A kind of WEDM control system stepper motor driving circuit
阅读说明：本技术 一种线切割控制系统步进电机驱动电路 (A kind of WEDM control system stepper motor driving circuit ) 是由 潘建华 徐振伟 朱高凯 郎干勇 石荣 吴红英 刘静 杨永广 李香 于 2019-09-19 设计创作，主要内容包括：一种线切割控制系统步进电机驱动电路。涉及线切割控制系统,尤其涉及一种线切割控制系统步进电机驱动电路。提供了一种无论电机是在锁定状态还是在运行状态,均使导通相绕组的电流保持额定值的一种线切割控制系统步进电机驱动电路。包括步进电机脉冲使能电路、步进电机驱动及斩波电路、全电流工作及半流锁定电流控制电路和微控制单元；所述电阻R70的一端与二极管D70的一端电性连接,另一端连接至迟滞比较器U4与电阻R7之间；所述二极管的另一端连接至场效应管Q1与电阻R6之间。本发明具有结构紧凑合理,性能稳定,在锁定状态还是在运行状态,均使导通相绕组的电流保持额定值等特点。(A kind of WEDM control system stepper motor driving circuit.It is related to WEDM control system more particularly to a kind of WEDM control system stepper motor driving circuit.Providing one kind, no matter motor is so that the electric current that phase winding is connected is kept a kind of WEDM control system stepper motor driving circuit of rated value in lock state or in operating status.Circuit, stepper motor driving and chopper circuit, total current work and semi-fluid lock current control circuit and micro-control unit are enabled including stepper motor pulse；One end of the resistance R70 and one end of diode D70 are electrically connected, and the other end is connected between hysteresis comparator U4 and resistance R7；The other end of the diode is connected between field-effect tube Q1 and resistance R6.The present invention have it is compact-sized rationally, performance stablize, in lock state still in operating status, make be connected phase winding electric current holding rated value the features such as.)
1. a kind of WEDM control system stepper motor driving circuit, which is characterized in that including stepper motor pulse enable circuit, Stepper motor driving and chopper circuit, total current work and semi-fluid lock current control circuit and micro-control unit；
It includes capacitor C1, photo-coupler U1, resistance R2, resistance R3, phase inverter U2 and electricity that the stepper motor pulse, which enables circuit, Hinder R4；
A connecting pin of the photo-coupler U1 is electrically connected by resistance R1 and the phase drive pulse signal end stepper motor A；
Two connecting pins of the photo-coupler U1 drive enable signal end telecommunications to connect with stepper motor A phase；
One end of the capacitor C1 is connected between the phase drive pulse signal end stepper motor A and photo-coupler U1, another End is connected to the stepper motor A phase and drives between enable signal end and photo-coupler U1；
Three connecting pins of the photo-coupler U1 are grounded；
Four connecting pins of the photo-coupler U1 are electrically connected by a connecting pin of resistance R3 and phase inverter U2；
Two connecting pins of the phase inverter U2 and the stepper motor drive and chopper circuit is electrically connected；
One end of the resistance R2 is connected between resistance R3 and photo-coupler U1, and the other end connects to power supply；
One end of the resistance R4 is connected between the phase inverter U2 and stepper motor driving and chopper circuit, the other end and electricity Source connection；
The stepper motor driving and chopper circuit include door U3, resistance R5, field-effect tube Q1, sustained diode 0, sluggish ratio Compared with device U4, resistance R6, resistance R7, resistance R8, resistance R9, resistance R16 and capacitor C2；
The door U3, resistance R5 and field-effect tube Q1 are successively electrically connected；
A connecting pin of the door U3 and two connecting pins of the phase inverter U2 are electrically connected；
The drain electrode of the field-effect tube Q1 is electrically connected by stepper motor winding r1 and working power；
The sustained diode 0 is connected in parallel on the both ends of the stepper motor winding r1；
Two connecting pins of the hysteresis comparator U4 and one end of the resistance R7 are electrically connected, and the other end is with field-effect tube Q1's Source electrode is electrically connected；
One end of the resistance R6 and the source electrode of field-effect tube Q1 are electrically connected, other end ground connection；
One end of the capacitor C2 is connected to hysteresis comparator U4 between resistance R7, other end ground connection；
One end of the resistance R8 and three connecting pins of hysteresis comparator U4 are electrically connected, and the other end works with total current and semi-fluid Lock current control circuit and micro-control unit are electrically connected；
A connecting pin of the hysteresis comparator U4 and one end of resistance R9 are electrically connected with the pin two of the door U3 respectively；Institute The other end for stating resistance R9 is connected to hysteresis comparator U4 between resistance R8；
The connecting pin V2 of the micro-control unit and a connecting pin of hysteresis comparator U4 are electrically connected, and the one of the resistance R16 End is electrically connected in-between, and the other end connects to power supply；
