CN106357110B - A kind of BUCK constant voltage drive circuits and BUCK constant-voltage drivers - Google Patents
A kind of BUCK constant voltage drive circuits and BUCK constant-voltage drivers Download PDFInfo
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- CN106357110B CN106357110B CN201610852019.8A CN201610852019A CN106357110B CN 106357110 B CN106357110 B CN 106357110B CN 201610852019 A CN201610852019 A CN 201610852019A CN 106357110 B CN106357110 B CN 106357110B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/157—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators with digital control
Abstract
A kind of BUCK constant voltage drive circuits and BUCK constant-voltage drivers,Including voltage output module,Output control signal is to control the control module of the main switch in voltage output module being turned on and off,According to the overcurrent benchmark generation module for controlling the turn-on time of signal acquisition main switch and being compensated to the overcurrent reference voltage of low input,The overcurrent protection module of overcurrent protection is carried out when according to overcurrent reference voltage output feedback signal to control module to be carried to voltage output module band,Sampling and outputting voltage and the Isobarically Control module that constant pressure Regulate signal is exported according to output voltage and output reference voltage,Feedback signal is exported to control module to be adjusted to the peak point current in voltage output module and then adjust output voltage as the PWM control modules of constant voltage according to constant pressure Regulate signal,The present invention is on the basis of maintaining prior art low cost,Keep high-low pressure driving capability closer,Peak point current can be fallen at light load,To optimize underloading response and no-load power consumption characteristic.
Description
Technical field
The present invention relates to field of power electronics more particularly to a kind of BUCK constant voltage drive circuits and including the driving circuit
BUCK constant-voltage drivers.
Background technology
The typical case of prior art BUCK constant voltage drive circuits is as shown in Figure 1.Its operation principle is as follows：When CLK is generated
After device sends out set signal, high-voltage MOS pipe M1 is opened by drive module, and the electric current of high-voltage MOS pipe M1 conductings, inductance L will be with solid
Determine slope increase, Vcs voltages also increase therewith, when the electric current of inductance L increases to so that Vcs and comparison voltage inside controller
When Vref is equal, drive module will close metal-oxide-semiconductor M1, be allowed to end, Vs will drop quickly to-V at this timeD1, the electric current on inductance L
Declined with fixed slope through diode D1, while Vout is powered by diode D2 to VCC, then：
VL=Vout+VD1=VCC+VD2 (1)
It is assumed that VD1=VD2, then Vcc=Vout, therefore Vout can be sampled by VCC voltages, using resistance
Feedback voltage Vfb is obtained after partial pressure, and is compared with internal reference voltage Vref2.When output voltage Vout is relatively high,
VCC and Vfb is also accordingly raised, and when Vfb is higher than Vref2, reset signal R1=1, metal-oxide-semiconductor M1 will be closed, and then Vout will
Decline, VCC and Vfb also accordingly decline, and when Vfb is less than Vref2, reset signal R1=0, M1 will be connected again.Finally make Vfb
Average value it is equal with Vref2, it is assumed that electric resistance partial pressure ratio be α, then：
Vout=VCC=α * Vref2 (2)
The advantages of existing Buck constant-voltage drivers is：It is simple in structure, it is at low cost.But there is following apparent problem：
1), theoretically inductance peak point current Ipk is Vref/Rcs, but the delay due to comparator and MOS shutdown delays
In the presence of peak point current Ipk is：
Wherein L is inductance sensibility reciprocal, and Td is the sum of comparator delay and MOS shutdown delays, and due to Vin ＞ Vout, (3) can letter
It turns to：
As can be seen from the above equation, peak point current increases with input voltage vin and is increased, when so as to cause low input
Driving capability obviously than high input voltage when it is weak；
2), for BCM and DCM operating modes, the relationship of output power and peak point current Ipk and working frequency F is：Since the prior art does not reduce in the peak point current of underloading or even idle condition, underloading frequency is too
It is low, it is very big not only to respond relatively slow and no-load power consumption.
Invention content
The technical problem to be solved in the present invention is, for the drawbacks described above of the prior art, provides a kind of BUCK constant pressures drive
Dynamic circuit and BUCK constant-voltage drivers.
