CN209417172U - A kind of analog voltage step instrument - Google Patents

Abstract

The utility model relates to a kind of analog voltage step instrument, including control circuit, driving circuit and switch switching circuit, the output end of the control circuit and the input terminal of driving circuit connect, the output end of driving circuit and the input terminal of switch switching circuit connect, one input terminal of the switch switching circuit connects high-end voltage, its another input terminal connects lower terminal voltage, and the output end of the switch switching circuit and load connect, and the feeder ear of the control circuit is connect with the high-end voltage.Analog voltage step instrument described in the utility model, circuit is simple, portable, and shakes small when voltage jump, Voltage Drop that circuit is generated in voltage jump and overshoots smaller, shakes smaller.

Description

A kind of analog voltage step instrument

Technical field

The utility model relates to DC/DC converter the field of test technology, and in particular to a kind of analog voltage step instrument.

Background technique

Input voltage step is the important indicator of DC/DC converter, mainly examination when input voltage two kinds of voltages it Between when mutually switching, the variable quantity and transformation period of output voltage, since voltage step time requirement is Microsecond grade, armrest Dynamic switching cannot achieve, and programmable power supply inside programming can not reach requirement.

Utility model content

The purpose of this utility model is to provide a kind of analog voltage step instrument, circuit is simple, less using device, suitable It carries, is very suitable to the occasion that high-volume tests power supply.

To achieve the above object, the utility model uses following technical scheme:

A kind of analog voltage step instrument, including control circuit, driving circuit and switch switching circuit, the control circuit The connection of the input terminal of output end and driving circuit, the output end of driving circuit and the input terminal of switch switching circuit connect, described One input terminal of switch switching circuit connects high-end voltage, and another input terminal connects lower terminal voltage, the switch switching circuit Output end and load connect, and the feeder ear of the control circuit is connect with the high-end voltage.

As a further improvement of the above technical scheme:

The control circuit is formed using 555 timers and peripheral circuit.

The driving circuit includes triode V1, resistance R3 and resistance R5, the base stage and control circuit of the triode V1 Output end connection, the collector of triode V1 connects through resistance R3 and the input terminal of switch switching circuit, the hair of triode V1 The emitter grounding and emitter is connect through resistance R5 with its base stage.

The switch switching circuit includes metal-oxide-semiconductor VS, diode V3, resistance R4 and capacitor C1, the grid of the metal-oxide-semiconductor VS It is connect with driving circuit, the drain of the metal-oxide-semiconductor VS is connect through capacitor C1 with its source electrode, one end of the resistance R4 and metal-oxide-semiconductor The grid of VS connects, and the other end is connect with the source electrode of metal-oxide-semiconductor VS, and the source electrode of metal-oxide-semiconductor VS is through connecting to power supply, the diode The cathode of V3 is connect with the drain of metal-oxide-semiconductor VS, and the anode of diode V3 connects to power supply.

It further include auxiliary power supply circuit, the auxiliary power supply circuit includes triode V2, resistance R6, capacitor C2 and diode The emitter of D1, the triode V2 connect to the control circuit, and the collector of triode V2 connects to power supply, the triode V2 Base stage connect through resistance R6 with its collector, the cathode of the diode D1 is connect with the base stage of triode V2, diode D1 Plus earth.

As shown from the above technical solution, analog voltage step instrument described in the utility model, circuit is simple, portable, and electricity It is shaken when pressing transition small.This circuit uses P-channel metal-oxide-semiconductor, and metal-oxide-semiconductor switching speed reaches nanosecond, behind experiments have shown that circuit Transit times can achieve 10~20us or so, meet use condition.The voltage that this circuit is generated in voltage jump simultaneously Fall and overshoot smaller, there is no shake.

Detailed description of the invention

Fig. 1 is the circuit block diagram of the utility model；

Fig. 2 is the circuit diagram of the utility model；

Fig. 3 is the internal circuit diagram of 555 timer of the utility model；

Fig. 4 is 555 timer of the utility model output pulse diagram.

