CN219933113U - Coil current control circuit - Google Patents
Coil current control circuit Download PDFInfo
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- CN219933113U CN219933113U CN202320749384.1U CN202320749384U CN219933113U CN 219933113 U CN219933113 U CN 219933113U CN 202320749384 U CN202320749384 U CN 202320749384U CN 219933113 U CN219933113 U CN 219933113U
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- 238000005070 sampling Methods 0.000 claims abstract description 64
- 238000003745 diagnosis Methods 0.000 claims abstract description 15
- 238000005259 measurement Methods 0.000 claims abstract description 5
- 239000003990 capacitor Substances 0.000 claims description 40
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
The utility model provides a coil current control circuit, which is used for controlling a coil and comprises the following components: the driving module is used for providing a switch controlled by on-off, and the switch is connected in series in a main circuit connected with the coil between a power supply and the ground; the current sampling module is used for sampling and measuring the current of the main line and is connected to the driving module in a feedback manner; and the diagnosis module is used for judging the connection state of the coil by sampling the measurement voltage when the circuit is electrified and initialized. Therefore, the driving module realizes the closed loop control of the coil current through the externally-mounted circuit, and the circuit diagnosis protection not only meets the system requirements, but also reduces the hardware cost, has more flexible control scheme, greatly increases the types of selectable chips and relieves the core-missing pressure.
Description
Technical Field
The utility model belongs to the field of electromagnetic control, and particularly relates to a coil current control circuit.
Background
In the prior art, a linear control system is used for controlling a current type coil in order to realize the requirements of adjustable opening degree, small heating, high braking response speed, good NVH (Noise, vibration, harshness, noise, vibration and harshness) effect and the like of an electromagnetic valve, and the current of the electromagnetic valve coil needs to be controlled in a closed loop mode. Meanwhile, the braking system belongs to a functional safety product, has functional safety requirements, and the hardware circuit module is required to have the functional requirements of short circuit and open circuit diagnosis, failure and shutdown and the like. In order to meet the requirements, the electromagnetic valve drive of the current hydraulic braking system mainly uses an integrated chip drive, and the scheme has the defects of high price, easiness in being influenced by chip shortage, difficulty in purchasing, few alternative scheme choices and the like.
Disclosure of Invention
The technical problems to be solved by the utility model are as follows: how to provide the coil current control circuit can reduce the price, avoid the dependence on an integrated chip, improve the universality, increase the substitution and reduce the purchasing difficulty.
In order to solve the technical problems, the utility model provides a coil current control circuit, which aims to adopt a discrete coil current closed-loop control driving circuit, can achieve the maximum support of electromagnetic valve control frequency to 20kHz, can realize current closed-loop control, and simultaneously meets the diagnosis requirement of a functional hardware circuit. The realization scheme is flexible, the chip selection is more, and the problems of limited current driving capability, high cost and difficult supply of the electromagnetic valve driving chip of the hydraulic braking system are solved.
In order to achieve the above object, the present utility model provides a coil current control circuit for controlling a coil, comprising:
the driving module is used for providing a switch controlled by on-off, and the switch is connected in series in a main circuit connected with the coil between a power supply and the ground;
the current sampling module is used for sampling and measuring the current of the main line and is connected to the driving module in a feedback manner;
and the diagnosis module is used for judging the connection state of the coil by sampling the measurement voltage when the circuit is electrified and initialized.
Preferably, the switch is a switch tube, and the driving module further comprises a current limiting resistor and a pre-driving circuit.
Preferably, the switch tube is an NMOS switch tube;
the pre-driving circuit is an in-phase buffer or a PMOS tube;
the micro control unit outputs a pulse width modulation signal to the pre-driving circuit, the pre-driving circuit is connected to the grid electrode of the NMOS switching tube through the current limiting resistor, the source electrode of the NMOS switching tube is grounded, and the drain electrode of the NMOS switching tube is connected with the low potential side of the coil.
Preferably, the current sampling module comprises: the sampling resistor, the filter resistor, the freewheeling diode, the operational amplifier and the filter capacitor;
the sampling resistor is connected in series in the main circuit, a first end of the sampling resistor is connected with a high potential side of the coil, and a second end of the sampling resistor is connected with a power supply;
the first end of the freewheel diode is connected with the second end of the sampling resistor, and the second end of the freewheel diode is connected with the low potential side of the coil;
the non-inverting input end of the operational amplifier is connected to the second end of the sampling resistor, the inverting input end of the operational amplifier is connected to the first end of the sampling resistor, and the output end of the operational amplifier is connected to the first end of the filter resistor;
the second end of the filter resistor is connected with the first end of the filter capacitor, the second end of the filter capacitor is grounded, the filter resistor and the filter capacitor form a low-pass filter circuit, and a current sampling point is led out from the second end of the filter resistor and the first end of the filter capacitor.
