A kind of control circuit of Switching Power Supply
Technical field
The present invention relates to a kind of electronic circuit, is related specifically to a kind of high frequency switch power control circuit.
Background technology
Currently, plasma technology has been widely used, industrially applied to plasma ignition, plasma spraying, gold
Belong to smelting, heating plasma manufacture nano material, cutting, waste incineration and waste processing etc..In recent years, plasma is utilized
The technology of the dangerous harmful discarded object of processing and house refuse have developed rapidly, the processing mode of plasma and general burning side
Formula is made a world of difference, and plasma is a kind of state formed under ionosphere or electric discharge phenomena, will with electric discharge phenomena
Generate excited atom, excitation molecule, dissociation atom, free atomic group, atom or molecular ion group activity chemistry thing and
Reacted caused by they and other chemicals collisions.In plasma generator, discharge process causes work gas molecule
Lose outer-shell electron and form ionic condition, produce high temperature through mutually collision, the central temperature of plasma flare may be up to
More than 50,000 degree Celsius, torch lip temperature also can reach more than 3,000 degree, processed junk be subject to high temperature and pressure etc.
When gas ions are impacted, its molecule, atom will reconfigure and generate new material, so that harmful substance is changed into harmless object
Matter.Using plasma torch being sprayed into again in Domestic garbage gasification furnace or in coal gasifier after steam gasification agent heat resolve
Chemically reacted with coke, the reaction occurred is exothermic reaction, can be provided for gasification furnace needed for raw material stoving and pyrolysis
Heat so that gasification furnace is not required to input air or oxygen, the fraction scale of hydrogen is high in the synthesis gas of production, and exhaust gas contains
Measure it is low, can as production methanol unstripped gas utilize.Therefore, gasifying agent is done come gas with plasma torch heat resolve water vapour
Change coal or rubbish by as first choice from now on.
Plasma pyrolysis water hydrogen producing technology is one of water hydrogen manufacturing candidate technologies put forward recent years, because water is a kind of
The material of quite stable, in atmospheric conditions, temperature hydrone in 2000K hardly decompose, and there is 25% water hair in when 2500K
Solution estranged, the molar fraction of hydrogen and oxygen reaches maximum during 3400~3500K, is respectively 18% and 6%, when temperature reaches
During 4200K, hydrone will all be decomposed into hydrogen, hydrogen, oxygen, oxygen and hydrogen-oxygen atomic group, and general mode of heating is difficult to reach
So high temperature, and be then easily done using plasma torch.
Plasma torch for decomposing hydrone needs high voltage power supply to carry out striking, Chinese patent notification number
CN105072794A, which has been opened, discloses " a kind of drive control circuit of high-frequency arc strike power supply ", uses not circuit as master control member
Part, including vibration door, inverse gate, delay gate, the first out gate and the second out gate.In the circuit, inverse gate and the first output
The two level negative circuit that door is formed obtains the preceding half-cycle signal of cycle of oscillation, for driving upper power switch pipe;Second output
The level-one negative circuit that door is formed obtains the second half signal of cycle of oscillation, for driving lower power switch pipe.The circuit is
Avoid power switch pipe and lower power switch pipe common conduct and cause to damage, by dead zone function resistance and delay capacitor
The delay circuit of composition come set the first out gate output before half cycle switching signal duty cycle and the second out gate output after
The duty cycle of half cycle switching signal.The duty cycle of preceding half cycle switching signal and the duty of second half switching signal of the circuit
Time shares delay circuit and sets, and has the characteristics that simple in structure, but the circuit only has when the output that vibrate door
When end with the cathode of delay capacitor be at the same time high level, the output terminal ability output switching signal of the first out gate, only when
When the output terminal of vibration door and the cathode of delay capacitor are at the same time low level, the output terminal of the second out gate could export switch
Signal, due to being influenced by component parameters, charging interval and the discharge time of delay capacitor can be inconsistent, and therefore, which deposits
Positive half cycle pulse width and negative half period pulse width are inconsistent the shortcomings that, and there are positive and negative half-cycle signal conditions of streaking, make
It is big to obtain switching loss.
