CN114487544B - Current detection circuit and load driving device - Google Patents
Current detection circuit and load driving device Download PDFInfo
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- CN114487544B CN114487544B CN202111658517.6A CN202111658517A CN114487544B CN 114487544 B CN114487544 B CN 114487544B CN 202111658517 A CN202111658517 A CN 202111658517A CN 114487544 B CN114487544 B CN 114487544B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/30—Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
- H02P25/18—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
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Abstract
A current detection circuit connected to a drive circuit for driving a load, comprising: a conversion circuit connected to the drive circuit, configured to collect a voltage on a low potential side of the load, and convert the voltage into a current; and the mapping amplification circuit is connected with the conversion circuit and is configured to generate a corresponding mapping current with a certain amplification factor according to the current, and the mapping current has a mapping relation with the output current of the driving circuit. According to the application, the corresponding mapping current generated by a certain amplification factor can be obtained according to the voltage on the low potential side of the load through the conversion circuit and the mapping amplification circuit, the mapping current and the output current of the driving circuit have a mapping relation, and the high-precision detection of the output current can be realized by detecting the mapping current.
Description
Technical Field
The application belongs to the technical field of current detection, and particularly relates to a current detection circuit and a load driving device.
Background
At present, in most electronic devices, monitoring the current in the circuit is the most basic technology, and if the current in the circuit is not monitored, the electronic devices are easily damaged. Especially, nowadays, more and more electronic devices need to use motor driving, and for such electronic devices, the output driving capability thereof has very strict requirements, when the output overcurrent capability is not enough, the power tube is easily burned, and the whole chip or even the electronic device may be burned seriously, so that the current to be output needs to be strictly monitored. The current main method is to directly add a sampling resistor at the output end of a load to carry out current detection to protect a chip, the design of the method is simple, however, if the resistance value of the sampling resistor is too large, the overall power consumption of a circuit can be increased, and if the resistance value of the sampling resistor is too small, the sampling value is too small, the detection precision is not high, and the result is not accurate.
Disclosure of Invention
An object of the application is to provide a current detection circuit and a load driving device, which aim at solving the problem that the current detection precision is not high in the conventional current detection.
A first aspect of an embodiment of the present application provides a current detection circuit, connected to a driving circuit for driving a load, including: a conversion circuit connected to the drive circuit, configured to collect a voltage on a low potential side of the load, and convert the voltage into a current; and the mapping amplification circuit is connected with the conversion circuit and is configured to generate a corresponding mapping current with a certain amplification factor according to the current, and the mapping current has a mapping relation with the output current of the driving circuit.
In one embodiment, the conversion circuit comprises an error adjusting circuit and a conversion output circuit; the error adjusting circuit is arranged between the conversion output circuit and the driving circuit, and is configured to generate an adjusting voltage according to a feedback voltage of a current output end of the conversion output circuit and the voltage; the conversion output circuit is configured to convert the regulated voltage into the current.
In one embodiment, the error adjusting circuit includes an error amplifier, a non-inverting input terminal of the error amplifier is connected to the low potential side of the load, an inverting input terminal of the error amplifier is connected to the current output terminal of the switching output circuit, an output terminal of the error amplifier is connected to the switching output circuit, and the error amplifier is configured to adjust the adjusting voltage output to the switching output circuit according to a magnitude relationship between the feedback voltage and the voltage, so that the feedback voltage is equal to the voltage.
In one embodiment, the conversion output circuit includes an adjusting tube, a first conduction end of the adjusting tube is connected to the mapping amplification circuit, a controlled end of the adjusting tube is connected to an output end of the error amplifier, a second conduction end of the adjusting tube is a current output end of the conversion output circuit, and the adjusting tube is configured to generate the corresponding current according to the adjustment voltage.
In one embodiment, the conversion circuit further comprises a conversion control circuit, and a current output end of the conversion output circuit is grounded through the conversion control circuit; the switching control circuit is configured to be turned on when there is an output on a low potential side of the load under control of the drive circuit.
