CN100544185C - DC motor control circuit - Google Patents

DC motor control circuit Download PDF

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CN100544185C
CN100544185C CNB2007100053719A CN200710005371A CN100544185C CN 100544185 C CN100544185 C CN 100544185C CN B2007100053719 A CNB2007100053719 A CN B2007100053719A CN 200710005371 A CN200710005371 A CN 200710005371A CN 100544185 C CN100544185 C CN 100544185C
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resistance
transistor
switch element
voltage
output
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CN101030750A (en
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大盛浩二
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Omron Corp
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Omron Corp
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Abstract

Provide at a low price and on each product, do not have the DC motor control circuit of deviation.DC motor that on DC power supply (1), is connected in series (2) and switch element (3), and by voltage (En) dividing potential drop of bleeder circuit (4) with switch element (3) two ends, carry out the switch of switch element (3) by the output that connects the hysteresis circuitry (6) that a plurality of transistors (TR1, TR2) are constituted, so that voltage output (V8) with respect to the output voltage (V5) of bleeder circuit (4), utilizes lagging characteristics and changes two values.

Description

DC motor control circuit
Technical field
The present invention relates to DC motor control circuit, particularly be used to the DC motor control circuit of the trigger switch of rechargeable power tool.
Background technology
DC motor control circuit as the trigger switch use, as described in patent documentation 1, control circuit is arranged, this control circuit has transtation mission circuit, and make the switch element conducting/shutoff at high speed that is connected in series with DC motor, utilize the bias voltage of potentiometer (volume) change transtation mission circuit, make the change in duty cycle of switch (switching) thus.
And, known a kind of DC motor control circuit, when the stopcock element, DC motor produces back electromotive force because of its rotation, so pass through comparator, compare the voltage at switch element two ends and the threshold voltage that sets by potentiometer, thereby make the switch element conduction and cut-off, the voltage at the switch element two ends is reduced to threshold voltage when following, makes the switch element conducting, threshold voltage is uprised, and the state continuance that makes the switch element conducting thus to a certain degree.
In patent documentation 2, put down in writing a kind of DC motor control circuit, this DC motor control circuit is compared with the 1st threshold voltage that is set by potentiometer by the voltage of the 1st comparator with the switch element two ends, thereby make the switch element conducting, and make the time of the conducting state continuation of switch element by the decision of the 2nd comparator.
Above IC such as DC motor control circuit employing comparator control DC motor, so the high such problem of cost is arranged.
And then employed variable resistor uses variable resistor at a low price mostly in the DC motor control circuit, and this quasi-resistance is the layer that forms resistive element on substrate, and movable terminal is slided and cuts apart resistance.Such variable resistor having on the resistance value ± about 30% very big deviation, in DC motor control circuit in the past, also have such problem, and promptly in the scope of the controllable rotating speed of DC motor, each product has deviation.
[patent documentation 1] spy opens flat 8-66084 communique
[patent documentation 2] spy opens flat 11-168893 communique
Summary of the invention
In view of the above problems, problem of the present invention provides at a low price and does not have the DC motor control circuit of deviation on each product.
In order to solve above-mentioned problem, DC motor control circuit of the present invention has: switch element, and itself and DC motor are connected in series on the DC power supply; Bleeder circuit is with the voltage dividing potential drop at described switch element two ends; And hysteresis circuitry, connect a plurality of transistors and constitute, with output voltage, utilize the voltage output of two values of lagging characteristics conversion, by the described switch element of output switch of described hysteresis circuitry with respect to described bleeder circuit.
According to this structure, do not change the reference voltage that the back electromotive force with DC motor when switch element is ended compares, and the voltage dividing potential drop at the switch element two ends that will produce by back electromotive force, and this voltage ratio is changed, so when changing voltage ratio and making the set point change of rotating speed, the hysteresis circuitry that is made of transistor even do not use the such IC of comparator, its output voltage characteristic does not change yet.Thus, the control DC motor can be stablized, control circuit at a low price can be made simultaneously.