The content of the invention
The shortcomings that the purpose of the present invention is overcoming the prior art, there is provided a kind of control circuit of Switching Power Supply, not only makes height
Press striking power supply architecture simple and reliable operation, and make the switching signal characteristic of control circuit output good, reduce switching loss,
Make the more efficient of Switching Power Supply.
The control circuit of a kind of Switching Power Supply of the present invention, mainly by not circuit, resistance, capacitor and diode group
Include vibration door, inverse gate, delay gate and out gate into, not circuit, oscillation resistance be connected to the input terminal of vibration door with it is defeated
Between outlet, there is oscillating capacitor between the input terminal and ground wire of vibration door, it is characterized in that vibration door(IC1)Output terminal connect
It is connected to inverse gate(IC2)Input terminal, the first discharge resistance(R2)First end and the first dead zone function resistance(R3)First
End, the first discharge resistance(R2)Second end be connected to the first discharge diode(VD1)Cathode, the first dead zone function resistance
(R3)Second end be connected to the first delay capacitor(C2)First end, the first discharge diode(VD1)Anode and first
Delay gate(IC3)Input terminal, the first delay capacitor(C2)Second end be connected to ground wire, the first delay gate(IC3)It is defeated
Outlet is connected to the first out gate(IC4)Input terminal, the first out gate(IC4)Output terminal pass through the first output resistance(R8)
It is connected to positive half cycle signal output part(1);Inverse gate(IC2)Output terminal be connected to the second discharge resistance(R4)First end and
Second dead zone function resistance(R5)First end, the second discharge resistance(R4)Second end be connected to the second discharge diode
(VD2)Cathode, the second discharge diode(VD2)Anode be connected to the second dead zone function resistance(R5)Second end, second
Delay capacitor(C3)First end and the second delay gate(IC5)Input terminal, the second delay capacitor(C3)Second end connect
It is connected to ground wire, the second delay gate(IC5)Output terminal be connected to the second out gate(IC6)Input terminal, the second out gate(IC6)
Output terminal pass through the second output resistance(R9)It is connected to negative half-cycle signal output terminal(3).
There is the first potentiometer in the present invention, in control circuit(RP1)With the second potentiometer(RP2), the first potentiometer(RP1)
With the second potentiometer(RP2)Coaxially to synchronize the duplex potentiometer of adjusting;When there is the first potentiometer in control circuit
(RP1)With the second potentiometer(RP2)When, the first potentiometer(RP1)It is connected to the first dead zone function resistance(R3)Second end with
First delay capacitor(C2)First end between, the second potentiometer(RP2)It is connected to the second dead zone function resistance(R5)
Two ends and the second delay capacitor(C3)First end between;There is overload signal feedback end in control circuit(2)Protected with overload
Protection circuit, overload protecting circuit is by voltage comparator(IC7), level pressure resistance(R10), zener diode(VD5), anti-interference capacitor
Device(C4), the first isolating diode(VD3)With the second isolating diode(VD4)Composition, voltage comparator(IC7)Homophase input
End is connected to overload signal feedback end(2), voltage comparator(IC7)Inverting input pass through level pressure resistance(R10)It is connected to
The cathode of working power, zener diode(VD5)And anti-interference condenser(C4)Voltage comparator is connected to parallel way
(IC7)Inverting input and ground wire between, voltage comparator(IC7)Output terminal be connected to the first isolating diode(VD3)
Anode and the second isolating diode(VD4)Anode;When there is overload protecting circuit in control circuit, in the first delay gate
(IC3)Output terminal and the first out gate(IC4)There is the first isolation resistance between input terminal(R6), the first isolating diode(VD3)
Cathode be connected to the first isolation resistance(R6)With the first out gate(IC4)On circuit between input terminal, the second delay gate
(IC5)Output terminal and the second out gate(IC6)There is the second isolation resistance between input terminal(R7), the second isolating diode(VD4)
Cathode be connected to the second isolation resistance(R7)With the second out gate(IC6)On circuit between input terminal.
