CN109787596A - Current foldback circuit, switch tube driving circuit and electrical equipment - Google Patents
Current foldback circuit, switch tube driving circuit and electrical equipment Download PDFInfo
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Abstract
A kind of current foldback circuit of switching tube circuit, it include switching tube and the source driving signal for driving the switching tube on-off, the current foldback circuit includes first diode and judgment module, current foldback circuit is by being added judgment module and first diode, in on-off switching tube when being greater than the conducting electric current for setting threshold values or switching tube greater than threshold value of the driving signal of source driving signal output, the function of instant on-off switching tube is realized by hardware circuit, and then improve the corresponding speed of the protection of switch tube, it is single to solve protection mechanism present in traditional technical solution, process is complicated and protects slow-footed problem.
Description
Technical field
The invention belongs to current protection technology field more particularly to a kind of current foldback circuits of switching tube circuit, switch
Tube drive circuit and electrical equipment.
Background technique
Currently, software control is usually used in the shutdown control of traditional switching tube, passed for example, circuital current is sampled through AD
It is defeated into MCU, after being calculated by MCU, according to calculated result control PWM (Pulse Width Modulation, impulse modulation
Width) output, and then the on-off of control switch pipe, protection mechanism is single, and this control mode is after switching tube overcurrent,
On-off switching tube is just arrived by AD sampling, software calculating, the adjustment PWM output to electric current, thus process is complicated and protection is fast
Degree is slow.
Therefore, that there are protection mechanisms in traditional technical solution is single, process is complicated and the protection slow problem of speed.
Summary of the invention
In view of this, the embodiment of the invention provides a kind of current foldback circuits of switching tube circuit, switching tube driving electricity
Road and electrical equipment, it is intended to solve that protection mechanism present in traditional technical solution is single, process is complicated and protection speed
Slow problem.
The first aspect of the embodiment of the present invention provides a kind of electrical equipment, including motor, further includes a kind of switching tube drive
Dynamic circuit, the switching tube is for driving the motor.
The second aspect of the embodiment of the present invention provides a kind of above-mentioned switch tube driving circuit, including overcurrent protection electricity
Road, source driving signal, switching tube, load and second source, the source driving signal are connect with the control terminal of the switching tube,
Wherein:
The second source, the load, the switching tube are sequentially connected in series to ground；Or
The second source, the switching tube, the load are sequentially connected in series to ground.
The third aspect of the embodiment of the present invention provides a kind of above-mentioned current foldback circuit, for preventing switching tube circuit
Overcurrent, the switching tube circuit include switching tube and the source driving signal for driving the switching tube on-off, and the overcurrent is protected
Protection circuit includes:
First diode, cathode are connect with the input terminal of the switching tube or output end；
Judgment module, the first input end incoming reference signal of the judgment module, the second end of the judgment module with
The anode of the first diode is connected with the source driving signal, and the judgment module is configured as in the source driving signal
Output control signal when the conducting electric current for being greater than the first threshold values or the switching tube of the driving signal of output is greater than second threshold
Turn off the driving signal that the control terminal of the switching tube receives.
In one embodiment, the judgment module includes first resistor, first capacitor and voltage comparator, and described
The first end of one resistance is connect with the source driving signal, the first end of the second end of the first resistor, the first capacitor
And the first input end of the voltage comparator is connect with the anode of the first diode, the second end of the first capacitor
Second input terminal of ground connection, the voltage comparator accesses the reference signal.
In one embodiment, the judgment module further includes 3rd resistor, the first end of the 3rd resistor with it is described
The anode connection of first diode, second end, the first capacitor of the second end of the 3rd resistor and the first resistor
First end and the voltage comparator first input end connection.
It in one embodiment, further include reference signal output module to generate the reference signal, the reference
The input terminal of signal output module is connect with the first power supply, the output end and the judgment module of the reference signal output module
First input end connection.
In one embodiment, the reference signal output module includes the 4th resistance and the 5th resistance, the 4th electricity
First end of resistance is connected to second source, the second end of the 4th resistance and the first end of the 5th resistance be connected to altogether described in sentence
Second input terminal of disconnected module, the second end ground connection of the 5th resistance.
In one embodiment, the output end of the judgment module is connect with the source driving signal, the driving signal
Source receives the control signal.
