CN106982491B - Buck-boost type constant-current drive circuit and constant current driving method - Google Patents
Buck-boost type constant-current drive circuit and constant current driving method Download PDFInfo
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- CN106982491B CN106982491B CN201710229603.2A CN201710229603A CN106982491B CN 106982491 B CN106982491 B CN 106982491B CN 201710229603 A CN201710229603 A CN 201710229603A CN 106982491 B CN106982491 B CN 106982491B
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- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
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Abstract
The present invention relates to a kind of buck-boost type constant-current drive circuit and constant current driving method, which includes constant-flow driver and buck main structure；It further include the sampling feedback resistance being connected between the power tube, power inductance and freewheeling diode, one end of the sampling feedback resistance is connect with power inductance, the connection of the source electrode of the other end and power tube, and the sampling pin connection of one end and constant-flow driver for being connect with power tube of sampling feedback resistance, the sampling feedback resistance maintains the rear end constant output current of power tube for sampling to the size of current in the back-end circuit of power tube；The constant-flow driver is used to obtain sampled signal by sampling pin, and the on-off of power tube is controlled by driving pin output pulse width modulated signal, and then the constant current accuracy of regulation power pipe output electric current and the component in protection circuit.
Description
Technical field
The present invention relates to constant-current supply technical fields, drive more particularly to a kind of buck-boost type constant-flow driver and constant current
Method.
Background technique
With being gradually increased for professional standard, more and more countries and regions propose power factor for LED power
Requirement, that is, require input current to need that input voltage is followed to change to reduce to the harmonic pollution of power grid.Since tradition is gone up and down
Die mould circuit has the characteristics that high-efficient, exportable high current and quiescent current are small, so buck-boost type circuit is gradually applied
To in LED constant-current driver.In addition, how to provide a kind of safety for taking into account cost and performance with the increase of production cost
Reliable scheme becomes research hotspot.
On implementation, there are two types of traditional solution, the first traditional solution party for buck-boost type LED constant current controller
Case, in this way can be with convection current as shown in Figure 1, Constant flow sample feedback resistance Rcs is placed between sustained diode and power inductance L
Whole electric currents through LED carry out sampling feedback, then are aided with high-precision closed loop operational amplifier and external integrating capacitor C1
Error-free high precision constant current output control on realization theory.But when input voltage is uprushed and turn-on time fixation can draw
Inductive current is played to increase suddenly, and sampling resistor can not acquire the electric current during power tube Q1 conducting so will appear electricity in the case
Sense saturation even power tube Q1 overcurrent burns risk.
Second of traditional solution is as shown in Fig. 2, be placed in sustained diode and function for Constant flow sample feedback resistance Rcs
Between rate pipe Q1, as traditional primary-side-control technology.Maximum value protection can be carried out to the electric current for flowing through power tube Q1 in this way,
It is not in aircraft bombing risk caused by being uprushed due to input voltage.But it is flowed through since sampling feedback resistance can not be acquired directly
The electric current of LED needs so chip 2 needs complicated feedback control loop design by adopting to the peak point current for flowing through Q1
The information that output electric current is calculated of sample and inductive current time of afterflow is to indirectly control output electric current, and thus bring is most
Big problem be export electric current precision can with input voltage, inductance error and driving speed variation and change.
In conclusion the first traditional solution can not directly sample the electric current during conducting there are sampling feedback resistance
Information increases suddenly there are electric current and inductance is caused to be saturated the risk that even power tube Q1 overcurrent is burnt.Second of traditional solution party
Case, constant current output are changed by input voltage, inductance error and driving speed and are changed, and cause constant current accuracy poor.
Summary of the invention
Based on this, it is necessary to be directed to present in traditional buck-boost type constant-current control circuit because sampling feedback resistance can not be straight
Power tube is caused to burn for current information during connecing sampling conducting and the problem of constant current output low precision, providing one kind can be real
When monitoring power tube conducting electric current and improve the buck-boost type constant-current drive circuit and constant current driving method of constant current output precision.