In one embodiment, the mapping amplifying circuit includes a current mirror and a mapping resistor, an input terminal of the current mirror is connected to a power supply, a first output terminal of the current mirror is connected to a current input terminal of the converting circuit, and a second output terminal of the current mirror is grounded through the detecting circuit; the current mirror is configured to generate a corresponding mapping current at a second output terminal of the current mirror with a certain amplification factor according to the magnitude of the current transmitted by a first output terminal of the current mirror to the conversion circuit, so as to generate a corresponding mapping voltage on the mapping resistor according to the mapping current.
A second aspect of the embodiments of the present application provides a load driving apparatus including the current detection circuit as described above, the driving circuit connected to the current detection circuit, the driving circuit including a load circuit configured to drive the load, and a control circuit configured to control the load circuit to drive the load according to an external instruction.
In one embodiment, the load circuit includes a first power switch, a second power switch, a first control switch and a second control switch; the first conduction end of the first power switch is connected with a power supply, the second conduction end of the first power switch is connected with the first load end of the load, the controlled end of the first power switch is connected with a control circuit, the first conduction end of the second power switch is connected with the power supply, the second conduction end of the second power switch is connected with the second load end of the load, and the controlled end of the second power switch is connected with the control circuit; the first conducting end of the first control switch is connected with the first load end of the load, the second conducting end of the first control switch is grounded, the controlled end of the first control switch is connected with the control circuit, the first conducting end of the second control switch is connected with the second load end of the load, the second conducting end of the second control switch is grounded, and the controlled end of the second control switch is connected with the control circuit.
In one embodiment, the control circuit includes a control module, and the control module is respectively connected to the first load terminal, the second load terminal, the controlled terminal of the first power switch, the controlled terminal of the second power switch, the controlled terminal of the first control switch, and the controlled terminal of the second control switch; the control module is configured to output the voltage of the first load end to a voltage output end of the control module when the control module controls the second power switch and the first control switch to be switched on and controls the first power switch and the second control switch to be switched off according to an external instruction; the control module is further configured to output the voltage of the second load terminal to a voltage output terminal of the control module when the control module controls the first power switch and the second control switch to be turned on and controls the second power switch and the first control switch to be turned off according to an external instruction; the control module is further configured to output the voltages of the first load end and the second load end to a voltage output end of the control module when the control module controls the first power switch and the second power switch to be turned off and controls the first control switch and the second control switch to be turned on according to an external instruction.
In one embodiment, the load circuit further includes a plurality of first auxiliary switches and a plurality of second auxiliary switches, each of the first auxiliary switches is connected in parallel with the first control switch, and each of the second auxiliary switches is connected in parallel with the second control switch.
Compared with the prior art, the embodiment of the application has the beneficial effects that: the mapping current generated by a certain amplification factor can be obtained according to the voltage on the low potential side of the load through the conversion circuit and the mapping amplification circuit, the mapping current and the output current of the driving circuit have a mapping relation, and the high-precision detection of the output current can be realized by detecting the mapping current.
Drawings
Fig. 1 is a circuit diagram of a load driving apparatus according to a first embodiment of the present application;
FIG. 2 is a schematic block diagram of a current detection circuit according to a second embodiment of the present application;
fig. 3 is a circuit schematic diagram of a current detection circuit according to a second embodiment of the present application.
The above figures illustrate: 100. a load circuit; 200. a control circuit; 210. a control module; 300. a conversion circuit; 310. an error adjusting circuit; 320. a conversion output circuit; 330. a switching control circuit; 400. a mapping amplification circuit; 410. a current mirror; 500. a drive circuit; 600. a current detection circuit.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
Fig. 1 shows a circuit schematic diagram of a load driving apparatus according to a first embodiment of the present application, which is detailed as follows:
a load driving device includes a current detection circuit 600 and a driving circuit 500 connected to the current detection circuit 600, the driving circuit 500 including a load circuit 100 and a control circuit 200.