It in one embodiment, further include switch module, the control terminal of the switch module is defeated with the judgment module
Outlet connection, and it is connected to the source driving signal and described between the control terminal of the switching tube, the switch module quilt
It is configured to control the on-off of the driving signal according to the control signal that the judgment module exports.
In one embodiment, the switch module includes second resistance and power switch tube, the power switch tube
Control terminal is connected to the control terminal of the switch module through the second resistance, and the input terminal of the power switch tube is connected to described
Source driving signal and described between the control terminal of the switching tube, the output end ground connection of the power switch tube.
The current foldback circuit of above-mentioned switching tube circuit is believed by the way that judgment module and first diode is added in driving
The on-off switching tube when conducting electric current that being greater than of the driving signal of number source output sets threshold values or switching tube is greater than threshold value, passes through hardware
Circuit realizes the function of instant on-off switching tube, and then improves the corresponding speed of the protection of switch tube, traditional technical solution
Present in protection mechanism is single, process is complicated and the slow-footed problem of protection.
Detailed description of the invention
It to describe the technical solutions in the embodiments of the present invention more clearly, below will be to embodiment or description of the prior art
Needed in attached drawing be briefly described, it should be apparent that, the accompanying drawings in the following description is only of the invention some
Embodiment for those of ordinary skill in the art without any creative labor, can also be according to these
Attached drawing obtains other attached drawings.
Fig. 1 is the circuit diagram for the switch tube driving circuit that one embodiment of the invention provides；
Fig. 2 be another embodiment of the present invention provides switch tube driving circuit circuit diagram；
Fig. 3 be another embodiment of the present invention provides switch tube driving circuit circuit diagram；
Fig. 4 is the circuit diagram of the current foldback circuit for the switching tube circuit that one embodiment of the invention provides；
Fig. 5 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram；
Fig. 6 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram；
Fig. 7 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram；
Fig. 8 is the exemplary circuit schematic diagram of judgment module in the current foldback circuit of switching tube circuit shown in Fig. 4；
Fig. 9 is another exemplary circuit schematic diagram of judgment module in the current foldback circuit of switching tube circuit shown in Fig. 4；
Figure 10 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram；
Figure 11 is the exemplary circuit of reference signal output module in the current foldback circuit of switching tube circuit shown in Fig. 10
Schematic diagram；
Figure 12 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram；
Figure 13 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram；
Figure 14 is the exemplary circuit schematic diagram of switch module in the current foldback circuit of switching tube circuit shown in Figure 13；
Figure 15 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram；
Figure 16 be another embodiment of the present invention provides switching tube circuit current foldback circuit circuit diagram.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
A kind of electrical equipment that first embodiment of the invention provides, including motor, further include switch tube driving circuit, switch
It is effective with driving motor.
Fig. 1 and Fig. 2 are please referred to, second embodiment of the invention provides a kind of switch tube driving circuit, including overcurrent protection
Circuit 200, source driving signal 101, switching tube 102, load 103 and power supply 104, current foldback circuit 200 is for driving
On-off switching tube when being greater than the conducting electric current for setting threshold values or switching tube 102 greater than threshold value for the driving signal that signal source 101 exports
102, it should be appreciated that load can be the non-production capacity device such as resistance, brake module or equipment, in which:
In one embodiment, referring to Fig. 1, power supply 104, load 103, switching tube 102 is sequentially connected in series to ground.
In one embodiment, referring to Fig. 2, power supply 104, switching tube 102, load 103 are sequentially connected in series to ground.
In one embodiment, referring to Fig. 3, power supply 104, load 103, switching tube 102 and division module 105 successively
It is connected in series to ground, can be made of the device for having partial pressure effect, such as resistance or potentiometer.
It should be understood that the switch tube driving circuit of the present embodiment includes at least one switching tube, when comprising N number of switching tube,
Corresponding includes N number of current foldback circuit.
In the present embodiment, by the way that current foldback circuit is added, realizes and do not need only pass through hard wired feed back by software
Can switch tube carried out overcurrent protection, and then improve the corresponding speed of the protection of switch tube, solve traditional technology
Process present in scheme is complicated and protects slow-footed problem.
