferencing signal of No. 3 pins; Inductance T2 secondary winding on the one hand is delivered to No. 5 pins of chip, the power supply during on the other hand as the chip operate as normal by resistance R 4 with the inductive current zero cross signal; The chip drives signal is linked the gate pole of metal-oxide-semiconductor by resistance R 5, and resistance R 7 parallel connections detect resistance as inductive current, and this resistance one is terminated at systematically, and the other end is connected on the source electrode of metal-oxide-semiconductor, signal feedback is given No. 4 pins of chip after R6 dividing potential drop, C4 filtering; Resistance R 8, R9, R11, R12 constitute resistance pressure-dividing network, form the negative feedback loop of output voltage; Capacitor C 5 is connected between 1, No. 2 pins of chip, forms the compensating network of Voltage loop; Capacitor C 2, diode D12, D13, voltage-stabiliser tube ZD1 provide the starting resistor of chip when switching in system.

4. as claimed in claim 1 pair of straight pipe type electric ballast, it is characterized in that: in described self-maintained circuit, inversion/booster circuit, resistance R 18 and capacitor C 10 are formed series resonant circuit, producing resonance signal intercouples through three windings of oscillating impulse transformer T3 and produces the high frequency square wave pulse of two opposite polarity phase places, make bipolar transistor Q2, the work of Q3 cycling switch, make the fluorescent lamp operate as normal by choke induction T4, T5 again.

5. as claimed in claim 1 pair of straight pipe type electric ballast; it is characterized in that: in described protective circuit; the zero load and the overload signal of capacitor C 14, C15 sampling fluorescent tube; after R22, D11, R21, R20, D15 ballast, dividing potential drop; feedback drives the Q4SCR element, and resonant circuit is quit work.

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