CN203423841U

CN203423841U - High-frequency inversion circuit with over-current protection

Info

Publication number: CN203423841U
Application number: CN201320495701.8U
Authority: CN
Inventors: 左涛; 李令言; 葛玲; 姜岩; 杨玉玲; 黄富传
Original assignee: FENGTAI TECHNOLOGY DEVELOPMENT Co OF 16TH RESEARCH INSTITUTE OF CHINA ELECTRONICS TECHNOLOGY GROUP Corp; CETC 16 Research Institute
Current assignee: FENGTAI TECHNOLOGY DEVELOPMENT Co OF 16TH RESEARCH INSTITUTE OF CHINA ELECTRONICS TECHNOLOGY GROUP Corp; CETC 16 Research Institute
Priority date: 2013-08-14
Filing date: 2013-08-14
Publication date: 2014-02-05
Anticipated expiration: 2023-08-14

Abstract

The utility model discloses a high-frequency inversion circuit with over-current protection. The high-frequency inversion circuit comprises a drive protection circuit having functions of MOSFET switching tube true-false over-current judgment and protection, an electrodeless lamp starting ignition circuit, a drive circuit having functions of feeding back a self-excited oscillation voltage and clamping a MOSFET switching tube drive voltage, a half-bridge inversion circuit, a resonance output circuit for frequency selection and power supply of the electrodeless lamp, and an exception protection circuit for protection in the case of exceptions, such as bulb leakage, etc. According the utility model, the drive protection circuit has the functions of MOSFET switching tube true-false over-current judgment and MOSFET switching tube over-current protection; when the lamp is in exception, the high-frequency inversion circuit provides an output exception protection function, thereby achieving the purposes of improving the reliability and safety of the self-excited oscillation high-frequency inversion circuit.

Description

A kind of high-frequency inverter circuit with overcurrent protection

Technical field

The utility model relates to Non-polarized lamp technical field, particularly relevant with the high-frequency inverter circuit in electronic ballast of electrodeless lamp.

Background technology

Along with social development, demand to energy-conserving and environment-protective green illumination constantly increases, high-frequency electromagnetic induction Non-polarized lamp (being called for short Non-polarized lamp below) is owing to not having electrode to be called as Non-polarized lamp, can reach 60,000 hours its theoretical service life, there is energy-conservation, light efficiency high, will become replace Halogen lamp LED and high pressure sodium lamp the 4th generation green illumination light source.Affect two factors that mainly contain in Non-polarized lamp life-span, the one, light source itself, the 2nd, the working life of electric ballast, electric ballast becomes the main factor of Non-polarized lamp life-span that affects at present.Current electronic ballast of high-frequency electrodeless lamp mostly adopts self-excited oscillation type half-bridge inversion circuit, operating frequency is up to 2.65MHz, the switching tube MOSFET that forms half-bridge circuit works under so high frequency, upper underarm MOSFET pipe drives the Dead Time of signal unreasonable, and the loss of MOSFET pipe range time service is large, temperature is high, aging speed is fast, capital causes MOSFET straight-through, makes switching tube burn in the short time.Half-bridge circuit switching tube occurs when straight-through, equals the 400V high pressure of APFC output to be directly added to that MOSFET pipe leaks, the two poles of the earth, source, and the electric current that flows through the drain electrode of MOSFET pipe can sharply increase, and even can cause the damage of circuit board unrepairable.

Current electronic ballast of high-frequency electrodeless lamp has abnormity protection circuit, adopts output current or Voltage Feedback, trigger protection circuit working, thus turn-off upper pipe or lower pipe, stop resonance, play a protective role.But the resonant circuit overvoltage that these feedback protection circuits cause extremely mainly for bulb or excessively flow problem.

Summary of the invention

For problems such as burning of overcoming that high frequency electronic ballast of electrodeless lamp causes because the MOSFET pipe of high-frequency inverter circuit is straight-through, bombings, the utility model has provided a kind of high-frequency inverter circuit with overcurrent protection.