Referring to Fig. 4, the circuit that third embodiment of the invention provides a kind of current foldback circuit of switching tube circuit shows
It is intended to, for ease of description, only the parts related to this embodiment are shown, and details are as follows:
The current foldback circuit of switching tube circuit in one embodiment, switching tube circuit include switching tube 102 and use
It connect, switchs with source driving signal 101 in the control terminal of the source driving signal 101 of 102 on-off of driving switch pipe, switching tube 102
Pipe 102 can be constituted by having the three terminal type switching tube of control circuit on-off function or switch tube chip, such as metal-oxide-semiconductor,
IGBT thyristor or triode, in order to make it easy to understand, being exemplified below: when switching tube 102 is NMOS tube, the grid of NMOS tube
For the control terminal of switching tube 102, the drain electrode of NMOS tube is the input terminal of switching tube 102, the source switch pipe 102 that NMOS is it is defeated
Outlet；When switching tube 102 is PMOS tube, the grid of PMOS tube is the control terminal of switching tube 102, and the source electrode of PMOS tube is switch
The input terminal of pipe 102, the drain electrode that PMOS is are the output end of switching tube 102, correspondingly, also with such when selecting other devices
It pushes away.
Current foldback circuit includes diode D1 and judgment module 210, the input of the cathode and switching tube 102 of diode D1
End or output end connection, the first input end incoming reference signal of judgment module 210, the second end of judgment module 210 and two poles
The anode and source driving signal 101 of pipe D1 connects, and current foldback circuit utilizes the unilateral conduction of diode D1, avoids switching tube
The electric current of circuit flows to the second end of the judgment module 210 of current foldback circuit, and then influences the judgement of judgment module 210, sentences
Disconnected module 210 is configured as the conducting for being greater than the first threshold values or switching tube 102 of the driving signal exported in source driving signal 101
The driving signal that the control terminal of output control signal on-off switching tube 102 receives when electric current is greater than second threshold, judgment module
210 can by can compare the voltage swing of two input terminals and exported according to comparing result the device of different level signals with
And the device for having debugging level voltage is constituted, such as voltage comparator or microprocessor and resistance or capacitor etc., is answered
Understand, driving signal and reference signal can be level signals, and reference signal is pre- according to the driving signal maximum value of circuit
If with adjustment.
Current foldback circuit in the embodiment of the present invention passes through real-time monitoring switching tube 102 when opening work, switching tube
Whether the voltage value between 102 input terminal-output end is more than design threshold values, and judgement flows through the electric current of the switching tube 102 according to this
Value whether be more than design code maximum current value, stayed open or turn off by hard wired feed back opening switching tube 102.When opening
Pipe 102 is closed when being not switched on, what feedback signal did not influenced drive system switch tube 102 opens shutdown control；When the normal work of system
Make, switching tube 102 is opening state, and what feedback signal did not influenced drive system switch tube 102 opens shutdown control；Work as system
It is simultaneously turned in abnormal working position, such as drive system upper and lower bridge arm, braking resistor short circuit etc., so that switching tube 102
Input terminal-output end between voltage value be more than design threshold values, and input terminal-output end of switching tube 102 normally opens work
When making, internal resistance value can be learnt by specifications, according to formula I=U/R, so as to judge to flow through the electric current of the switching tube 102 accordingly
Value is more than design current maximum threshold values, so that hard wired feed back signal can not carry out in time switching tube 102 by the control of software
The switching tube 102 is turned off, protects circuit safety in time.
Refering to fig. 1 and Fig. 5, in one embodiment, when power supply 104, load 103, switching tube 102 are sequentially connected in series
Ground, that is to say, that when the output end of switching tube 102 is directly grounded, the cathode of diode D1 is connect with the input terminal of switching tube 102,
The first input end incoming reference signal of judgment module 210, the second end of judgment module 210 and the anode of diode D1 and driving
Signal source 101 connects, its working principles are as follows: when switching tube circuit does not work, i.e., when source driving signal 101 exports low level
When, switching tube 102 is in an off state, and the second end level of judgment module 210 is 0, and the first end level of judgment module 210 is
Preset reference level Uref, the preset reference level Uref debugging are switching tube circuit normal working voltage, judge mould at this time
The first end level of block 210 is greater than second end level, because without exporting the driving that can be turned off the switch the control terminal of pipe 102 and receive
Signal；When switching tube circuit works normally, source driving signal 101 exports high level, and switching tube 102 is connected, and debugging makes at this time
The summation for obtaining the voltage of switching tube 102 and the voltage of diode D1 is less than or equal to reference level Uref；When switching tube circuit
When non-normal working, such as the driving signal that source driving signal 101 exports is greater than the former default level that should be exported or because of other
Problem and when leading to switching tube circuit overcurrent, voltage+diode D1 voltage of switching tube 102 is greater than reference level Uref, sentences
The driving signal that the control terminal of the disconnected output of module 210 control signal on-off switching tube 102 receives.