The technical solution adopted by the present invention to solve the technical problems is：A kind of BUCK constant voltage drive circuits are constructed, including：
For input voltage being adjusted to provide the voltage output module of constant voltage for load, for exporting control signal to control
Make the control module of the main switch in the voltage output module being turned on and off, for according to the control signal acquisition
The turn-on time and then the information of acquisition input voltage of main switch simultaneously compensate the overcurrent reference voltage of low input
Overcurrent benchmark generation module, for according to the overcurrent reference voltage output feedback signal to control module with to voltage output
The overcurrent protection module, defeated with the matched peripheral circuit of the driving circuit for sampling of overcurrent protection is carried out when modular belt carries
Go out voltage and the Isobarically Control module of constant pressure Regulate signal is exported according to the output voltage and output reference voltage, is used for basis
The constant pressure Regulate signal export feedback signal to control module with to the peak point current in voltage output module be adjusted into
And adjust the PWM control modules that the output voltage is constant voltage；
The control module be separately connected the voltage output module, overcurrent benchmark generation module, overcurrent protection module,
PWM control modules, the overcurrent protection module are also connected with the overcurrent benchmark generation module, voltage output module, the constant pressure
Control module connects the PWM control modules and the peripheral circuit, the voltage output module are additionally coupled to peripheral circuit.
In BUCK constant voltage drive circuits of the present invention, the overcurrent benchmark generation module includes being opened for sampling master
It closes the maximum integral voltage in each turn-on time and the maximum integral voltage in the constant time lag time and accumulates two maximums
Component voltage remains to the sampling hold circuit of main switch conducting next time and simultaneously for being generated according to two maximum integral voltages
The overcurrent reference generator of overcurrent reference voltage, the overcurrent protection module include first comparator；The sampling hold circuit
Input terminal link control module and output end connection overcurrent reference generator input terminal, the overcurrent reference generator it is defeated
Outlet connects the positive input terminal of first comparator, and the negative input end of first comparator connects voltage output module, first comparator
Output end link control module, wherein the overcurrent reference generator is built with following relationship：Its
In, A is normal number, and Ton indicates that the turn-on time of main switch, Td indicate the constant time lag time, is delayed for first comparator
The sum of delay is turned off with main switch, Vref indicates the overcurrent reference voltage.
In BUCK constant voltage drive circuits of the present invention, the control signal forms high electricity within each clock cycle
Flat time span is the first pwm signal of Ton, and the sampling hold circuit includes：Impulse generator, PWM signal generator, two
The charge switch be connected when a N-type metal-oxide-semiconductor, two capacitances, two constant-current sources, two high level, the impulse generator is by institute
It states the triggering of the first pwm signal rising edge and generates pulse signal, the PWM signal generator is triggered by the first pwm signal rising edge
Generate the second pwm signal that high level time length is Td；
Impulse generator, PWM signal generator are respectively connected to the control module, and the drain electrode of each N-type metal-oxide-semiconductor is logical
It crosses a charge switch connection one and is all connected with capacitance, a source grounding, two N-types between constant-current source, source electrode and drain electrode
The grid of metal-oxide-semiconductor is connected to impulse generator, and the control terminal of a charge switch is connected to PWM signal generator to receive
The first pwm signal is stated, the control terminal of another charge switch is connected to the control module to receive second pwm signal.
In BUCK constant voltage drive circuits of the present invention, the overcurrent reference generator includes：Divider, multiplication
Device, two voltage followers, metal-oxide-semiconductor mirror current source, first resistor, second resistance；
Two input terminals of divider are respectively connected to the drain electrode of two N-type metal-oxide-semiconductors, and an input terminal of multiplier receives
The output end of constant A, another input terminal connection divider, the input terminal of first voltage follower are used to receive the ginseng of A volts
One end of the output end and first resistor of the reference arm of voltage, output end connection metal-oxide-semiconductor mirror current source is examined, first resistor
The other end connects the output end of second voltage follower, the output of the input terminal connection multiplier of second voltage follower
End, the first end of the output end connection second resistance of the output branch of metal-oxide-semiconductor mirror current source, the second termination of second resistance
Ground, the first end of second resistance are additionally coupled to the positive input terminal of the first comparator.