A kind of buck-boost type constant-current drive circuit, including：
Constant-flow driver draws equipped with driving pin and by driving pin output pulse width modulated signal, equipped with sampling
Foot simultaneously passes through sampling pin input sample signal；
Buck main structure, including power tube interconnected, power inductance and freewheeling diode；The wherein power
The driving pin of the grid of pipe and constant-flow driver connects, and the constant-flow driver is according to the pulse width modulating signal pair of input
Power tube carries out on-off control；
It is characterized in that, further including the sampling feedback being connected between the power tube, power inductance and freewheeling diode
One end of resistance, the sampling feedback resistance is connect with power inductance, the source electrode connection of the other end and power tube, and sampling feedback
The sampling pin of one end and constant-flow driver that resistance is connect with power tube connects, and the sampling feedback resistance is used for power tube
Back-end circuit in size of current sampled, and then maintain power tube rear end constant output current；The power inductance
It is connect again with source electrode one end of power tube with after the series connection of sampling feedback resistance, the cathode of the freewheeling diode and the source of power tube
Pole is directly connected to；
The constant-flow driver is used to obtain sampled signal by sampling pin, and passes through driving pin output pulse width
Modulated signal controls the on-off of power tube, and then the constant current accuracy of regulation power pipe output electric current and first device in protection circuit
Part.
The constant-flow driver further includes in one of the embodiments,：
Compensation pin is used for input offset signal；
Pin is detected, for inputting detection signal；
Operational amplifier, sampled signal and constant current output benchmark for that will sample pin input carry out operation amplifier, obtain
To error result, and export amplified sampled signal；
First comparator, for the sampled signal for sampling pin input to be compared with overcurrent protection benchmark, and in institute
The first overcurrent protection signal is exported when stating sampled signal more than the overcurrent protection benchmark；
Second comparator for the output result of operational amplifier to be compared with triangular signal, and is put in operation
The output result of big device exports the second overcurrent protection signal when being more than the triangular signal；
Drive module receives the first overcurrent protection signal and the first overcurrent protection signal, and defeated by driving pin
Pulse width modulating signal out；
The inverting input terminal of the operational amplifier connect with sampling pin, and is sampling the anti-of pin and operational amplifier
Feedback switch is provided between phase input terminal, the conducting timing of the feedback switch and the conducting timing of power tube are opposite.
It in one of the embodiments, further include the integrating capacitor for carrying out error compensation, the one of the integrating capacitor
End is connect with the compensation pin of constant-flow driver, and the other end is connected between sampling feedback resistance and power inductance.
It in one of the embodiments, further include the first resistor and second resistance for demagnetization detection and over-voltage detection,
The first resistor is connected with second resistance, and concatenated first resistor and second resistance and concatenated sampling feedback resistance and function
Rate inductance in parallel, the detection pin are connected between first resistor and second resistance.
The non-inverting input terminal of the operational amplifier inputs constant current output benchmark in one of the embodiments, and reverse phase is defeated
Enter to hold input sample signal, the output end of operational amplifier is connect with the reverse input end of the second comparator.
The non-inverting input terminal of the first comparator is connect with sampling pin in one of the embodiments, input sample
Signal；Inverting input terminal inputs overcurrent protection benchmark；Output end is connect with drive module.
The non-inverting input terminal of second comparator inputs triangular signal in one of the embodiments,；Reversed input
End is connect with the output end of compensation pin and operational amplifier, and input carries out the sampled signal after error compensation；Output end and drive
The connection of dynamic model block.
It in one of the embodiments, further include detection module, the detection module includes demagnetization detection unit and over-voltage
Detection unit, the input terminal of detection module connects with detection pin, by detection pin input detection signal, to detect signal into
Row demagnetization detection and over-voltage detection, and demagnetization signal is exported by demagnetization detection unit, pass through over-voltage detection unit output overvoltage
Protect signal.