Refering to Fig. 2 and Fig. 6, in one embodiment, when power supply 104, switching tube 102, load 103 are sequentially connected in series
Ground, that is to say, that when the output end of switching tube 102 is through 103 ground connection of load, the output of the cathode and switching tube 102 of diode D1
End connection, the first input end incoming reference signal of judgment module 210, the second end and diode D1 of judgment module 210 are just
Pole and source driving signal 101 connect, its working principles are as follows: when switching tube circuit does not work, i.e., when source driving signal 101 is defeated
Out when low level, switching tube 102 is in an off state, and the second end level of judgment module 210 is 0, the first of judgment module 210
End level is preset reference level Uref, and preset reference level Uref debugging is switching tube circuit normal working voltage, this
When judgment module 210 first end level be greater than second end level, because without export can turn off the switch pipe 102 control terminal reception
The driving signal arrived；When switching tube circuit works normally, source driving signal 101 exports high level, and switching tube 102 is connected, this
When debugging so that the voltage of diode D1 and the value that is added of voltage of load 103 less than or equal to reference level Uref；When opening
When closing pipe circuit non-normal working, for example, the driving signal that exports of source driving signal 101 be greater than the former default level that should be exported or
When person leads to switching tube circuit overcurrent because of other problems, the value that the voltage of diode D1 is added with the voltage of load 103 is greater than
Reference level Uref, the driving signal that the control terminal of the output control signal on-off switching tube 102 of judgment module 210 receives.
Refering to Fig. 3 and Fig. 7, in one embodiment, when power supply 104, load 103 and switching tube 102 be sequentially connected in series, and
When the output end of switching tube 102 is grounded through division module 105, the cathode of diode D1 is connect with the output end of switching tube 102, is sentenced
The first input end incoming reference signal of disconnected module 210, the second end of judgment module 210 and the anode of diode D1 and driving are believed
Number source 101 connects, and working principle can refer to an embodiment.
Refering to Fig. 8, in one embodiment, judgment module 210 includes first resistor R1, first capacitor C1 and voltage ratio
Compared with device U1, the first end of first resistor R1 is connect with source driving signal 101, the second end of first resistor R1, first capacitor C1
The first input end of first end and voltage comparator U1 are connect with the anode of diode D1, the second termination of first capacitor C1
Ground, the second input terminal incoming reference signal of voltage comparator U1, it should be appreciated that in this embodiment, first resistor R1 can be debugged
With the value of first capacitor C1 or selection suitable first resistor R1 and first capacitor C1 according to actual needs so that switching tube is electric
In normal work, the first input end level of voltage comparator U1 is not higher than reference signal on road, wherein switching tube 102 just
(from by the end of fully on period) in normal turn on process, using first capacitor C1 charge characteristic to avoid voltage comparator U1's
First input end is higher than reference signal.
Refering to Fig. 9, in one embodiment, judgment module 210 further includes 3rd resistor R3, the first end of 3rd resistor R3
Connect with the anode of diode D1, the first of the second end of the second end of 3rd resistor R3 and first resistor R1, first capacitor C1
The connection of the first input end of end and voltage comparator U1.
Refering to fig. 10, in one embodiment, current foldback circuit further includes the reference signal to generate reference signal
Output module 230, the input terminal of reference signal output module 230 are connect with the first power supply, reference signal output module 230 it is defeated
Outlet is connect with the first end of judgment module 210.
Refering to fig. 11, in one embodiment, reference signal output module 230 includes the 4th resistance R4 and the 5th resistance
R5, the first end of the 4th resistance R4 are connected to power supply 104, and the second end of the 4th resistance R4 and the first end of the 5th resistance R5 are connected to altogether
Second input terminal of judgment module 210, the second end ground connection of the 5th resistance R5.
Refering to fig. 12, in one embodiment, the output end of judgment module 210 is connect with source driving signal 101, Ying Li
Solution, source driving signal 101 can be made of driving chip, the control signal that judgment module 210 exports, and be delivered directly to driving letter
In number source 101, so that source driving signal 101 stops output drive signal or output low level, and then on-off switching tube 102.