As shown in fig. 1, the load circuit 100 is configured to be connected to a load M, which is a motor in this embodiment, to provide a driving voltage to the load M; the control circuit 200 is connected to the load circuit 100, configured to control the load circuit 100 to drive the load M according to an external instruction, and collect a voltage (output voltage) on the low potential side of the load M, which is also the output voltage of the load circuit 100, and the control circuit 200 is provided with a voltage output terminal for outputting the collected output voltage. The current detection circuit 600 is connected to the voltage output terminal of the control circuit 200, and collects the output voltage of the voltage output terminal of the control circuit 200, and the current detection circuit 600 can convert the output voltage into a mapping current having a mapping relation with the output current of the driving circuit 500, where the output current of the driving circuit 500 is the output current of the low potential side of the load M.
For example, the load M is a motor, the direction of the current supplied by the driving circuit 500 may be changed alternately during driving, and thus the low potential side thereof refers to the current flowing-out side.
In another embodiment, unlike the present embodiment, the low potential side (load circuit 100) of the load M is connected to the current detection circuit 600 to directly output the output voltage of the load M to the current detection circuit 600.
Finally, the mapping current can be acquired through corresponding detection equipment, and indirect high-precision detection on the output current of the driving circuit 500 can be realized.
As shown in fig. 1, in the present embodiment, the load circuit 100 includes a first power switch Q1, a second power switch Q2, a first control switch Q3, and a second control switch Q4; a first conduction end of the first power switch Q1 is connected with a power supply, a second conduction end of the first power switch Q1 is connected with a first load end OUT1 of a load M, a controlled end of the first power switch Q1 is connected with the control circuit 200, a first conduction end of the second power switch Q2 is connected with the power supply, a second conduction end of the second power switch Q2 is connected with a second load end OUT2 of the load M, and a controlled end of the second conduction end is connected with the control circuit 200; the first conduction end of the first control switch Q3 is connected with the first load end OUT1 of the load M, the second conduction end of the first control switch Q3 is grounded, the controlled end of the first control switch Q3 is connected with the control circuit 200, the first conduction end of the second control switch Q4 is connected with the first load end OUT1 of the load M, the second conduction end of the second control switch Q4 is grounded, and the controlled end of the second control switch Q4 is connected with the control circuit 200. The on-off of the first power switch Q1, the second power switch Q2, the first control switch Q3 and the second control switch Q4 are controlled respectively, so that the direction of current flowing through the load M is changed, and the load M can be driven in different working modes.
Specifically, the first power switch Q1, the second power switch Q2, the first control switch Q3 and the second control switch Q4 are all PMOS transistors. The first conduction end of the first power switch Q1 is a drain electrode of a PMOS (P-channel metal oxide semiconductor) tube, the second conduction end of the first power switch Q1 is a source electrode of the PMOS tube, and the controlled end of the first power switch Q1 is a grid electrode of the PMOS tube. The first conduction end of the second power switch Q2 is a drain electrode of a PMOS transistor, the second conduction end of the second power switch Q2 is a source electrode of the PMOS transistor, and the controlled end of the second power switch Q2 is a gate electrode of the PMOS transistor. The first conduction end of the first control switch Q3 is a drain electrode of a PMOS (P-channel metal oxide semiconductor) transistor, the second conduction end of the first control switch Q3 is a source electrode of the PMOS transistor, and the controlled end of the first control switch Q3 is a grid electrode of the PMOS transistor. The first conduction end of the second control switch Q4 is a drain electrode of a PMOS transistor, the second conduction end of the second control switch Q4 is a source electrode of the PMOS transistor, and the controlled end of the second control switch Q4 is a gate electrode of the PMOS transistor.