The drive module includes rest-set flip-flop and driving unit, the R of the rest-set flip-flop in one of the embodiments,
End and the end S are connected separately at least one OR circuit；
The end S of the rest-set flip-flop is connect with the output end of the first OR circuit, the input terminal of first OR circuit
Input the demagnetization signal of on-off clock signal and/or detection module output；
The end R of the rest-set flip-flop is connect with the output end of the second OR circuit, the input terminal of second OR circuit
Input the first overcurrent protection signal and/or the second overcurrent protection signal and/or overvoltage protection signal；
The end Q of the rest-set flip-flop is connect with driving unit.
A kind of constant current driving method, for making the back-end circuit of power tube export constant current, institute by driving power pipe
The method of stating includes：
Sampled signal is obtained, the sampled signal is compared to obtain the first comparison result with overcurrent protection benchmark；
The sampled signal and constant current output benchmark are subjected to operation amplifier, obtain error result and amplified signal；
Amplified signal is compensated according to the error result, obtains compensated amplified signal；
It is compared the compensated amplified signal to obtain the second comparison result with triangular signal；
The power tube conducting is driven according to first comparison result and the second comparison result.
Above-mentioned buck-boost type constant-current drive circuit and constant current driving method, by the way that sampling feedback resistance is set to power
, not only can be with the output current information of sampled power pipe conduction device between pipe, power inductance and freewheeling diode, but also can sample
Afterflow device flows through the current information of output loading；By defeated in the sampling pin of constant-flow driver and the reverse phase of operational amplifier
Enter and feedback switch is set between end, and the conducting timing of the feedback switch and the conducting timing of power tube are on the contrary, more accurately
The sampling to output electric current is obtained, sampling precision is improved.In conclusion the embodiment of the present invention, which is realized, is connected the phase to power tube
Between maximum current protection, reach direct output current feedback and high-precision constant current output effect.
Detailed description of the invention
Fig. 1 is the schematic diagram of the buck-boost type constant-current drive circuit of traditional scheme one；
Fig. 2 is the schematic diagram of the buck-boost type constant-current drive circuit of traditional scheme two；
Fig. 3 is the schematic diagram of the buck-boost type constant-current drive circuit of one embodiment of the invention；
Fig. 4 is the constant-flow driver module map of one embodiment of the invention；
Fig. 5 is power tube, the conducting timing of feedback switch and power inductor current and amplifier in one embodiment of the invention
The comparison of wave shape figure of input current；
Fig. 6 is the schematic diagram of the buck-boost type constant-current drive circuit of another embodiment of the present invention；
Fig. 7 is the constant-flow driver module map of another embodiment of the present invention；
Fig. 8 is the constant current driving method flow chart of one embodiment of the invention.
Specific embodiment
To facilitate the understanding of the present invention, a more comprehensive description of the invention is given in the following sections with reference to the relevant attached drawings.In attached drawing
Give presently preferred embodiments of the present invention.But the invention can be realized in many different forms, however it is not limited to this paper institute
The embodiment of description.On the contrary, purpose of providing these embodiments is keeps the understanding to the disclosure more thorough
Comprehensively.
Unless otherwise defined, all technical and scientific terms used herein and belong to technical field of the invention
The normally understood meaning of technical staff is identical.Term as used herein in the specification of the present invention is intended merely to description tool
The purpose of the embodiment of body, it is not intended that the limitation present invention.Term as used herein "and/or" includes one or more related
Listed item any and all combinations.
A kind of buck-boost type constant-flow driver and constant current driving method presented below, for regulation power pipe output electric current
Component in constant current accuracy and protection circuit.
As shown in fig.3, the schematic diagram of the buck-boost type constant-current drive circuit for one embodiment of the invention, the buck
Type constant-current drive circuit includes constant-flow driver 100, buck main structure 200 and sampling feedback resistance Rcs；The constant current driving
Device 100 is equipped with driving pin GATE, sampling pin CS, compensation pin COMP and detection pin FB；The buck main structure 200
Including power tube Q1, power inductance L and sustained diode；Optionally, the power tube Q1 can be transistor or metal-oxide-semiconductor.
