CN205721469U - A kind of PWM constant current output circuit - Google Patents
A kind of PWM constant current output circuit Download PDFInfo
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- CN205721469U CN205721469U CN201620631612.5U CN201620631612U CN205721469U CN 205721469 U CN205721469 U CN 205721469U CN 201620631612 U CN201620631612 U CN 201620631612U CN 205721469 U CN205721469 U CN 205721469U
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Abstract
The utility model discloses a kind of PWM constant current output circuit, belong to pwm signal processing technology field.This utility model includes the first resistance to the 17th resistance, the first electric capacity to the 4th electric capacity, the first audion, and the first metal-oxide-semiconductor, the first operational amplifier is to the 5th operational amplifier, signal input part, signal output part.This utility model has good stability, fast response time, advantage that control accuracy is high.
Description
Technical field
This utility model belongs to pwm signal processing technology field, relates to a kind of PWM constant current output circuit.
Background technology
PWM constant current output refers to that pulse width modulation, pulse width modulation are to utilize the numeral output after micro-process
Control analog circuit etc., and pulse width modulation is widely used in from the many fields measuring, communicating power control and conversion
In.Pulse width modulation is a kind of analog control mode, and it is the change of resistance of resistance according to the change of respective loads, comes
Modulation transistor base stage or the biasing of metal-oxide-semiconductor grid, realize transistor or the change of metal-oxide-semiconductor ON time, thus change defeated
Enter the effective frequency range controlling voltage in circuit.This mode can make the output voltage of power supply keep permanent when operation conditions change
Fixed, and the load change in circuit often cannot be made and adjusting timely by existing pwm control circuit in time, thus PWM control
The stability of circuit processed is not enough.
Summary of the invention
The purpose of this utility model is to there are the problems referred to above for existing technology, it is proposed that a kind of good stability, response
The PWM constant current output circuit that speed is fast, control accuracy is high.
The purpose of the present invention can be realized by following technical proposal: a kind of PWM constant current output circuit, described PWM constant current
Output circuit includes the first resistance to the 17th resistance, the first electric capacity to the 4th electric capacity, the first audion, the first metal-oxide-semiconductor, first
Operational amplifier is to the 5th operational amplifier, signal input part, signal output part；Described signal input part connects after the first resistance
The normal phase input end of the first operational amplifier, the outfan of described first operational amplifier is successively through the 3rd resistance, the second resistance
The normal phase input end of rear company the first operational amplifier, the outfan of described first operational amplifier also connects first after the 5th resistance
The inverting input of operational amplifier, the inverting input of described first operational amplifier ground connection after the 4th resistance, described
The positive power source terminal ground connection of one operational amplifier, the negative supply termination 1.5V negative pole input voltage of the first operational amplifier, and negative electricity
Source is ground connection after the first electric capacity；The outfan of described first operational amplifier also connects the positive input of the second operational amplifier
End, the outfan of described second operational amplifier connects the inverting input of the second operational amplifier after the second electric capacity, and described the
The inverting input of two operational amplifiers ground connection after the 6th resistance, the 7th resistance successively, described second operational amplifier defeated
Going out end and connect the normal phase input end of the 5th operational amplifier after the 8th resistance, the outfan of described 5th operational amplifier is through first
The base stage of audion, the emitter stage of described first audion connects signal output part successively after the anode, negative electrode of the first diode,
The colelctor electrode of described first audion connects the grid of the first metal-oxide-semiconductor, the grid warp of described first metal-oxide-semiconductor after the 16th resistance
Connecting the source electrode of the first metal-oxide-semiconductor after 17th resistance, the source electrode of described first metal-oxide-semiconductor connects 2.4V positive pole input voltage, and described first
The drain electrode of metal-oxide-semiconductor connects signal output part.
According to above-mentioned a kind of PWM constant current output circuit, the inverting input of described 5th operational amplifier is through warp successively
Connecting the outfan of four-operational amplifier after 9th resistance, the 13rd resistance, the outfan of described four-operational amplifier is through
Connecting the inverting input of four-operational amplifier after three electric capacity, the inverting input of described four-operational amplifier is through the 11st electricity
Connecting the outfan of the 3rd operational amplifier after resistance, the normal phase input end of described four-operational amplifier connects the 3rd operational amplifier
Inverting input, the positive that the outfan of described four-operational amplifier also connects the 3rd operational amplifier after the 12nd resistance is defeated
Entering end, the outfan of described 3rd operational amplifier U3 connects the normal phase input end of the 3rd operational amplifier after the tenth resistance.
According to above-mentioned a kind of PWM constant current output circuit, described 5th resistance is variable resistance, the resistance of the 5th resistance with
Load in circuit changes and changes.
Compared with prior art, being provided with in PWM constant current output circuit circuit disclosed in the utility model can be with temperature
The variable resistance of change resistance improves the response efficiency of circuit, and variable resistance automatically adjusts resistance thus changes output simultaneously
The size of electric current improves the stability of signal transmission, and circuit disclosed in the utility model uses the defeated of voltage switching current
Go out mode, reduce the interference to signal of the external factor, improve the accuracy of signal transmission.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of PWM constant current output circuit.
