CN219016420U - Current sampling circuit compatible with small current sampling - Google Patents
Current sampling circuit compatible with small current sampling Download PDFInfo
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- CN219016420U CN219016420U CN202222837168.0U CN202222837168U CN219016420U CN 219016420 U CN219016420 U CN 219016420U CN 202222837168 U CN202222837168 U CN 202222837168U CN 219016420 U CN219016420 U CN 219016420U
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- 238000005070 sampling Methods 0.000 title claims abstract description 124
- 239000003990 capacitor Substances 0.000 claims description 15
- 230000010355 oscillation Effects 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 description 12
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- 230000009286 beneficial effect Effects 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The utility model provides a current sampling circuit compatible with small current sampling, which comprises an MCU, and a large current acquisition module and a small current acquisition module which are connected with the MCU; the MCU comprises a large current sampling port and a small current sampling port, the large current sampling module is connected with the large current sampling port, and the small current sampling module is connected with the small current sampling port. The MCU can control the small current acquisition module to be started and the large current acquisition module to be closed according to the occasion required to be used, so that corresponding small current can be output, and when the current gradually becomes larger, the large current acquisition module can be automatically started, so that the compatibility is high, and the accuracy of the current value is high.
Description
Technical Field
The utility model relates to the technical field of circuits, in particular to a current sampling circuit compatible with small current sampling.
Background
At present, with respect to current collection in a small household appliance, a large current is generally used to flow through a sampling resistor, and a current value is calculated by collecting a voltage drop generated by the sampling resistor.
The sampling resistor can generate larger power consumption and larger temperature rise under the condition of long-time working under large current, so that the type selection of the sampling resistor can not select a large resistance value, but the selection resistance value is smaller; however, in a small current state, the voltage drop at two ends of the sampling resistor with a small resistance value is also small, so that the problem that MCU (micro control unit) acquires data inaccurately or even cannot acquire the data is caused.
Disclosure of Invention
In order to solve the above problems, the present utility model provides a current sampling circuit compatible with small current sampling.
The main content of the utility model comprises:
the current sampling circuit compatible with small current sampling comprises an MCU, a large current sampling module and a small current sampling module, wherein the MCU comprises a large current sampling port and a small current sampling port;
the high-current sampling module comprises a first sampling resistor connected in series between a discharge MOS tube and the negative electrode of the battery pack, and the high-current sampling port is connected between the first sampling resistor and the discharge MOS tube;
the small current sampling module comprises a control starting unit, a switching unit and a second sampling resistor; the MCU is connected with the switch unit through the opening unit; the first sampling resistor is connected with the switch unit in series, one end of the switch unit is connected between the charging MOS tube and the discharging MOS tube, one end of the first sampling resistor is connected with the negative electrode of the battery pack, and the low-current sampling port is connected between the second sampling resistor and the switch unit.
Preferably, the starting unit comprises a starting control interface, an NPN type first control triode, a PNP type second control triode and a starting power supply; the base of the first control triode is connected with the MCU through the starting control interface, the emitting electrode of the first control triode is grounded, the collecting electrode of the first control triode is connected with the base of the second control triode, the emitting electrode of the second control triode is connected with the starting power supply, and the collecting electrode of the second control triode is connected with the switch unit.
Preferably, the switch unit is an NMOS, an emitter of the second control triode is connected to a gate of the switch unit, a drain of the switch unit is connected between the charge MOS and the discharge MOS, and a source of the switch unit is connected to the second sampling resistor.
Preferably, the circuit further comprises a first current limiting resistor, a first pull-down resistor, a second current limiting resistor, a second pull-down resistor, a third current limiting resistor and a third pull-down resistor; the first current limiting resistor is connected between the starting control interface and the base electrode of the first control triode; the first pull-down resistor is connected between the base electrode and the emitter electrode of the first control triode; the second current limiting resistor is connected between the collector electrode of the first control triode and the base electrode of the second control triode; the second pull-down resistor is connected between the base electrode and the collector electrode of the second control resistor; the third current limiting resistor is connected between the emitter of the second control triode and the grid electrode of the switch unit; the third pull-down resistor is connected between the gate and the source of the switching unit.