The connecting pin V0 of the micro-control unit is connected between the resistance R3 and phase inverter U2；
Total current work and semi-fluid lock current control circuit include resistance R15, diode D1, resistance R14, capacitor C4, Resistance R12, resistance R13, operational amplifier U5, resistance R10, resistance R11 and capacitor C3
The connecting pin V1 of the micro-control unit passes sequentially through diode D1, resistance R14 and the pin three of operational amplifier U5 is gone here and there Connection；
One end of the resistance R15 is connected between diode D1 and micro-control unit, and the other end connects to power supply；
One end of the resistance R12 is connected between resistance R14 and comparator U5, and the other end connects to power supply；
One end of the resistance R13 is connected between resistance R14 and comparator U5, other end ground connection；
One end of the capacitor C4 is connected between resistance R14 and comparator U5, other end ground connection；
The pin one of the comparator U5 passes through the resistance R10 being sequentially connected in series and resistance R11 ground connection；
The pin two of the comparator U5 is connected between the pin one of comparator U5 and resistance R10；
The capacitor C3 is connected in parallel on the both ends of the resistance R11；
The resistance R8 and capacitor C3 is electrically connected.
2. a kind of WEDM control system stepper motor driving circuit according to claim 1, which is characterized in that described anti- The model 74HC14D of phase device U2.
3. a kind of WEDM control system stepper motor driving circuit according to claim 1, which is characterized in that the step It further include the resistance R70 and diode D70 being sequentially connected in series into motor driven and chopper circuit；
One end of the resistance R70 and one end of diode D70 are electrically connected, and the other end is connected to hysteresis comparator U4 and resistance Between R7；
The other end of the diode is connected between field-effect tube Q1 and resistance R6.
4. a kind of WEDM control system stepper motor driving circuit according to claim 1, which is characterized in that described two The negative pole end and resistance R70 of pole pipe D70 is electrically connected.
5. a kind of WEDM control system stepper motor driving circuit according to claim 1, which is characterized in that described two The positive terminal and resistance R70 of pole pipe D70 is electrically connected.
6. a kind of WEDM control system stepper motor driving circuit according to claim 1, which is characterized in that described micro- The model STM8GC104R8 of control unit.
Technical field
The present invention relates to WEDM control system more particularly to a kind of WEDM control system stepper motor driving circuits.
Background technique
Existing high speed WEDM control system mostly uses stepper motor to drive X, Y, U, V axis, X, Y, U, V shaft step motor Driving power generally uses 24V DC power supply to be powered, opened loop control, and system control is simple, at low cost.
When actual motion, if stepper motor is run at high speed, the influence of electrical time constant is significantly increased: the conducting phase Between, electric current cannot rapidly rise to rated value；During cut-off, winding current cannot disappear immediately.Thus, the torque that motor generates It is decreased obviously.In addition to this, excitation winding both ends can also generate very high back-emf in cut-off time, if taking no action to, It is possible that damage switch element.For these problems, usually there is following requirement to driving circuit:
(1) rising edge and failing edge of current waveform can be improved, generate the current waveform close to rectangle.Consider circuit letter The factors such as single, at low cost, low-power stepper motor can be reduced time constant by series limiting resistor, widen working frequency model It encloses.But phase current rated value when in order to maintain continuous motor static, supply voltage must increase, it is therefore desirable to DC power supply hold It measures bigger.When motor is static, the major part of power supply output is consumed on concatenated current-limiting resistance, is at this moment produced on current-limiting resistance Raw heat must distribute rapidly, otherwise be likely to occur problem.It can be seen that simple series limiting resistor is to improve speed degree The inefficient method of one kind of range.For high-power or relatively high power stepper motor, it is often used the side such as high-low pressure or copped wave Formula driving.These driving methods are although more complex, but drive characteristic is good, and have higher efficiency.