As shown in fig. 1, in the present embodiment, the control circuit 200 includes a control module 210, and the control module 210 is respectively connected to the first load terminal OUT1, the second load terminal OUT2, the controlled terminal of the first power switch Q1, the controlled terminal of the second power switch Q2, the controlled terminal of the first control switch Q3, and the controlled terminal of the second control switch Q4.
It should be noted that the control module 210 is configured to output the output voltage of the first load terminal OUT1 to the voltage output terminal of the control module 210 when the control module 210 controls the second power switch Q2 and the first control switch Q3 to be turned on and controls the first power switch Q1 and the second control switch Q4 to be turned off according to an external instruction. The input current driving the load M at this time is input from the second load terminal OUT2, and the output current is output from the first load terminal OUT1, where the first load terminal OUT1 is the low potential side of the load M.
When the control module 210 controls the first power switch Q1 and the second control switch Q4 to be turned on and controls the second power switch Q2 and the first control switch Q3 to be turned off according to the external instruction, the output voltage of the second load terminal OUT2 is output to the voltage output terminal of the control module 210. The input current driving the load M at this time is input from the first load terminal OUT1, and the output current is output from the second load terminal OUT2, and the second load terminal OUT2 is the low potential side of the load M at this time.
When the control module 210 controls the first power switch Q1 and the second power switch Q2 to be turned off and controls the first control switch Q3 and the second control switch Q4 to be turned on according to an external instruction, the output voltages of the first load terminal OUT1 and the second load terminal OUT2 are both output to the voltage output terminal of the control module 210. At this time, the load M is in a braking state, and the output voltages of the first load terminal OUT1 and the second load terminal OUT2 are simultaneously collected, so that the original current direction of the load M during operation does not need to be considered, and both the first load terminal OUT1 and the second load terminal OUT2 can be the low-potential side of the load M.
In this embodiment, the load circuit 100 further includes N first auxiliary switches and M second auxiliary switches, each first auxiliary switch is connected in parallel with the first control switch Q3, and each second auxiliary switch is connected in parallel with the second control switch, and is configured to share the output current, so as to avoid that the current of a single power transistor is too large and burned out. Wherein N and M are both non-negative integers. The controlled terminal of each first auxiliary switch and the controlled terminal of each second auxiliary switch are connected to the control module 210.
In this embodiment, the on-resistances of the first power switch Q1, the second power switch Q2, the first control switch Q3, the second control switch Q4, the first auxiliary switch and the second auxiliary switch are equal and are all R1.
Fig. 2 shows a schematic block diagram of a current detection circuit provided in a second embodiment of the present application, and for convenience of illustration, only the parts related to this embodiment are shown, and detailed descriptions are as follows:
based on the above embodiments, a current detection circuit 600 includes a conversion circuit 300 and a mapping amplification circuit 400. The conversion circuit 300 is connected to an output terminal (voltage output terminal of the control circuit 200) of the drive circuit 500, and is configured to collect a voltage (output voltage) on the low potential side of the load M and convert the output voltage into a current (conversion current). The mapping amplifying circuit 400 is connected to the converting circuit 300, and configured to generate a mapping current with a certain amplification factor according to the converting current, wherein the mapping current has a mapping relation with the output current of the driving circuit 500.
Compared with the traditional mode of directly detecting the output current on the low-potential side of the load M through the sampling resistor, even though the same detection device is finally used, the mapping current which has the mapping relation with the output current of the embodiment can amplify partial values which cannot be detected by the original detection device in the output current, so that the high-precision detection of the output current is realized.
As shown in fig. 2 and 3, in the present embodiment, the conversion circuit 300 includes an error adjustment circuit 310 and a conversion output circuit 320; the error adjusting circuit 310 is provided between the conversion output circuit 320 and an output terminal of the drive circuit 500 (an output terminal of the control circuit 200), the error adjusting circuit 310 being configured to generate an adjustment voltage from the feedback voltage of the conversion output circuit 320 and the output voltage; the conversion output circuit 320 is configured to generate a conversion current according to the regulation voltage.