Preferably, the low-current sampling module further comprises a wake-up unit, one end of the wake-up unit is connected between the second sampling resistor and the switch unit, and the other end of the wake-up unit is connected with the MCU.
Preferably, the wake-up unit comprises a wake-up comparator, wherein the positive input end of the wake-up comparator is connected with a power supply, the negative input end of the wake-up comparator is connected between the second sampling resistor and the switch unit, and the output end of the wake-up comparator is connected with a wake-up signal port of the MCU.
Preferably, the wake-up unit further comprises a filtering component and an oscillating component, the filtering component comprises a filtering resistor and a filtering capacitor which are connected in series, one end of the filtering resistor is connected between the second sampling resistor and the switch unit, and the other end of the filtering capacitor is grounded; the oscillating component comprises an oscillating resistor and an oscillating capacitor, wherein the oscillating resistor is connected between the output end of the wake-up comparator and the wake-up signal port of the MCU, one end of the oscillating capacitor is grounded, and the other end of the oscillating capacitor is connected with the wake-up signal port of the MCU.
The utility model has the beneficial effects that: the utility model provides a current sampling circuit compatible with small current sampling, which comprises an MCU, and a large current acquisition module and a small current acquisition module which are connected with the MCU; MCU can control the occasion that uses as required and open little current acquisition module and close heavy current acquisition module to can export corresponding little current, and after the electric current grows gradually, also can open heavy current acquisition module automatically, the compatibility is strong, and the current value accuracy is high.
Drawings
Fig. 1 is a circuit diagram of the present utility model.
Description of the embodiments
The technical scheme protected by the utility model is specifically described below with reference to the accompanying drawings.
As shown in fig. 1, the utility model provides a current sampling circuit compatible with small current sampling, which comprises an MCU, a large current sampling module and a small current sampling module, wherein the MCU comprises a large current sampling port CS and a small current sampling port ICS, the large current sampling module is connected with the large current sampling port CS, and the small current sampling module is connected with the small current sampling port ICS.
Specifically, the high-current sampling module comprises a first sampling resistor R1 connected in series between a discharge MOS tube Q1 and a battery pack negative electrode B-, and the high-current sampling port CS is connected between the first sampling resistor R1 and the discharge MOS tube Q1; the small current sampling module is connected with the large current collecting module in parallel, one end of the small current sampling module is connected with the negative electrode B-of the battery pack, the other end of the small current sampling module is connected between the discharging MOS tube Q1 and the charging MOS tube Q2, the small current sampling module comprises a second sampling resistor R4, one end of the second sampling resistor R4 is connected with the negative electrode B-of the battery pack, and the small current sampling port ICS is connected with the other end of the second sampling resistor R4.
In this embodiment, the low-current sampling module includes a control opening unit and a switching unit connected in series with the second sampling resistor; the MCU controls the opening and closing of the switch unit through the control opening unit, so that the starting and closing of the small-current sampling module are realized.
Specifically, the starting unit includes a starting control interface p_dsg, a first NPN control triode Q7, a second PNP control triode Q4, and a starting power VCCBAT; the base electrode of the first control triode Q7 is connected with the starting control interface P_DSG through a first current limiting resistor R14, and the starting control interface P_DSG is connected with the MCU; the emitter of the first control triode Q7 is grounded, a first pull-down resistor R15 is connected between the base and the emitter of the first control triode Q7, the collector of the first control triode Q is connected with the base of the second control triode Q4 through the second current-limiting resistor R13, the emitter of the second control triode Q4 is connected with the starting power supply VCCBAT, the collector of the second control triode Q is connected with the switch unit Q3, and a second pull-down resistor R10 is connected between the emitter and the base of the second control triode Q; a third current limiting resistor R9 is connected between the emitter of the second control triode Q4 and the gate of the switching unit Q3, the third pull-down resistor R7 is connected between the gate and the source of the switching unit Q3, and the switching unit Q3 is an NMOS tube.