In order to achieve the above object, the utility model is realized by the following technical solutions: a kind of high-frequency inverter circuit with overcurrent protection, comprises Drive Protecting Circuit, firing circuit, drive circuit, half-bridge inversion circuit, resonant circuit and abnormity protection circuit; Described Drive Protecting Circuit is electrically connected to abnormity protection circuit; starter firing circuit is connected with input power; described firing circuit is electrically connected to drive circuit; described drive circuit and circuits for triggering are electrically connected to half-bridge inversion circuit; described half-bridge inversion circuit is electrically connected to resonance output circuit, is connected with described resonant circuit and driving circuit abnormality protective circuit.

Two switch mosfet pipe Q1 of described Drive Protecting Circuit judgement half-bridge inversion circuit and the true and false over current fault of Q2, for false over current fault, the fast quick-recovery normal operating conditions of Drive Protecting Circuit; For true over current fault, Drive Protecting Circuit by switch mosfet pipe driving voltage clamper below conducting voltage.

Described high-frequency inverter circuit is the half bridge inverter circuit based on self-oscillation, and the self-excitation feedback circuit of described drive circuit is transformer feedback circuit.

Described resonant circuit is LC resonant circuit.

This high-frequency inverter circuit also comprises and is arranged at the input filter capacitor C1 of power input and C2, condenser type high-frequency filter circuit.

Input filter capacitor C1 and C2, for the high-frequency signal of filtering input direct voltage, absorb surge current, reduces the electromagnetic interference to rear class high frequency half bridge inverter circuit.

Described Drive Protecting Circuit; while raising for two switching tube Q1 of half-bridge inversion circuit and Q2 both end voltage; judge whether to have occurred straight-through over current fault; the function with the true and false over current fault of judgement, and can return to normal operating conditions for false over-current phenomenon avoidance, by switching tube grid source both end voltage clamper below conducting voltage; thereby protection switch pipe; avoid as far as possible the irrecoverability of circuit board to damage, after fault is got rid of, can also restart circuit working.

Described firing circuit, the ignition voltage (1300V ~ 3000V) when Non-polarized lamp starter is provided.

Described drive circuit and half bridge inverter circuit comprise self-excitation feedback loop, high frequency transformer, MOSFET pipe clamp circuit and MOSFET pipe, be used to MOSFET pipe that stable self-oscillation driving voltage is provided, thereby output high frequency oscillation voltage, powers to Non-polarized lamp by resonant circuit 5.

In the high-frequency inverter circuit with overcurrent protection described in the utility model, also comprise output abnormality protective circuit, for bulb gas leakage, the protection of the abnormal work states such as power flash-up.

the beneficial effects of the utility model:by Drive Protecting Circuit, can effectively prevent by the straight-through fault causing of half-bridge switch pipe; can realize self-oscillation and produce 2.65M high-frequency signal simultaneously; and there is bulb-damage protection etc.; thereby effectively guarantee the security reliability of high-frequency inverter circuit, improved the useful life of HF lamp without electrodes.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the utility model is further illustrated.

Fig. 1 is structural representation of the present utility model.

Fig. 2 is half-bridge inversion circuit upper arm Drive Protecting Circuit schematic diagram.

In Fig. 1,1. Drive Protecting Circuit, 2. firing circuit, 3. drive circuit, 4. half-bridge inversion circuit, 5. resonant circuit, 6. abnormity protection circuit.

Embodiment

Below in conjunction with accompanying drawing, by preferred embodiment, the utility model is described in detail.For Drive Protecting Circuit, the upper arm MOSFET pipe Drive Protecting Circuit of half-bridge inversion circuit of take here describes as example, and underarm switch mosfet pipe Drive Protecting Circuit principle and function class seemingly, repeat no more.

Shown in Figure 1; a kind of high-frequency inverter circuit with overcurrent protection; comprise (MOSFET) Drive Protecting Circuit 1; the Non-polarized lamp starter firing circuit 2 being connected with input power; the drive circuit 3 being connected with described firing circuit 2; the half-bridge inversion circuit 4 being connected with circuits for triggering 2 with described drive circuit 3, the resonance output circuit 5 being connected with described half-bridge inversion circuit 4, the abnormity protection circuit 6 being connected with described resonant circuit 5 and drive circuit 3.The high-frequency filter circuit that first prime APFC circuit output 400V voltage consist of capacitor C 1 and C2, filtering high frequency clutter; Then by Non-polarized lamp starter firing circuit 2, to Non-polarized lamp, provide the ignition voltage up to 1300V ~ 3000V; After Non-polarized lamp igniting starter, the Q value of resonant circuit 5 diminishes, along with stablizing of bulb, and operating frequency convergence 2.65MHz, drive circuit 3 adopts high frequency transformers feedback driving voltages to switch mosfet pipe, the work of driving switch pipe; In order to prevent MOSFET pipe Q1 and the straight-through over current fault of Q2 appearance in high-frequency inverter circuit, Drive Protecting Circuit 1 judges true and false straight-through overcurrent by the voltage at Q1 and Q2 two ends, and can take fast protection and recover action.