Refering to fig. 13, in one embodiment, current foldback circuit further includes switch module 220, and switch module 220 is matched
Be set to according to judgment module 210 export control signal conduction perhaps shutdown so that make switching tube 102 end or conducting, open
Closing module 220 can be by having different according to control end signal and the device of the function of on and off is constituted, such as switching tube
102 or switch chip, the control terminal of switch module 220 connect with the output end of judgment module 210, switch module 220 it is defeated
Enter end to connect with the control terminal of switching tube 102, the output end ground connection of switch module 220.
Refering to fig. 14, in one embodiment, switch module 220 includes second resistance R2 and power switch tube Q2, power
The control terminal of switching tube Q2 is connected to the control terminal of switch module 220, the input terminal connection of power switch tube Q2 through second resistance R2
Between source driving signal 101 and the control terminal of switching tube Q1, the output end of power switch tube Q2 is grounded, and power switch tube Q2 can
Different power switch tube devices is selected according to the type selecting of switching tube Q1 and the type selecting of voltage comparator.
In order to make it easy to understand, power switch tube Q2 is illustration for triode below using switching tube Q1 as NMOS tube
The type selecting of power switch tube Q2:
When the first input end of voltage comparator U1 is negative-phase input, the second input terminal of voltage comparator U1 is positive
Input terminal, power switch tube Q2 should select PNP triode, at this point, its working principles are as follows: the negative as voltage comparator U1 is defeated
Enter to hold voltage to be less than normal phase input end voltage, that is, when electric current is not above threshold values, voltage comparator U1 exports high level,
Power switch tube Q2 is not turned at this time, former switching tube normal operation circuit；When the negative-phase input voltage of voltage comparator U1 is big
In normal phase input end voltage, that is, when the current exceeds a threshold value, voltage comparator U1 exports low level, at this time power switch tube
Q2 conducting, and then timely on-off switching tube Q1；
When the first input end of voltage comparator U1 is normal phase input end, the second input terminal of voltage comparator U1 is negative
Input terminal, power switch tube Q2 should select NPN triode, at this point, its working principles are as follows: the positive as voltage comparator U1 is defeated
Enter to hold voltage to be less than negative-phase input voltage, that is, when electric current is not above threshold values, voltage comparator U1 exports low level,
Power switch tube Q2 is not turned at this time, former switching tube normal operation circuit；When the normal phase input end voltage of voltage comparator U1 is big
In negative-phase input voltage, that is, when the current exceeds a threshold value, voltage comparator U1 exports high level, at this time power switch tube
Q2 conducting, and then timely on-off switching tube Q1.
It should be understood that should herewith be managed when selecting other kinds of switching tube Q2.
Refering to fig. 15, by taking one of specific embodiment as an example, the working principle of current foldback circuit is elaborated, is switched
Pipe circuit includes source driving signal 101, switching tube Q1, resistance R6,103 and power supply VCC1 of load, current foldback circuit packet
Diode D1, judgment module 210 and switch module 220 are included, it is assumed that the first power supply VCC1 is 24V, and second source VCC2 is
15V is DRIVE_G=15V in the level of opening of 101 driving switch pipe Q1 of the source driving signal, by the specifications of switching tube Q1
Can accurately it know, under conditions of 15V drive level, the conducting internal resistance of D-S is R (Q1), in conjunction with the condition of gate electrode resistance R6,
Knowing that its service time is t seconds, then the reference level Uref of the second input terminal of voltage comparator U1 is 15V*R5/ (R4+R5),
Assuming that the resistance value of R3 is 0 ohm (in practical application, designer can debug this resistance value according to design threshold values demand), by two
The specifications of pole pipe D1 can accurately know that the conducting tube voltage drop of diode D1 is U (D1).
When source driving signal 101 exports low level, switching tube Q1 is off state, then the of voltage comparator U1 at this time
One input terminal level is 0V, and the second input terminal level of voltage comparator U1 is 15V*R5/ (R4+R5), voltage comparator U1's
Second input terminal level is greater than the first input end level of voltage comparator U1, then the high electricity of output end output of voltage comparator U1
Flat 15V, switching tube Q2 are not turned on, and switching tube Q1 is to be held off.