Further, the grid of the power tube Q1 is connect with the driving pin GATE of constant-flow driver 100, the constant current
Driver 100 carries out on-off control to power tube Q1 according to the pulse width modulating signal of input；The power inductance L and sampling
It is connect again with source electrode one end of power tube Q1 after feedback resistance Rcs series connection, the power inductance L is used in power tube Q1 conducting
The current storage that power tube Q1 is exported, and electric current is provided when power tube Q1 disconnects for the back-end circuit of power tube Q1；It is described
The cathode of sustained diode and the source electrode of power tube connect, and the sustained diode plays the role of afterflow in circuit, and protects
Component in protection circuit is not damaged.
The sampling feedback resistance Rcs is connected between power tube Q1, power inductance L and sustained diode, the sampling
One end of feedback resistance Rcs is connect with power inductance L, and the other end is connect with the source electrode of power tube Q1, and sampling feedback resistance Rcs
The one end connecting with power tube Q1 is connect with sampling pin CS；The sampling feedback resistance Rcs is used for the rear end to power tube Q1
The size of current of circuit output is sampled, and then maintains the rear end constant output current of power tube, and is realized to flowing through power
The current maxima of pipe Q1 is protected；The constant-flow driver 100 is used to control function by the sampled signal that sampling pin CS is obtained
The on-off of rate pipe Q1, and then the constant current accuracy of regulation power pipe output electric current and the component in protection circuit.
In one embodiment, the buck-boost type constant-current drive circuit further include integrating capacitor C1, first resistor R1 and
Second resistance R2, one end of the integrating capacitor C1 are connect with the compensation pin COMP of constant-flow driver 100, and the other end is connected to
Between sampling feedback resistance Rcs and power inductance L, the integrating capacitor C1 releasable electricity after charging passes through compensation pin
COMP gives constant-flow driver 100 input offset signal.
The first resistor R1 connects with second resistance R2, and concatenated first resistor R1 and second resistance R2 with it is concatenated
Sampling feedback resistance Rcs and power inductance L is in parallel, the detection pin FB be connected to first resistor R1 and second resistance R2 it
Between, for realizing the detection of demagnetization signal, it is electric that the detection pin FB passes through first by the first resistor R1 and second resistance R2
Hinder R1 and second resistance R2 size of current detection power inductance L whether demagnetization；Meanwhile because first resistor R1 and then the second electricity
R2 is hindered there are partial pressure relationship, and the detection pin FB can detect this by the voltage relationship of first resistor R1 and second resistance R2
When circuit whether over-voltage.
As shown in fig.4, in one embodiment, the constant-flow driver 100 further includes first comparator 110, operation
Amplifier 120, the second comparator 130, detection module 140 and drive module 150, the detection module 140 are detected including demagnetization
Unit 141 and over-voltage detection unit 142, the drive module 150 include rest-set flip-flop 151 and driving unit 152, the operation
Amplifier 120 is used to sample the sampled signal of pin CS input and constant current output benchmark carries out operation, obtains error result simultaneously
Output；The first comparator 110 is used to for the sampled signal for sampling pin CS input being compared with overcurrent protection benchmark, and
The first overcurrent protection signal is exported when the sampled signal is more than the overcurrent protection benchmark；Second comparator 130 is used
It is compared in by the output result of operational amplifier 120 with triangular signal, and is more than in the output result of operational amplifier
The second overcurrent protection signal is exported when the triangular signal；The detection module 140 is used for the back-end circuit to power tube Q1
Carry out demagnetization detection and over-voltage detection, and output over-voltage protection signal and demagnetization signal；The drive module 150 is for receiving institute
The first overcurrent protection signal, the second overcurrent protection signal, overvoltage protection signal and demagnetization signal are stated, and passes through driving pin output
Pulse width modulating signal.