Referring to Fig. 2, be depicted as the basic circuit diagram of Q1 Drive Protecting Circuit 1, comprise R1, R2, R3, R4 power circuit, be respectively Q3 switching voltage is provided, for Q4 provides collector voltage.A_Port point is drive voltage signal, and during normal operation, Q3 is always in cut-off state, and during driving voltage high level, Q4 is conducting, and Q5 ends, thereby guarantee that two ends, Q1 grid source clamp voltage can make Q1 fast conducting; When driving voltage low level, Q5 conducting, Q4 cut-off, Q1 grid source both end voltage clamper is in low level, and Q1 ends, and D1 oppositely turn-offs.When there is overcurrent phenomenon, MOSFET pipe drain-source two pole tensions become large, and D1 oppositely turn-offs, the conducting voltage of D2 is set higher than the conducting voltage of D5, if false over-current phenomenon avoidance, overcurrent continues the short period, D5 conducting, thereby Q6 conducting, Q1 grid source both end voltage clamper slightly lower than the value of MOSFET pipe conducting voltage, the voltage of D2 front nodal point also deficiency so that D2 conducting, Q3 will continue cut-off, D5 will end after of short duration conducting, and Q6 also can end, and Q1 recovers normal operation again; If true over-current phenomenon avoidance, D1 will oppositely turn-off for a long time, along with the rising of voltage; D2 will conducting, Q3 conducting, and Q5 is by conducting for a long time; Q1 grid source both end voltage is by clamper in low level like this, and Q1, in off state, enters oversampling circuit guard mode.

Above example is preferably implementation of the utility model, and protection range of the present utility model is not limited to the cited scope of embodiment, and protection range of the present utility model is as the criterion with claim.

Claims

1. a high-frequency inverter circuit with overcurrent protection, is characterized in that: comprise Drive Protecting Circuit (1), firing circuit (2), drive circuit (3), half-bridge inversion circuit (4), resonant circuit (5) and abnormity protection circuit (6);

Described Drive Protecting Circuit (1) is electrically connected to abnormity protection circuit (6); starter firing circuit (2) is connected with input power; described firing circuit (2) is electrically connected to drive circuit (3); described drive circuit (3) and circuits for triggering (2) are electrically connected to half-bridge inversion circuit (4); described half-bridge inversion circuit (4) is electrically connected to resonance output circuit (5), is connected with described resonant circuit (5) and drive circuit (3) abnormity protection circuit (6).

2. the high-frequency inverter circuit with overcurrent protection according to claim 1, is characterized in that being:

Two switch mosfet pipe Q1 of described Drive Protecting Circuit (1) judgement half-bridge inversion circuit and the true and false over current fault of Q2, for false over current fault, the fast quick-recovery normal operating conditions of Drive Protecting Circuit (1); For true over current fault, Drive Protecting Circuit by switch mosfet pipe driving voltage clamper below conducting voltage.

3. a kind of high-frequency inverter circuit with overcurrent protection according to claim 1; it is characterized in that being: described high-frequency inverter circuit (4) is the half bridge inverter circuit based on self-oscillation, the self-excitation feedback circuit of described drive circuit (3) is transformer feedback circuit.

4. the high-frequency inverter circuit with overcurrent protection according to claim 1, is characterized in that: described resonant circuit (5) is LC resonant circuit.

5. the high-frequency inverter circuit with overcurrent protection according to claim 1, is characterized in that: this high-frequency inverter circuit also comprises and is arranged at the input filter capacitor C1 of power input and C2, condenser type high-frequency filter circuit.