In BUCK constant voltage drive circuits of the present invention, the Isobarically Control module includes that bleeder circuit and error are put
Big device, the PWM control modules include the second comparator, bleeder circuit connection peripheral circuit and error amplifier it is negative defeated
Enter end, the positive input terminal of error amplifier is for receiving output reference voltage, the output end connection second of the error amplifier
The positive input terminal of the negative input end of comparator, the second comparator connects voltage output module, the output end connection of the second comparator
Control module.
In BUCK constant voltage drive circuits of the present invention, the Isobarically Control module further includes compensation resistance and compensation
The output end of capacitance, error amplifier is connected to voltage output module via the compensation resistance and compensating electric capacity.
In BUCK constant voltage drive circuits of the present invention, the voltage output module includes the main switch and inspection
Leakage resistance, the main switch are N-type metal-oxide-semiconductor, and the control module includes clock generator, rest-set flip-flop, drive module, when
Clock generator connects the set end of rest-set flip-flop, two reset terminals of rest-set flip-flop be separately connected first comparator output end and
The output end of second comparator, the input of the input terminal and sampling hold circuit of the output end connection drive module of rest-set flip-flop
End, the grid of the output end connection N-type metal-oxide-semiconductor of drive module, the input voltage outside receiving that drains of N-type metal-oxide-semiconductor, N-type MOS
The source electrode of pipe be separately connected the negative input end of first comparator, the second comparator positive input terminal and examine leakage resistance first
End, the second end for examining leakage resistance are connected to the output end of error amplifier via the compensation resistance and compensating electric capacity.
The invention also discloses a kind of BUCK constant-voltage drivers, the BUCK constant pressures driving is packaged in the driver
Circuit.
The BUCK constant voltage drive circuits for implementing the present invention, have the advantages that：On the one hand, the present invention is in existing typical case
Increase overcurrent benchmark generation module on the basis of driving circuit, therefore compared with prior art, the overcurrent of overcurrent protection module is joined
It is not unalterable to examine voltage, but passes through overcurrent benchmark generation module and carried out to the overcurrent reference voltage of low input
Compensation, on the basis of maintaining prior art advantage of low cost, makes high-low pressure driving capability be more nearly；On the other hand, this hair
Bright Isobarically Control module and PWM control modules coordinates the comparison for substituting and adjusting output voltage in existing typical driving circuit jointly
The function of device can be adjusted peak point current according to constant pressure Regulate signal and then adjust output voltage, therefore remain existing
On the basis of having technology advantage of low cost, peak point current can fallen at light load, to optimize underloading response and unloaded work(
Consume characteristic.
Description of the drawings
Present invention will be further explained below with reference to the attached drawings and examples, in attached drawing：
Fig. 1 is the circuit diagram of the typical case of prior art BUCK constant voltage drive circuits；
Fig. 2 is the circuit diagram of the application of BUCK constant voltage drive circuits of the present invention；
Fig. 3 is the circuit diagram of overcurrent benchmark generation module in Fig. 2；
Fig. 4 is the corresponding oscillogram of operation principle of sampling hold circuit.
Specific implementation mode
For a clearer understanding of the technical characteristics, objects and effects of the present invention, now control attached drawing is described in detail
The specific implementation mode of the present invention.
As shown in Fig. 2, being the circuit diagram of the application of BUCK constant voltage drive circuits of the present invention.
The present invention BUCK constant voltage drive circuits include：Power supply module, voltage output module 100, control module 200, mistake
Flow benchmark generation module 300, overcurrent protection module 400, Isobarically Control module 500, PWM control modules 600.
The control module 200 is separately connected the voltage output module 100, overcurrent benchmark generation module 300, overcurrent and protects
Module 400, PWM control modules 600 are protected, the overcurrent protection module 400 is also connected with the overcurrent benchmark generation module 300, electricity
Output module 100, the Isobarically Control module 500 is pressed to connect the PWM control modules 600 and the peripheral circuit, the electricity
Pressure output module 100 is additionally coupled to peripheral circuit.