Detailed description of the invention
The following is the specific embodiment of the present invention and combine accompanying drawing, technical scheme is further described,
But the present invention is not limited to these embodiments.
As it is shown in figure 1, a kind of PWM constant current output circuit, described PWM constant current output circuit includes the first resistance R1 to the tenth
Seven resistance R17, the first electric capacity C1 to the 4th electric capacity C4, the first audion Q1, the first metal-oxide-semiconductor T2, the first operational amplifier U1 is extremely
5th operational amplifier U5, signal input part Vin, signal output part Vout；Described signal input part Vin is after the first resistance R1
The even normal phase input end of the first operational amplifier U1, the outfan of described first operational amplifier U1 successively through the 3rd resistance R3,
Connecting the normal phase input end of the first operational amplifier U1 after second resistance R2, the outfan of described first operational amplifier U1 is also through
Connecting the inverting input of the first operational amplifier U1 after five resistance, the inverting input of described first operational amplifier U1 is through the 4th
Ground connection after resistance R4, the positive power source terminal ground connection of described first operational amplifier U1, the negative supply termination of the first operational amplifier U1
1.5V negative pole input voltage, and negative power end ground connection after the first electric capacity C1；The outfan of described first operational amplifier U1 is also
The even normal phase input end of the second operational amplifier U2, the outfan of described second operational amplifier U2 connects the after the second electric capacity C2
The inverting input of two operational amplifier U2, the inverting input of described second operational amplifier U2 successively through the 6th resistance R6,
Ground connection after 7th resistance R7, the outfan of described second operational amplifier U2 connects the 5th operational amplifier U5 after the 8th resistance R8
Normal phase input end, the outfan of described 5th operational amplifier U5 is through the base stage of the first audion Q1, described first audion
The emitter stage of Q1 connects signal output part Vout successively after the anode, negative electrode of the first diode D1, described first audion Q1's
Colelctor electrode connects the grid of the first metal-oxide-semiconductor T1 after the 16th resistance R16, and the grid of described first metal-oxide-semiconductor T1 is through the 17th resistance
Connecting the source electrode of the first metal-oxide-semiconductor T1 after R17, the source electrode of described first metal-oxide-semiconductor connects 2.4V positive pole input voltage, described first metal-oxide-semiconductor
Drain electrode connect signal output part Vout.
According to above-mentioned a kind of PWM constant current output circuit, the inverting input of described 5th operational amplifier U5 is through successively
The outfan of four-operational amplifier U4 is connected after the 9th resistance R9, the 13rd resistance R13, described four-operational amplifier U4's
Outfan connects the inverting input of four-operational amplifier U4 after the 3rd electric capacity C3, and described four-operational amplifier U4's is anti-phase
Input connects the outfan of the 3rd operational amplifier U3, the positive of described four-operational amplifier U4 after the 11st resistance R11
Input connects the inverting input of the 3rd operational amplifier U3, and the outfan of described four-operational amplifier U4 is also through the 12nd electricity
Connecting the normal phase input end of the 3rd operational amplifier U3 after resistance R12, the outfan of described 3rd operational amplifier U3 is through the tenth resistance
The normal phase input end of the 3rd operational amplifier U3 is connected after R10.
According to above-mentioned a kind of PWM constant current output circuit, described 5th resistance R5 is variable resistance, the resistance of the 5th resistance R5
Value can change with the change of the load in circuit.
Voltage signal in PWM constant current output circuit is through signal input part Vin input circuit, described first operational amplifier
U1 act as non-inverting amplifier, signal input part Vin the voltage signal inputted is defeated after the first operational amplifier U1 amplifies
Go out to the normal phase input end of the second operational amplifier U2.Wherein the amplification of the first operational amplifier U1 by the 5th resistance R5 with
And the 4th resistance R4 resistance size determine.Described 5th resistance R5 is variable resistance, and the resistance of the 5th resistance R5 is with in circuit
Load change and change, such as when during variations in temperature causes circuit load change time, the 5th resistance R5 then can adjust automatically
The multiple making voltage signal amplify after and is adjusted, thus the change adjusting voltage signal adjusts final when defeated in circuit
The pulsewidth of the current signal gone out.Assume that the voltage swing of voltage signal through signal input part Vin input is Va, it is assumed that through the
Voltage after one operational amplifier U1 amplifies is Vb, assumes that the resistance of the 4th resistance R4 is Ra, the resistance of the 5th resistance R5 simultaneously
For Rb, formula can be obtained:
Voltage signal after the first operational amplifier U1 amplifies is electric through the 8th again after the second operational amplifier U2 filtering
Export to the interference acting as eliminating alternating impulse of the 5th operational amplifier U5, described second operational amplifier U2 after resistance R8,
When the part interference signal that voltage signal produces after non-inverting amplifier amplifies, then use the second operational amplifier U2 to dry
Disturb signal to filter.
