CN207251470U

CN207251470U - A kind of adaptive structure BUCK control devices

Info

Publication number: CN207251470U
Application number: CN201721067215.0U
Authority: CN
Inventors: 王建钦; 冉扬眉
Original assignee: KTD ELECTRONICS Co Ltd
Current assignee: KTD ELECTRONICS Co Ltd
Priority date: 2017-08-24
Filing date: 2017-08-24
Publication date: 2018-04-17
Anticipated expiration: 2027-08-24

Abstract

The utility model discloses a kind of adaptive structure BUCK control devices, including capacity voltage dropping circuit, sample circuit, feedback circuit, the sample circuit is parallel to capacity voltage dropping circuit, the feedback circuit is connected to the output terminal of sample circuit, and the output terminal of the feedback circuit is connected to the control terminal of capacity voltage dropping circuit；The capacity voltage dropping circuit, including input voltage VIN, decompression capacitor C1, output capacitance C2, switch S1, switch S2, switch S3, switch S4；The sample circuit is parallel to output capacitance C2 both ends；The feedback circuit includes voltage comparator PWM, reference voltage Vref and reverser INV, the voltage comparator PWM is connected to switch S1, switchs the control terminal of S3, reverser INV connecting valves S2, the control terminal for switching S4, the reference voltage Vref are input to the input terminal of voltage comparator PWM；Thereby, its have the advantages that framework is simple, realizability is strong, reaction speed is fast, using space is small, manufacture cost is low etc..

Description

A kind of adaptive structure BUCK control devices

Technical field

Circuit field technology is the utility model is related to, refers in particular to a kind of adaptive structure BUCK control devices.

Background technology

As shown in Figure 1, a kind of traditional BUCK Topology Switch type circuit structures, it mainly includes input voltage VIN, inductance L1, sustained diode 1, output capacitance C1, controlling switch K1, output sample circuit, error amplifier EA and PWM comparator group Into；One end connection inductance L1 of wherein VIN and the cathode of sustained diode 1, other end ground connection；The other end of inductance L1 connects Connect output capacitance C1 cathodes and output sample circuit；The anode connecting valve K1 of output capacitance C1, the other end of load and afterflow The anode of diode D1；Export other end connecting valve K1, the anode and fly-wheel diode of output capacitance C1 of sample circuit The anode of D1；Anode connecting valve K1, the other end of sample circuit and the anode of output capacitance C1 of sustained diode 1；Error The output of amplifier EA negative terminals input connection sample circuit, negative terminal input connection reference level Vref, error amplifier EA outputs The anode input of end connection PWM comparators, negative terminal input connection fixed cycle signal CLK of PWM comparators；PWM comparators are defeated Go out the control terminal of connecting valve K1；Switch the other end ground connection of K1.

Wherein, Fig. 2 is the BUCK topology voltage transformation schematic diagrams of Fig. 1.IL is the electric current of inductance L1 in BUCK topologys；Open When closing K1 conductings, input voltage VIN, inductance L1, output capacitance C1 and sample circuit, switch K1 composition conductings circuit, input electricity VIN is pressed to charge by inductance L1 to output capacitance C1 and sample circuit, while energy input to inductance L1.Switch K1 shut-offs When, input voltage VIN does not provide energy, inductance L1, output capacitance C1 and output sample circuit, the composition conducting of sustained diode 1 Circuit, the energy of inductance L1 storages pass to output by sustained diode 1.Sampling circuit samples output voltage, sampled voltage Vsample compared with reference level Vref, produces error voltage Vea by error amplifier EA；Error voltage Vea is input to electricity Comparator PWM is pressed to produce the control signal of switch K1 compared with fixed cycle signal CLK；

Above-mentioned traditional BUCK Topology Switch type circuit structures, feedback control loop operation principle are：If input voltage VIN slightly rises Height, then output voltage rise, output voltage rise then export sampled voltage rise, and sampled voltage Vsample and Vref pass through mistake Poor amplifier compares, and output voltage Vea is reduced；Vea is reduced and fixed clock cycle CLK（Sawtooth waveforms）Compare, intersection point shifts to an earlier date, and opens The ON time for closing K1 shortens, and declines output voltage；Similarly, if input voltage VIN declines, switch K1 ON times prolong It is long, output voltage is remained unchanged, realizes that output voltage is constant.

