CN202979438U

CN202979438U - Fluorescent lamp electronic ballast adopting frequency modulation and dimming

Info

Publication number: CN202979438U
Application number: CN 201220734695
Authority: CN
Inventors: 张新安
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-12-28
Filing date: 2012-12-28
Publication date: 2013-06-05
Anticipated expiration: 2022-12-28

Abstract

The utility model provides a fluorescent lamp electronic ballast adopting frequency modulation and dimming, which comprises an EMI filter circuit, a rectifier filter circuit, a PFC circuit, a frequency modulation and dimming circuit, a half-bridge inversion and protection circuit, a step-up ballast circuit, and a lamp current feedback circuit connected in sequence, wherein the input end of the lamp current feedback circuit is connected with the lamp filament, and the output end is connected with the alternating current lamp current feedback input end of the half-bridge inversion circuit; the EMI filter circuit is a low-pass filter circuit made up of a capacitor and an inductor; the PFC circuit is a valley-filled passive power factor correction circuit made up of diodes and capacitors; the frequency modulation and dimming circuit is a voltage regulation circuit made up of components such as a potentiometer; the half-bridge inversion and protection circuit is made up of an integrated circuit chip IRS2530D and the peripheral components thereof; and the lamp current feedback circuit is a lamp current sampling and feedback network made up of resistors and a capacitor. The fluorescent lamp electronic ballast adopting frequency modulation and dimming has the beneficial effects of small volume, light weight, good dimming performances, high power factor, perfect protection functions, and long service life.

Description

A kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation

Technical field

The utility model relates to fluorescent lamp ballast, is specifically related to a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation.

Background technology

In recent years, the high-frequency florescent lamp electric ballast because of its have that efficient is high, volume is little, lightweight, without stroboscopic with lamp tube service life is long etc. that advantage progressively is accepted.Domestic electronic ballast for fluoresent lamp, majority all adopt the separating component assembling, and advantage is that circuit is simple, cost is low, but need magnetic ring transformer to drive, and operating frequency is unstable, and reliability is low.And there is no preheating and dimming function, easily cause filament open circuit and semi-bridge inversion output transistor to damage, the life-span of fluorescent lamp is short.Along with the raising that people require lighting quality, traditional constant brightness fluorescent lamp can not satisfy people's demand, also is unfavorable for energy savings.High performance electronic ballast for fluoresent lamp need to increase dimming function, and the occasion in unnecessary full power output reduces power output, and is not only energy-conservation, and can also reach the purpose of conversion visual effect.

Summary of the invention

For solving the deficiency of existing electronic ballast for fluoresent lamp, the utility model discloses a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation.The volume of this ballast is little, lightweight, dimming behavior is good, power factor (PF) is high, defencive function is perfect, long service life, can be widely used in the electronic ballast for fluoresent lamp field.

For achieving the above object, the utility model adopts following technical scheme: the utility model is comprised of the EMI filter circuit that is linked in sequence successively, current rectifying and wave filtering circuit, pfc circuit, frequency modulation light adjusting circuit, semi-bridge inversion and protective circuit, boost ballasting circuit and lamp current feedback circuit.The input termination filament of lamp current feedback circuit, the AC lamp current feedback input end of output termination half-bridge inversion circuit.

The low-pass filter circuit that the EMI filter circuit is comprised of capacitor C 1 and inductance L 1.Diode D1, D2, D3, D4 and capacitor C 2 form current rectifying and wave filtering circuit.The valley fill type Passive Power factor correction circuit that pfc circuit is comprised of diode D5, D6, D7 and capacitor C 3, C4.The frequency modulation light adjusting circuit is by resistance R 1, R2, R3, R4, voltage stabilizing didoe D8, the regulating circuit that capacitor C 5 and potentiometer W1 form.Semi-bridge inversion and protective circuit be by integrated circuit die I RS2530D and peripheral resistance R 5～R14, capacitor C 6～C14, and voltage stabilizing didoe D9, diode D10 and MOSFET pipe Q1, Q2 form.The series resonance that the ballasting circuit that boosts is comprised of inductance L 2 and capacitor C 15 is boosted and the inductance ballast circuit.Lamp current sampling and feedback network that lamp current feedback circuit is comprised of resistance R 14, R9 and capacitor C 11.The low-limit frequency of half-bridge inversion circuit is 34KHz, and highest frequency is 115KHz, and filament preheating time is 0.9S.

Good effect of the present utility model is: volume is little, lightweight, dimming behavior is good, power factor (PF) is high, defencive function is perfect, long service life.

Description of drawings

Fig. 1 is block diagram of the present utility model.

Fig. 2 is circuit theory diagrams of the present utility model.