The present invention applies in the high-voltage switch power supply for plasma torch striking, the work frequency of high-voltage switch power supply
Rate is 10-100KHz.High-voltage switch power supply is mainly made of working power, control circuit, drive circuit and power boost circuit,
Wherein, power boost circuit is made of power switch pipe and step-up transformer, and power switch pipe includes upper power switch pipe with
Power switch pipe, step-up transformer include primary low-voltage coil and secondary high pressure coil.During work, control circuit is by driving electricity
Road makes power switch pipe and lower power switch pipe alternate conduction so that flows through alternation in the primary low-voltage coil of step-up transformer
Electric current, secondary high pressure coil just senses the high voltage for producing tens thousand of to hundreds thousand of volts, for plasma torch striking.
In the present invention, the frequency of oscillation that vibration door IC1 is produced is determined by the value of oscillation resistance R1 and oscillating capacitor C1, i.e.,
F=1/1.4RC, the output of vibration door IC1 is the alternate rectangular wave pulse of high and low level.When vibration door IC1 outputs are high level
During rectangular wave pulse, vibration door IC1 output for positive half cycle high level signal, positive half cycle high level signal is through the first dead zone function
Resistance(R3)With the first delay capacitor(C2)The first delay gate is input to after delay(IC3)Input terminal, then again through first
Delay gate(IC3), the first out gate(IC4)By the first output resistance after two level is anti-phase(R8)Export the high level signal of positive half cycle
To late-class circuit, power switch pipe conducting in driving;When it is low level rectangular wave pulse to vibrate door IC1 outputs, the first output
Door(IC4)Output terminal be reversed to low level, upper power switch pipe cut-off, meanwhile, the IC1 outputs of vibration door for the low electricity of negative half period
The inverted door of ordinary mail number(IC2)After anti-phase, become negative half period high level signal, negative half period high level signal is through the second dead zone function
Resistance(R5)With the second delay capacitor(C3)The second delay gate is input to after delay(IC5)Input terminal, then again through second
Delay gate(IC5), the second out gate(IC6)By the second output resistance after two level is anti-phase(R9)Export the high level signal of negative half period
To late-class circuit, lower power switch pipe conducting is driven;When being reversed to high level rectangular wave pulse when vibrating door IC1 outputs, the
Two out gates(IC6)Output terminal be reversed to low level, lower power switch pipe cut-off, meanwhile, the positive half cycle of vibration door IC1 outputs
High level signal is again through the first dead zone function resistance(R3)With the first delay capacitor(C2)The first delay gate is input to after delay
(IC3)Input terminal, so in cycles, make power switch pipe and lower power switch pipe alternate conduction or cut-off.The present invention
Positive half cycle high level signal and negative half period high level signal postponed respectively by each independent element, easily reach just half
All pulse widths are consistent with negative half period pulse width;When positive half cycle signal terminates, door is vibrated(IC1)Output terminal it is anti-by high level
When switching to low level, the first delay capacitor(C2)Pass through the first discharge diode(VD1)With the first discharge resistance(R2)Carry out
Repid discharge, eliminates the conditions of streaking during reversion of positive half cycle signal, the switching loss of power switch pipe in reduction;Work as negative half period
Signal terminates, and vibrates door(IC1)Output terminal when being reversed to high level by low level, inverse gate(IC2)Output terminal be reversed to
Low level, the second delay capacitor(C3)Pass through the second discharge diode(VD2)With the second discharge resistance(R4)Quickly put
Electricity, eliminates conditions of streaking during negative half-cycle signal reversion, reduces the switching loss of lower power switch pipe.
