CN114113767A - Circuit for improving small current acquisition precision of solid-state power controller - Google Patents
Circuit for improving small current acquisition precision of solid-state power controller Download PDFInfo
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- CN114113767A CN114113767A CN202111336654.8A CN202111336654A CN114113767A CN 114113767 A CN114113767 A CN 114113767A CN 202111336654 A CN202111336654 A CN 202111336654A CN 114113767 A CN114113767 A CN 114113767A
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- 238000005070 sampling Methods 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 7
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- 238000003199 nucleic acid amplification method Methods 0.000 abstract description 3
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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
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
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Abstract
The invention relates to a circuit for improving the low current acquisition precision of a solid-state power controller, which comprises a low current acquisition circuit and a reference source circuit; the small current acquisition circuit comprises an operational amplifier M5B, resistors R64, R65, R67, R69, R11, R72 and R88, filter capacitors C44 and C45, and a reference source circuit comprising a reference source chip U5; capacitor C106-C110, resistor R95. According to the invention, the lifting level circuit is arranged, so that the acquisition error caused by an operational amplifier dead zone is avoided, and the accuracy of an output signal is ensured; and a reference source circuit is adopted, so that the accuracy of the lifting level is improved, and the integral acquisition accuracy of the small current signal is ensured. Can accurately collect small current signals of 20mA-200mA, and realize high-precision amplification of weak signals of 0.1 mV-1 mV.
Description
Technical Field
The invention relates to a circuit for improving the small current acquisition precision of a solid-state power controller, and belongs to the technical field of power electronics.
Background
The use of the solid-state power controller is derived from the requirement of the airplane from mechanization to electrification, is an important component applied to an airplane power supply system, and bears the power supply and management functions of all-airplane electrical loads. At present, a large amount of 20mA-200mA small current collection is required in the electrical equipment of the airplane, and the required collection precision range is +/-5 mA.
When the traditional small current acquisition circuit acquires a small current of 20mA-200mA, a weak signal of 0.1 mV-1 mV is output after the acquisition of 5m ohm sampling resistor. Traditional undercurrent acquisition circuit directly enlargies through operational amplifier, because the signal that undercurrent was gathered is very little, has input voltage less, and the output distortion is put to the fortune, receives resistance, ambient temperature influence great, causes final undercurrent output deviation great, and the collection precision can't satisfy the requirement of 5 mA.
Disclosure of Invention
The invention aims to provide a circuit for improving the small current acquisition precision of a solid-state power controller, aiming at acquiring a small current signal of 20-200 mA, and realizing high-precision amplification of a weak signal of 0.1-1 mV by the circuit so as to realize accurate acquisition and report of the small current signal.
The technical scheme of the invention is as follows:
a circuit for improving the small current acquisition precision of a solid-state power controller comprises a small current acquisition circuit and a reference source circuit;
the small current acquisition circuit comprises an operational amplifier M5B; resistors R64, R65, R67, R69, R11, R72, R88; filter capacitors C44, C45; the VCC pin of the operational amplifier M5B is connected with a 3.3V power supply Q3.3V, the GND pin of the operational amplifier M5B is connected with ground QGND after passing through a filter capacitor C45, two ends of a resistor R64 are respectively connected with the input negative terminal of the operational amplifier M5B and the output terminal of the operational amplifier M5B, one end of a resistor R72 is connected with the output terminal of the reference source circuit, the other end of the resistor R72 is respectively connected with one end of a resistor R65 and one end of a resistor R69, the other end of the resistor R69 is connected with ground QGND, the other end of the resistor R65 is respectively connected with one end of a resistor R11 and the input positive terminal of the operational amplifier M5B, the other end of the resistor R11 is connected with ground QGND, the input negative terminal of the operational amplifier M5B is connected with one end of a resistor R67, the other end of the resistor R67 is connected with an external input end signal CURR _ N, the other end of the resistor R67 is also connected with one end of a resistor R88, and the other end of the resistor R88 is connected with ground QGND;
a reference source circuit including a reference source chip U5; capacitors C106-C110, resistor R95; the power supply positive end of the reference source chip U5 is connected with a 9V power supply Q9V, the ground end is connected with the ground QGND, the output end is connected with one end of capacitors C107 and C108, and the feedback end is connected with one end of a resistor R95; the other end of the resistor R95 is connected with one end of a capacitor C106, the other end of the capacitor C106 is connected with the output end of the reference source chip U5, and the other ends of the capacitor C107 and the capacitor C108 are both connected with the ground QGND; the capacitor C109 is connected in parallel with the capacitor C110 and then connected between the power supply positive terminal and the ground terminal of the reference source chip U5.
The resistors R72, R69, R65, and R11 are voltage dividing resistors, and divide the reference source circuit output voltage to Vref.
The voltage divider is characterized in that the resistors R64 and R67 are voltage dividing resistors, and voltage division is carried out on the voltage between the external input end signals CURR _ N and Vref.
The circuit is characterized in that the resistor R88 is a sampling resistor and is used for collecting the current of an external input end signal CURR _ N.