Embodiment

As shown in Figure 1, formed by the EMI filter circuit that is linked in sequence successively, current rectifying and wave filtering circuit, pfc circuit, frequency modulation light adjusting circuit, semi-bridge inversion and protective circuit, boost ballasting circuit and lamp current feedback circuit by the utility model.The input termination filament of lamp current feedback circuit, the AC lamp current feedback input end of output termination half-bridge inversion circuit.

As shown in Figure 2, the low-pass filter circuit that the EMI filter circuit is comprised of capacitor C 1 and inductance L 1, C1 are used for suppressing the series mode interference signal, and L1 is used for suppressing common mode interference signal.Diode D1, D2, D3, D4 and capacitor C 2 form current rectifying and wave filtering circuit, the 220V alternating current are obtained the direct voltage of 300V left and right through rectifying and wave-filtering, are half-bridge inversion circuit and the power supply of frequency modulation light adjusting circuit.

The valley fill type Passive Power factor correction circuit that pfc circuit is comprised of diode D5, D6, D7 and capacitor C 3, C4.Capacitor C 3, C4 serial connection charge, parallel discharge.At alternating current in each half period, AC-input voltage was elongated higher than the time of VD, the angle of flow of rectifier diode increases, the zero passage Dead Time of supply voltage shortens, its current waveform trends towards continuously, envelope trends towards sine wave, makes the interchange input current chase supply voltage transient change track.This valley fill type passive PFC circuit can be provided to power factor more than 0.9, total harmonic distortion THD＜30%.

Semi-bridge inversion and protective circuit be by integrated circuit die I RS2530D and peripheral resistance R 5～R14, capacitor C 6～C14, and voltage stabilizing didoe D9, diode D10 and MOSFET pipe Q1, Q2 form.Have electronic ballast for fluoresent lamp must preheating, igniting, operation and filament open circuit, non-ZVS and crest factor defencive function.

The series resonance that the ballasting circuit that boosts is comprised of inductance L 2 and capacitor C 15 is boosted and the inductance ballast circuit, lamp current sampling and feedback network that lamp current feedback circuit is comprised of resistance R 14, R9 and capacitor C 11, the frequency modulation light adjusting circuit is by resistance R 1, R2, R3, R4, voltage stabilizing didoe D8, the regulating circuit that capacitor C 5 and potentiometer W1 form.Regulate the pressure regulation potentiometer semi-bridge inversion frequency is changed in the scope of 34kHz～115kHz, can realize 100%～2% brightness regulation.

Connect the AC mains supply, current rectifying and wave filtering circuit output is the DC bus voltage of 300V left and right approximately, and R5 charges to C6 by starting resistance.When the voltage on IC1 pin VCC surpassed 12.5V, pin HO and LO produced driver output and starting oscillation.When half-bridge low side Q2 conducting, to the charging of the bootstrap capacitor C12 between pin VB and VS, when the voltage on C12 surpassed 9V, the high-end of IC1 enabled the voltage on pin VCC, drove the Q1 conducting through inside bootstrapping MOSFET.During the Q1 conducting, Q2 cut-off, the C12 discharge, the voltage on C12 is Q1 cut-off Q2 conducting again during lower than 8V.So go round and begin again, Q1 and Q2 alternate conduction, the pulse of pin VS output high frequency square wave is lamp tube power supply through the ballasting circuit that boosts.

IC1 is in case start, and to external capacitor C 9 chargings, ballast output highest frequency is the square-wave pulse of 115KHz, begins to filament pre-heating the voltage U on the VCO pin at the current source of the quick starting current of 50 μ A of pin 4 inside and 1 a μ A _VCORise to rapidly 0.85V, 50 μ A electric currents of IC1 inside are cut off, and only have the current source of 1 μ A to the capacitor charging on the VCO pin, U _VCORising, frequency begins linear decline from highest frequency, and two auxiliary winding L 3 of resonant inductor L2, L4 provide pre-thermal voltage for filament.L3, C15 and L4, C16 are band pass filter, and after filament spot, the filament pre-heating voltage attenuation is to reduce the thermal losses on filament.When the ballast output frequency reached resonance frequency, filament pre-heating finished, and series resonance occurs for L2 and C15, produces a sufficiently high voltage and fluorescent tube is triggered and light on C15.C9 of the present utility model is designed to 0.22 μ F, and filament preheating time is 0.9S.In case fluorescent tube is lit, IC1 enters light-modulating mode.If fluorescent tube is not lighted, U _VCOWill be over 4V, IC1 enters fault mode and closes its output.