Further, the non-inverting input terminal of the first comparator 110 is connect with sampling pin CS, input sample signal；
The inverting input terminal of first comparator 110 inputs overcurrent protection benchmark；The output end and drive module 150 of first comparator 110
Connection；The output electric current during power tube Q1 conducting is obtained by sampling pin CS, that is, the electric current of power inductance L is flowed through, by institute
Output electric current is stated to be compared with overcurrent protection benchmark in real time, when the output electric current is more than the overcurrent protection benchmark, the
One comparator 110 sends the first overcurrent protection signal to drive module 150, and drive module 150 receives first overcurrent protection
Power tube Q1 is driven to disconnect after signal, to protect the back-end circuit of power tube Q1 safely and reliably to work；It is described to flow through power electricity
The waveform relationship for feeling the electric current and overcurrent protection benchmark of L is as shown in Figure 5.
Further, the reverse input end of the operational amplifier 120 is connect with sampling pin CS, the operational amplifier
120 inverting input terminal input sample signal, non-inverting input terminal inputs constant current output benchmark, and puts in sampling pin CS with operation
Feedback switch S1 is provided between the inverting input terminal of big device 120, the feedback switch S1 is for controlling operational amplifier 120
Anti-phase input, when feedback switch S1 is disconnected, the inverting input terminal no signal input of operational amplifier 120.As shown in fig.5,
The conducting timing of the feedback switch S1 and the drive control timing of driving pin GATE output are on the contrary, work as drive module 150
When driving power pipe Q1 is connected, the feedback switch S1 is disconnected；It is described anti-when 150 driving power pipe Q1 of drive module is disconnected
Present switch S1 conducting；Due to providing electric current by power inductance L for the back-end circuit of power tube Q1 when power tube Q1 is disconnected, this
When feedback switch S1 be connected, enable the complete output information of input terminal sampled power inductance L of operational amplifier 120, and
The output electric current of the power inductance L of sampling and constant current output benchmark are subjected to operation amplifier, obtain error result, and export
Amplified sampled signal, to reach current constant control purpose.The waveform of the inverting input terminal input current of operational amplifier 120 is such as
Shown in Fig. 5.
Further, the output end of the operational amplifier 120 is connect with the reverse input end of the second comparator 130；Institute
State the non-inverting input terminal input triangular signal of the second comparator 130；The reverse input end of second comparator 130 respectively with compensation
Pin COMP is connected with the output end of operational amplifier 120, and input carries out the sampled signal after error compensation；Second comparator
130 output end is connect with drive module 150；The mistake that the compensation pin COMP is calculated according to the operational amplifier 120
Poor result obtains error compensation, from integrating capacitor C1 to compensation pin COMP input offset signal, exports to operational amplifier 120
Amplified sampled signal compensate, compensated sampled signal is input to the inverting input terminal of the second comparator 130,
The compensated sampled signal is compared by two comparators 130 with triangular signal, when the compensated sampled signal
When more than the triangular signal, the second comparator 130 sends the second overcurrent protection signal, drive module to drive module 150
150 drive power tube Q1 to disconnect after receiving the second overcurrent protection signal, to protect the back-end circuit of power tube Q1 to pacify
It reliably works entirely.
The input terminal of the demagnetization detection unit 141 and over-voltage detection unit 142 is connect with detection pin FB respectively；Demagnetization
The output end of detection unit 141 and over-voltage detection unit 142 is connect with drive module 150 respectively；Pass through detection pin FB input
Signal is detected, demagnetization detection is carried out to the detection signal and over-voltage detects, the demagnetization detection unit 141 is detecting demagnetization
Demagnetization signal is exported after signal, drive module 150 drives power tube Q1 to be connected after receiving the demagnetization signal；The over-voltage
The output over-voltage protection signal when detecting circuit over-voltage of detection unit 142, and pass through fault protection logic to drive module 150
Error protection request is sent, the driving power tube Q1 after receiving the error protection request of drive module 150 is disconnected.By disappearing
Magnetic testi unit 141 and over-voltage detection unit 142 carry out demagnetization detection and over-voltage detection to the back-end circuit of power tube Q1, can
Circuit is more effectively protected, the component steady operation in maintenance circuitry.