(2) circuit for release current energy during cut-off is set, the back-emf that winding both ends generate is reduced, accelerates electric current Decaying.
(3) the low in energy consumption, high-efficient of driving circuit is required.
Summary of the invention
In view of the above problems, providing one kind, no matter motor is made in lock state or in operating status to the present invention The electric current that phase winding is connected keeps a kind of WEDM control system stepper motor driving circuit of rated value.
The technical scheme is that including the enabled circuit of stepper motor pulse, stepper motor driving and chopper circuit, complete Current work and semi-fluid lock current control circuit and micro-control unit；
It includes capacitor C1, photo-coupler U1, resistance R2, resistance R3, phase inverter U2 that the stepper motor pulse, which enables circuit, With resistance R4；
A connecting pin of the photo-coupler U1 is electrically connected by resistance R1 with stepper motor A phase drive pulse signal end It connects；
Two connecting pins of the photo-coupler U1 drive enable signal end telecommunications to connect with stepper motor A phase；
One end of the capacitor C1 is connected between the phase drive pulse signal end stepper motor A and photo-coupler U1, The other end is connected to the stepper motor A phase and drives between enable signal end and photo-coupler U1；
Three connecting pins of the photo-coupler U1 are grounded；
Four connecting pins of the photo-coupler U1 are electrically connected by a connecting pin of resistance R3 and phase inverter U2；
Two connecting pins of the phase inverter U2 and the stepper motor drive and chopper circuit is electrically connected；
One end of the resistance R2 is connected between resistance R3 and photo-coupler U1, and the other end connects to power supply；
One end of the resistance R4 is connected between the phase inverter U2 and stepper motor driving and chopper circuit, the other end It connects to power supply；
Stepper motor driving and chopper circuit include door U3, resistance R5, field-effect tube Q1, sustained diode 0, late Stagnant comparator U4, resistance R6, resistance R7, resistance R8, resistance R9, resistance R16 and capacitor C2；
The door U3, resistance R5 and field-effect tube Q1 are successively electrically connected；
A connecting pin of the door U3 and two connecting pins of the phase inverter U2 are electrically connected；
The drain electrode of the field-effect tube Q1 is electrically connected by stepper motor winding r1 and working power；
The sustained diode 0 is connected in parallel on the both ends of the stepper motor winding r1；
Two connecting pins of the hysteresis comparator U4 and one end of the resistance R7 are electrically connected, the other end and field-effect tube The source electrode of Q1 is electrically connected；
One end of the resistance R6 and the source electrode of field-effect tube Q1 are electrically connected, other end ground connection；
One end of the capacitor C2 is connected to hysteresis comparator U4 between resistance R7, other end ground connection；
One end of the resistance R8 and three connecting pins of hysteresis comparator U4 are electrically connected, the other end and total current work and Semi-fluid lock current control circuit and micro-control unit are electrically connected；
A connecting pin of the hysteresis comparator U4 and one end of resistance R9 electrically connect with the pin of the door U3 two respectively It connects；The other end of the resistance R9 is connected to hysteresis comparator U4 between resistance R8；
The connecting pin V2 of the micro-control unit and a connecting pin of hysteresis comparator U4 are electrically connected, the resistance R16 One end be electrically connected in-between, the other end connects to power supply；
The connecting pin V0 of the micro-control unit is connected between the resistance R3 and phase inverter U2；
The total current work and semi-fluid lock current control circuit include resistance R15, diode D1, resistance R14, capacitor C4, resistance R12, resistance R13, operational amplifier U5, resistance R10, resistance R11 and capacitor C3；
The connecting pin V1 of the micro-control unit passes sequentially through the pin of diode D1, resistance R14 and operational amplifier U5 Three series connection；
One end of the resistance R15 is connected between diode D1 and micro-control unit, and the other end connects to power supply；
One end of the resistance R12 is connected between resistance R14 and comparator U5, and the other end connects to power supply；
One end of the resistance R13 is connected between resistance R14 and comparator U5, other end ground connection；
One end of the capacitor C4 is connected between resistance R14 and comparator U5, other end ground connection；
The pin one of the comparator U5 passes through the resistance R10 being sequentially connected in series and resistance R11 ground connection；
The pin two of the comparator U5 is connected between the pin one of comparator U5 and resistance R10；
The capacitor C3 is connected in parallel on the both ends of the resistance R11；
The resistance R8 and capacitor C3 is electrically connected.
