CN201039557Y - Electronic rectifier with temperature negative feedback circuit - Google Patents

Abstract

Translated fromChinese

本实用新型涉及一种带有温度负反馈电路的电子镇流器，包括整流电路、半桥逆变电路和保护电路，半桥逆变电路包括若干个三极管，三极管的发射极和基极之间接入一负温度系数的热敏电阻NTC。本实用新型热敏电阻NTC调节电器的输出功率，随温度和输入电压的上升，电器内部温度随之上升，而负温度系数的热敏电阻NTC阻值变小，从而调节产品的输出功率下降，达到了控制产品内部温度的效果，有效地保护了电子镇流的过热损坏，大大地提高了产品可靠性、延长了电子镇流器的使用寿命。

The utility model relates to an electronic ballast with a temperature negative feedback circuit, which includes a rectifier circuit, a half-bridge inverter circuit and a protection circuit. Into a negative temperature coefficient of thermistor NTC. The thermistor NTC of the utility model adjusts the output power of the electric appliance. With the rise of the temperature and the input voltage, the internal temperature of the electric appliance rises accordingly, and the resistance value of the thermistor NTC with a negative temperature coefficient becomes smaller, thereby adjusting the output power of the product to drop. It achieves the effect of controlling the internal temperature of the product, effectively protects the electronic ballast from overheating damage, greatly improves product reliability, and prolongs the service life of the electronic ballast.

Description

The electric ballast that has the temperature negative-feedback circuit

Technical field

The utility model relates to the application electric technology field, is meant a kind of electric ballast that has the temperature negative-feedback circuit specifically.

Background technology

Existing electric ballast, electricity-saving lamp, electronic transformer etc. are to adopt voltage feed semi-bridge type inverter circuit mostly, its power output rises along with the rising of temperature and input voltage, make the electrical equipment temperature inside also along with rising, as traditional in the market electric ballast when ambient temperature or line voltage are higher, heater members such as inductance, the switching tube temperature can be up to 120-130 degree centigrade, cause the mistake cause thermal damage of electronic component easily, influence the serviceability of electric ballast, shortened the useful life of electric ballast.

Summary of the invention

The utility model provides a kind of electric ballast that has the temperature negative-feedback circuit that can be used for regulating power output.

A kind of electric ballast comprises rectification circuit, half-bridge inversion circuit and protective circuit, and half-bridge inversion circuit comprises several triodes, inserts the thermistor NTC of a negative temperature coefficient between the emitter of described triode and the base stage.

When the emitter of triode has resistance, described thermistor NTC can insert between transistor base and any end of resistance.

The negative temperature coefficient of described thermistor NTC is selected according to the adjusting ratio of output power of electronic ballast.

The negative temperature coefficient of the thermistor NTC of described negative temperature coefficient can be selected as required.

The utility model inserts a negative temperature coefficient between the transistor base of half-bridge inversion circuit and emitter thermistor NTC (has resistance on the emitter as triode; this thermistor NTC can insert any end of resistance); regulate the power output of electrical equipment by this thermistor NTC; rising with temperature and input voltage; the electrical equipment internal temperature rises thereupon; and the thermistor NTC resistance of negative temperature coefficient diminishes; thereby the power output of regulating product descends; as rising when operatingambient temperature 15% the time; power output descends about 15% automatically; when line voltage rises 15% the time; power output can rise to earlier about 20%; rising along with the ballast internal temperature; the power of output will descend gradually, and final stable back has reached the effect of control product internal temperature about rising 5-10%; protect the mistake cause thermal damage of electronic ballast effectively, improved product reliability widely; prolonged the useful life of electric ballast.

The utility model is easy to use, cost is low, and the internal temperature rise of product descends significantly, applied range.

Description of drawings

Fig. 1 is a circuit theory schematic diagram of the present utility model;

Fig. 2 is the electrical block diagram of another connection of the utility model temperature feedback circuit.

Embodiment

A kind of electric ballast; comprise rectification circuit, half-bridge inversion circuit and protective circuit; Figure 1 shows that the electrical block diagram of single tube electric ballast; as shown in the figure; it is triode T1 and triode T2 that half-bridge inversion circuit includes two triodes; insert the thermistor NTCR22 of a negative temperature coefficient between the emitter of triode T1 and the base stage, insert the thermistor NTCR23 of a negative temperature coefficient between the emitter of triode T2 and the base stage.

When the emitter of triode T1, T2 had resistance, thermistor R22, R23 can be connected on any end of resistance, promptly distinguished connection as shown in Figure 1, 2.