The end R and the end S of the rest-set flip-flop 151 are connected separately at least one OR circuit, the rest-set flip-flop 151
The end S is connect with the output end of the first OR circuit (figure is not marked), the input terminal input on-off clock letter of first OR circuit
Number and/or demagnetization detection unit 141 export demagnetization signal；The end R of the rest-set flip-flop and the second OR circuit (figure is not marked)
Output end connection, second OR circuit input terminal input first comparator 110 export the first overcurrent protection signal
And/or second comparator 130 export the second overcurrent protection signal and/or over-voltage detection unit 142 export overvoltage protection letter
Number；The end Q of the rest-set flip-flop 151 is connect with driving unit 152；According to the trigger theory of rest-set flip-flop 151, when the end S inputs
Shutdown clock signal and/or when effective demagnetization signal, the end Q of rest-set flip-flop 151 sets 1, and drives function by driving unit 152
Rate pipe Q1 conducting；When the first overcurrent protection signal of the end R input and/or the second overcurrent protection signal and/or overvoltage protection signal
When effective, the end Q of rest-set flip-flop 151 sets 0, and is disconnected by 152 driving power pipe Q1 of driving unit.
Above-mentioned lifting type constant-current drive circuit, by the way that sampling feedback resistance is set to power tube, power inductance and afterflow
Between diode, realizing not only can be with the output current information of sampled power pipe conduction device, but also can sample afterflow device stream
Current information through output loading；By being set between sampling pin and the inverting input terminal of operational amplifier of constant-flow driver
Feedback switch is set, and the conducting timing of the feedback switch and the conducting timing of power tube are on the contrary, more accurately obtain to output
The sampling of electric current, improves sampling precision.In conclusion the embodiment of the present invention is realized to maximum electricity during power tube conducting
Stream protection, reaches direct output current feedback and high-precision constant current output effect.Sampled signal is obtained by sampling pin,
And the on-off of power tube is controlled by driving pin output pulse width modulated signal, improve the constant current output precision of circuit simultaneously
Circuit is protected, the component steady operation in circuit is made.
It in other embodiments, should as shown in fig.6, being another kind of embodiment of the present invention lifting type constant-current drive circuit
Lifting type constant-current drive circuit, which works in, to be determined under frequency mode, then reduces the electricity for demagnetization detection and over-voltage detection in circuit
It hinders, the working principle of other devices in circuit is identical as circuit shown in Fig. 3, and please refers to shown in Fig. 7, and frequency mode is being determined in work
Under constant-flow driver 100 ' reduce detection pin, and reduce detection module constant-flow driver 100 ' is internal；It is touched in RS
Frequency clock signal is determined in the end the S input of hair device 151 ', and the end Q by determining frequency clock enabling signal rest-set flip-flop 151 ' sets 1, and passes through drive
152 ' driving power pipe Q1 of moving cell conducting.
In the case where determining frequency mode, the constant-flow driver in the lifting type constant-current drive circuit is by determining frequency clock driving power
The shutdown of pipe reduces demagnetization detection and over-voltage detection, to keep the current constant control of lifting type constant-current drive circuit simpler, increases
The drive efficiency of constant-flow driver is added.
As shown in fig.8, being the constant current driving method flow chart of one embodiment of the invention, this method is used for through driving function
Rate pipe makes the back-end circuit of power tube export constant current, the described method comprises the following steps S210~S250.
S210：Sampled signal is obtained, is tied compared with the sampled signal is compared to obtain first with overcurrent protection benchmark
Fruit；
S220：The sampled signal and constant current output benchmark are subjected to operation amplifier, obtain error result and amplified signal；
S230：Amplified signal is compensated according to the error result, obtains compensated amplified signal；
S240：It is compared the compensated amplified signal to obtain the second comparison result with triangular signal；
S250：The power tube conducting is driven according to first comparison result and the second comparison result.
Above-mentioned constant current driving method is compared to obtain the first ratio with overcurrent protection benchmark by the sampled signal that will acquire
Relatively result；And the sampled signal and constant current output benchmark are subjected to operation amplifier and obtain compensated amplified signal；It will be described
Compensated amplified signal is compared to obtain the second comparison result with triangular signal；According to first comparison result and
The conducting of two comparison result driving power pipes, improves the constant current output precision of circuit and protects circuit, keep the component in circuit steady
Fixed work.It improves the constant current output precision of circuit and protects circuit, make the component steady operation in circuit.