Cause to damage in order to avoid upper power switch pipe and lower power switch pipe common conduct, the present invention is respectively just half
The first dead zone function resistance is set on the signal path in week(R3)With the first delay capacitor(C2), in the signal path of negative half period
The second dead zone function resistance of upper setting(R5)With the second delay capacitor(C3), positive half cycle signal and negative half-cycle signal is had extremely
Area's control time, the dead zone function time be output switching signal duty cycle, slightly larger than power switch pipe storage when
Between.The dead zone function time of positive half cycle is by the first dead zone function resistance(R3)With the first delay capacitor(C2)Value determine, when
When the rectangular wave pulse for vibrating door IC1 output terminals is in high level, high level passes through the first dead zone function resistance(R3)Prolong to first
Slow capacitor(C2)Charge, in the first delay capacitor(C2)Charging voltage when being less than 2/3 operating voltage, the first delay
Door(IC3)Output terminal be high level, the first out gate(IC4)Output terminal lock in low level, make power switch pipe
Cut-off, until the first delay capacitor(C2)Charging voltage when reaching 2/3 operating voltage, the first delay gate(IC3)Output
End is reversed to low level, makes the first out gate(IC4)Output switching signal, upper power switch pipe conducting, at this moment, upper power switch
The ON time of pipe has obtained delay, its delay time is the positive half cycle dead time of cycle of oscillation;Similarly, negative half period is dead
Area's control time is by the second dead zone function resistance(R5)With the second delay capacitor(C3)Value determine, the second dead zone function resistance
(R5)With the second delay capacitor(C3)Operation principle and the first dead zone function resistance(R3)With the first delay capacitor(C2)
Operation principle it is identical, repeat no more.In the present invention, the dead zone function element of positive half cycle and the dead zone function element of negative half period are
Each independent, therefore, dead zone function is more reliable, can more effectively avoid power switch pipe and lower power switch pipe common-mode from leading
It is logical.
In the present invention, the first potentiometer(RP1)With the second potentiometer(RP2)It is connected as the mode of variable resistor, the first electricity
Position device(RP1)For adjusting the first delay capacitor(C2)Charging interval, adjusted on the basis of with the dead zone function time
The pulse width of positive half cycle signal, the ON time of upper power switch pipe, the second potentiometer are adjusted with this(RP2)For adjusting
Two delay capacitors(C3)Charging interval, on the basis of with the dead zone function time adjust negative half-cycle signal pulse it is wide
Degree, the ON time of lower power switch pipe is adjusted with this, when the conducting of power switch pipe and lower power switch pipe is gone up by adjusting
Between, so as to adjust the magnetic energy of step-up transformer, make the voltage amplitude of step-up transformer secondary high pressure coil regulated, to adapt to
The needs of plasma torch striking.
Damaged in order to avoid power switch pipe overloads, when the electric current for flowing through power switch pipe reaches setting value, power is opened
Close level circuit and feedback signal is input to by voltage comparator by sample resistance(IC7)In-phase input end, when feedback signal
Voltage amplitude exceedes voltage comparator(IC7)During the magnitude of voltage of inverting input setting, voltage comparator(IC7)Output terminal it is anti-
Switch to high level, high level passes through the first isolating diode respectively(VD3)With the second isolating diode(VD4)It is defeated to be input to first
Go out(IC4)Input terminal and the second out gate(IC6)Input terminal, make the first out gate(IC4)Output terminal and second defeated
Go out(IC6)Output terminal be low level, end power switch pipe and lower power switch pipe, realize by all overcurrent protections.
By varying zener diode(VD5)Voltage stabilizing value set the scope of overload protection.
