CN105188187A - Drive circuit of ultraviolet lamp - Google Patents

Abstract

The present invention provides a drive circuit of an ultraviolet lamp, relating to the field of the electronic technique. The drive circuit of the ultraviolet lamp is characterized in that: a LM117 is an adjustable voltage stabilizer which has three pins; a first pin is an input end, a second pin is a voltage adjustment end (an adjustment end for short), and a third pin is an output end; and the maximum output current of the LM117 is 1.5A, and the operating temperature range of the LM117 is from -55 DEG C to 150 DEG C. A depth negative voltage feedback is led into the LM117 circuit, R1 and R2 are external sampling resistors, and the adjustment end is connected with connections of the R1 and the R2. According to the invention, the circuit layout is reasonable, and the implementation effect is good.

Description

The drive circuit of uviol lamp

Technical field

The present invention relates to electronic technology field, be specifically related to a kind of drive circuit of uviol lamp.

Background technology

Ultraviolet light source is the core of ionization chamber, ultraviolet light source is exactly the energy source making tested gas ionization, the scope of the detectable substance of PID whole system is just direct to be decided by ultraviolet light source, in addition, the sensitivity of system detection results and accuracy are also closely bound up with ultraviolet light source, can say, the quality of ultraviolet light source performance plays conclusive effect to transducer overall performance index.

Summary of the invention

The object of this invention is to provide a kind of drive circuit of uviol lamp, its reasonable circuit layout, implementation result is good.

For solving background technology Problems existing, the present invention is by the following technical solutions: in the present invention, LM117 is adjustable pressurizer, LM117 has three pins, and wherein 1 pin is input, and 2 pin are Voltage Cortrol end (being called for short adjustment end), 3 pin are output, the maximum output current of LM117 is 1.5A, and operating temperature range is-55 DEG C ~ 150 DEG C, introduces the negative voltage feedback of the degree of depth at LM117 inside circuit, R1, R2 are external sampling resistor, and adjustment terminates on their tie point.

The present invention adopts and recommends self-oscillation mode, and utilize two transistors and output transformer to form self-maintained circuit, produce high-voltage AC signal, concrete steps are:

First, switch on power, starting current exports through pressurizer LM117, and output end voltage is about 1.25 × [1=(R ₂+ R _w)/R ₁] (V), first electric current is L charging when flowing through inductance L, after battery charger completes, L is to follow-up circuit discharging, mainly play the effect of buffering, resistance R6 and R7 is 2.3k, flow through R6, the electric current of R7 is respectively D4 and D3 provides base current, the armature winding NF of transformer T2 is as feedback winding, connect the base stage of two transistors, the armature winding NP of T1 is divided into NP1 and NP2, the electric current flowing through NP1 and NP2 is respectively D4 and D3 provides collector current, D4 and D3 to be all β (direct current multiplication factor) be 135 NPN transistor, and in actual applications, for two devices that nominal value is identical, its each term coefficient also can not be identical, little bit different will inevitably be there is, therefore, because the β (direct current multiplication factor) of two transistors there are differences, and R6, the actual resistance of R7 two resistance also can not be completely the same, so a transistor will be had lead over the first conducting of another in D3 and D4,

Suppose the first conducting of transistor D4, when D4 maintains conducting state, the magnetic flux density of transformer constantly rises, can magnetic saturation be caused within the regular hour, cause transformer magnetically saturated moment, having very large collector current and flow through transistor D4, relative to base current now, β value is large not, and the induced voltage therefore fed back on winding NF declines, and D4 will end immediately.Simultaneously, feedback winding NF forms opposite polarity inverse electromotive force, the base stage of D3 is made to be in forward bias, make its conducting, so the same with situation during D4 conducting, under the effect of reversed polarity magnetic flux, can again cause transformer magnetic saturation, D4 conducting D3 is ended, D4 and D3 alternate conduction, so move in circles, High Level AC Voltage can be formed, electric capacity C two ends are connected with the collector electrode of transistor D4 with D3 respectively, two transistor turns can be controlled by electric capacity C, the frequency of closing, and then control the frequency of the alternating voltage exported, wherein, each ratio of winding NP1:NP2:NF:NS=1:1:1:100 in transformer, like this, just can obtain peak-to-peak value by the power supply of storage battery supply 12V is 1500V, frequency is that the alternating current of 50kHz is to drive uviol lamp continuous illumination.

Accompanying drawing illustrates:

Fig. 1 is structural representation of the present invention.

Embodiment

With reference to Fig. 1, a drive circuit for uviol lamp, wherein LM117 is adjustable pressurizer, and LM117 has three pins, wherein 1 pin is input, 2 pin are Voltage Cortrol end (being called for short adjustment end), and 3 pin are output, and the maximum output current of LM117 is 1.5A, operating temperature range is-55 DEG C ~ 150 DEG C, introduce the negative voltage feedback of the degree of depth at LM117 inside circuit, R1, R2 are external sampling resistor, and adjustment terminates on their tie point.