Each technical characteristic of embodiment described above can be combined arbitrarily, for simplicity of description, not to above-mentioned reality
It applies all possible combination of each technical characteristic in example to be all described, as long as however, the combination of these technical characteristics is not deposited
In contradiction, all should be considered as described in this specification.
The embodiments described above only express several embodiments of the present invention, and the description thereof is more specific and detailed, but simultaneously
It cannot therefore be construed as limiting the scope of the patent.It should be pointed out that coming for those of ordinary skill in the art
It says, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to protection of the invention
Range.Therefore, the scope of protection of the patent of the invention shall be subject to the appended claims.
Claims (9)
1. a kind of buck-boost type constant-current drive circuit, including：
Constant-flow driver is equipped with driving pin and by driving pin output pulse width modulated signal, being equipped with sampling pin simultaneously
By sampling pin input sample signal；
Buck main structure, including power tube interconnected, power inductance and freewheeling diode；The wherein power tube
The connection of the driving pin of grid and constant-flow driver, the constant-flow driver is according to the pulse width modulating signal of input to power
Pipe carries out on-off control；
It is characterized in that, further include the sampling feedback resistance being connected between the power tube, power inductance and freewheeling diode,
The power inductance is connected with each other by the sampling feedback resistance and the power tube and freewheeling diode, wherein institute
The one end for stating sampling feedback resistance is connect with power inductance, the connection of the source electrode of the other end and power tube, and sampling feedback resistance with
One end of power tube connection and the sampling pin of constant-flow driver connect, and the sampling feedback resistance is used for the rear end to power tube
Size of current in circuit is sampled, and then maintains the rear end constant output current of power tube；The power inductance and sampling
It is connect again with source electrode one end of power tube after feedback resistance series connection, the cathode of the freewheeling diode and the source electrode of power tube are direct
Connection；Wherein, the power tube is transistor；
The constant-flow driver is used to obtain sampled signal by sampling pin, and passes through driving pin output pulse width modulation
Signal controls the on-off of power tube, and then the constant current accuracy of regulation power pipe output electric current and the component in protection circuit；
The constant-flow driver further includes：
Compensation pin is used for input offset signal；
Pin is detected, for inputting detection signal；
Operational amplifier, sampled signal and constant current output benchmark for that will sample pin input carry out operation amplifier, are missed
Difference is as a result, and export amplified sampled signal；
First comparator for the sampled signal for sampling pin input to be compared with overcurrent protection benchmark, and is adopted described
Sample signal exports the first overcurrent protection signal when being more than the overcurrent protection benchmark；
Second comparator, for the output result of operational amplifier to be compared with triangular signal, and in operational amplifier
Output result be more than the triangular signal when export the second overcurrent protection signal；
Drive module receives the first overcurrent protection signal and the second overcurrent protection signal, and exports arteries and veins by driving pin
Rush bandwidth modulation signals；
The inverting input terminal of the operational amplifier is connect with sampling pin, and defeated in the reverse phase of sampling pin and operational amplifier
Enter and be provided with feedback switch between end, the conducting timing of the feedback switch and the conducting timing of power tube are opposite.
2. buck-boost type constant-current drive circuit according to claim 1, which is characterized in that further include for carrying out error benefit
The integrating capacitor repaid, one end of the integrating capacitor and the compensation pin of constant-flow driver connect, and it is anti-that the other end is connected to sampling
Between feed resistance and power inductance.
3. buck-boost type constant-current drive circuit according to claim 1, which is characterized in that further include for demagnetization detection with
The first resistor and second resistance of over-voltage detection, the first resistor connects with second resistance, and concatenated first resistor and the
Two resistance are in parallel with concatenated sampling feedback resistance and power inductance, and the detection pin is connected to first resistor and second resistance
Between.
4. buck-boost type constant-current drive circuit according to claim 1, which is characterized in that the same phase of the operational amplifier
Input terminal inputs constant current output benchmark, inverting input terminal input sample signal, the output end of operational amplifier and the second comparator
Reverse input end connection.