The reference source circuit is characterized in that the reference source circuit outputs an accurate 2.5V reference level.
The SMALL current acquisition circuit is characterized in that a sampling resistor R88 acquires the current of an external input end signal CURR _ N, converts the current into a voltage signal, lifts the voltage signal, amplifies the voltage signal by an operational amplifier M5B and outputs a signal CURR _ SIG _ L1_ SMALL meeting the precision of an ARM processor.
Wherein the reference source circuit output voltage is divided into Vref
Vref＝2.5*R69*R11/(R69+R72)/(R11+R65)。
The low-current acquisition circuit is characterized in that a SMALL-current acquisition circuit output end signal CURR _ SIG _ L1_ SMALL is
CURR_SIG_L1_SMALL＝(CURR_N+Vref)*(R64+R67)/R67。
The low-current sampling circuit is characterized in that when a small current range of a signal at an external input end is 20mA-200mA, after the signal is collected by a 5m ohm sampling resistor R88, a signal at an input end CURR _ N is 0.1 mV-1 mV.
The method is characterized in that R65-R69-R67-1K omega, R11-R72-R64-100K omega are selected, the voltage division of the output voltage of a reference source circuit is calculated to be 24.5mV, and the signal of the output end of a low current acquisition circuit is 2.48V-2.57V.
The invention has the beneficial effects that:
compared with the existing product, the invention avoids the acquisition error caused by the operational amplifier dead zone by arranging the lifting level circuit, and ensures the accuracy of the output signal; and a reference source circuit is adopted, so that the accuracy of the lifting level is improved, and the integral acquisition accuracy of the small current signal is ensured. Can accurately collect small current signals of 20mA-200mA, and realize high-precision amplification of weak signals of 0.1 mV-1 mV.
Drawings
FIG. 1 is a circuit diagram for improving the small current collection accuracy of a solid state power controller
Detailed Description
The connection structure of the present invention will be described in detail with reference to the accompanying drawings and examples.
The invention relates to a circuit for improving the low current acquisition precision of a solid-state power controller.
The reference source circuit shown in fig. 1 comprises a reference source chip U5; capacitors C106-C110, resistor R95; the power supply positive end of the reference source chip U5 is connected with a 9V power supply Q9V, the ground end is connected with the ground QGND, the output end is connected with one end of capacitors C107 and C108, and the feedback end is connected with one end of a resistor R95; the other end of the resistor R95 is connected with one end of a capacitor C106, the other end of the capacitor C106 is connected with the output end of the reference source chip U5, and the other ends of the capacitor C107 and the capacitor C108 are both connected with the ground QGND; the capacitor C109 and the capacitor C110 are connected in parallel and then connected between the power supply positive end and the grounding end of the reference source chip U5, the used U5 is an ultrahigh precision reference voltage source chip, and when an external input power supply supplies power for 5V, the reference source circuit outputs a stable reference level of 2.5V for the rear-end small current acquisition circuit to use; c109 and C110 are input end filter capacitors, and C107 and C108 are output end filter capacitors, so that the stability of output signals is ensured.
The small current acquisition circuit shown in fig. 1 comprises an operational amplifier M5B; resistors R64, R65, R67, R69, R11, R72, R88; filter capacitors C44, C45; the VCC pin of the operational amplifier M5B is connected with a 3.3V power supply Q3.3V, the GND pin of the operational amplifier M5B is connected with ground QGND after passing through a filter capacitor C45, two ends of a resistor R64 are respectively connected with the input negative terminal of the operational amplifier M5B and the output terminal of the operational amplifier M5B, one end of a resistor R72 is connected with the output terminal of the reference source circuit, the other end of the resistor R72 is respectively connected with one end of a resistor R65 and one end of a resistor R69, the other end of the resistor R69 is connected with ground QGND, the other end of a resistor R65 is respectively connected with one end of a resistor R11 and the input positive terminal of the operational amplifier M5B, the other end of a resistor R11 is connected with ground QGND, the input negative terminal of the operational amplifier M5B is connected with one end of a resistor R67, the other end of the resistor R67 is connected with an external input end signal CURR _ N, the other end of the resistor R67 is also connected with one end of a resistor R88, and the other end of the resistor R88 is connected with ground QGND.
Introducing a reference source circuit to divide the output voltage into Vref
Vref＝Q2.5V*R69*R11/(R69+R72)/(R11+R65)
The reference source circuit output voltage is calculated to be Vref of 24.5mV by selecting R65 ═ R69 ═ R67 ═ 1K Ω, R11 ═ R72 ═ R64 ═ 100K Ω.
When the external small current range is 20mA-200mA, after the external small current range is collected by a 5m ohm sampling resistor R88, the signal of the input end CURR _ N of the circuit is 0.1 mV-1 mV.