During work, connect the electric ballast power supply, then power supply is through 5 chargings of 1 pair of capacitor C of resistance R, be elevated to breakover voltage (about 32V) value of diac DB3 to the voltage atcapacitor C 5 two ends after, diac DB3 avalanche breakdown, thencapacitor C 5 is by base stage and the discharge of emitter network of triode T2, the conducting of triode T2 forward bias, current trend is in the circuit at this moment: primary coil L3 (b)-triode T2-ground connection of power supply-capacitor C 2-fluorescent tube lower end filament-capacitor C 9-fluorescent tube upper end filament-choke L4-pulse transformer L3.The electric current instantaneous variation di/dt of triode T2 collector electrode, produce induced electromotive force by primary coil L3 (b) at two secondary winding L3 (a), L3 (c) two ends of pulse transformer L3, polarity is that each winding end of the same name is for negative, base stage and the collector current of triode T2 are further increased, and the positive feedback of interlock type makes triode T2 jump to the saturation conduction state immediately.When triode T2 conducting,capacitor C 5 discharges electric charge by diode D7 and triode T2, produces trigger impulse once more to stop the base stage to triode T2.

After pulse transformer L3 is saturated, each winding L 3 (a), the induced potential vanishing of L3 (c), the base potential of triode T2 becomes downward trend, collector current also descends thereupon, then the induced electricity among the primary coil L3 (b) certainly will stop its minimizing, polarity is end of the same name for just, then the base potential of triode T2 descends, the base potential of triode T1 raises, the positive feedback of this kind interlock type makes triode T2 withdraw from saturation conduction immediately and jumps to cut-off state, on the contrary, triode T1 is from ending the saturation conduction state that jumps to, in triode T1 conduction period, current trend is in the circuit: power supply just-triode T1-pulse transformer L3 primary coil L3 (b)-choke L4-fluorescent tube upper end filament-capacitor C 9-fluorescent tube lower end filament-capacitor C 3-ground connection.

After pulse transformer L3 magnetic core was saturated once more, the positive feedback of interlock type made triode T1 end immediately, and triode T2 saturation conduction so goes round and begins again.

Because triode T1 and triode T2 take turns conducting, the sense of current that makes the lamp that is parallel to lamp tube ends start capacitor C 9 constantly changes, rapidly the LC network generation series resonance of being made up of choke L4 and capacitor C 9.Produce high-voltage pulse at capacitor C 9 two ends and be applied to lamp tube ends, lamp is started.

Have two thermistor R22 of negative temperature coefficient and base stage and the emitter two ends that R23 is connected on triode T1 and triode T2 respectively, when the electric ballast operate as normal, the stabilization of operating point of triode T1 and triode T2 is kept operate as normal.When external condition generation ANOMALOUS VARIATIONS, unusually raise as line voltage, perhaps ambient temperature uprises unusually, this moment, the transistor collector electrorheological was big, the pipe consumption increases the pipe temperature rise, very easily damage triode, and behind the reload temperature negative-feedback circuit, if triode makes collector current become big because of external condition unusually, the pipe temperature rise, the thermistor NTC resistance that then has negative temperature coefficient descends thereupon, this directly causes the basic radio of triode T1 and triode T2 to press Vbe to descend, the base current Ib decline that Vbe descends and causes triode T1 and triode T2, thus collector current Ic is diminished, stablized the working point of triode T1 and T2.Whole procedural representation is as follows: Ic ↑ → Guan Wen ↑ → NTCR ↓ → Vbe ↓ → Ib ↓ → Ic ↓.

The negative temperature coefficient of thermistor NTCR22, R23 can be selected according to the adjusting ratio of output power of electronic ballast.

In like manner, the power output that two-tube or three pipe electric ballasts also can be regulated electrical equipment by the thermistor that connects a negative temperature coefficient between the basic emitter-base bandgap grading of triode, in the actual mechanical process, often compensate the deficiency of thermistor NTC when resistance is seriously fallen at resistance of serial connection on the thermistor NTC.

Table (one), table (two) are respectively the index contrasts before and after the electric ballast reload temperature negative-feedback circuit

Table (one): install preceding index additional

Sample: straight tube, 36W, T8 pipe

Table (two): install the back index additional

Sample: straight tube, 36W, T8 pipe

From top data contrast as can be seen, when line voltage raise, the power output of electric ballast had nearly 20% slippage behind the reload temperature feedback circuit, and its protection ballast overload effect is fairly obvious, has reached intended purposes.

Claims (3)

1. electric ballast that has the temperature negative-feedback circuit; comprise rectification circuit, half-bridge inversion circuit and protective circuit; half-bridge inversion circuit comprises several triodes, it is characterized in that: the thermistor NTC that inserts a negative temperature coefficient between the emitter of described triode and the base stage.

2. electric ballast as claimed in claim 1 is characterized in that: when the emitter of triode has resistance, described thermistor NTC can insert between transistor base and any end of resistance.

3. electric ballast as claimed in claim 1 is characterized in that: the negative temperature coefficient of described thermistor NTC is selected according to the adjusting ratio of output power of electronic ballast.

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