In addition, in DC motor control circuit of the present invention, described hysteresis circuitry also can constitute to be had: base stage is transfused to the 1st transistor of the output voltage of described bleeder circuit, and when ending, described the 1st transistor is switched on, the 2nd transistor that when described the 1st transistor turns, is cut off, described the 1st transistor and described the 2nd transistor, emitter interconnects, and shared emitter resistance, the described the 1st transistorized collector electrode is connected to the anode of described DC power supply, and be connected to the negative terminal of described DC power supply by two resistance that are connected in series, the described the 2nd transistorized base stage connects the tie point of described two resistance, the described the 2nd transistorized collector electrode becomes the output of described hysteresis circuitry, and the described the 2nd transistorized emitter current is bigger than the described the 1st transistorized emitter current.
According to this structure, can constitute hysteresis circuitry simply, and manufacturing cost reduces.
In addition, in DC motor control circuit of the present invention, described bleeder circuit also can be to be made of two divider resistances and variable resistor, described two divider resistances are made of the fixed resistance at the two ends that are connected in series to described switch element, ratio arbitrarily till described variable resistor is divided into from 0:1 to 1:0 with movable electrode the resistive element between two fixed electrodes, described variable-resistance described two fixed electrodes are connected to the two ends of described switch element, and described movable electrode is connected to the tie point between the described divider resistance.
According to this structure, when variable-resistance voltage ratio was 1:0 and 0:1, variable-resistance resistance value was not reflected on the output voltage of bleeder circuit.That is to say that even variable-resistance resistance value has deviation, it is certain that the control range of DC motor also keeps.And, two threshold values of the hysteresis circuitry that is made of transistor become the intermediate potential of both ends of power current potential, but when bypass resistance is set, the voltage ratio of bleeder circuit can be set in and not be in 0 or 1 limited scope, and the output that can make bleeder circuit changes in the rotating speed according to DC motor comprises the wide region of two threshold values.That is to say that hysteresis circuitry can be changed two output states, regardless of the position of fixed electrode, conduction and cut-off that can both the diverter switch element, thus can control the rotating speed of DC motor.
And, in DC motor control circuit of the present invention, also can also have match circuit, this match circuit makes the output of described hysteresis circuitry be matched with the input characteristics of described switch element.
According to this structure, two outputs of the hysteresis circuitry that is made of transistor are voltage output, and wherein at least one is the intermediate potential of supply voltage, and can make two outputs of hysteresis circuitry consistent with the input characteristics of switch element by match circuit.Thus, can consider the input characteristics of switch element and design hysteresis circuitry, so can make the control stabilization and the good operability of DC motor.
In DC motor control circuit of the present invention, described match circuit can also be the transistor that comprises the voltage of the low level side that can export described DC power supply.
According to this structure, can drive and connect the low switch element of voltage (turn-on voltage).
More than, according to the present invention, with the voltage dividing potential drop at the two ends of switch element, thus can obtain sluggishness output by the circuit that transistor constitutes corresponding to the back electromotive force of DC motor, and DC motor control circuit at a low price can be provided.
Description of drawings
Fig. 1 is the circuit diagram of the DC motor control circuit of one embodiment of the present invention.
Fig. 2 is the curve of potential change of each several part of the DC motor control circuit of presentation graphs 1.
Embodiment
Below, with reference to accompanying drawing embodiments of the present invention are described.
Fig. 1 is an one embodiment of the present invention, employed DC motor control circuit in the Spin Control of expression electric drill.This DC motor control circuit is on the DC power supply (storage battery) 1 of E (V) at the voltage of two ends P1, P2, and DC motor 2 that makes the electric drill rotation and the switch element 3 that is made of FET are being connected in series.
And then this DC motor control circuit has: be connected to two ends P1, the P3 of switch element 3, with the bleeder circuit 4 of the voltage dividing potential drop between P1-P3; Level and smooth smoothing circuit 5 is carried out in the output of bleeder circuit 4; Output is corresponding to the output of smoothing circuit 5 and change sluggishness (hysteresis) circuit 6 of two voltages; And, carry out the match circuit 7 of the switch of switch element 3 according to the output of hysteresis circuitry 6.In this DC motor control circuit, the input and output of the negative terminal P1 of DC power supply and each circuit 4,5,6,7 are shared, and are used as the benchmark of the current potential of each point in the following description.
Bleeder circuit 4 has two divider resistance R1, R2 that are made of the fixed resistance that is connected in series between P1-P3, the voltage V4 of the tie point P4 of divider resistance R1 and divider resistance R2 is the output of bleeder circuit 4.And, the bypass resistance R3 that bleeder circuit 4 has variable resistor VR and is made of fixed resistance.Fixed electrode T1, the T2 of variable resistor VR is connected to two ends P1, the P3 of switch element 3, and movable electrode T3 is connected to the tie point P4 of divider resistance R1, R2 by bypass resistance R3.Variable resistor VR is the slidingtype potentiometer, and it forms the layer of resistive element between two fixed electrode T1-T2, and movable electrode T3 is slidably connected to described resistive element, thus the ratio arbitrarily till the resistance between T1-T2 being divided into from 0:1 to 1:0.