Used in the present invention, in circuit structure using not circuit as master element, not circuit is digitized integrated electricity
Road, is very suitable for the formation and control of rectangular wave pulse, its switching signal produced is used for driving power switching tube also very
Match somebody with somebody, cmos digital integrated circuit or a kind of micro energy lose element, have that supply voltage working range is wide, strong antijamming capability, defeated
Enter the characteristics of impedance is high, circuit interface is simple, reliable operation and service life are long.First out gate(IC4)With the second out gate
(IC6)It is preferred that the Schmidt trigger not circuit with shaping feature, when it is implemented, vibration door(IC1), inverse gate
(IC2), the first delay gate(IC3), the first out gate(IC4), the second delay gate(IC5), the second out gate(IC6)Share one
There are the digital integrated electronic circuit of the CMOS hex inverters of the model CC40106 of Schmidt trigger, the power supply of digital integrated electronic circuit
End is connected to the cathode of working power, and the ground terminal of digital integrated electronic circuit is connected to ground wire.
The beneficial effects of the invention are as follows:A kind of control circuit of the Switching Power Supply provided, the dead zone function element of positive half cycle
Dead zone function element with negative half period is respective independence, and the pulse-width regulated element of positive and negative half cycle is each independently and simultaneously adjusted, no
Only make high-voltage arc strike power supply architecture simple and reliable operation, and make the switching signal characteristic of control circuit output good, eliminate
Conditions of streaking during positive and negative half-cycle signal reversion, reduces the switching loss of power switch pipe, makes the more efficient of Switching Power Supply.
Brief description of the drawings
Attached drawing 1 is a kind of electric operation control circuit figure of Switching Power Supply of the present invention.
In figure:R1. oscillation resistance, the first discharge resistances of R2., R3. the first dead zone function resistance, the second discharge resistances of R4.,
R5. the second dead zone function resistance, the first isolation resistances of R6., the second isolation resistances of R7., the first output resistances of R8., R9. second are defeated
Go out resistance, R10. level pressure resistance, the first potentiometers of RP1., the second potentiometers of RP2., C1. oscillating capacitors, the first deferred telegrams of C2.
Container, the second delay capacitors of C3., C4. anti-interference condensers, the first discharge diodes of VD1., the second discharge diodes of VD2.,
VD3. the first isolating diode, the second isolating diodes of VD4., VD5. zener diodes, IC1. vibration doors, IC2. inverse gates,
IC3. the first delay gate, the first out gates of IC4., the second delay gates of IC5., the second out gates of IC6., IC7. voltage comparators, V
The cathode of+working powers, 1. positive half cycle signal output parts, 2. overload signal feedback ends, 3. negative half-cycle signal output terminals.
Embodiment
In embodiment shown in 1 attached drawing 1 of embodiment, a kind of control circuit of Switching Power Supply is mainly by not circuit, electricity
Resistance, capacitor and diode composition, not circuit include vibration door(IC1), inverse gate(IC2), the first delay gate(IC3),
One out gate(IC4), the second delay gate(IC5)With the second out gate(IC6), oscillation resistance(R1)It is connected to vibration door(IC1)
Input terminal and output terminal between, vibration door(IC1)Input terminal and ground wire between have oscillating capacitor(C1), vibrate door
(IC1)Output terminal be connected to inverse gate(IC2)Input terminal, the first discharge resistance(R2)First end and the first dead zone function
Resistance(R3)First end, the first discharge resistance(R2)Second end be connected to the first discharge diode(VD1)Cathode, first
Dead zone function resistance(R3)Second end be connected to the first delay capacitor(C2)First end, the first discharge diode(VD1)
Anode and the first delay gate(IC3)Input terminal, the first delay capacitor(C2)Second end be connected to ground wire, the first delay
Door(IC3)Output terminal be connected to the first out gate(IC4)Input terminal, the first out gate(IC4)Output terminal pass through first
Output resistance(R8)It is connected to positive half cycle signal output part(1);Inverse gate(IC2)Output terminal be connected to the second discharge resistance