The model 74HC14D of the phase inverter U2.
The stepper motor driving and chopper circuit further include the resistance R70 and diode D70 being sequentially connected in series；
One end of the resistance R70 and one end of diode D70 are electrically connected, the other end be connected to hysteresis comparator U4 with Between resistance R7；
The other end of the diode is connected between field-effect tube Q1 and resistance R6.
The negative pole end and resistance R70 of the diode D70 is electrically connected.
The positive terminal and resistance R70 of the diode D70 is electrically connected.
The present invention includes that stepper motor pulse enables circuit, stepper motor driving and chopper circuit, total current work and half Flow lock current control circuit and micro-control unit；Stepper motor driving uses chopping wave constant current driving method, by cleverly electric Road design, no matter motor is so that the electric current that phase winding is connected is kept rated value in lock state or in operating status.Together When, solve because the stepper motor drive pulse parameters of different single board computer manufacturers it is inconsistent caused by the driving of practical stepper motor Electric current problem bigger than normal or less than normal.It is compact-sized reasonable that the present invention has, and performance is stablized, in lock state still in operation shape State, make be connected phase winding electric current keep rated value the features such as.
Detailed description of the invention
Fig. 1 is stepper motor A phase drive circuit works schematic diagram of the present invention,
Fig. 2 is the amplifying circuit schematic diagram that stepper motor pulse enables circuit in Fig. 1,
Fig. 3 is the amplifying circuit schematic diagram of stepper motor driving and chopper circuit in Fig. 1,
Fig. 4 is the amplifying circuit schematic diagram of total current work and semi-fluid lock current control circuit in Fig. 1,
Fig. 5 is the circuit diagram for reducing stepper motor output electric current,
Fig. 6 is the circuit diagram for increasing stepper motor output electric current；
In figure 1 be stepper motor pulse enable circuit, 2 be stepper motor driving and chopper circuit, 3 be total current work and Semi-fluid lock current control circuit.
Specific embodiment
The present invention as shown in figures 1 to 6, including stepper motor pulse enable circuit 1, stepper motor driving and chopper circuit 2, Total current work and semi-fluid lock current control circuit 3 and micro-control unit；
It includes capacitor C1, photo-coupler U1, resistance R2, resistance R3, phase inverter U2 that the stepper motor pulse, which enables circuit 1, With resistance R4；
A connecting pin of the photo-coupler U1 is electrically connected by resistance R1 with stepper motor A phase drive pulse signal end It connects；
Two connecting pins of the photo-coupler U1 drive enable signal end telecommunications to connect with stepper motor A phase；
One end of the capacitor C1 is connected between the phase drive pulse signal end stepper motor A and photo-coupler U1, The other end is connected to the stepper motor A phase and drives between enable signal end and photo-coupler U1；
Three connecting pins of the photo-coupler U1 are grounded；
Four connecting pins of the photo-coupler U1 are electrically connected by a connecting pin of resistance R3 and phase inverter U2；
Two connecting pins of the phase inverter U2 and the stepper motor drive and chopper circuit is electrically connected；
One end of the resistance R2 is connected between resistance R3 and photo-coupler U1, and the other end connects to power supply；
One end of the resistance R4 is connected between the phase inverter U2 and stepper motor driving and chopper circuit, the other end It connects to power supply；
Stepper motor pulse enables circuit in Fig. 1, controls the control pulse input and shaping pulse of stepper motor A phase.When When stepper motor A phase phase shortage, stepper motor A phase control pulse is forbidden to work.