Preferably, a high-side switch is connected between the sampling resistor and the power supply;
the power supply end of the operational amplifier is connected with an operational amplifier power supply, the operational amplifier power supply is connected with a decoupling capacitor, and the decoupling capacitor is grounded; the ground of the operational amplifier is grounded.
Preferably, the diagnosis module comprises a diagnosis resistor, a voltage dividing resistor, a pull-down resistor and a bypass capacitor;
the diagnosis resistor is connected with the coil in parallel;
the first end of the divider resistor is connected with the low potential side of the coil, and the second end of the divider resistor is connected with the first end of the pull-down resistor and the first end of the bypass capacitor;
the second end of the pull-down resistor is grounded, and the second end of the bypass capacitor is grounded;
and a voltage sampling point is led out at the joint of the second end of the voltage dividing resistor, the first end of the pull-down resistor and the first end of the bypass capacitor.
Preferably, in the main line, a high-side switch is provided at the power supply.
Preferably, when the circuit is powered on and initialized, the switch and the high-side switch are disconnected, and the voltage of the voltage sampling point is measured to judge the connection state of the coil.
Compared with the prior art, the utility model provides a coil current control circuit, which is used for controlling a coil and comprises the following components: the driving module is used for providing a switch controlled by on-off, and the switch is connected in series in a main circuit connected with the coil between a power supply and the ground; the current sampling module is used for sampling and measuring the current of the main line and is connected to the driving module in a feedback manner; and the diagnosis module is used for judging the connection state of the coil by sampling the measurement voltage when the circuit is electrified and initialized. Therefore, the driving module realizes the closed loop control of the coil current through the externally-mounted circuit, and the circuit diagnosis protection not only meets the system requirements, but also reduces the hardware cost, has more flexible control scheme, greatly increases the types of selectable chips and relieves the core-missing pressure.
Drawings
Fig. 1 is a schematic diagram of a connection frame of an embodiment of a coil current control circuit according to the present utility model.
Fig. 2 is a schematic device connection diagram of an embodiment of a coil current control circuit according to the present utility model.
Reference numerals illustrate:
100 coil
Low potential side of 101 coil
High potential side of 102 coil
200 drive module
210 switch
211 grid electrode
212 source electrode
213 drain electrode
220 current limiting resistor
230 pre-driving circuit
240 micro control unit
300 current sampling module
310 sampling resistor
First end of 311 sampling resistor
312 second end of sampling resistor
320 filter resistor
First end of 321 filter resistor
322 second end of the filter resistor
330 freewheel diode
331 first end of flywheel diode
332 second end of the freewheel diode
340 operational amplifier
341 op amp non-inverting input
342 op amp inverting input
Output terminal of 343 operational amplifier
Power supply terminal of 344 operational amplifier
345 operational amplifier ground
350 filter capacitor
351 first end of filter capacitor
352 second end of filter capacitor
360 current sampling point
370 operation discharge source
380 decoupling capacitor
400 diagnostic module
410 diagnostic resistor
420 voltage dividing resistor
421 first end of voltage dividing resistor
422 second terminal of the voltage dividing resistor
430 pull-down resistor
431 pull-down resistor first end
432 pull-down resistor second end
440 bypass capacitor
441 first end of bypass capacitor
442 second end of bypass capacitor
450 voltage sampling point
500 power supply
600 floor
700 high side switch.
Detailed Description
A preferred embodiment of the present utility model will be described in detail with reference to the accompanying drawings. It is to be understood that the utility model is not limited to the specific embodiments described above, wherein devices and structures not described in detail are to be understood as being implemented in a manner common in the art; any person skilled in the art can make many possible variations and modifications to the technical solution of the present utility model or modifications to equivalent embodiments without departing from the scope of the technical solution of the present utility model, using the methods and technical contents disclosed above, without affecting the essential content of the present utility model.
Referring to fig. 1, the present utility model provides a coil current control circuit for controlling a coil 100, comprising: a driving module 200, a current sampling module 300, a diagnostic module 400. The drive module 200 provides an on-off controlled switch 210. The switch 210 is connected in series in a main line connecting the coil 100 between the power supply 500 and the ground 600. The current sampling module 300 samples the current of the measurement main line and is feedback-connected to the driving module 200. The diagnostic module 400 is used to determine the connection state of the coil 100 by sampling the measured voltage at the time of power-up initialization of the circuit.