When a small current needs to be collected, the MCU transmits a high level to the on control interface p_dsg, and provides a bias voltage to the base of the first control triode Q7 after the voltage is divided by the first current limiting resistor R14 and the first pull-down resistor R15, so that the first control triode Q7 is turned on, and due to the conduction of the first control triode Q7, the on power VCCBAT is divided by the second pull-down resistor R10 and the second current limiting resistor R13, so that the base of the second control triode Q4 provides a bias voltage, so that the second control triode Q4 is turned on, so that the on power VCCBAT is enabled to flow to the battery pack negative electrode B-through the third current limiting resistor R9 and the third pull-down resistor R7, so that the switch unit Q3 is turned on, and the load current is transmitted to the battery pack negative electrode B-through the switch unit Q3 and the second sampling resistor R4, and meanwhile, the current generated on the second sampling resistor R4 is also transmitted to the battery pack negative electrode B-, so that the voltage drop of the second sampling resistor R4 is enabled to be recognized even if the current is small.
In one embodiment, when the small current is not required to be collected, the MCU is used for controlling the on control interface p_dsg to transmit a low level so that the switch unit Q3 is turned off to turn off the small current sampling module, in other embodiments, the small current sampling module may be further switched between a small current sampling state and a large current sampling state by the wake-up unit, and when the collected current exceeds a set threshold value in the process of collecting the small current, the small current sampling module may be turned off by the wake-up unit to turn on the large current sampling module.
Specifically, one end of the WAKE-UP unit is connected between the second sampling resistor R4 and the switch unit Q3, and the other end of the WAKE-UP unit is connected with the WAKE-UP signal port i_wake_up of the MCU. The WAKE-UP unit comprises a WAKE-UP comparator, the positive input end of the WAKE-UP comparator is connected with a power supply VDD3.3, the negative input end of the WAKE-UP comparator is connected between the second sampling resistor R4 and the switch unit Q3, and the output end of the WAKE-UP comparator is connected with a WAKE-UP signal port I_WAKE_UP of the MCU; a filtering component is connected between the small current sampling point, namely the second sampling resistor R4 and the switch unit Q3 and the ground, the filtering component comprises a filtering resistor R11 and a filtering capacitor C2 which are connected in series, one end of the filtering resistor R11 is connected between the second sampling resistor R4 and the switch unit Q3, and the other end of the filtering capacitor C2 is grounded; meanwhile, a WAKE-UP signal port I_WAKE_UP of the MCU is connected with an output end of the WAKE-UP comparator through an oscillation component, the oscillation component comprises an oscillation resistor R16 and an oscillation capacitor C3, the oscillation resistor R16 is connected between the output end of the WAKE-UP comparator and the WAKE-UP signal port I_WAKE_UP of the MCU, one end of the oscillation capacitor C3 is grounded, and the other end of the oscillation capacitor C3 is connected with the WAKE-UP signal port I_WAKE_UP of the MCU.
When the external load current is greater than a set threshold value, a small current sampling port ICS of the MCU detects that the voltage drop of the second sampling resistor R4 is greater than the set threshold value, the output end of the wake-up comparator outputs a low level, at the moment, the MCU turns on the discharge MOS tube Q1, and then turns off the first control triode Q7 through turning on a control interface P_DSG, so that the switch unit Q3 is turned off, the small current sampling module is thoroughly turned off, and the switching from small current to large current sampling is realized; when the high current is sampled, the MCU cannot detect the voltage drop generated on the first sampling resistor R1, and at the moment, the MCU can control the start control interface P_DSG to input high level and start the low current sampling, so that the high current sampling is switched to the low current sampling.
The foregoing description is only illustrative of the present utility model and is not intended to limit the scope of the utility model, and all equivalent structures or equivalent processes or direct or indirect application in other related technical fields are included in the scope of the present utility model.