The output end signal CURR _ SIG _ L1_ SMALL of the SMALL current acquisition circuit is
CURR_SIG_L1_SMALL＝(CURR_N+Vref)*(R64+R67)/R67
Outputting the data to a later ARM processor for collection and reporting;
a) when the external SMALL current is 20mA, CURR _ N is 0.1mV, and a SMALL current acquisition circuit output end signal CURR _ SIG _ L1_ SMALL is 2.48V;
b) when the external SMALL current is 200mA, CURR _ N is 1mV, and a SMALL current acquisition circuit output end signal CURR _ SIG _ L1_ SMALL is 2.57V;
c) when the external SMALL current is 20mA-200mA, the output end signal CURR _ SIG _ L1_ SMALL of the SMALL current acquisition circuit is between 2.48V-2.57V, and the voltage is reasonable within the acquisition range (0V-3.3V) of the ARM processor.
Claims (10)
1. A circuit for improving the small current acquisition precision of a solid-state power controller comprises a small current acquisition circuit and a reference source circuit;
the small current acquisition circuit comprises an operational amplifier M5B; resistors R64, R65, R67, R69, R11, R72, R88; filter capacitors C44, C45; the VCC pin of the operational amplifier M5B is connected with a 3.3V power supply Q3.3V, the GND pin of the operational amplifier M5B is connected with ground QGND after passing through a filter capacitor C45, two ends of a resistor R64 are respectively connected with the input negative terminal of the operational amplifier M5B and the output terminal of the operational amplifier M5B, one end of a resistor R72 is connected with the output terminal of the reference source circuit, the other end of the resistor R72 is respectively connected with one end of a resistor R65 and one end of a resistor R69, the other end of the resistor R69 is connected with ground QGND, the other end of the resistor R65 is respectively connected with one end of a resistor R11 and the input positive terminal of the operational amplifier M5B, the other end of the resistor R11 is connected with ground QGND, the input negative terminal of the operational amplifier M5B is connected with one end of a resistor R67, the other end of the resistor R67 is connected with an external input end signal CURR _ N, the other end of the resistor R67 is also connected with one end of a resistor R88, and the other end of the resistor R88 is connected with ground QGND;
a reference source circuit including a reference source chip U5; capacitors C106-C110, resistor R95; the power supply positive end of the reference source chip U5 is connected with a 9V power supply Q9V, the ground end is connected with the ground QGND, the output end is connected with one end of capacitors C107 and C108, and the feedback end is connected with one end of a resistor R95; the other end of the resistor R95 is connected with one end of a capacitor C106, the other end of the capacitor C106 is connected with the output end of the reference source chip U5, and the other ends of the capacitor C107 and the capacitor C108 are both connected with the ground QGND; the capacitor C109 is connected in parallel with the capacitor C110 and then connected between the power supply positive terminal and the ground terminal of the reference source chip U5.
2. The circuit for improving the small current collection accuracy of the solid state power controller of claim 1, wherein the resistors R72, R69, R65 and R11 are voltage dividing resistors for dividing the output voltage of the reference source circuit into Vref.
3. The circuit for improving the small current collection accuracy of the solid state power controller as claimed in claim 2, wherein the resistors R64 and R67 are voltage dividing resistors for dividing the voltage between the external input signals CURR _ N and Vref.
4. The circuit for improving the small current collection accuracy of the solid-state power controller as claimed in claim 3, wherein the resistor R88 is a sampling resistor for collecting the current of the external input signal CURR _ N.
5. The circuit for improving the small current collection accuracy of a solid state power controller of claim 4, wherein the reference source circuit outputs an accurate 2.5V reference level.
6. The circuit for improving the collection accuracy of the SMALL current of the solid state power controller as claimed in claim 5, wherein the SMALL current collection circuit collects the current of the signal CURR _ N at the external input terminal by the sampling resistor R88, converts the current into a voltage signal, and then lifts the voltage signal, and then amplifies the voltage signal by the operational amplifier M5B to output the signal CURR _ SIG _ L1_ SMALL meeting the accuracy of the ARM processor.
7. The circuit for improving the small current collection accuracy of a solid state power controller of claim 6, wherein the reference source circuit output voltage is divided by Vref
Vref＝2.5*R69*R11/(R69+R72)/(R11+R65)。
8. The circuit for improving collection accuracy of SMALL current of a solid state power controller of claim 7, wherein the output signal CURR _ SIG _ L1_ SMALL of the SMALL current collection circuit is
CURR_SIG_L1_SMALL＝(CURR_N+Vref)*(R64+R67)/R67。
9. The circuit for improving the small current collection precision of the solid-state power controller according to claim 8, wherein when the small current range of the signal at the external input end is 20mA to 200mA, the signal at the input end CURR _ N is 0.1mV to 1mV after being collected by a 5m ohm sampling resistor R88.
10. The circuit for improving the small current collection accuracy of the solid-state power controller of claim 9, wherein R65-R69-R67-1K Ω, R11-R72-R64-100K Ω are selected, the calculated reference source circuit output voltage division voltage is Vref 24.5mV, and the signal at the output end of the small current collection circuit is 2.48V-2.57V.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111336654.8A CN114113767A (en) | 2021-11-12 | 2021-11-12 | Circuit for improving small current acquisition precision of solid-state power controller |
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| CN202111336654.8A CN114113767A (en) | 2021-11-12 | 2021-11-12 | Circuit for improving small current acquisition precision of solid-state power controller |
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2021
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