CN201403054Y - Improved device for realizing switching power supply pulse width modulation technology - Google Patents

Abstract

The utility model discloses an improved device for realizing the switching power supply pulse width modulation technology. A voltage detection device, an error magnifier, a simulation multi-way selector, a comparator and a drive circuit are connected in sequence; the input terminal of a voltage interval judging device is connected with the output terminal of the error magnifier, and the output terminal thereof is connected with the simulation multi-way selector. Different voltage signals are selected to be compared with carrier wave in the comparator based on the different intervals where theerror signals stay, the compare output acts as a drive signal to be used for controlling the operation of a main power switch pipe, so as to adjust the output voltage of the switching power supply. The device can be used for controlling the switching power supply of various topological structures, and has the outstanding advantages that the switching power supply adopting the control scheme has quick transient state response speed.

Description

Improved technique for pulse-width modulation of switching power supply implement device

Technical field

The utility model relates to switch power supply equipment, and especially technique for pulse-width modulation of switching power supply and implement device thereof are made the field.

Background technology

Switching Power Supply is to use a kind of very widely power electronic equipment in fields such as electronics, communication, electric, the energy, Aero-Space, military affairs and household electrical appliances.Advantage such as it has the energy conversion efficiency height, volume is little, in light weight, control precision is high and rapidity is good, in low power range, replaced linear adjustment power supply basically, and rapidly in high-power scope advance, replaced the close rectifier power source of thyristor to a great extent.We can say that switch power technology is the mainstream technology of present middle low power direct current energy converting means.Switching Power Supply mainly is made of power inverter and controller two parts.Power inverter is called power circuit again, mainly comprises switching device, device for transformer and current rectifying and wave filtering circuit.Common power inverter topological structure has Buck buck converter, Boost booster converter, Buck-Boost buck-boost converter, forward converter, anti exciting converter etc.Controller can detection power translation circuit output voltage or other state of circuit, and the work that produces respective switch signal controlling power conversion circuit switching device in view of the above, thus the output valve of the output of by-pass cock power supply to obtain expecting.The structure of controller and operation principle are determined by the control method that Switching Power Supply adopted.For same power circuit topology, adopt different control methods to exert an influence, thereby the research of control method seem and become more and more important to aspects such as the stable state accuracy of system and dynamic properties.

Traditional pulse width modulation (PWM) technology is to be very much the extensive a kind of Switching Power Supply modulation technique that adopts, and it can satisfy general control requirement.Its control thought is: with error amplifier the output voltage and the reference voltage of Switching Power Supply compared the acquisition error signal, by comparator this error signal and sawtooth signal are compared the acquisition pulse width signal again, conducting, shutoff with the control switch device make output voltage reach desired value.When input voltage or load appearance fluctuation, because the error amplifier amplification coefficient is limited and the existence of compensating network, cause error signal variations slow relatively, thereby the variation of pulse duration is also comparatively slow, this makes that the dynamic responding speed of Switching Power Supply is slower.Thereby along with some application scenario for the raising of Switching Power Supply at performance requirement aspect the transient response speed, pulse width modulating technology has been difficult to satisfy this requirement, and this adopts new control method to promote the transient response speed of Switching Power Supply with regard to exigence.

The utility model content

The purpose of this utility model provides a kind of improved technique for pulse-width modulation of switching power supply, to improve Switching Power Supply in the performance aspect the transient response.

The utility model is for solving its technical problem, the technical scheme that is adopted is: improved technique for pulse-width modulation of switching power supply implement device, form by voltage check device, error amplifier, simulation MUX, voltage range determining device, comparator and drive circuit; Voltage check device, error amplifier, simulation MUX, comparator and drive circuit are linked in sequence; Voltage range determining device input links to each other with the output of error amplifier, and its output links to each other with the simulation MUX.

Compared with prior art, the beneficial effects of the utility model are: compare with existing pulse width modulating technology, adopt Switching Power Supply of the present utility model when input voltage or load change, controller is the by-pass cock device action immediately, make Switching Power Supply reach stable state rapidly, promoted the transient response speed of Switching Power Supply greatly.

Description of drawings

Fig. 1 is the utility model control system implement device structured flowchart.

Fig. 2 is the electrical block diagram of the utility model embodiment one.

Fig. 3 is a simulation MUX output and error signal relation schematic diagram in the utility model controller.

Fig. 4 is Switching Power Supply output voltage simulation waveform figure when input voltage mutation of the utility model embodiment one and traditional electrical die mould PWM modulation.(a) input voltage waveform (b) is the output voltage of Switching Power Supply when input voltage mutation of traditional electrical die mould PWM modulation; (c) be the output voltage of Switching Power Supply when input voltage mutation of the utility model embodiment one.

Fig. 5 is Switching Power Supply output voltage simulation waveform figure when input voltage mutation of the utility model embodiment one and traditional electrical die mould PWM modulation.(a) load current waveform (b) is the output voltage of Switching Power Supply when load changing of traditional electrical die mould PWM modulation; (c) be the output voltage of Switching Power Supply when load changing of the utility model embodiment one.

Fig. 6 is the electrical block diagram of the utility model embodiment two.

Embodiment

Below in conjunction with the drawings and specific embodiments the utility model is described in further detail.