When source driving signal 101 export 15V level when, it is assumed that source driving signal 101 start export high level at the time of be
T0, suitable resistance R1, capacitor C1, resistance R4, resistance R5 value are verified in selection respectively, so that in time t0~in the t0+t time
(this time is switching tube Q1 by closing to the period opened, and the drain electrode C of switching tube Q1 remains high level), voltage compares
The charging voltage Ut of the first input end of device U1 < [15V*R5/ (R4+R5)], the value of the first input end Ut of voltage comparator U1
It can be calculated by its RC charge and discharge formula (Ut=0V+ (15V-0V) * [1-exp^ (- t/ (R1*C1))]), after the t0+t moment,
Switching tube Q1 is fully finished opening process, it is assumed that the maximum current value thereafter through switching tube Q1 is I (Q1), and the current value is by setting
Meter person designs different I (Q1) values according to different applications, and the usual value can be chosen by the rated current of switching tube, according to
I (Q1) selects different switching tubes, and the maximum current value of switching tube has to be larger than I (Q1), the suitable U (D1) of selection verifying,
R4, R5 value, so that there are relationships according to I (Q1): [I (Q1) * R (Q1)+U (D1)]≤[15V*R5/ (R4+R5)], and work as and flow through
When the current value I of switching tube Q1 is greater than I (Q1), there are following voltage relationships in entire circuit: [I*R (Q1)+U (D1)]
> [15V*R5/ (R4+R5)], the current value that when source driving signal normal driving flows through switching tube Q1 are less than or equal to I (Q1), this
When voltage comparator U1 the second input terminal be greater than the first input end level of voltage comparator U1, then voltage comparator U1's is defeated
Outlet exports high level 15V, and switching tube Q2 is not turned on, and switching tube Q1 keeps opening state.
When the generation driving signal of source driving signal 101, and the current value I for flowing through switching tube Q1 is greater than the valve design of designer
It is the abnormal driving of source driving signal, by analyzing above, there are relationships: [I*R (Q1)+U (D1)] > [15V*R5/ when value I (Q1)
(R4+R5)], the second input terminal of voltage comparator U1 is less than the first input end level of voltage comparator U1, then voltage at this time
The output end of comparator U1 exports low level, and Q4 conducting is saturation opening state, and the grid of switching tube Q1 is pulled to low level, from
And switching tube Q1 is turned off, so that the current value of switching tube Q1 be avoided further to increase, timely protective switch pipe Q1 is burned, greatly
The big reliability and safety for improving switching tube circuit.
This scheme can design the maximum current value for flowing through switching tube, pass through the data hand of device according to practical application request
Different switching tubes, diode, resistance configuration are verified in volume, selection, to realize that the electric current for flowing through switching tube is greater than design threshold values
When, by hard wired feed back signal, on-off switching tube, to improve the reliability and safety of switching tube circuit.
Refering to fig. 16, by taking another specific embodiment therein as an example, the working principle of current foldback circuit is elaborated,
Switching tube circuit includes source driving signal 101, switching tube Q1, resistance R6, loads 103, resistance R7 and power supply VCC1, in order to
Understand convenient for calculating, resistance R7 here can be used as division module 105, also can be used as another load, the output of switching tube Q1
End is grounded through resistance R7, and current foldback circuit includes diode D1, judgment module 210 and switch module 220, it is assumed that first
Power supply VCC1 is 24V, and second source VCC2 is 15V, is in the level of opening of 101 driving switch pipe Q1 of the source driving signal
DRIVE_G=15V can accurately be known by the specifications of switching tube Q1, under conditions of 15V drive level, in the conducting of D-S
Resistance is R (Q1), in conjunction with the condition of gate electrode resistance R6, it is known that its service time is t seconds, then the second input terminal of voltage comparator U1
Reference level Uref be 15V*R5/ (R4+R5), it is assumed that the resistance value of R3 be 0 ohm (in practical application, designer can basis
Threshold values demand is designed, this resistance value is debugged)；The conducting tube voltage drop that can accurately know diode D1 by the specifications of diode D1 is
U(D1)。
When source driving signal 101 exports low level, switching tube Q1 is off state, then the of voltage comparator U1 at this time
One input terminal level is 0V, and the second input terminal level of voltage comparator U1 is 15V*R5/ (R4+R5), voltage comparator U1's
Second input terminal level is greater than the first input end level of voltage comparator U1, then the high electricity of output end output of voltage comparator U1
Flat 15V, switching tube Q2 are not turned on, and switching tube Q1 is to be held off.