Four-operational amplifier U4 in PWM constant current output circuit and the circuit of the 3rd operational amplifier U3 connected component with
5th operational amplifier U5 is connected, and wherein the outfan of four-operational amplifier U4 is after the 13rd resistance R13, the 9th resistance R9
The even inverting input of the 9th operational amplifier U5, the effect of this partial circuit is when using multiple operational amplifier in circuit
Time, the pin of operational amplifier therein all can not leave unused, and otherwise the outfan of the operational amplifier in circuit is likely to occur short
The situation on road, simultaneously in order to prevent the heating of each operational amplifier excessively serious, the 5th operational amplifier U5 not directly ground connection, because of
The circuit of this four-operational amplifier U4 and the 3rd operational amplifier U3 connected component is for improving the stability of circuit.
Voltage signal, after the 5th operational amplifier U5, exports to the base stage of the first audion Q1, and voltage signal is through first
After the process of audion Q1, by the emitter stage output current signal of the first audion Q1, this signal is again after the first diode D1
Exported by signal output part Vout, automatically adjust the pulsewidth of output through the current signal of signal output part Vout output through circuit
After, control more stable, the most accurate.
The grid of the first metal-oxide-semiconductor T1 in PWM constant current output circuit connects the collection of the first audion Q1 after the 16th resistance
Electrode, and the drain electrode of the first metal-oxide-semiconductor connects signal output part Vout, the acting as of the first metal-oxide-semiconductor keeps the first audion Q1 and letter
Voltage difference between number output end vo ut, is also used for protecting the first audion Q1 simultaneously, prevents voltage breakdown excessive in circuit
First audion Q1, improves the stability of circuit.
Specific embodiment described herein is only to present invention spirit explanation for example.Technology neck belonging to the present invention
Described specific embodiment can be made various amendment or supplements or use similar mode to replace by the technical staff in territory
Generation, but without departing from the spirit of the present invention or surmount scope defined in appended claims.
Claims (3)
1. a PWM constant current output circuit, it is characterised in that described PWM constant current output circuit includes that the first resistance is to the 17th
Resistance, the first electric capacity to the 4th electric capacity, the first audion, the first metal-oxide-semiconductor, the first operational amplifier to the 5th operational amplifier,
Signal input part, signal output part；Described signal input part connects the normal phase input end of the first operational amplifier after the first resistance,
The outfan of described first operational amplifier connects the positive input of the first operational amplifier successively after the 3rd resistance, the second resistance
End, the outfan of described first operational amplifier also connects the inverting input of the first operational amplifier after the 5th resistance, described
The inverting input of the first operational amplifier is ground connection after the 4th resistance, the positive power source terminal ground connection of described first operational amplifier,
The negative supply termination 1.5V negative pole input voltage of the first operational amplifier, and negative power end ground connection after the first electric capacity；Described
The outfan of one operational amplifier also connects the normal phase input end of the second operational amplifier, the outfan of described second operational amplifier
The inverting input of the second operational amplifier is connected, the inverting input warp successively of described second operational amplifier after the second electric capacity
Ground connection after 6th resistance, the 7th resistance, the outfan of described second operational amplifier connects the 5th operation amplifier after the 8th resistance
The normal phase input end of device, the outfan of described 5th operational amplifier through the base stage of the first audion, described first audion
Emitter stage connects signal output part successively after the anode, negative electrode of the first diode, and the colelctor electrode of described first audion is through the tenth
Connecting the grid of the first metal-oxide-semiconductor after six resistance, the grid of described first metal-oxide-semiconductor connects the source electrode of the first metal-oxide-semiconductor after the 17th resistance,
The source electrode of described first metal-oxide-semiconductor connects 2.4V positive pole input voltage, and the drain electrode of described first metal-oxide-semiconductor connects signal output part.
A kind of PWM constant current output circuit the most according to claim 1, it is characterised in that described 5th operational amplifier
Inverting input through connecting the outfan of four-operational amplifier successively after the 9th resistance, the 13rd resistance, described 4th computing
The outfan of amplifier connects the inverting input of four-operational amplifier after the 3rd electric capacity, described four-operational amplifier anti-
Phase input connects the outfan of the 3rd operational amplifier, the normal phase input end of described four-operational amplifier after the 11st resistance
The even inverting input of the 3rd operational amplifier, the outfan of described four-operational amplifier also connects the 3rd after the 12nd resistance
The normal phase input end of operational amplifier, the outfan of described 3rd operational amplifier U3 connects the 3rd operation amplifier after the tenth resistance
The normal phase input end of device.
A kind of PWM constant current output circuit the most according to claim 1, it is characterised in that described 5th resistance is can power transformation
Resistance, the resistance of the 5th resistance changes with the load in circuit and changes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620631612.5U CN205721469U (en) | 2016-06-21 | 2016-06-21 | A kind of PWM constant current output circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620631612.5U CN205721469U (en) | 2016-06-21 | 2016-06-21 | A kind of PWM constant current output circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205721469U true CN205721469U (en) | 2016-11-23 |
Family
ID=57315242
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620631612.5U Active CN205721469U (en) | 2016-06-21 | 2016-06-21 | A kind of PWM constant current output circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205721469U (en) |
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2016
- 2016-06-21 CN CN201620631612.5U patent/CN205721469U/en active Active
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