Embodiment one

Fig. 1 illustrates, embodiment of the present utility model is: a kind of improved technique for pulse-width modulation of switching power supply, its controller (Controller) mainly are made up of voltage check device VD, error amplifier EA, simulation MUX AM, voltage range determining device VIJ, comparator C OM and drive circuit DC.Power inverter PTD output voltage is compared with reference voltage behind voltage check device VD, obtains error signal then behind error amplifier EA and compensating network CN; Voltage range determining device VIJ produces corresponding signal and goes control simulation MUX AM work according to the size of error voltage; The control signal that simulation MUX AM generates according to voltage range determining device VIJ selects the correspondent voltage signal as output, compares with carrier signal CS then and obtains final control impuls; At last, control impuls is used for the switching device of power controlling converter PTD behind drive circuit DC, obtain the regulated output voltage of expecting thus.

Fig. 2 has provided the application of the utility model in the Buck converter.Output voltage (V _o) and reference voltage (V _Ref) behind error amplifier EA and compensating network CN, obtain error signal (V _e), voltage range determining device VIJ produces corresponding signal according to the error voltage size and controls simulation MUX AM work.Fig. 3 shows simulation MUX AM output and error signal relation schematic diagram.Voltage range determining device VIJ is divided into three intervals with voltage, and promptly voltage is less than V _-Interval, voltage greater than V ₊Interval and voltage range (V _-, V ₊).When error signal is in voltage range (V _-, V ₊) time, voltage range determining device VIJ control simulation MUX AM Select Error signal is as its output (V _c); When error signal less than V _-The time, the fixed voltage V that the controller selection configures in advance _LAs its output; And work as error signal greater than V ₊The time, the output of simulation MUX AM then is V _HV _cAnd V _eRelation very clearly through type (1) represent:

$V_c=\left\{\begin{array}{cc}{V}_L& V_e<V_{-}\\ V_e& V_{-}\&le;V_e\&le;V_{+}\\ V_H& V_e>V_{+}\end{array}\right.---\left(1\right)$

The realization of this relation is then finished by voltage range determining device VIJ and simulation MUX AM.V _cCompare with carrier signal CS and obtain final control impuls, by the work of drive circuit DC control master power switch pipe, the output of by-pass cock power supply is constant to keep again for control impuls.When input voltage or load appearance variation, can cause the respective change of error signal.In case (V between the error signal deviation area _-, V ₊), simulation MUX AM will specify a voltage to compare with carrier signal as new control signal, thus the bigger variation that causes the driving pulse duty ratio obtains fast dynamic responding speed.If V _cBe constantly equal to V _eThen control mode is traditional voltage-type pulse width modulating technology, this also is unique difference of the utility model and traditional electrical die mould pulse width modulating technology, also just because of error signal is handled, thereby has improved the transient response speed of Switching Power Supply.Thereby V _-And V ₊Difference should not be bigger, otherwise dynamic responding speed will can not get tangible lifting.In addition, V _LAnd V _HValue should choose V according to the minimum and the maximum of carrier signal _LAnd V _HValue determined minimum and maximum duty cycle respectively.

Analysis of simulation result:

Fig. 4 is for adopting Pspice software to the Buck converter that adopts traditional electrical die mould pulse width modulating technology and the utility model method respectively output voltage waveforms when the input voltage mutation, the transverse axis of Fig. 4 component (a) and (b), (c) is the time (ms), and the longitudinal axis is voltage (V).As can be seen, when input voltage mutation, adopt Buck converter of the present utility model to have transient response speed faster in Fig. 4, the output voltage fluctuation is little, and carries out new stable state very soon.Simulated conditions: output voltage V _o=V _Ref=6V, inductance L=5.6uH, capacitor C=1000uF, load R=5 Ω, switch periods is 27us.

Fig. 5 occurs output voltage dynamic response time-domain-simulation oscillogram under the sudden change situation for adopting traditional electrical die mould PWM modulation and Switching Power Supply of the present utility model in load, component (a) is a load current, (b) and (c) corresponding respectively traditional electrical die mould pulse width modulation and the output voltage of the present utility model of adopting, transverse axis is the time (ms), (a) be electric current (A) in length and breadth, (b) and (c) longitudinal axis is voltage (V).Among Fig. 5, load current is changed to 3.2A by the 1.2A step when 17ms, and load current is suddenlyd change to 1.2A by 3.2A when 19ms, promptly simulates moment loading and off-load process.Figure is by as seen, when Switching Power Supply loads suddenly or during off-load, for traditional electrical die mould PWM modulation, system response time is long, and can produce higher voltage deviation; And adopting Switching Power Supply transient response speed of the present utility model very fast, system enters new stable state immediately.This shows and adopt Switching Power Supply of the present utility model to have good load dynamic characteristic.Simulated conditions: output voltage V _In=14V, V _o=V _Ref=6V, inductance L=5.6uH, capacitor C=1000uF, switch periods is 27us.

Embodiment two

Fig. 6 illustrates, and this example is compared with embodiment one, and power inverter is an anti exciting converter, and control device is identical with embodiment one.Prove by emulation equally, adopt the output voltage stabilization of anti exciting converter of the present utility model, rapid dynamic response speed.

The utility model also can be used for the Switching Power Supply of Boost converter, Buck-boost converter, forward converter, half-bridge converter, full-bridge converter constant power circuit composition except can be used for controlling two kinds of power inverters in the foregoing description.

Claims (1)

1, a kind of improved technique for pulse-width modulation of switching power supply implement device is made up of voltage check device, error amplifier, simulation MUX, voltage range determining device, comparator and drive circuit; It is characterized in that: voltage check device, error amplifier, simulation MUX, comparator and drive circuit are linked in sequence; Voltage range determining device input links to each other with the output of error amplifier, and its output links to each other with the simulation MUX.

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