Claims (7)
1. The current sampling circuit compatible with small current sampling is characterized by comprising an MCU, a large current sampling module and a small current sampling module, wherein the MCU comprises a large current sampling port and a small current sampling port;
the high-current sampling module comprises a first sampling resistor connected in series between a discharge MOS tube and the negative electrode of the battery pack, and the high-current sampling port is connected between the first sampling resistor and the discharge MOS tube;
the small current sampling module comprises a control starting unit, a switching unit and a second sampling resistor; the MCU is connected with the switch unit through the opening unit; the first sampling resistor is connected with the switch unit in series, one end of the switch unit is connected between the charging MOS tube and the discharging MOS tube, one end of the first sampling resistor is connected with the negative electrode of the battery pack, and the low-current sampling port is connected between the second sampling resistor and the switch unit.
2. The current sampling circuit compatible with small current sampling according to claim 1, wherein the turn-on unit comprises a turn-on control interface, a first control triode of NPN type, a second control triode of PNP type, and a turn-on power supply; the base of the first control triode is connected with the MCU through the starting control interface, the emitting electrode of the first control triode is grounded, the collecting electrode of the first control triode is connected with the base of the second control triode, the emitting electrode of the second control triode is connected with the starting power supply, and the collecting electrode of the second control triode is connected with the switch unit.
3. The current sampling circuit compatible with small current sampling according to claim 2, wherein the switching unit is an NMOS transistor, an emitter of the second control transistor is connected to a gate of the switching unit, a drain of the switching unit is connected between the charge MOS transistor and the discharge MOS transistor, and a source of the switching unit is connected to the second sampling resistor.
4. A current sampling circuit compatible with small current sampling according to claim 3 and further comprising a first current limiting resistor, a first pull-down resistor, a second current limiting resistor, a second pull-down resistor, a third current limiting resistor and a third pull-down resistor; the first current limiting resistor is connected between the starting control interface and the base electrode of the first control triode; the first pull-down resistor is connected between the base electrode and the emitter electrode of the first control triode; the second current limiting resistor is connected between the collector electrode of the first control triode and the base electrode of the second control triode; the second pull-down resistor is connected between the base electrode and the collector electrode of the second control resistor; the third current limiting resistor is connected between the emitter of the second control triode and the grid electrode of the switch unit; the third pull-down resistor is connected between the gate and the source of the switching unit.
5. The current sampling circuit compatible with small current sampling according to claim 1, wherein the small current sampling module further comprises a wake-up unit, one end of the wake-up unit is connected between the second sampling resistor and the switch unit, and the other end of the wake-up unit is connected with the MCU.
6. The current sampling circuit compatible with small current sampling according to claim 5, wherein the wake-up unit comprises a wake-up comparator, a positive input end of the wake-up comparator is connected with a power supply, a negative input end of the wake-up comparator is connected between the second sampling resistor and the switch unit, and an output end of the wake-up comparator is connected with a wake-up signal port of the MCU.
7. The current sampling circuit compatible with small current sampling according to claim 6, wherein the wake-up unit further comprises a filter component and an oscillation component, the filter component comprises a filter resistor and a filter capacitor which are connected in series, one end of the filter resistor is connected between the second sampling resistor and the switch unit, and the other end of the filter capacitor is grounded; the oscillating component comprises an oscillating resistor and an oscillating capacitor, wherein the oscillating resistor is connected between the output end of the wake-up comparator and the wake-up signal port of the MCU, one end of the oscillating capacitor is grounded, and the other end of the oscillating capacitor is connected with the wake-up signal port of the MCU.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222837168.0U CN219016420U (en) | 2022-10-27 | 2022-10-27 | Current sampling circuit compatible with small current sampling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222837168.0U CN219016420U (en) | 2022-10-27 | 2022-10-27 | Current sampling circuit compatible with small current sampling |
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| Publication Number | Publication Date |
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| CN219016420U true CN219016420U (en) | 2023-05-12 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202222837168.0U Active CN219016420U (en) | 2022-10-27 | 2022-10-27 | Current sampling circuit compatible with small current sampling |
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- 2022-10-27 CN CN202222837168.0U patent/CN219016420U/en active Active
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