Smoothing circuit 5 is made of resistance R 4 and capacitor C1, is that the output V4 with bleeder circuit 4 carries out smoothly (blocking the above high fdrequency component of MHz), thereby makes the level and smooth low pass filter of waveform.The current potential V5 of the output point P5 of smoothing circuit 5 becomes the input to hysteresis circuitry 6.
Hysteresis circuitry 6 is made of transistor T R1, TR2 and a plurality of resistance R 5, R6, R7, R8, R9, the R10 of two maqting types, and the output V5 of smoothing circuit 5 (the output V4 of the bleeder circuit 4 after level and smooth) is input to the base stage of transistor T R1.Each emitter of transistor T R1 and transistor T R2 interconnects at the P6 point, and is connected to the negative terminal P1 of DC power supply 1 by emitter resistance R5.The collector electrode of transistor T R1 is connected to the anode P2 of DC power supply 1 by resistance R 6, and the negative terminal P1 that is connected to DC power supply 1 by the resistance R 7 that is connected in series and resistance R 8.On the other hand, connect the tie point P7 of resistance R 7 and resistance R 8 on the base stage of transistor T R2, connect resistance R 9 and the R10 that is connected in series on the collector electrode of transistor T R2, the tie point P8 of resistance R 9 and resistance R 10 becomes the output of hysteresis circuitry 6.
Match circuit 7 has: transistor T R3, and base stage is transfused to the current potential V8 that the P8 of hysteresis circuitry 6 is ordered, and emitter is connected to the anode P2 of DC power supply 1, the negative terminal P1 that collector electrode is connected to DC power supply 1 by the resistance R 11 that is connected in series and resistance R 12; And transistor T R4, base stage is connected to the tie point P9 of resistance R 11 and resistance R 12, collector electrode is connected to the anode P2 of DC power supply 1 by resistance R 13, is also connected to the grid of switch element 3 simultaneously by resistance R 14, and emitter is directly connected to the negative terminal P1 of DC power supply 1.
The effect of the DC motor control circuit that is made of above structure then, is described.
DC motor 2 is because of producing back electromotive force Vn (V), so the voltage between the two ends P1-P3 of switch element 3 (is the current potential of the P3 of benchmark with P1) is provided with En=E-Vn, this voltage En is negative proportionate relationship for rotating speed.Under the situation that switch element 3 is cut off, DC motor 2 is kept rotation because of inertia, but rotary speed reduces because of rotation resistance etc., and voltage En rises.
Bleeder circuit 4 will output between P1-P4 the voltage after partial voltage V4 between P1-P3, but this voltage V4 also changes because of the ration of division (resistance between T1-T3 and the ratio of the resistance between T3-T2) that the movable terminal T3 of variable resistor VR produces.The ration of division of variable resistor VR is under the situation of 1:0, output voltage V 4=En * R2/ (R2+R1//R3), and the ration of division of variable resistor VR is under the situation of 0:1, output voltage V 4=En * (R1//R3)/(R1+R2//R3).Wherein, ' // ' is the operator of the combined resistance of expression parallel resistance.Like this, with irrelevant maximum and the minimum value that decides the output voltage V 4 of bleeder circuit 4 of the resistance value of variable resistor VR.The control range that this means the DC motor 2 that this DC motor control circuit produces does not change because of the deviation of variable resistor VR.
In addition, exist under the bypass resistance R3, the ration of division of variable resistor VR can not make P4 point and P1 point or the short circuit of P3 point when 1:0 or 0:1, so can constitute with the ration of division of variable resistor VR irrelevant, and with the output voltage V 4 of bleeder circuit 4 as to the input of the hysteresis circuitry 6 discussed later and maintain the circuit of suitable scope.
Hysteresis circuitry 6 is that the 1st current potential VD (V) is when following at current potential V5 that P5 is ordered (the output V4 of the bleeder circuit 4 after level and smooth), the 1st transistor T R1 is ended, make the 2nd transistor T R2 conducting simultaneously, and, the current potential V5 that P5 is ordered becomes the 2nd current potential VU (V) when above, make transistor T R1 conducting, transistor T R2 is ended.
Specifically, at first, start soon in DC motor 2, because of rotating speed is low, so the current potential V5 height of P5 is transistor T R1 conducting.So the collector current of transistor T R1 flows through resistance R 6, and because of the voltage drop in the resistance R 6, the current potential V7 that P7 is ordered reduces.Thus, set each resistance R 5, R6, R7, R8, R9, R10, so that the voltage between the base-emitter of transistor T R2 is below the connection voltage of transistor T R2.Transistor T R2 by the time, do not flow through electric current in the resistance R 9, so the current potential V8 of ordering as the P8 of the output of hysteresis circuitry 6 becomes the identical voltage E (V) of P2 point with the anode of DC power supply.