Specific embodiment

The utility model is described further with reference to the accompanying drawing:

As shown in Figure 1, the analog voltage step instrument of the present embodiment, including control circuit, driving circuit and switching electricity The input terminal of road, the output end of control circuit and driving circuit connects, the output end of driving circuit and switch switching circuit it is defeated Enter end connection, an input terminal of switch switching circuit connects high-end voltage, and another input terminal connects lower terminal voltage, which cuts The output end and load for changing circuit connect, and the feeder ear of control circuit is connect with high-end voltage.

Control circuit is formed using 555 timers and peripheral circuit.555 timer is for providing an adjustable frequency Carry out driving switch pipe with the pwm signal of pulsewidth, driving circuit is the turn-off speed opened in order to accelerate metal-oxide-semiconductor VS.

Driving circuit includes triode V1, resistance R3 and resistance R5, the base stage of triode V1 and the output end of control circuit The collector of connection, triode V1 is connected through resistance R3 and the input terminal of switch switching circuit, the emitter ground connection of triode V1 And the emitter is connect through resistance R5 with its base stage.

Switch switching circuit includes metal-oxide-semiconductor VS, diode V3, resistance R4 and capacitor C1, and the grid of metal-oxide-semiconductor VS is through resistance R3 It is connect with the collector of triode V1, the drain of metal-oxide-semiconductor VS is connect through capacitor C1 with its source electrode, one end of resistance R4 and metal-oxide-semiconductor The grid of VS connects, and the other end is connect with the source electrode of metal-oxide-semiconductor VS, the source electrode of metal-oxide-semiconductor VS through connecting to power supply, diode V3's Cathode is connect with the drain of metal-oxide-semiconductor VS, and the anode of diode V3 connects to power supply.

The present embodiment further includes auxiliary power supply circuit, the auxiliary power supply circuit include triode V2, resistance R6, capacitor C2 and The emitter of diode D1, triode V2 connect to the control circuit, and the collector of triode V2 connects to power supply, the triode The base stage of V2 is connect through resistance R6 with its collector, and the cathode of the diode D1 is connect with the base stage of triode V2, diode The plus earth of D1.

Working principle: the moment that circuit as shown in Figure 1 powers on, since capacitor C has little time to charge, Vc=0v, so 555 timer states are 1, and output Vo is high level.Then T ends, and collector output disconnects over the ground, and power Vcc capacitor C fills Electricity, charge circuit are VCC-R1-R2-C-ground, are exponentially risen, and circuit enters temporary stable state I.When rising to 2Vcc/3 When (TH, end level be greater than Vc), output switching activity is low level.Vo is low level, and T conducting, C electric discharge, discharge loop is C-R2- T-ground, exponentially declines, and circuit enters temporary stable state.(TH, end level are less than Vc), output switching activity when dropping to Vcc/3 For high level, discharge tube T cut-off, capacitor charges again, so generates periodically output pulse such as Fig. 4 institute again and again Show.

The parameter of multivibrator two temporary stable states held time depending on RC charge and discharge circuit.Such as the dimension of temporary stable state I It holds the time, that is, exports 0.7 (R1+R2) C of direct impulse width T1 ≈ of Vo；Temporary stable state II is held time, i.e., output Vo's is negative To pulse width T2 ≈ 0.7R2C.Therefore, cycle of oscillation T=T1+T2=0.7 (R1+2R2) C, frequency of oscillation f=1/T.Direct impulse The ratio between width T1 and cycle of oscillation T claim the duty ratio D of rectangular wave, D=(R1+R2)/(R1+2R2) can be obtained by above-mentioned condition, if making R2 > > R1, then D ≈ 1/2, the i.e. equal rectangular wave (square wave) of the positive negative sense pulse width of output signal.

The metal-oxide-semiconductor that this circuit uses, in order to increase the driving capability of PWM, increases by one for IRF9530 type P-channel MOSFET Grade transistor drive circuit, the collector of triode V1 are followed by the VS of metal-oxide-semiconductor by divider resistance R3, R4, and emitter passes through one A resistance eutral grounding.The effect of increase divider resistance is the Vgs > -20V due to MOSFET, is set as 12V here, then divides at this time Resistance R3/R4=2.33, taking R3 is 15k Ω, therefore R4 takes 6.4 Ω.