Referring to fig. 2, the switch 210 is a switch tube, and the driving module 200 further includes a current limiting resistor 220 and a pre-driving circuit 230. The pre-driving circuit 230 is used to increase driving capability, ensure that the NMOS switching transistor used as the switch 210 works in a switching state, and the delay time of on/off can meet the precision requirement of the system and the minimum switching loss.
The switching tube is an NMOS switching tube. The pre-driver circuit 230 is an in-phase buffer (an embodiment of a logic driver) or a PMOS transistor. The micro control unit 240 outputs a Pulse Width Modulation (PWM) signal to the pre-driving circuit 230, the pre-driving circuit 230 is connected to the gate 211 of the NMOS switching tube through the current limiting resistor 220, the source 212 of the NMOS switching tube is grounded 600, and the drain 213 of the NMOS switching tube is connected to the low potential side 101 of the coil. The frequency of the PWM signal may be 20kHz.
The current sampling module 300 includes: sampling resistor 310, filter resistor 320, freewheeling diode 330, operational amplifier 340, and filter capacitor 350. The sampling resistor 310 is connected in series in the main circuit, a first end 311 of the sampling resistor is connected to the high potential side 102 of the coil, and a second end 312 of the sampling resistor is connected to the power supply 500. The first end 331 of the freewheel diode is connected to the second end 312 of the sampling resistor and the second end 332 of the freewheel diode is connected to the low potential side 101 of the coil. By the connection of the freewheeling diode 330, the accuracy of the sampling of the closed loop of the coil 100 current is ensured, while the low-side driving MOSFET (i.e., an embodiment of the NMOS switching transistor as switch 210) is protected from damage due to overvoltage breakdown or virtual conduction. The noninverting input 341 of the operational amplifier is connected to the second end 312 of the sampling resistor, the inverting input 342 of the operational amplifier is connected to the first end 311 of the sampling resistor, and the output 343 of the operational amplifier is connected to the first end 321 of the filter resistor. The second end 322 of the filter resistor is connected with the first end 351 of the filter capacitor, the second end 352 of the filter capacitor is grounded 600, the filter resistor 320 and the filter capacitor 350 form a low-pass filter circuit, and a current sampling point 360 is led out from the second end 322 of the filter resistor and the first end 351 of the filter capacitor. The low-pass filter circuit can ensure that the current sampling signal can effectively filter out high-frequency interference signals, and ensure the stability of the signals.
The current sampling module 300 can also detect whether the coil 100 has an overcurrent fault, and if so, can rapidly cut off the driving module 200 of the coil, and protect the hardware circuit and the coil 100 from damage.
The magnitude of the resistance of the sampling resistor 310 and the amplification factor of the operational amplifier 340 are selected appropriately according to the magnitude of the current required to pass through the coil 100, so as to ensure the accuracy of sampling.
A high-side switch 700 is connected between the sampling resistor 310 and the power supply 500. The power supply end 344 of the operational amplifier is connected with the operational amplifier power supply 370, the operational amplifier power supply 370 is connected with the decoupling capacitor 380, and the decoupling capacitor 380 is grounded 600; the ground 345 of the operational amplifier is connected to ground 600.
Diagnostic module 400 includes a diagnostic resistor 410, a divider resistor 420, a pull-down resistor 430, and a bypass capacitor 440. The diagnostic resistor 410 is connected in parallel with the coil 100. The first terminal 421 of the divider resistor is connected to the low potential side 101 of the coil, and the second terminal 422 of the divider resistor is connected to the first terminal 431 of the pull-down resistor and the first terminal 441 of the shunt capacitor. The second end 432 of the pull-down resistor is connected to ground 600 and the second end 442 of the bypass capacitor is connected to ground 600. A voltage sampling point 450 is led out at the joint of the second end 422 of the voltage dividing resistor, the first end 431 of the pull-down resistor and the first end 441 of the bypass capacitor.
In the main line, a high-side switch 700 is provided at the power supply 500.
At the time of power-up initialization of the circuit, the switch 210 and the high-side switch 700 are turned off, and the voltage of the voltage sampling point 450 is measured to determine the connection state of the coil 100.
In the case of opening the switch 210 and the high-side switch 700, the connection state of the coil 100 and the hardware circuit state are determined by sampling the voltage of the voltage sampling point 450 according to different test conditions.
The diagnostic module 400 can determine whether a fault (connection state of the coil 100 belonging to abnormality) such as a short circuit, an open circuit, an overvoltage exists in the coil.