Power supply module for starting entire driving circuit, voltage output module 100 be used for by input voltage be adjusted with
Constant voltage is provided for load；Control module 200 is for exporting control signal to control the master in the voltage output module 100
Switching tube is turned on and off；Overcurrent benchmark generation module 300 is used for the conducting according to the control signal acquisition main switch
The information of time and then acquisition input voltage simultaneously compensates the overcurrent reference voltage of low input；Overcurrent protection module
400 are used for according to the overcurrent reference voltage output feedback signal to control module 200 to be carried out to voltage output module 100
Stream protection；Isobarically Control module 500 is for sampling with the output voltage of the matched peripheral circuit of the driving circuit and according to institute
It states output voltage and exports constant pressure Regulate signal with output reference voltage；PWM control modules 600, which are used to be adjusted according to the constant pressure, to be believed
Number output feedback signal to control module 200 with to the peak point current in voltage output module 100 be adjusted so that adjust institute
It is constant voltage to state output voltage.
Since the present invention increases overcurrent benchmark generation module on the basis of existing typical driving circuit, with existing skill
Art is compared, and the overcurrent reference voltage of overcurrent protection module is not unalterable, but passes through overcurrent benchmark generation module pair
The overcurrent reference voltage of low input compensates, and on the basis of maintaining prior art advantage of low cost, high-low pressure is made to drive
Kinetic force is more nearly.And the Isobarically Control module and PWM control modules of the present invention coordinates the existing typical driving of replacement jointly
The function of the comparator of output voltage is adjusted in circuit, peak point current can be adjusted and then be adjusted according to constant pressure Regulate signal
Whole output voltage, therefore on the basis of maintaining prior art advantage of low cost, peak point current can fallen at light load, from
And optimize underloading response and no-load power consumption characteristic.
In a specific embodiment, the voltage output module 100 includes the main switch and inspection leakage resistance
Rcs, the main switch are N-type metal-oxide-semiconductor M1, and the control module 200 includes clock generator, rest-set flip-flop, drive module,
In this driving circuit of application, need to connect corresponding peripheral circuit, peripheral circuit include sustained diode 1, diode D2,
Capacitance, inductance L.In Fig. 2 by taking one encapsulates the driver of this driving circuit as an example, VCC, Vin, Vs are the three of driver in figure
A pin.Vin connects external power supply as input pin, and specific is usually to connect a current rectifying and wave filtering circuit.Vs is as defeated
Go out the cathode of one end and sustained diode 1 of pin connection inductance L, the plus earth of sustained diode 1, inductance L's is another
The voltage node as output voltage Vout is held, on the other hand which connects on the one hand via capacity earth via diode D2
The power supply module of driver connected VCC pin, internal drive connects Vin and VCC, is VCC sections when for starting for driver
Point provides voltage, and after driver life's work, power supply module no longer will provide electric current for VCC.
The overcurrent benchmark generation module 300 includes sampling hold circuit 310 and overcurrent reference generator 320, the mistake
It includes first comparator to flow protection module 400, and the Isobarically Control module 500 includes bleeder circuit 510 and error amplifier, institute
It includes the second comparator to state PWM control modules 600.
Clock generator connects the set end of rest-set flip-flop, and two reset terminals of rest-set flip-flop are separately connected first comparator
Output end and the second comparator output end, rest-set flip-flop output end connection drive module input terminal and sampling keep electricity
The input terminal on road 310, the input terminal of the output end connection overcurrent reference generator 320 of sampling hold circuit 310, the overcurrent base
The positive input terminal of the output end connection first comparator of quasi- generator 320, the output end connection N-type metal-oxide-semiconductor M1's of drive module
Grid, the input voltage outside receiving that drains of N-type metal-oxide-semiconductor M1, the source electrode of N-type metal-oxide-semiconductor M1 are separately connected first comparator
The first end of negative input end, the positive input terminal of the second comparator and inspection leakage resistance Rcs, the second end of inspection leakage resistance Rcs via
The compensation resistance Rc and compensating electric capacity Cc is connected to the output end of error amplifier, and the output end of the error amplifier also connects
The negative input end of the second comparator is connect, the positive input terminal of error amplifier is used to receive output reference voltage, error amplifier
Negative input end connects the output end of the bleeder circuit 510, and the input terminal of the bleeder circuit 510 connects VCC nodes, i.e., peripheral
The cathode of diode D2 in circuit.