Stepper motor driving and chopper circuit 2 include door U3, resistance R5, field-effect tube Q1, sustained diode 0, late Stagnant comparator U4, resistance R6, resistance R7, resistance R8, resistance R9, resistance R16 and capacitor C2；
The door U3, resistance R5 and field-effect tube Q1 are successively electrically connected；
A connecting pin of the door U3 and two connecting pins of the phase inverter U2 are electrically connected；
The drain electrode of the field-effect tube Q1 is electrically connected by stepper motor winding r1 and working power；
The sustained diode 0 is connected in parallel on the both ends of the stepper motor winding r1；
Two connecting pins of the hysteresis comparator U4 and one end of the resistance R7 are electrically connected, the other end and field-effect tube The source electrode of Q1 is electrically connected；
One end of the resistance R6 and the source electrode of field-effect tube Q1 are electrically connected, other end ground connection；
One end of the capacitor C2 is connected to hysteresis comparator U4 between resistance R7, other end ground connection；
One end of the resistance R8 and three connecting pins of hysteresis comparator U4 are electrically connected, the other end and total current work and Semi-fluid lock current control circuit and micro-control unit are electrically connected；
A connecting pin of the hysteresis comparator U4 and one end of resistance R9 electrically connect with the pin of the door U3 two respectively It connects；The other end of the resistance R9 is connected to hysteresis comparator U4 between resistance R8；
The connecting pin V2 of the micro-control unit and a connecting pin of hysteresis comparator U4 are electrically connected, the resistance R16 One end be electrically connected in-between, the other end connects to power supply；
The connecting pin V0 of the micro-control unit is connected between the resistance R3 and phase inverter U2；
Stepper motor driving and chopper circuit, control the on-off and current chopping of stepper motor A phase in Fig. 1.When stepping electricity When machine A phase control pulse is worked, electric current is generated in stepper motor A phase, stepper motor A phase acts, and A phase current is passed through electricity Sample resistance R6 sampling is flowed, U4 comparator is responsible for current chopping.
The total current work and semi-fluid lock current control circuit 3 include resistance R15, diode D1, resistance R14, electricity Hold C4, resistance R12, resistance R13, operational amplifier U5, resistance R10, resistance R11 and capacitor C3
The connecting pin V1 of the micro-control unit passes sequentially through the pin of diode D1, resistance R14 and operational amplifier U5 Three series connection；
One end of the resistance R15 is connected between diode D1 and micro-control unit, and the other end connects to power supply；
One end of the resistance R12 is connected between resistance R14 and operational amplifier U5, and the other end connects to power supply；
One end of the resistance R13 is connected between resistance R14 and operational amplifier U5, other end ground connection；
One end of the capacitor C4 is connected between resistance R14 and operational amplifier U5, other end ground connection；
The pin one of the comparator U5 passes through the resistance R10 being sequentially connected in series and resistance R11 ground connection；
The pin two of the comparator U5 is connected between the pin one of operational amplifier U5 and resistance R10；
The capacitor C3 is connected in parallel on the both ends of the resistance R11；
The resistance R8 and capacitor C3 is electrically connected.
Total current work and semi-fluid lock current control circuit in Fig. 1, control stepper motor are in normal drive condition also It is in semi-fluid lock state.When stepper motor normal driving lathe works, stepper motor exports total current, at this time V1 in Fig. 1 Export high level；When the corresponding axis of lathe placed in a suspend state when, for avoid generate offset, it is necessary to make stepper motor be in make Energy state, exports a constant current, so that the axis is generated displacement to avoid external force or gravity, V1 exports low level at this time.Specific full electricity The size of stream work and semi-fluid lock current is determined that the electric current of general lock state is normal driving operating current by R8~R14 Half or so, therefore be commonly called as semi-fluid locking.