(R4)First end and the second dead zone function resistance(R5)First end, the second discharge resistance(R4)Second end be connected to second
Discharge diode(VD2)Cathode, the second discharge diode(VD2)Anode be connected to the second dead zone function resistance(R5)
Two ends, the second delay capacitor(C3)First end and the second delay gate(IC5)Input terminal, the second delay capacitor(C3)'s
Second end is connected to ground wire, the second delay gate(IC5)Output terminal be connected to the second out gate(IC6)Input terminal, second is defeated
Go out(IC6)Output terminal pass through the second output resistance(R9)It is connected to negative half-cycle signal output terminal(3).The control of the present embodiment
First potentiometer can be set in circuit(RP1)With the second potentiometer(RP2), the first potentiometer(RP1)With the second potentiometer(RP2)
Coaxially to synchronize the duplex potentiometer of adjusting;When there is the first potentiometer in control circuit(RP1)With the second potentiometer
(RP2)When, the first potentiometer(RP1)It is connected to the first dead zone function resistance(R3)Second end and the first delay capacitor(C2)
First end between, the second potentiometer(RP2)It is connected to the second dead zone function resistance(R5)Second end and the second delay electric capacity
Device(C3)First end between.Overload protecting circuit can be set in the control circuit of the present embodiment, and overload protecting circuit is by voltage
Comparator(IC7), level pressure resistance(R10), zener diode(VD5), anti-interference condenser(C4), the first isolating diode
(VD3)With the second isolating diode(VD4)Composition, voltage comparator(IC7)In-phase input end be connected to overload signal feedback
End(2), voltage comparator(IC7)Inverting input pass through level pressure resistance(R10)It is connected to the cathode of working power, voltage stabilizing two
Pole pipe(VD5)And anti-interference condenser(C4)Voltage comparator is connected to parallel way(IC7)Inverting input and ground wire
Between, voltage comparator(IC7)Output terminal be connected to the first isolating diode(VD3)Anode and the second isolating diode
(VD4)Anode;When there is overload protecting circuit in control circuit, in the first delay gate(IC3)Output terminal and the first out gate
(IC4)There is the first isolation resistance between input terminal(R6), the first isolating diode(VD3)Cathode be connected to the first isolation resistance
(R6)With the first out gate(IC4)On circuit between input terminal, the second delay gate(IC5)Output terminal and the second out gate
(IC6)There is the second isolation resistance between input terminal(R7), the second isolating diode(VD4)Cathode be connected to the second isolation resistance
(R7)With the second out gate(IC6)On circuit between input terminal.
The present embodiment is applied in the high-voltage switch power supply for plasma torch striking, the work of high-voltage switch power supply
Frequency is 10-100KHz, when oscillation resistance R1 values are 5K Ω, oscillating capacitor C1 values are 0.0033uF, vibrates door IC1
Output frequency is the rectangular wave pulse of 43KHz.High-voltage switch power supply is mainly by working power, control circuit, drive circuit and work(
Rate booster circuit forms, wherein, power boost circuit is made of power switch pipe and step-up transformer, and power switch pipe includes upper
Power switch pipe and lower power switch pipe, step-up transformer include primary low-voltage coil and secondary high pressure coil.During work, control
Circuit makes upper power switch pipe and lower power switch pipe alternate conduction by drive circuit so that the primary low pressure of step-up transformer
Coil midstream crosses alternating current, and secondary high pressure coil just senses the high voltage for producing tens thousand of to hundreds thousand of volts, for plasma
Spray gun striking.During the circuit work of the present embodiment, the output of vibration door IC1 is the alternate rectangular wave pulse of high and low level, when shaking
When to swing IC1 output be high level rectangular wave pulse, the IC1 outputs of vibration door for positive half cycle high level signal, positive half cycle it is high electric
Ordinary mail number is through the first dead zone function resistance(R3)With the first delay capacitor(C2)The first delay gate is input to after delay(IC3)'s
Input terminal, then again through the first delay gate(IC3), the first out gate(IC4)By the first output resistance after two level is anti-phase(R8)It is defeated