Bleeder circuit 510 can be common resistor voltage divider circuit, and resistor voltage divider circuit is the known circuits of this field, this
Place repeats no more.
Preferably, in the present embodiment, in order to ensure stability, the Isobarically Control module 500 further includes compensation resistance
The output end of Rc and compensating electric capacity Cc, error amplifier are connected to inspection leakage resistance via the compensation resistance Rc and compensating electric capacity Cc
The second end of Rcs.
On the one hand, the operation principle for the problems such as power consumption when present invention solves to be lightly loaded or is unloaded is high and light-load efficiency is low is such as
Under：When deviation occurs in output voltage Vout, the corresponding deviation of feedback voltage Vfb that bleeder circuit 510 exports, error amplifier is defeated
The constant pressure Regulate signal Comp gone out will adjust peak point current, so as to adjust inductive current, when system loop is stablized, Vfb=
Vref2, to realize the adjustment of output voltage.At light load, loop will export constant pressure Regulate signal Comp automatically, to reduce peak
It is worth electric current.
The driving capability problem weaker than high input voltage when on the other hand, in order to make up high low input increases sampling
Holding circuit 310, overcurrent reference generator 320.Sampling hold circuit 310 is for sampling in each turn-on time of main switch most
Big integral voltage and maximum integral voltage in the constant time lag time simultaneously remain to two maximum integral voltages next simultaneously
Secondary main switch conducting, overcurrent reference generator are used to generate overcurrent reference voltage according to two maximum integral voltages.The control
Signal forms the first pwm signal that high level time length is Ton, because output voltage is constant, institute within each clock cycle
It is negatively correlated with the turn-on time (i.e. main switch turn-on time Ton) of the first pwm signal and input voltage, the first PWM is believed thus
Number turn-on time is converted to integral voltage.
Wherein, the overcurrent reference generator 320 is built with following relationship：Wherein, A is normal
Number, Ton indicate that main switch turn-on time, Td indicate the constant time lag time, generally first comparator delay and main switch
The sum of shutdown delay, Vref indicates the overcurrent reference voltage.
It is assumed that upper one week turn-on time is Ton, then can obtain：
(5) are substituted into (4) of background technology part, then
Assuming that Td is fixed, since overcurrent reference generator 320 is constructed such as next relationship：
Then (6) become：
It compares (4) and (8), it can be seen that Ipk of the invention is unrelated with input voltage vin, can be very good to compensate low defeated
Enter the problem of voltage conditions driving capability deficiency.
The structure of the physical circuit with regard to over-sampling holding circuit 310 and overcurrent reference generator 320 provides a tool below
The example of body.
Such as Fig. 3, the sampling hold circuit 310 includes：(figure is not for impulse generator (not shown), PWM signal generator
Show), two N-type metal-oxide-semiconductors MN1 and MN2, two capacitances C1 and C2, two constant-current sources, two high level when the charge switch that is connected
K1 and K2, the impulse generator is triggered by the first pwm signal rising edge generates pulse signal, and the pwm signal occurs
Device is triggered the second pwm signal for generating that high level time length is Td by the first pwm signal rising edge.Wherein charge switch K1 and
K2 can be metal-oxide-semiconductor or triode of N-type etc..