Specifically, the error adjusting circuit 310 includes an error amplifier U1, a non-inverting input terminal of the error amplifier U1 is connected to the output terminal (the output terminal of the control circuit 200) of the driving circuit 500, and an inverting input terminal of the error amplifier U1 is connected to the current output terminal of the switching output circuit 320.
It should be noted that the error amplifier U1 is configured to output a corresponding regulated voltage based on a voltage difference between the feedback voltage at the inverting input terminal and the output voltage at the non-inverting input terminal. Specifically, if the feedback voltage is less than the output voltage, the error amplifier U1 increases the output regulated voltage; if the feedback voltage is greater than the output voltage, the error amplifier U1 will reduce the output regulated voltage, eventually making the feedback voltage equal to the output voltage. The feedback voltage is the voltage at the current output of the switching output circuit 320.
As shown in fig. 2 and fig. 3, in the present embodiment, the conversion output circuit 320 includes a tuning tube Q5, a first conduction terminal of the tuning tube Q5 is connected to the mapping amplifying circuit 400, a controlled terminal of the tuning tube Q5 is connected to the output terminal of the error amplifier U1, and a second conduction terminal of the tuning tube Q5 is connected to the inverting input terminal of the error amplifier U1. The adjusting transistor Q5 may be a PMOS transistor, a first conduction terminal of the adjusting transistor Q5 is a drain of the PMOS transistor, a second conduction terminal of the adjusting transistor Q5 is a source of the PMOS transistor and is a current output terminal of the converting output circuit 320, and a controlled terminal of the adjusting transistor Q5 is a gate of the PMOS transistor. The adjusting tube Q5 can adjust the magnitude of the current that it can pass according to the voltage of its controlled end, that is, adjust the magnitude of the switching current output by the current output end of the switching output circuit 320.
In this embodiment, the switching circuit further includes a switching control circuit 330 for controlling the on/off of the switching circuit 300. The current output of the switching output circuit 320 is connected to ground through the switching control circuit 330, while the switching current generates a feedback voltage on the switching control circuit 330.
For example, based on the first embodiment, as shown in fig. 2 and 3, the conversion control circuit 330 includes an or operation logic circuit U2 and a conversion switch Q6; a first input end of the or operation logic circuit U2 is connected with a controlled end of the first control switch Q3, and a second input end of the or operation logic circuit U2 is connected with a controlled end of the second control switch Q4; a first conduction end of the transfer switch Q6 is connected with the current output end of the transfer output circuit 320, a second conduction end of the transfer switch Q6 is grounded, and a controlled end of the transfer switch Q6 is connected with the output end of the or operation logic circuit U2.
It should be noted that the transfer switch Q6 may be a PMOS transistor, a first conduction terminal of the transfer switch Q6 is a drain of the PMOS transistor, a second conduction terminal of the transfer switch Q6 is a source of the PMOS transistor, and a controlled terminal of the transfer switch Q6 is a gate of the PMOS transistor. When the voltage at any one or both of the first input end of the or operation logic circuit U2 and the second input end of the or operation logic circuit U2 is at a high level, the output end of the or operation logic circuit U2 outputs a high level, so that the transfer switch Q6 is turned on, that is, when the first control switch Q3 and/or the second control switch Q4 are turned on, the transfer switch Q6 is also turned on.
As shown in fig. 2 and fig. 3, in the present embodiment, the mapping amplifying circuit 400 includes a current mirror 410 and a mapping resistor Rout, an input terminal of the current mirror 410 is connected to the power supply, a first output terminal of the current mirror 410 is connected to a current input terminal (a first conducting terminal of the tuning transistor Q5) of the converting circuit 300, and a second output terminal of the current mirror 410 is grounded through the detecting circuit; the current mirror 410 is configured to generate a mapping current corresponding to the conversion current at a second output terminal of the current mirror 410 with a certain amplification factor according to the magnitude of the conversion current transmitted by the first output terminal of the current mirror 410 to the conversion circuit 300, so as to generate a corresponding mapping voltage Vout on the mapping resistor Rout according to the mapping current.