Fig. 1 is stepper motor A phase drive circuit works schematic diagram.CTR_A is stepper motor A phase drive pulse signal, CTR_0 is that stepper motor A phase drives enable signal.When CTR_0 is high level, forbid stepper motor A phase drive pulse signal CTR_A effect.When CTR_0 is low level, stepper motor A phase drive pulse signal CTR_A is allowed to act on, the output of optocoupler U1 The rp pulse of 4 foot output control pulses is held, optocoupler U1 plays buffer action.The inverted device U2 output of rp pulse and starting A phase Drive pulse signal CTR_A is with the pulse signal of phase, and phase inverter uses 74HC14D, in addition to making signal inversion, moreover it is possible to input arteries and veins Rush in row shaping.The pulse signal of phase inverter U2 output is sent into 1 foot of input terminal with door U3, when 2 foot of input terminal with door U3 is When high level, stepper motor A phase drive pulse signal is exported with 3 foot of output end of door U3, through resistance R5 driving FET Q1 Work.In Fig. 1, r1 is stepper motor winding, and D0 is freewheeling diode, and 24V is stepper motor working power.As stepper motor A When phase drive pulse signal is high level, field-effect tube Q1 conducting, stepper motor A phase winding r1 alives；Conversely, working as stepping When motor A phase drive pulse signal is low level, field-effect tube Q1 cut-off, stepper motor A phase winding r1 does not have electric current.R6 is to take Sample resistance, the single order RC filter that the electric current of stepper motor A phase winding r1 is formed through resistance R7 and capacitor C2 in the form of voltage It is sent into the inverting input terminal of comparator U4 afterwards.
V0 is normally set as the input port of MCU, and when MCU detects stepper motor A phase phase shortage, V0 is changed into MCU's Output port exports high level, to block the output of stepper motor drive pulse signal.
V1 is set as the output port of MCU, when stepper motor works normally 13: when V1 exports low level, stepper motor In semi-fluid lock state；When V1 exports high level, stepper motor is in driving working condition.It makes a concrete analysis of as follows:
When V1 exports low level,V4=V3=0.5V.
At this point, the upper limit trigging signal V8 of hysteresis comparator U4:That is:V8=0.2V.
The lower limit trigging signal V8 of hysteresis comparator U4:That is:V8=0.1V.
Here it is:
When V1 exports high level,That is:V3=1.9V.
V4=V3=1.9V.
At this point, the upper limit trigging signal V8 of hysteresis comparator U4:That is:V8=0.4V.
The lower limit trigging signal V8 of hysteresis comparator U4:That is:V8=0.3V.
Stepper motor drive pulse signal CTR_A frequency is generally within 500Hz, i.e. 2000 μ s.Resistance R7 and capacitor C2 The single order RC filter time constant of composition are as follows: R7C2=10 × 103×4.7×10-9=47 μ s.Therefore, stepper motor drives Between the high period of moving pulse signal CTR_A, by comparator U4, drive pulse signal will be chopped into as numerous subpulses Signal send 2 foot of input terminal with door U3 by the output end 1 of comparator U4, is at this time high level with 1 foot of input terminal of door U3, Therefore the subpulse signal will be by driving stepper motor through resistance R5 with door U3 output end 3.Stepper motor drive pulse signal Between the high period of CTR_A, 1 foot of input terminal with door U3 is low level, therefore is always low level, nothing with door U3 output end 3 Stepper motor drive pulse signal.At this point, 2 foot of inverting input terminal of comparator U4 is 0, therefore the output end 1 of comparator U4 is High level.
V2 is set as the input port of MCU.According to the above analysis, the high level of stepper motor drive pulse signal CTR_A Period, 1 foot of output end of comparator U4 will have the appearance of subpulse signal.But when phase shortage, since V6 is always 0, compare The output end 1 of device U4 is always high level, and thus MCU may determine that motor phase failure, and V0 is changed into the output port of MCU, High level is exported, to block the output of stepper motor drive pulse signal.