Such as Fig. 3, the overcurrent reference generator 320 includes：Divider, multiplier, two voltage followers EA1 and EA2,
The metal-oxide-semiconductor mirror current source that first resistor R1, second resistance R2, p-type metal-oxide-semiconductor MP1 and MP2 are constituted, the source electrode of MP1 and MP2's
Source electrode connects the grid of the grid connection MP2 of internal electric source vdd, MP1, the drain electrode of the grid connection MP1 of MP1；
Impulse generator, PWM signal generator are respectively connected to the output end of rest-set flip-flop to receive the first pwm signal,
The drain electrode of each N-type metal-oxide-semiconductor connects one by a charge switch and is all connected with an electricity between constant-current source, source electrode and drain electrode
Hold, source grounding, the drain electrode of two N-type metal-oxide-semiconductors is respectively connected to two input terminals of divider, the grid of two N-type metal-oxide-semiconductors
Pole is connected to impulse generator, and the control terminal of charge switch K2 is connected to the PWM signal generator to receive described second
Pwm signal, the control terminal of charge switch K1 are connected to the rest-set flip-flop to receive first pwm signal, and the one of multiplier
The output end of a input terminal admiralty constant A, another input terminal connection divider, the input terminal of first voltage follower EA1
Output end (the i.e. leakage of MP1 for receiving the reference voltage of A volts, the reference arm of output end connection metal-oxide-semiconductor mirror current source
Pole) and first resistor R1 one end, the other end of first resistor R1 connects the output end of second voltage follower EA2, second
The output end of the input terminal connection multiplier of a voltage follower EA2, the output end of the output branch of metal-oxide-semiconductor mirror current source
(i.e. the drain electrode of MP2) connects the first end of second resistance R2, the second end ground connection of second resistance R2, the first end of second resistance R2
It is additionally coupled to the positive input terminal of the first comparator.
In Fig. 3, in conjunction with Fig. 4, Vrest1 and Vrest2 indicate impulse generator generate pulse signal, Vrest1 and
Vrest2 is actually the same pulse signal.
Due toIt is opened in main switch M1
During opening Ton, charge switch K1 is opened, and reference current ib charges to capacitance C1, and integral generates voltage and isIt should
Voltage remains to Vrest1 when setting high.Vrest1 is got higher, open MN1, clear to capacitance C1 0.During main switch M1 shutdowns, charging
Switch K1 is closed, and disconnects charging path.Meanwhile in constant time lag time Td, charge switch K2 is opened, identical ib electric currents pair
Capacitance C2 chargings, integral generate voltage and areThe voltage remains to Vrest2 when setting high.Vrest2 is got higher, right
Capacitance C2 clear 0.Two integral voltages obtain voltage during holding by divider(size of C1 and C2 is identical).This
Signal obtains signal with A constants by a multiplierAmplifier EA2 is clampedKeep it equal with VC voltages,
The clamped A points voltages of amplifier EA1, keep it equal with VD point voltages.The electric current for flowing through MP1 is：PMOS tube
The mirroring ratios of MP1 and MP2 are 1；1, so the electric current for flowing through MP2 is equal to the voltage generated on the electric current .R1 for flowing through MP1
VR1=IP1*R1=(wherein：R1=R2).Using VR1 voltages as Vref, then have：
Certainly, overcurrent reference generator is not limited to the above circuit, can also realize above formula by internal processes
(7), these all should be within protection scope of the present invention.In addition, it is involved in the present invention to the model of metal-oxide-semiconductor be also not limited to
Shown in the present embodiment.
In conclusion implementing the BUCK constant voltage drive circuits of the present invention, have the advantages that：On the one hand, of the invention
Increase overcurrent benchmark generation module on the basis of existing typical driving circuit, therefore compared with prior art, overcurrent protection mould
The overcurrent reference voltage of block is not unalterable, but passes through overcurrent benchmark generation module and join to the overcurrent of low input
It examines voltage to compensate, on the basis of maintaining prior art advantage of low cost, high-low pressure driving capability is made to be more nearly；It is another
Aspect, Isobarically Control module of the invention and PWM control modules coordinate to substitute in existing typical driving circuit jointly adjusts output
The function of the comparator of voltage can be adjusted peak point current according to constant pressure Regulate signal and then adjust output voltage, because
This at light load can fall peak point current on the basis of maintaining prior art advantage of low cost, be rung to optimize underloading
It should be with no-load power consumption characteristic.
The embodiment of the present invention is described with above attached drawing, but the invention is not limited in above-mentioned specific
Embodiment, the above mentioned embodiment is only schematical, rather than restrictive, those skilled in the art
Under the inspiration of the present invention, without breaking away from the scope protected by the purposes and claims of the present invention, it can also make very much
Form, all of these belong to the protection of the present invention.