When source driving signal 101 export 15V level when, it is assumed that source driving signal 101 start export high level at the time of be
T0, suitable resistance R1, capacitor C1, resistance R4, resistance R5 value are verified in selection respectively, so that in time t0~in the t0+t time
(this time is switching tube Q1 by closing to the period opened, and the drain electrode C of switching tube Q1 remains high level), voltage compares
The charging voltage Ut of the first input end of device U1 < [15V*R5/ (R4+R5)], the first input end voltage Ut of voltage comparator U1
Value can be calculated, the t0+t moment by its RC charge and discharge formula (Ut=0V+ (15V-0V) * [1-exp^ (- t/ (R1*C1))])
Afterwards, switching tube Q1 is fully finished opening process, it is assumed that thereafter through the maximum current value of switching tube Q1, that is, is equal to and passes through electricity
The maximum current value for hindering R7 is I (R7), which designs different I (R7) values according to different applications by designer, usually
The value can be chosen by the rated current of switching tube Q1, and different switching tube Q1, and the maximum of switching tube are selected according to I (R7)
Current value has to be larger than I (R7), can choose and verify suitable U (D1), resistance R4, resistance R5 value, so that according to electric current I
(R7) there are relationships: [I (R7) * R (R7)+U (D1)]≤[15V*R5/ (R4+R5)], and when the current value I for flowing through resistance R7 is big
When I (Q1), there are relationships: [I*R7+U (D1)] > [15V*R5/ (R4+R5)]；When 101 normal driving of source driving signal, flow through
The current value of switching tube Q1 is less than or equal to I (R7), and the second input terminal of voltage comparator U1 is greater than voltage comparator U1 at this time
First input end level, then the output end of voltage comparator U1 exports high level 15V, and switching tube Q2 is not turned on, switching tube Q1
Keep opening state.
When the generation driving signal of source driving signal 101, and the current value I for flowing through switching tube Q1 is greater than the valve design of designer
When value I (R7), for abnormal braking, (such as source driving signal, which exports abnormal driving signal or braking system short circuit, causes braking system
The electric current of system generates damage to system), by analyzing above, there are relationships: [I*R (R7)+U (D1)] > [15V*R5/ (R4+R5)],
The second input terminal of voltage comparator U1 is less than the first input end level of voltage comparator U1 at this time, then voltage comparator U1
Output end exports low level, and Q4 conducting is saturation opening state, and the grid of switching tube Q1 is pulled to low level, thus switching tube Q1
Shutdown, so that the current value of switching tube Q1 be avoided further to increase, timely protective switch pipe Q1 is burned, and substantially improves switch
The reliability and safety of pipe circuit.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.
Claims (10)
1. a kind of current foldback circuit of switching tube circuit, the switching tube circuit includes switching tube and for driving the switch
The source driving signal of pipe on-off, which is characterized in that the current foldback circuit includes:
First diode, cathode are connect with the input terminal of the switching tube or output end；
Judgment module, the first input end incoming reference signal of the judgment module, the second end of the judgment module with it is described
The anode of first diode is connected with the source driving signal, and the judgment module is configured as exporting in the source driving signal
Output control signal shutdown when being greater than second threshold of the conducting electric current for being greater than the first threshold values or the switching tube of driving signal
The driving signal that the control terminal of the switching tube receives.
2. current foldback circuit as described in claim 1, which is characterized in that the judgment module includes first resistor, first
Capacitor and voltage comparator, the first end of the first resistor are connect with the source driving signal, and the of the first resistor
The first input end at two ends, the first end of the first capacitor and the voltage comparator and the anode of the first diode
Connection, the second end ground connection of the first capacitor, the second input terminal of the voltage comparator access the reference signal.
3. current foldback circuit as claimed in claim 2, which is characterized in that the judgment module further includes 3rd resistor, institute
The first end for stating 3rd resistor is connect with the anode of the first diode, the second end of the 3rd resistor and first electricity
The first input end of the second end of resistance, the first end of the first capacitor and the voltage comparator connects.
4. current foldback circuit as described in any one of claims 1 to 3, which is characterized in that further include to generate the ginseng
The reference signal output module of signal is examined, the input terminal of the reference signal output module is connect with the first power supply, the reference
The output end of signal output module is connect with the first input end of the judgment module.