The specific structural form of the coil current control circuit provided by the utility model is described above in detail. The utility model has the following technical effects: the technical scheme of the utility model is that the current closed-loop control of the current type coil, circuit diagnosis and other functional requirements are realized through externally-mounted discrete circuits; the circuit provided by the utility model adopts the electrical components with higher universality, reduces the hardware cost on the premise of meeting the system requirement, has more flexible control scheme, greatly increases the types of selectable chips and relieves the core-missing pressure.
The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Various modifications and variations of the present utility model will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.
Claims (8)
1. A coil current control circuit for controlling a coil, comprising:
the driving module is used for providing a switch controlled by on-off, and the switch is connected in series in a main circuit connected with the coil between a power supply and the ground;
the current sampling module is used for sampling and measuring the current of the main line and is connected to the driving module in a feedback manner;
and the diagnosis module is used for judging the connection state of the coil by sampling the measurement voltage when the circuit is electrified and initialized.
2. The coil current control circuit of claim 1, wherein the switch is a switching tube, and the drive module further comprises a current limiting resistor and a pre-drive circuit.
3. The coil current control circuit according to claim 2, wherein,
the switch tube is an NMOS switch tube;
the pre-driving circuit is an in-phase buffer or a PMOS tube;
the micro control unit outputs a pulse width modulation signal to the pre-driving circuit, the pre-driving circuit is connected to the grid electrode of the NMOS switching tube through the current limiting resistor, the source electrode of the NMOS switching tube is grounded, and the drain electrode of the NMOS switching tube is connected with the low potential side of the coil.
4. The coil current control circuit of claim 1 wherein,
the current sampling module comprises: the sampling resistor, the filter resistor, the freewheeling diode, the operational amplifier and the filter capacitor;
the sampling resistor is connected in series in the main circuit, a first end of the sampling resistor is connected with a high potential side of the coil, and a second end of the sampling resistor is connected with a power supply;
the first end of the freewheel diode is connected with the second end of the sampling resistor, and the second end of the freewheel diode is connected with the low potential side of the coil;
the non-inverting input end of the operational amplifier is connected to the second end of the sampling resistor, the inverting input end of the operational amplifier is connected to the first end of the sampling resistor, and the output end of the operational amplifier is connected to the first end of the filter resistor;
the second end of the filter resistor is connected with the first end of the filter capacitor, the second end of the filter capacitor is grounded, the filter resistor and the filter capacitor form a low-pass filter circuit, and a current sampling point is led out from the second end of the filter resistor and the first end of the filter capacitor.
5. The coil current control circuit of claim 4 wherein,
a high-side switch is connected between the sampling resistor and the power supply;
the power supply end of the operational amplifier is connected with an operational amplifier power supply, the operational amplifier power supply is connected with a decoupling capacitor, and the decoupling capacitor is grounded; the ground of the operational amplifier is grounded.
6. The coil current control circuit of claim 1 wherein,
the diagnosis module comprises a diagnosis resistor, a voltage dividing resistor, a pull-down resistor and a bypass capacitor;
the diagnosis resistor is connected with the coil in parallel;
the first end of the divider resistor is connected with the low potential side of the coil, and the second end of the divider resistor is connected with the first end of the pull-down resistor and the first end of the bypass capacitor;
the second end of the pull-down resistor is grounded, and the second end of the bypass capacitor is grounded;
and a voltage sampling point is led out at the joint of the second end of the voltage dividing resistor, the first end of the pull-down resistor and the first end of the bypass capacitor.
7. The coil current control circuit according to claim 6, wherein a high-side switch is provided at the power supply in the main line.
8. The coil current control circuit of claim 7, wherein the switch and the high-side switch are turned off at the time of power-on initialization of the circuit, and the voltage of the voltage sampling point is measured to determine the connection state of the coil.
Priority Applications (1)
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CN202320749384.1U CN219933113U (en) | 2023-04-07 | 2023-04-07 | Coil current control circuit |
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CN202320749384.1U CN219933113U (en) | 2023-04-07 | 2023-04-07 | Coil current control circuit |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN118025105A (en) * | 2024-04-10 | 2024-05-14 | 万向钱潮股份公司 | Control device of braking system |
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2023
- 2023-04-07 CN CN202320749384.1U patent/CN219933113U/en active Active
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN118025105A (en) * | 2024-04-10 | 2024-05-14 | 万向钱潮股份公司 | Control device of braking system |
CN118025105B (en) * | 2024-04-10 | 2024-07-16 | 万向钱潮股份公司 | Control device of braking system |
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