Metal-oxide-semiconductor will switch two-way input, and the input voltage of low side is directly connect by a Schottky diode V3 to be exported End, high-end input voltage are connect by switching tube V2 in output end, and when metal-oxide-semiconductor turns off, circuit directly exports lower terminal voltage, metal-oxide-semiconductor When conducting, high-end voltage-drop loading reversely ends in output end, while by the Schottky diode that low side inputs, and circuit output is high Hold voltage.

Fig. 3 is the internal circuit diagram of 555 timers, as shown in figure 3,5 foot meridian capacitors of 555 timers are grounded, comparator The comparison voltage of C1 and C2 are as follows: UR1=2/3VCC, UR2=1/3VCC.Work as VI1 > 2/3VCC, when VI2 > 1/3VCC, comparator C1 is defeated Low level out, comparator C2 export high level, and basic RS filpflop sets 0, G3 output high level, and discharge diode TD conducting is fixed When device export low level.As VI1<2/3VCC, VI2>1/3VCC, comparator C1 exports high level, the high electricity of comparator C2 output Flat, basic RS filpflop maintains the original state constant, and 555 timer output states remain unchanged.Work as VI1>2/3VCC, VI2<1/ When 3VCC, comparator C1 exports low level, and comparator C2 exports low level, and it is low that basic RS filpflop both ends are all set to 1, G3 output Level, discharge diode TD cut-off, timer export high level.As VI1 < 2/3VCC, VI2 < 1/3VCC, comparator C1 output High level, comparator C2 export low level, and basic RS filpflop sets 1, G3 output low level, discharge diode TD cut-off, timing Device exports high level.

Embodiment described above is only that preferred embodiments of the present invention are described, not practical to this Novel range is defined, and under the premise of not departing from the spirit of the design of the utility model, those of ordinary skill in the art are to this The various changes and improvements that the technical solution of utility model is made should all fall into the protection that the utility model claims book determines In range.

Claims (5)

1. a kind of analog voltage step instrument, it is characterised in that: described including control circuit, driving circuit and switch switching circuit The output end of control circuit and the input terminal of driving circuit connect, the output end of driving circuit and the input terminal of switch switching circuit Connection, an input terminal of the switch switching circuit connect high-end voltage, and another input terminal connects lower terminal voltage, which cuts The output end and load for changing circuit connect, and the feeder ear of the control circuit is connect with the high-end voltage.

2. analog voltage step instrument according to claim 1, it is characterised in that: the control circuit uses 555 timers And peripheral circuit composition.

3. analog voltage step instrument according to claim 1, it is characterised in that: the driving circuit include triode V1, The output end of the base stage and control circuit of resistance R3 and resistance R5, the triode V1 connects, and the collector of triode V1 is through electricity The input terminal for hindering R3 and switch switching circuit connects, and the emitter of triode V1 is grounded and the emitter is through resistance R5 and its base stage Connection.

4. analog voltage step instrument according to claim 1, it is characterised in that: the switch switching circuit includes metal-oxide-semiconductor VS, diode V3, resistance R4 and capacitor C1, the grid of the metal-oxide-semiconductor VS are connect with driving circuit, the drain of the metal-oxide-semiconductor VS It is connect through capacitor C1 with its source electrode, one end of the resistance R4 is connect with the grid of metal-oxide-semiconductor VS, and the other end is with metal-oxide-semiconductor VS's Source electrode connection, the source electrode of metal-oxide-semiconductor VS is through connecting to power supply, and the cathode of the diode V3 is connect with the drain of metal-oxide-semiconductor VS, two poles The anode of pipe V3 connects to power supply.

5. analog voltage step instrument according to claim 1, it is characterised in that: it further include auxiliary power supply circuit, it is described auxiliary Helping power supply circuit includes triode V2, resistance R6, capacitor C2 and diode D1, the emitter and control circuit of the triode V2 Connection, the collector of triode V2 connect to power supply, and the base stage of the triode V2 is connect through resistance R6 with its collector, described The cathode of diode D1 is connect with the base stage of triode V2, the plus earth of diode D1.