Due to simple in structure, it is widely used this control mode, but its there are problems with：Contain a power inductance L1, causes overall volume big；And contain a fast reaction diode D1 so that of high cost；Whole backfeed loop not only needs Reference level Vref is provided, also needs to provide fixed cycle signal CLK (sawtooth signal)；Can profit to some application scenarios, such as PCB With space it is small, cannot there is the component of large volume, high-frequency application to use power inductance etc., have larger limitation.

Utility model content

In view of this, in view of the existing deficiencies of the prior art, its main purpose is to provide a kind of adaptive the utility model Structure BUCK control devices, its with framework is simple, realizability is strong, reaction speed is fast, using space is small, manufacture cost is low etc. Advantage.

To achieve the above object, the utility model is using following technical solution：

A kind of adaptive structure BUCK control devices, including capacity voltage dropping circuit, sample circuit, feedback circuit, it is described to adopt For sample circuit in parallel in capacity voltage dropping circuit, the feedback circuit is connected to the output terminal of sample circuit, the feedback circuit it is defeated Outlet is connected to the control terminal of capacity voltage dropping circuit；

The capacity voltage dropping circuit, including input voltage VIN, decompression capacitor C1, output capacitance C2, switch S1, switch S2, Switch S3, switch S4；The sample circuit is parallel to output capacitance C2 both ends；The cathode connecting valve of the input voltage VIN One end of S1, the anode ground connection of input voltage VIN, switchs one end of the other end connecting valve S2 and decompression capacitor C1 of S1, opens Close other end connecting valve S3, the output capacitance C2 of S2 and one end of sample circuit, output capacitance C2 other ends connection input electricity The anode of VIN is pressed, the sample circuit other end connects the anode of input voltage VIN；Switch the other end connection decompression capacitor C1 of S3 The other end and switch S4, switch S4 the other end connection input voltage VIN anode；

The feedback circuit, including voltage comparator PWM, reference voltage Vref and reverser INV, the reference voltage Vref is input to the input terminal of voltage comparator PWM；The negative input end of the output terminal connection voltage comparator PWM of sample circuit, The positive input terminal connection reference voltage Vref of voltage comparator PWM, output terminal connecting valve S1, the switch of voltage comparator PWM The control terminal of S3 and the input terminal of reverser INV, the output terminal connecting valve S2 of reverser INV, the control terminal for switching S4.

As a preferred embodiment, the switch S1 is mutually switched with switch S3 to be same, and switch S2 and switch S4 mutually open to be same Close, switch S1 and switch S2 are phase-veversal switch；

As switch S1 and switch S3 conductings, when switch S2 and switch S4 are disconnected, decompression capacitor C1 and output capacitance C2 series connection, Input voltage VIN charges decompression capacitor C1, output capacitance C2, and provides load current；

When switch S1 and switch S3 are disconnected, and switch S2 and switch S4 conductings, decompression capacitor C1 and output capacitance C2 are in parallel, Decompression capacitor C1, output capacitance C2 discharge and provide load current.

As a preferred embodiment, the switch S1, switch S2, switch S3, switch S4 open for NMOS tube switch, metal-oxide-semiconductor Close or FET pipes switch.

As a preferred embodiment, the sample circuit includes resistance R1, the resistance R2 being in series, and the sample circuit leads to Cross resistance ratio pressure-dividing output voltage value；The reference voltage Vref and resistance ratio of voltage comparator PWM determines output voltage values Vout=Vref(R1+R2)/R1。

The utility model has clear advantage and beneficial effect compared with prior art, specifically, by above-mentioned technology Scheme understands that it is mainly by way of capacitance and switch are combined control, without power inductance and fly-wheel diode so that Overall volume is small, and reduces cost；Series connection and the decompression in parallel for realizing input voltage by two capacitances, using feeding back to Road, regulated output voltage；W-response speed is fast, makes output voltage not affected by a load；The capacitance of small size realizes BUCK Topological structure, the adaptive function that adjusts realize input voltage and output voltage ripple inhibitory action, effectively reduce ripple Influence to output loading.