Claims (7)
1. a kind of BUCK constant voltage drive circuits, which is characterized in that including：For being adjusted input voltage to be provided for load
The voltage output module (100) of constant voltage controls signal to control the master in the voltage output module (100) for exporting
The control module (200) of switching tube being turned on and off, for according to it is described control signal acquisition main switch turn-on time
And then the overcurrent benchmark generation module for obtaining the information of input voltage and the overcurrent reference voltage of low input being compensated
(300), it is used for according to the overcurrent reference voltage output feedback signal to control module (200) with to voltage output module
(100) with load the overcurrent protection module (400) of overcurrent protection is carried out when, for sampling and the matched peripheral electricity of the driving circuit
The output voltage on road and the Isobarically Control module that constant pressure Regulate signal is exported according to the output voltage and output reference voltage
(500), it is used to export feedback signal to control module (200) according to the constant pressure Regulate signal with to voltage output module
(100) peak point current in is adjusted and then adjusts the PWM control modules (600) that the output voltage is constant voltage；
The control module (200) is separately connected the voltage output module (100), overcurrent benchmark generation module (300), overcurrent
Protection module (400), PWM control modules (600), the overcurrent protection module (400) are also connected with the overcurrent benchmark and generate mould
Block (300), voltage output module (100), the Isobarically Control module (500) connect PWM control modules (600) and described
Peripheral circuit, the voltage output module (100) are additionally coupled to peripheral circuit；
Wherein, the overcurrent benchmark generation module (300) includes for sampling the maximum integral in each turn-on time of main switch
Two maximum integral voltages are simultaneously remained to master next time and opened by voltage and maximum integral voltage in the constant time lag time simultaneously
Close the sampling hold circuit (310) of conducting and the overcurrent benchmark for generating overcurrent reference voltage according to two maximum integral voltages
Generator (320), the overcurrent protection module (400) includes first comparator；The input terminal of the sampling hold circuit (310)
The input terminal of link control module (200) and output end connection overcurrent reference generator (320), the overcurrent reference generator
(320) positive input terminal of output end connection first comparator, the negative input end of first comparator connect voltage output module
(100), the output end link control module (200) of first comparator, wherein the overcurrent reference generator (320) is built with
Following relationship：Wherein, A is normal number, and Ton indicates that the turn-on time of main switch, Td indicate the fixation
Delay time, Vref indicate the overcurrent reference voltage,
Wherein, the constant time lag time is the sum of first comparator delay and main switch shutdown delay, and integral voltage is
The voltage that capacitor charging is generated using electric current of finger.
2. BUCK constant voltage drive circuits according to claim 1, which is characterized in that the control signal is in each clock week
The first pwm signal that high level time length is Ton is formed in phase, the sampling hold circuit (310) includes：Pulse generation
The charge switch be connected when device, PWM signal generator, two N-type metal-oxide-semiconductors, two capacitances, two constant-current sources, two high level,
The impulse generator is triggered by the first pwm signal rising edge and generates pulse signal, and the PWM signal generator is by described
The triggering of first pwm signal rising edge generates the second pwm signal that high level time length is Td；
Impulse generator, PWM signal generator are respectively connected to the control module (200), and the drain electrode of each N-type metal-oxide-semiconductor is equal
One is connected by a charge switch, and capacitance, a source grounding, two N are all connected between constant-current source, source electrode and drain electrode
The grid of type metal-oxide-semiconductor is connected to impulse generator, the control terminal of a charge switch be connected to the PWM signal generator with
Second pwm signal is received, the control terminal of another charge switch is connected to the control module to receive the first PWM
Signal.
3. BUCK constant voltage drive circuits according to claim 2, which is characterized in that the overcurrent reference generator (320)
Including：Divider, multiplier, two voltage followers, metal-oxide-semiconductor mirror current source, first resistor (R1), second resistance (R2)；
Two input terminals of divider are respectively connected to the drain electrode of two N-type metal-oxide-semiconductors, an input terminal admiralty constant of multiplier
A, the output end of another input terminal connection divider, the input terminal of first voltage follower are used to receive the reference electricity of A volts
One end of the output end and first resistor (R1) of pressure, the reference arm of output end connection metal-oxide-semiconductor mirror current source, first resistor
(R1) the other end connects the output end of second voltage follower, the input terminal connection multiplier of second voltage follower
Output end, the first end of the output end connection second resistance (R2) of the output branch of metal-oxide-semiconductor mirror current source, second resistance (R2)
Second end ground connection, the first end of second resistance (R2) is additionally coupled to the positive input terminal of the first comparator.