A mapping voltage output end OUT3 is arranged at a connection point of the mapping resistor Rout and a second output end of the current mirror 410, the mapping voltage output end OUT3 is used for being connected with corresponding detection equipment, and a specific value of the mapping current can be obtained according to the resistance value of the mapping resistor Rout by collecting the mapping voltage Vout through the corresponding detection equipment, so that the magnitude of the output current can be deduced.
Specifically, in this embodiment, the on-resistance of the switch Q6 is also R1, and if the first power switch Q1 is turned off, the second power switch Q2 is turned on, the first control switch Q3 is turned on, and the second control switch Q4 is turned off, the motor serving as the load M rotates forward, and the output current in the forward rotation is I1, there is a first formula: v1= R1 × I1/N, where V1 is the output voltage of the first load terminal OUT1 and N is the first switching number sum of the first control switch Q3 and the first auxiliary switch, i.e., N = N +1. In the conversion circuit 300, since the feedback voltage is equal to the output voltage, there is a second formula: v1= R1 × I6, where I6 is the current output by the current mirror 410 to the conversion circuit 300.
In this embodiment, the amplification factor of the current mirror 410 is q, that is, the current ratio between the first output terminal of the current mirror 410 and the second output terminal thereof is 1: q, then there is a third formula: iout = I6 × q, where Iout is the current output by the current mirror 410 to the detection circuit. Combining the first formula, the second formula and the third formula can obtain a fourth formula: iout = I1/n × q. And by collecting the mapping voltage Vout and according to the mapping voltage formula: vout = Rout × Iout, where Vout is a mapping voltage Vout collected by a corresponding detection device, and when the mapping resistance Rout, the amplification factor q, the first switch number, and n are fixed and known, the specific magnitude of the output current I1 when the motor rotates forward can be calculated according to the mapping voltage Vout by using a fourth formula and a mapping voltage formula.
Similarly, if the first power switch Q1 is turned on, the second power switch Q2 is turned off, the first control switch Q3 is turned off, and the second control switch Q4 is turned on, the motor serving as the load M is reversed, and the output current during the reversal is I2, then there is a fifth formula: iout = I2/M × Q, where M is the second switching number sum of the second control switch Q4 and the second auxiliary switch, i.e., M = M +1. And calculating the specific magnitude of the output current when the motor rotates reversely by combining the fifth formula and the mapping voltage formula.
Similarly, if the first power switch Q1 is turned on, the second power switch Q2 is turned off, the first control switch Q3 is turned off, and the second control switch Q4 is turned on, the motor brake as the load M at this time has a sixth formula by combining the fourth formula and the fifth formula: iout = (I1/n + I2/m) × q, and the output current may be monitored in combination with the sixth equation and the mapped voltage equation.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present application, and they should be construed as being included in the present application.
Claims (8)
1. A current detection circuit connected to a drive circuit for driving a load, comprising:
a conversion circuit connected to the drive circuit and configured to collect a voltage on a low potential side of the load and convert the voltage into a current;
the mapping amplification circuit is connected with the conversion circuit and is configured to generate a corresponding mapping current with a certain amplification factor according to the current, and the mapping current has a mapping relation with the output current of the driving circuit;
the conversion circuit comprises an error adjusting circuit, a conversion output circuit and a conversion control circuit;
the error adjusting circuit is arranged between the conversion output circuit and the driving circuit, and is configured to generate an adjusting voltage according to a feedback voltage of a current output end of the conversion output circuit and the voltage; the conversion output circuit is configured to convert the regulated voltage to the current; the current output end of the conversion output circuit is grounded through the conversion control circuit; the switching control circuit is configured to be turned on when there is an output on a low potential side of the load under control of the drive circuit.