The rotating speed of DC motor 2 rises, thereby the current potential V5 that P5 is ordered descends, and when transistor T R1 connected, the collector current of transistor T R1 disappeared, so the voltage drop of resistance R 6 reduces, the current potential V7 that P7 is ordered rises.Thus, the voltage between the base-emitter of transistor T R2 rises, thereby makes transistor T R2 conducting.So, between collector electrode-emitter of transistor T R2, flow through electric current, so the current potential that P8 is ordered is lower than E (V) because of the voltage drop in the resistance R 9.As the current potential V8 of the some P8 of the output of hysteresis circuitry 6 be E-V (BE) (V).
Transistor T R1 and transistor T R2 emitter interconnect, shared emitter resistance R5.Set the resistance value of each resistance R 5, R6, R7, R8, R9, R10, so that the current potential V6 of the emitter of transistor T R1, TR2, some P6 resistance transistor T R1 during by, transistor T R2 conducting than transistor T R1 conducting, transistor T R2 by the time height, that is to say that the emitter current of transistor T R2 is bigger than the emitter current of transistor T R1.
Since the variation of the current potential V6 that this P6 is ordered, the current potential VD height when the current potential VU that the needed P5 of transistor T R1 conducting is ordered ends than transistor T R1.Thus, hysteresis circuitry 6 is utilized lagging characteristics and is made two output states conversion with respect to the output V8 of input V5.
The transistor T R3 of match circuit 7 is cut off when the output V8 of hysteresis circuitry 6 is E (V), when the output V8 of hysteresis circuitry 6 is lower than E (V), between base-emitter, produce potential difference, so base current flows through and conducting.Thus, the P8 current potential V8 of ordering becomes the correspondingly current potential of the emitter-to-base voltage (being typically 0.6V) of low transistor T R3 of the current potential of ordering than P2.During transistor T R3 conducting, the current potential of the tie point P9 of resistance R 11 and resistance R 12 rises, and makes transistor T R4 conducting.The current potential of point P10 is E (V) when transistor T R4 ends, still, and when transistor T R4 conducting, because of being connected to the negative terminal P1 of DC power supply 1, so become 0 (V).Be applied in the current potential that P10 is ordered on the grid of switch element 3, thus transistor T R4 by the time, switch element 3 conductings, and DC motor 2 applied supply voltage E (V).
Fig. 2 represents the current potential V5 as the some P5 of the input of hysteresis circuitry 6, the current potential V6 of the binding site P6 of the emitter of hysteresis circuitry 6 and the current potential V8 of output point P8, and how the grid voltage of switch element 3 changes.In the figure, it is certain that the ration of division of the variable resistor VR of bleeder circuit 4 (position of movable electrode T3) keeps, and the current potential En that current potential V5 that the P5 of the current potential V4 that P4 order after smoothly ordered and P3 are ordered is proportional.
The current potential V5 that P5 is ordered is because of the proportional decline of rotating speed rising of DC motor 2.Current potential V5 is the 1st current potential VD when following, and output voltage V 8 step-downs of hysteresis circuitry 6 are so switch element 3 ends.So, because of DC motor 2 rotary speeies constantly reduce, thus the En rising, thus voltage V5 is risen.Current potential V5 is the 2nd voltage VU when above, and output voltage V 8 becomes E (V) again, and switch element 3 is connected.
That is to say, DC motor control circuit is carried out the switch of switch element 3, with keep more than the 1st current potential VD by the current potential V5 that P5 is ordered, below the 2nd current potential VU, thereby the current potential V3 that P3 is ordered remains on the certain scope that voltage ratio determined by the 1st current potential VD and the 2nd current potential VU and bleeder circuit 4.
In hysteresis circuitry 6, according to the variation of current potential V5, the current potential V6 of emitter P6 also changes, but the value behind the connection voltage (emitter-to-base voltage) that has added transistor T R1 on two values of this current potential V6 respectively is VU and VD.
The movable electrode T3 that makes variable resistor VR moves and when changing the voltage ratio of bleeder circuit 4, the ratio of the current potential V5 of P5 and the current potential En that P3 is ordered changes, the velocity variations of rising/declines of current potential V5, so, the conduction and cut-off time change of switch element 3.In the present embodiment, the load of the conduction and cut-off cycle of switch element 3 because of rig changes, but is approximately the scope of hundred Hz～number kHz.
In the present embodiment, the switch element 3 that use is made of the FET that connects with low grid voltage, so, by match circuit 7 output voltage V 8 of hysteresis circuitry 6 is transformed into voltage in 0 (V) and E (V) conversion, thus with the input characteristics coupling of switch element 3.But, in the present invention, hysteresis circuitry 6 also can export the P6 point or the P7 point waits the current potential of other points, and can pass through the setting of resistance value of each resistance R 5, R6, R7, R8, R9, R10 or the selection of switch element 3, directly makes switch element 3 conduction and cut-off by the output of hysteresis circuitry 6.