4. BUCK constant voltage drive circuits according to claim 3, which is characterized in that Isobarically Control module (500) packet
Bleeder circuit (510) and error amplifier are included, the PWM control modules (600) include the second comparator, the bleeder circuit
(510) negative input end of peripheral circuit and error amplifier is connected, the positive input terminal of error amplifier is for receiving output reference
Voltage, the output end of the error amplifier connect the negative input end of the second comparator, the positive input terminal connection of the second comparator
Voltage output module (100), the output end link control module (200) of the second comparator.
5. BUCK constant voltage drive circuits according to claim 4, which is characterized in that the Isobarically Control module (500) is also
Including compensation resistance (Rc) and compensating electric capacity (Cc), the output end of error amplifier is via the compensation resistance (Rc) and compensation electricity
Hold (Cc) and is connected to voltage output module (100).
6. BUCK constant voltage drive circuits according to claim 5, which is characterized in that voltage output module (100) packet
The main switch and inspection leakage resistance (Rcs) are included, the main switch is N-type metal-oxide-semiconductor (M1), control module (200) packet
Include clock generator, rest-set flip-flop, drive module, clock generator connects the set end of rest-set flip-flop, two of rest-set flip-flop
Reset terminal is separately connected the output end of the output end and the second comparator of first comparator, the output end connection driving of rest-set flip-flop
The input terminal of the input terminal and sampling hold circuit (310) of module, the output end of drive module connect the grid of the main switch
Pole, the input voltage outside receiving that drains of the main switch, the source electrode of the main switch are separately connected first comparator
Negative input end, the second comparator positive input terminal and inspection leakage resistance (Rcs) first end, inspection leakage resistance (Rcs) second
End is connected to the output end of error amplifier via the compensation resistance (Rc) and compensating electric capacity (Cc).
7. a kind of BUCK constant-voltage drivers, which is characterized in that encapsulation is just like described in claim any one of 1-6 in the driver
BUCK constant voltage drive circuits.
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| CN111436171B (en) * | 2019-01-14 | 2024-04-12 | 新岸线(北京)科技集团有限公司 | LED driver and output current precision correction method thereof |
| CN110601683B (en) * | 2019-08-19 | 2023-02-10 | 麦歌恩电子(上海)有限公司 | Switch control circuit and control method |
| CN112072938B (en) * | 2020-09-14 | 2022-03-08 | 昂宝电子（上海）有限公司 | Apparatus and method for improving output voltage load regulation rate of switching power supply |
| CN112105124B (en) * | 2020-10-19 | 2023-09-08 | 美芯晟科技(北京)股份有限公司 | Loop type low-power-consumption constant-current control circuit and method |
| CN112398236B (en) * | 2021-01-20 | 2021-04-27 | 深圳赫兹创新技术有限公司 | Wireless charging system control method and device and wireless charging system |
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| CN113162511B (en) * | 2021-04-20 | 2022-08-30 | 江西省万佳通照明科技有限公司 | Broken wall machine integrated circuit |
| CN113193731B (en) * | 2021-04-22 | 2023-11-17 | 广州金升阳科技有限公司 | Current sampling compensation circuit of switching power supply |
| CN115694179B (en) * | 2021-07-21 | 2023-11-21 | 辉芒微电子(深圳)股份有限公司 | Buck constant voltage driver and application circuit thereof |
| CN114944748B (en) * | 2022-07-20 | 2022-11-18 | 中科(深圳)无线半导体有限公司 | Constant frequency control circuit and method for constant on-time control mode converter |
| CN115296259B (en) * | 2022-09-27 | 2022-12-20 | 深圳利普芯微电子有限公司 | Overvoltage protection circuit and LED drive power supply |
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