2. The current detection circuit according to claim 1, wherein the error adjustment circuit includes an error amplifier, a non-inverting input terminal of the error amplifier is connected to the low potential side of the load, an inverting input terminal of the error amplifier is connected to the current output terminal of the conversion output circuit, an output terminal of the error amplifier is connected to the conversion output circuit, and the error amplifier is configured to adjust the adjustment voltage output to the conversion output circuit so that the feedback voltage is equal to the voltage in accordance with a magnitude relation between the feedback voltage and the voltage.
3. The current detection circuit of claim 2, wherein the conversion output circuit comprises a tuning tube, a first conduction terminal of the tuning tube is connected to the mapping amplifying circuit, a controlled terminal of the tuning tube is connected to the output terminal of the error amplifier, and a second conduction terminal of the tuning tube is a current output terminal of the conversion output circuit, and the tuning tube is configured to generate the corresponding current according to the regulated voltage.
4. The current sensing circuit of any one of claims 1 to 3, wherein the mapping amplifying circuit comprises a current mirror and a mapping resistor, an input terminal of the current mirror is connected to a power supply, a first output terminal of the current mirror is connected to a current input terminal of the converting circuit, and a second output terminal of the current mirror is grounded through the sensing circuit;
the current mirror is configured to generate a corresponding mapping current at a second output terminal of the current mirror with a certain amplification factor according to the magnitude of the current transmitted by a first output terminal of the current mirror to the conversion circuit, so as to generate a corresponding mapping voltage on the mapping resistor according to the mapping current.
5. A load driving apparatus comprising the current detection circuit according to any one of claims 1 to 4, a driving circuit connected to the current detection circuit, the driving circuit including a load circuit configured to drive the load and a control circuit configured to control the load circuit to drive the load according to an external instruction.
6. The load driving apparatus according to claim 5, wherein the load circuit comprises a first power switch, a second power switch, a first control switch, and a second control switch;
the first conduction end of the first power switch is connected with a power supply, the second conduction end of the first power switch is connected with the first load end of the load, the controlled end of the first power switch is connected with a control circuit, the first conduction end of the second power switch is connected with the power supply, the second conduction end of the second power switch is connected with the second load end of the load, and the controlled end of the second power switch is connected with the control circuit;
the first conducting end of the first control switch is connected with the first load end of the load, the second conducting end of the first control switch is grounded, the controlled end of the first control switch is connected with the control circuit, the first conducting end of the second control switch is connected with the second load end of the load, the second conducting end of the second control switch is grounded, and the controlled end of the second control switch is connected with the control circuit.
7. The load driving apparatus according to claim 6, wherein the control circuit comprises a control module, and the control module is respectively connected to the first load terminal, the second load terminal, the controlled terminal of the first power switch, the controlled terminal of the second power switch, the controlled terminal of the first control switch, and the controlled terminal of the second control switch;
the control module is configured to output the voltage of the first load end to a voltage output end of the control module when the control module controls the second power switch and the first control switch to be switched on and controls the first power switch and the second control switch to be switched off according to an external instruction;
the control module is further configured to output the voltage of the second load terminal to a voltage output terminal of the control module when the control module controls the first power switch and the second control switch to be turned on and controls the second power switch and the first control switch to be turned off according to an external instruction;
the control module is further configured to output the voltages of the first load end and the second load end to a voltage output end of the control module when the control module controls the first power switch and the second power switch to be turned off and controls the first control switch and the second control switch to be turned on according to an external instruction.
8. The load driving apparatus according to claim 6, wherein the load circuit further comprises a plurality of first auxiliary switches each connected in parallel with the first control switch, and a plurality of second auxiliary switches each connected in parallel with the second control switch.
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