When lamp was lit, the brightness adjustment control loop was activated, and IC1 enters light-modulating mode.The upper alternating voltage that produces of the lamp current sample resistance R14 that is connected with filament also feeds back to the DIM pin of IC1, the dc voltage that the voltage on pin DIM arranges when regulating light adjusting potentiometer W1 for the user and the AC voltage sum of feeding back by C11 through R9 and C11.Voltage on the DIM pin is regulated by control loop, and AC voltage valley is always rested on the COM level.For making light dimmed, when regulating W1 DC reference voltage on the DIM pin reduced, the valley of AC voltage will extend to below the COM level, and adjusting control circuit will improve the ballast frequency and reduce lamp current, until at the AC voltage valley on the DIM pin again on the COM level.Be to increase the brightness of lamp, when regulating W1 and make that on the DIM pin, dc voltage increases, more than AC voltage valley will be elevated to COM, adjusting control circuit will reduce ballast frequency increase lamp current, until the AC valley on the DIM pin is returned on the COM level.Adopt this frequency modulation light-dimming method, when the ballast frequency raises, the induction reactance of the ballast inductance in ballasting circuit of boosting will increase, the capacitive reactance of the electric capacity of while and fluorescent lamp load parallel connection reduces thereupon, make the lamp current of fluorescent lamp reduce, realize the frequency modulation brightness adjustment control, and arrange at all light modulation level, adjusting control circuit can be with the value of AC lamp current peak-to-peak value amplitude adjusted to an expectation, and dimming behavior is good.When semi-bridge inversion frequency of the present utility model changes in the scope of 34kHz～115kHz, the luminosity of difference corresponding 100%～2%, dimming scope is wide.At light-modulating mode, VS sensing circuit, non-ZVS and crest factor protective circuit are all energized.

At light-modulating mode, if the voltage on pin VS during the dead band fails to get back to fully the COM level, when low side Q2 conducting, to produce a voltage between its drain-source utmost point, system works is too approaching or enter resonance capacitive side, non-ZVS capacitive mode to occur, produce large peak current in half-bridge MOSFET, MOSFET is damaged.For avoiding this situation to occur, when HO turn-offed, IC1 internal high pressure MOSFET was with conducting, and the VS current sensor is at the voltage V that will measure on the LO rising edge on the VS pin _VSIf greater than the threshold voltage of 4.5V, non-ZVS control circuit will improve the ballast frequency, until reach ZVS.

When the peak current that flows through MOSFET surpasses 5.5 times of average current, mean that filament lost efficacy, perhaps fluorescent tube does not access, and resonant inductance L2 will occur saturated.IC1 can enter the error protection pattern in the case, and closes voluntarily.

At fault mode, HO turn-offs, the LO open circuit, and IC1 only consumes the electric current of 250 μ A.If lamp does not access, more than resistance R 12 and R13 will draw high 8.75V to the voltage on pin LO, IC1 withdrawed from fault mode and enters the UVLO pattern.When connecting fluorescent tube, the voltage drop on pin LO is pulled down to below 8.75V, so IC1 withdraws from the UVLO pattern and enters preheating/trigger mode, lamp is lighted again.

Claims

1. electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation; it is characterized in that: it is comprised of the EMI filter circuit that is linked in sequence successively, current rectifying and wave filtering circuit, pfc circuit, frequency modulation light adjusting circuit, semi-bridge inversion and protective circuit, boost ballasting circuit and lamp current feedback circuit; the input termination filament of lamp current feedback circuit, the AC lamp current feedback input end of output termination half-bridge inversion circuit.

2. a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation according to claim 1, is characterized in that: the low-pass filter circuit that the EMI filter circuit is comprised of capacitor C 1 and inductance L 1.

3. a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation according to claim 1, is characterized in that: the valley fill type Passive Power factor correction circuit that pfc circuit is comprised of diode D5, D6, D7 and capacitor C 3, C4.

4. a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation according to claim 1, it is characterized in that: the frequency modulation light adjusting circuit is by resistance R 1, R2, R3, R4, voltage stabilizing didoe D8, the regulating circuit that capacitor C 5 and potentiometer W1 form.

5. a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation according to claim 1; it is characterized in that: semi-bridge inversion and protective circuit are by integrated circuit die I RS2530D and peripheral resistance R 5～R14; capacitor C 6～C14; voltage stabilizing didoe D9, diode D10 and MOSFET pipe Q1, Q2 form.

6. a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation according to claim 1, is characterized in that: lamp current sampling and feedback network that lamp current feedback circuit is comprised of resistance R 14, R9 and capacitor C 11.

7. a kind of electronic ballast for fluoresent lamp that adopts the frequency modulation light modulation according to claim 1, it is characterized in that: the low-limit frequency of half-bridge inversion circuit is 34KHz, and highest frequency is 115KHz, and filament preheating time is 0.9S.