5. buck-boost type constant-current drive circuit according to claim 1, which is characterized in that the same phase of the first comparator
Input terminal is connect with sampling pin, input sample signal；Inverting input terminal inputs overcurrent protection benchmark；Output end and drive module
Connection.
6. buck-boost type constant-current drive circuit according to claim 1, which is characterized in that the same phase of second comparator
Input terminal inputs triangular signal；Reverse input end is connect with the output end of compensation pin and operational amplifier, and input is missed
The compensated sampled signal of difference；Output end is connect with drive module.
7. buck-boost type constant-current drive circuit according to claim 1, which is characterized in that it further include detection module, it is described
Detection module includes demagnetization detection unit and over-voltage detection unit, and the input terminal of detection module is connect with detection pin, passes through inspection
Pin input detection signal is surveyed, demagnetization detection is carried out to detection signal and over-voltage detects, and is disappeared by the output of demagnetization detection unit
Magnetic signal passes through over-voltage detection unit output over-voltage protection signal.
8. buck-boost type constant-current drive circuit according to claim 1, which is characterized in that the drive module includes RS touching
Hair device and driving unit, the end R and the end S of the rest-set flip-flop are connected separately at least one OR circuit；
The end S of the rest-set flip-flop is connect with the output end of the first OR circuit, the input terminal input of first OR circuit
On-off clock signal and/or the demagnetization signal of detection module output；
The end R of the rest-set flip-flop is connect with the output end of the second OR circuit, the input terminal input of second OR circuit
First overcurrent protection signal and/or the second overcurrent protection signal and/or overvoltage protection signal；
The end Q of the rest-set flip-flop is connect with driving unit.
9. a kind of constant current driving method, described for making the back-end circuit of power tube export constant current by driving power pipe
Method includes：
The sampled signal for obtaining the sampling pin input of constant-flow driver, the sampled signal and overcurrent protection benchmark are compared
Relatively obtain the first comparison result；
The sampled signal and constant current output benchmark are subjected to operation amplifier by operational amplifier, obtain error result and amplification
Sampled signal afterwards；
The sampled signal is compensated according to the error result, obtains compensated sampled signal；
It is compared the compensated sampled signal to obtain the second comparison result with triangular signal；
The power tube conducting is driven according to first comparison result and the second comparison result；
Wherein, the inverting input terminal of the operational amplifier connect with sampling pin, and is sampling pin and operational amplifier
Feedback switch is provided between inverting input terminal, the conducting timing of the feedback switch and the conducting timing of power tube are opposite.
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| CN109217666A (en) * | 2018-11-21 | 2019-01-15 | 深圳市必易微电子有限公司 | ON-OFF control circuit and method, switch power supply system |
| CN114189962A (en) * | 2021-12-17 | 2022-03-15 | 深圳民爆光电股份有限公司 | High-precision LED constant-current driving circuit and driving power supply thereof |
| CN115190682B (en) * | 2022-09-07 | 2022-12-20 | 深圳利普芯微电子有限公司 | Overvoltage protection circuit and LED drive power supply |
| CN116384435B (en) * | 2023-03-30 | 2024-03-22 | 华能山东石岛湾核电有限公司 | System and method for judging neglected recording of high-temperature gas cooled reactor counter |
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| CN104113966B (en) * | 2014-06-13 | 2016-05-11 | 佛山市南海赛威科技技术有限公司 | The constant source flowing system of averagecurrent mode control and control method thereof |
| CN105048832A (en) * | 2015-06-18 | 2015-11-11 | 杭州士兰微电子股份有限公司 | Switch power supply controller and switch power supply including the switch power supply controller |
| CN106028557B (en) * | 2016-07-08 | 2018-01-05 | 上海灿瑞科技股份有限公司 | The constant current driver circuit for LED of the low total harmonic distortion of High Power Factor |
| CN206640842U (en) * | 2017-04-10 | 2017-11-14 | 深圳市必易微电子有限公司 | Buck-boost type constant-current drive circuit |
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