5. current foldback circuit as claimed in claim 4, which is characterized in that the reference signal output module includes the 4th electricity
Resistance and the 5th resistance, the first end of the 4th resistance is connected to second source, the second end and the described 5th of the 4th resistance
The first end of resistance is connected to the second input terminal of the judgment module, the second end ground connection of the 5th resistance altogether.
6. current foldback circuit as described in any one of claims 1 to 3, which is characterized in that the output end of the judgment module
It is connect with the source driving signal, the source driving signal receives the control signal.
7. current foldback circuit as described in any one of claims 1 to 3, which is characterized in that it further include switch module, it is described to open
The control terminal for closing module is connect with the output end of the judgment module, and is connected to the source driving signal and described is opened with described
Between the control terminal for closing pipe, the switch module is configured as controlling the drive according to the control signal that the judgment module exports
The on-off of dynamic signal.
8. current foldback circuit as claimed in claim 7, which is characterized in that the switch module includes second resistance and power
Switching tube, the control terminal of the power switch tube are connected to the control terminal of the switch module, the power through the second resistance
The input terminal of switching tube is connected to the source driving signal and described between the control terminal of the switching tube, the power switch
The output end of pipe is grounded.
9. a kind of switch tube driving circuit, which is characterized in that including the electricity of overcurrent protection described in claim 1-8 any one
Road, source driving signal, switching tube, load and second source, the source driving signal are connect with the control terminal of the switching tube,
Wherein:
The second source, the load, the switching tube are sequentially connected in series to ground；Or
The second source, the switching tube, the load are sequentially connected in series to ground.
10. a kind of electrical equipment, including motor, which is characterized in that it further include switch tube driving circuit as claimed in claim 9,
The switching tube is for driving the motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811588009.3A CN109787596B (en) | 2018-12-25 | 2018-12-25 | Overcurrent protection circuit, switching tube driving circuit and electric equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811588009.3A CN109787596B (en) | 2018-12-25 | 2018-12-25 | Overcurrent protection circuit, switching tube driving circuit and electric equipment |
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| CN109787596A true CN109787596A (en) | 2019-05-21 |
| CN109787596B CN109787596B (en) | 2023-08-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201811588009.3A Active CN109787596B (en) | 2018-12-25 | 2018-12-25 | Overcurrent protection circuit, switching tube driving circuit and electric equipment |
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| CN110368176A (en) * | 2019-07-24 | 2019-10-25 | 郑州大学第一附属医院 | Section's thermotherapeutic apparatus is immunized in rheumatism |
| CN112345908A (en) * | 2020-10-27 | 2021-02-09 | 郑州嘉晨电器有限公司 | Current detection circuit of power switch tube |
| CN112448702A (en) * | 2020-10-22 | 2021-03-05 | 珠海格力电器股份有限公司 | Drive protection circuit and method and electrical equipment |
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| CN209329673U (en) * | 2018-12-25 | 2019-08-30 | 深圳市优必选科技有限公司 | Current foldback circuit, switch tube driving circuit and electrical equipment |
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| JPH09135156A (en) * | 1995-11-07 | 1997-05-20 | Denso Corp | Electric load driving device |
| CN101399491A (en) * | 2007-11-06 | 2009-04-01 | 中国科学院电工研究所 | Overcurrent protection circuit for photovoltaic DC-to-AC converter |
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| CN110368176A (en) * | 2019-07-24 | 2019-10-25 | 郑州大学第一附属医院 | Section's thermotherapeutic apparatus is immunized in rheumatism |
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| CN112448702A (en) * | 2020-10-22 | 2021-03-05 | 珠海格力电器股份有限公司 | Drive protection circuit and method and electrical equipment |
| CN112345908A (en) * | 2020-10-27 | 2021-02-09 | 郑州嘉晨电器有限公司 | Current detection circuit of power switch tube |
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| Publication number | Publication date |
|---|---|
| CN109787596B (en) | 2023-08-04 |
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Effective date of registration: 20231212 Address after: Room 601, 6th Floor, Building 13, No. 3 Jinghai Fifth Road, Beijing Economic and Technological Development Zone (Tongzhou), Tongzhou District, Beijing, 100176 Patentee after: Beijing Youbixuan Intelligent Robot Co.,Ltd. Address before: 518000 16th and 22nd Floors, C1 Building, Nanshan Zhiyuan, 1001 Xueyuan Avenue, Nanshan District, Shenzhen City, Guangdong Province Patentee before: Shenzhen UBTECH Technology Co.,Ltd. |