Claims (5)

1, a kind of DC motor control circuit is characterized in that, has:
Switch element, itself and DC motor are connected in series on the DC power supply;
Bleeder circuit is with the voltage dividing potential drop at described switch element two ends; And
Hysteresis circuitry connects a plurality of transistors and constitutes, and to have the output voltage with respect to described bleeder circuit, utilizes the voltage output of two values of lagging characteristics conversion,
The described switch element of switch by the output of described hysteresis circuitry,
Described hysteresis circuitry has: base stage is transfused to the 1st transistor of the output voltage of described bleeder circuit, and described the 1st transistor by the time the 2nd transistor that is switched on, is cut off during in described the 1st transistor turns,
Described the 1st transistor and the described the 2nd transistorized emitter interconnect, and shared emitter resistance,
The described the 1st transistorized collector electrode is connected to the anode of described DC power supply, and is connected to the negative terminal of described DC power supply by two resistance that are connected in series,
The described the 2nd transistorized base stage connects the tie point of described two resistance, and the described the 2nd transistorized collector electrode becomes the output of described hysteresis circuitry,
The described the 2nd transistorized emitter current is bigger than the described the 1st transistorized emitter current.
2, DC motor control circuit as claimed in claim 1 is characterized in that:
Described bleeder circuit is made of two divider resistances and variable resistor, described two divider resistances are made of the fixed resistance at the two ends that are connected in series to described switch element, ratio arbitrarily till described variable resistor is divided into from 0:1 to 1:0 with movable electrode the resistive element between two fixed electrodes
Described variable-resistance described two fixed electrodes are connected to the two ends of described switch element, and described movable electrode is connected to the tie point between the described divider resistance.
3, DC motor control circuit as claimed in claim 2 is characterized in that:
With tie point between the described divider resistance and described movable electrode, connect by the bypass resistance that constitutes by fixed resistance.
4, as any one described DC motor control circuit of claim 1 to 3, it is characterized in that:
Also have match circuit, this match circuit makes the output of described hysteresis circuitry be matched with the input characteristics of described switch element.
5, DC motor control circuit as claimed in claim 4 is characterized in that:
Described match circuit comprises the transistor of the voltage of the low level side that can export described DC power supply.
CNB2007100053719A 2006-02-28 2007-02-14 DC motor control circuit Expired - Fee Related CN100544185C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2006051805A JP5002979B2 (en) 2006-02-28 2006-02-28 DC motor control circuit
JP051805/06 2006-02-28

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CN101030750A CN101030750A (en) 2007-09-05
CN100544185C true CN100544185C (en) 2009-09-23

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101599733B (en) * 2009-07-09 2011-06-15 浙江工商大学 Phase closed loop control direct current motor speed regulating method
EP3790177B1 (en) * 2019-09-09 2024-05-01 Andreas Stihl AG & Co. KG Electric processing device and method for operating same

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JPS5547726A (en) * 1978-10-03 1980-04-04 Mitsubishi Electric Corp Schmitt trigger circuit
JPS58186390A (en) * 1982-04-26 1983-10-31 Secoh Giken Inc Bridge servo circuit by chopper control
JPS5935580A (en) * 1982-08-24 1984-02-27 Olympus Optical Co Ltd Speed controller for dc motor
JP3455665B2 (en) * 1997-12-02 2003-10-14 佐鳥エス・テック株式会社 DC motor speed control circuit
JP3012616B1 (en) * 1998-10-28 2000-02-28 日本電気アイシーマイコンシステム株式会社 Overvoltage protection circuit

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TW200740103A (en) 2007-10-16
JP5002979B2 (en) 2012-08-15
TWI347739B (en) 2011-08-21
CN101030750A (en) 2007-09-05

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