More clearly to illustrate the architectural feature of the utility model, technological means and its specific purposes and work(reached Can, the utility model is described in further detail with specific embodiment below in conjunction with the accompanying drawings：

Brief description of the drawings

Fig. 1 is a kind of traditional BUCK topological circuit structures；

Fig. 2 is the voltage transformation schematic diagram of Fig. 1 topological circuits；

Fig. 3 is the circuit function block diagram of the embodiment of the utility model；

Fig. 4 is the specific circuit structure of the embodiment of the utility model；

Fig. 5 is the voltage transformation schematic diagram of the embodiment of the utility model.

Attached drawing identifier declaration：

10th, capacity voltage dropping circuit

20th, sample circuit

30th, feedback circuit.

Embodiment

It refer to shown in Fig. 3 to Fig. 5, that show the concrete structure of the embodiment of the utility model；It includes capacitance Reduction voltage circuit 10, sample circuit 20, feedback circuit 30, the sample circuit 20 are parallel to capacity voltage dropping circuit 10, the feedback Circuit 30 is connected to the output terminal of sample circuit 20, and the output terminal of the feedback circuit 30 is connected to the control of capacity voltage dropping circuit 10 End processed.

Wherein, the capacity voltage dropping circuit 10, including input voltage VIN, decompression capacitor C1, output capacitance C2, switch S1, Switch S2, switch S3, switch S4；The sample circuit 20 is parallel to output capacitance C2 both ends；The feedback circuit 30 includes electricity Comparator PWM, reference voltage Vref and reverser INV, the voltage comparator PWM is pressed to be connected to the control of switch S1, switch S3 End processed and reverser INV, reverser INV connecting valves S2, the control terminal for switching S4, the reference voltage Vref are input to voltage The input terminal of comparator PWM.

Specifically, one end of the cathode connecting valve S1 of the input voltage VIN, the anode ground connection of input voltage VIN, One end of the other end connecting valve S2 and decompression capacitor C1 of S1 are switched, switchs other end connecting valve S3, the output capacitance of S2 One end of C2 and sample circuit, the output capacitance C2 other ends connect the anode of input voltage VIN, and the connection of the sample circuit other end is defeated Enter the anode of voltage VIN；The other end and switch S4 of the other end connection decompression capacitor C1 of S3 is switched, the other end for switching S4 connects Connect the anode of input voltage VIN；

The negative input end of the output terminal connection voltage comparator PWM of sample circuit 20, the positive input terminal of voltage comparator PWM Reference voltage Vref is connected, the input terminal and switch S1 of the output terminal connection reverser INV of voltage comparator PWM, switch S3's Control terminal, the output terminal connecting valve S2 of reverser INV, the control terminal for switching S4；In addition, in this present embodiment, the sampling Circuit 20 includes resistance R1, the resistance R2 being in series.

As shown in figs. 4 and 5,4 switching tubes are controlled by voltage comparator PWM, within an actuation time, switch S1 and the switch same phases of S3, switch S2 and the switch same phases of S4, wherein switch S1 and switch S2 are anti-phase；When switching S1 and switch S3 conductings Between be Ton, switch S2 and switch S4 ON times be Toff；In switch S1 and switch S3 conductings, switch S2 and switch S4 shut-offs When, i.e., in the Ton periods, decompression capacitor C1 and output capacitance C2 series connection, input voltage VIN charges 2 capacitances, and provides Electric current needed for load；Turn in switch S2 and switch S4, when switching S1 and switch S3 shut-offs, i.e., in the Toff periods, be depressured Capacitance C1 and output capacitance C2 is in parallel, 2 capacitance electric discharges, provides load the energy of Ton period memory storages；

In this present embodiment, feedback circuit determines the size of output voltage values；In sample circuit, pass through resistance ratio point Press output voltage values；The reference voltage Vref and resistance ratio of voltage comparator PWM determines output voltage values Vout=Vref (R1+ R2)/R1；If output voltage Vout rise, output voltage sampling sampled level shift to an earlier date with Vref intersection points, shorten switch S1 with The ON time Ton of S3；Similarly, output voltage Vout declines, then extends the ON time Ton of switch S1 and S3；Toff by Input voltage, output voltage, capacitance C1 and C2 are determined；If the change of actual loading situation can also change Toff values, therefore Ton+ The Toff times are a changing values, are that frequency change is adjusted；Frequency is larger when overloaded, if decompression capacitor C1 and output capacitance C2 Equal, ignoring load has capacitive influence, its control signal duty cycle is 50%.