Go out the high level signal of positive half cycle to late-class circuit, power switch pipe conducting in driving;When vibration door IC1 outputs are low level square
During shape impulse wave, the first out gate(IC4)Output terminal be reversed to low level, upper power switch pipe cut-off, meanwhile, vibrate door
IC1 outputs for the inverted door of negative half period low level signal(IC2)After anti-phase, become negative half period high level signal, negative half period is high
Level signal is through the second dead zone function resistance(R5)With the second delay capacitor(C3)The second delay gate is input to after delay(IC5)
Input terminal, then again through the second delay gate(IC5), the second out gate(IC6)By the second output resistance after two level is anti-phase(R9)
The high level signal of negative half period is exported to late-class circuit, drives lower power switch pipe conducting;When again vibration door IC1 outputs are reversed to
During high level rectangular wave pulse, the second out gate(IC6)Output terminal be reversed to low level, lower power switch pipe cut-off, meanwhile,
The positive half cycle high level signal of door IC1 outputs is vibrated again through the first dead zone function resistance(R3)With the first delay capacitor(C2)Prolong
Lag and be input to the first delay gate(IC3)Input terminal, so in cycles, hand over power switch pipe and lower power switch pipe
For on or off.The positive half cycle high level signal and negative half period high level signal of the present embodiment are respectively by each independent element
Postponed, it is consistent with negative half period pulse width easily to reach positive half cycle pulse width;When positive half cycle signal terminates, door is vibrated
(IC1)Output terminal when being reversed to low level by high level, the first delay capacitor(C2)Pass through the first discharge diode(VD1)
With the first discharge resistance(R2)Carry out repid discharge;When negative half-cycle signal terminates, door is vibrated(IC1)Output terminal it is anti-by low level
When switching to high level, inverse gate(IC2)Output terminal be reversed to low level, the second delay capacitor(C3)Pass through the second electric discharge two
Pole pipe(VD2)With the second discharge resistance(R4)Carry out repid discharge.In the present embodiment, the dead zone function element of positive half cycle and negative half
The dead zone function element in week is each independent, and dead zone function is more reliable, can more effectively avoid power switch pipe and lower power from opening
Close pipe common conduct.
In the above embodiments, the first potentiometer(RP1)With the second potentiometer(RP2)The mode of variable resistor is connected as,
First potentiometer(RP1)With the second potentiometer(RP2)It is respectively intended to adjust the pulse width of positive and negative half-cycle signal, is adjusted with this
The ON time of upper power switch pipe and lower power switch pipe, so as to adjust the magnetic energy of step-up transformer, makes step-up transformer
The voltage amplitude of level high-tension coil is regulated, to adapt to the needs of plasma torch striking;When flowing through power switch pipe
When electric current reaches the protection value of setting, feedback signal is input to voltage comparator by power switch level circuit by sample resistance
(IC7)In-phase input end, when the voltage amplitude of feedback signal exceedes voltage comparator(IC7)The voltage of inverting input setting
During value, voltage comparator(IC7)Output terminal be reversed to high level, high level passes through the first isolating diode respectively(VD3)With
Second isolating diode(VD4)It is input to the first out gate(IC4)Input terminal and the second out gate(IC6)Input terminal, make
First out gate(IC4)Output terminal and the second out gate(IC6)Output terminal be low level, make power switch pipe and lower work(
Rate switching tube ends, and realizes by all overcurrent protections.By varying zener diode(VD5)Voltage stabilizing value set overload protection
Scope.
In above-described embodiment, door is vibrated(IC1), inverse gate(IC2), the first delay gate(IC3), the first out gate(IC4)、
Second delay gate(IC5), the second out gate(IC6)Share an only CMOS six of the model CC40106 of Schmidt trigger
The digital integrated electronic circuit of phase inverter, the power end of digital integrated electronic circuit are connected to the cathode of working power, digital integrated electronic circuit
Ground terminal is connected to ground wire.