The model 74HC14D of the phase inverter U2.In addition to making signal inversion, moreover it is possible to carry out shaping to input pulse.
High speed WEDM control system is generally the voluntarily production and sales of each manufacturer, the driving pulse of stepper motor Signal is from master control system, and pulse frequency etc. is not by the control of high speed WEDM control system, each main control system The drive pulse signal output of the stepper motor of system manufacturer is also not quite similar.Therefore, simple to use in actual application Above-mentioned stepper motor driving circuit is it is possible that export electric current situation bigger than normal or less than normal.Therefore, the present invention is to above-mentioned driving Circuit is further improved.
The stepper motor driving and chopper circuit further include the resistance R70 and diode D70 being sequentially connected in series；
One end of the resistance R70 and one end of diode D70 are electrically connected, the other end be connected to hysteresis comparator U4 with Between resistance R7；
The other end of the diode is connected between field-effect tube Q1 and resistance R6.
The negative pole end and resistance R70 of the diode D70 is electrically connected.
The positive terminal and resistance R70 of the diode D70 is electrically connected.
Fig. 2 and Fig. 3 is respectively to reduce stepper motor to export the improvement circuit of electric current and increase stepper motor output electric current Improve circuit.When board design, the position of D70 and R70 is reserved, further according to needing to change repair welding member device when if necessary to improve Part.
Fig. 2 is the improvement circuit for reducing stepper motor output electric current.Compared with Fig. 1 circuit, resistance R70 and two poles are increased The anode of pipe D70, diode D70 are connected with the source electrode of field-effect tube Q1, and the cathode of diode D70 is connected with resistance R70.On the spot When effect pipe Q1 is connected, electric current charges to capacitor C2 by R7//R70, and R7//R70 is 10//10=5 Ω, therefore charges to ratio The time of turnover voltage compared with device U4 will greatly shorten.When field-effect tube Q1 cut-off, since the reversed cut-off of diode D70 is special Property, compared with Fig. 1 circuit, voltage still only discharges by resistance R7 and R6 on capacitor C2.Therefore, the duty of output driving pulse Than becoming smaller, stepper motor driving current becomes smaller.In real process, the visual concrete condition of the resistance value of resistance R7, R70 is adjusted.
Fig. 3 is the improvement circuit for increasing stepper motor output electric current.Compared with Fig. 1 circuit, resistance R70 and two poles are increased The cathode of pipe D70, diode D70 are connected with the source electrode of field-effect tube Q1, and the anode of diode D70 is connected with resistance R70.On the spot When effect pipe Q1 is connected, due to the reversed cut-off characteristics of diode D70, compared with Fig. 1 circuit, electric current still passes through R7 to capacitor C2 charging, therefore the time for charging to the turnover voltage of comparator U4 will greatly shorten.When field-effect tube Q1 cut-off, due to two The forward conduction characteristic of pole pipe D70, compared with Fig. 1 circuit, voltage discharges by resistance R7//R70 and R6 on capacitor C2, and R7// R70 is 10//10=5 Ω.Therefore, the duty ratio of output driving pulse becomes larger, and stepper motor driving current becomes smaller.Real process In, the visual concrete condition of the resistance value of resistance R7, R70 is adjusted.
To sum up, the present invention solve because the stepper motor drive pulse parameters of different single board computer manufacturers it is inconsistent caused by Practical stepper motor driving current problem bigger than normal or less than normal.
The model STM8GC104R8 of micro-control unit.
For this case disclosure of that, need to illustrate there are also the following:
(1), this case the disclosed embodiments attached drawing relate only to structure involved by this case disclosed embodiment, His structure, which can refer to, to be commonly designed；
(2), in the absence of conflict, the feature in this case the disclosed embodiments and embodiment can be combined with each other with Obtain new embodiment；
More than, only specific embodiment disclosed in this case, but the protection scope of the disclosure is not limited thereto, this case Disclosed protection scope should be subject to the protection scope in claims.
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