The present invention adopts and recommends self-oscillation mode, and utilize two transistors and output transformer to form self-maintained circuit, produce high-voltage AC signal, concrete steps are:

First, switch on power, starting current exports through pressurizer LM117, and output end voltage is about 1.25 × [1=(R ₂+ R _w)/R ₁] (V), first electric current is L charging when flowing through inductance L, after battery charger completes, L is to follow-up circuit discharging, mainly play the effect of buffering, resistance R6 and R7 is 2.3k, flow through R6, the electric current of R7 is respectively D4 and D3 provides base current, the armature winding NF of transformer T2 is as feedback winding, connect the base stage of two transistors, the armature winding NP of T1 is divided into NP1 and NP2, the electric current flowing through NP1 and NP2 is respectively D4 and D3 provides collector current, D4 and D3 to be all β (direct current multiplication factor) be 135 NPN transistor, and in actual applications, for two devices that nominal value is identical, its each term coefficient also can not be identical, little bit different will inevitably be there is, therefore, because the β (direct current multiplication factor) of two transistors there are differences, and R6, the actual resistance of R7 two resistance also can not be completely the same, so a transistor will be had lead over the first conducting of another in D3 and D4,

Suppose the first conducting of transistor D4, when D4 maintains conducting state, the magnetic flux density of transformer constantly rises, can magnetic saturation be caused within the regular hour, cause transformer magnetically saturated moment, having very large collector current and flow through transistor D4, relative to base current now, β value is large not, and the induced voltage therefore fed back on winding NF declines, and D4 will end immediately.Simultaneously, feedback winding NF forms opposite polarity inverse electromotive force, the base stage of D3 is made to be in forward bias, make its conducting, so the same with situation during D4 conducting, under the effect of reversed polarity magnetic flux, can again cause transformer magnetic saturation, D4 conducting D3 is ended, D4 and D3 alternate conduction, so move in circles, High Level AC Voltage can be formed, electric capacity C two ends are connected with the collector electrode of transistor D4 with D3 respectively, two transistor turns can be controlled by electric capacity C, the frequency of closing, and then control the frequency of the alternating voltage exported, wherein, each ratio of winding NP1:NP2:NF:NS=1:1:1:100 in transformer, like this, just can obtain peak-to-peak value by the power supply of storage battery supply 12V is 1500V, frequency is that the alternating current of 50kHz is to drive uviol lamp continuous illumination.

Claims (2)

1. the drive circuit of uviol lamp, it is characterized in that LM117 is adjustable pressurizer, LM117 has three pins, and wherein 1 pin is input, and 2 pin are Voltage Cortrol end (being called for short adjustment end), 3 pin are output, the maximum output current of LM117 is 1.5A, and operating temperature range is-55 DEG C ~ 150 DEG C, introduces the negative voltage feedback of the degree of depth at LM117 inside circuit, R1, R2 are external sampling resistor, and adjustment terminates on their tie point.

2. the drive circuit of uviol lamp according to claim 1, is characterized in that self-oscillation mode is recommended in employing, and utilize two transistors and output transformer to form self-maintained circuit, produce high-voltage AC signal, concrete steps are:

First, switch on power, starting current exports through pressurizer LM117, and output end voltage is about 1.25 × [1=(R ₂+ R _w)/R ₁] (V), first electric current is L charging when flowing through inductance L, after battery charger completes, L is to follow-up circuit discharging, mainly play the effect of buffering, resistance R6 and R7 is 2.3k, flow through R6, the electric current of R7 is respectively D4 and D3 provides base current, the armature winding NF of transformer T2 is as feedback winding, connect the base stage of two transistors, the armature winding NP of T1 is divided into NP1 and NP2, the electric current flowing through NP1 and NP2 is respectively D4 and D3 provides collector current, D4 and D3 to be all β (direct current multiplication factor) be 135 NPN transistor, and in actual applications, for two devices that nominal value is identical, its each term coefficient also can not be identical, little bit different will inevitably be there is, therefore, because the β (direct current multiplication factor) of two transistors there are differences, and R6, the actual resistance of R7 two resistance also can not be completely the same, so a transistor will be had lead over the first conducting of another in D3 and D4,

Suppose the first conducting of transistor D4, when D4 maintains conducting state, the magnetic flux density of transformer constantly rises, can magnetic saturation be caused within the regular hour, cause transformer magnetically saturated moment, having very large collector current and flow through transistor D4, relative to base current now, β value is large not, and the induced voltage therefore fed back on winding NF declines, and D4 will end immediately, simultaneously, feedback winding NF forms opposite polarity inverse electromotive force, the base stage of D3 is made to be in forward bias, make its conducting, so the same with situation during D4 conducting, under the effect of reversed polarity magnetic flux, can again cause transformer magnetic saturation, D4 conducting D3 is ended, D4 and D3 alternate conduction, so move in circles, High Level AC Voltage can be formed, electric capacity C two ends are connected with the collector electrode of transistor D4 with D3 respectively, two transistor turns can be controlled by electric capacity C, the frequency of closing, and then control the frequency of the alternating voltage exported, wherein, each ratio of winding NP1:NP2:NF:NS=1:1:1:100 in transformer, like this, just can obtain peak-to-peak value by the power supply of storage battery supply 12V is 1500V, frequency is that the alternating current of 50kHz is to drive uviol lamp continuous illumination.