In addition, in this present embodiment, described 4 switch S1, S2, S3, and S4 is made of NMOS, can also be managed by MOS or FET Realize；Since decompression capacitor C1 and output capacitance C2 exist in overall charging and discharging circuit all the time, then equivalent string can be used Join the less capacitances of resistance ESR to improve transfer efficiency；Efficiency can be improved using suitable capacitance, output power is reached required Desired value.

In conclusion the design focal point of the utility model is, it is mainly combined control by capacitance and switch Mode, without power inductance and fly-wheel diode so that overall volume is small, and reduces cost；Pass through the series connection of two capacitances With the decompression in parallel for realizing input voltage, backfeed loop, regulated output voltage are utilized；W-response speed is fast, makes output voltage It is not affected by a load；The capacitance of small size realizes BUCK topological structures, it is adaptive adjust function realize input voltage with it is defeated Go out voltage ripple inhibitory action, effectively reduce influence of the ripple to output loading.

The above descriptions are merely preferred embodiments of the present invention, and not the technical scope of the utility model is made Any restrictions, therefore every any trickle amendment made according to the technical essence of the utility model to above example, equivalent change Change and modification, in the range of still falling within technical solutions of the utility model.

Claims

A kind of 1. adaptive structure BUCK control devices, it is characterised in that：Including capacity voltage dropping circuit, sample circuit, feedback electricity Road, the sample circuit are parallel to capacity voltage dropping circuit, and the feedback circuit is connected to the output terminal of sample circuit, the feedback The output terminal of circuit is connected to the control terminal of capacity voltage dropping circuit；

The capacity voltage dropping circuit, including input voltage VIN, decompression capacitor C1, output capacitance C2, switch S1, switch S2, switch S3, switch S4；The sample circuit is parallel to output capacitance C2 both ends；The cathode connecting valve S1's of the input voltage VIN One end, the anode ground connection of input voltage VIN, switchs one end of the other end connecting valve S2 and decompression capacitor C1 of S1, switchs S2 Other end connecting valve S3, output capacitance C2 and sample circuit one end, the output capacitance C2 other ends connection input voltage VIN Anode, the sample circuit other end connect input voltage VIN anode；Switch the another of the other end connection decompression capacitor C1 of S3 End and switch S4, switch the anode of the other end connection input voltage VIN of S4；

The feedback circuit, including voltage comparator PWM, reference voltage Vref and reverser INV, the reference voltage Vref are defeated Enter the input terminal to voltage comparator PWM；The negative input end of the output terminal connection voltage comparator PWM of sample circuit, voltage ratio Positive input terminal connection reference voltage Vref compared with device PWM, the output terminal connecting valve S1 of voltage comparator PWM, the control for switching S3 End processed and the input terminal of reverser INV, the output terminal connecting valve S2 of reverser INV, the control terminal for switching S4.
A kind of 2. adaptive structure BUCK control devices according to claim 1, it is characterised in that：The switch S1 and open It is with mutually switch to close S3, and switch S2 is that switch S1 and switch S2 are phase-veversal switch with mutually switch with switch S4；

As switch S1 and switch S3 conductings, when switch S2 and switch S4 are disconnected, decompression capacitor C1 and output capacitance C2 series connection, input Voltage VIN charges decompression capacitor C1, output capacitance C2, and provides load current；

When switch S1 and switch S3 are disconnected, and switch S2 and switch S4 conductings, decompression capacitor C1 and output capacitance C2 are in parallel, are depressured Capacitance C1, output capacitance C2 discharge and provide load current.
A kind of 3. adaptive structure BUCK control devices according to claim 1, it is characterised in that：The switch S1, open It is NMOS tube switch, metal-oxide-semiconductor switch or FET pipes switch to close S2, switch S3, switch S4.
A kind of 4. adaptive structure BUCK control devices according to claim 1, it is characterised in that：The sample circuit bag The resistance R1 being in series, resistance R2 are included, the sample circuit passes through resistance ratio pressure-dividing output voltage value；Voltage comparator PWM Reference voltage Vref and resistance ratio determine output voltage values Vout=Vref (R1+R2)/R1.