CN111953195A - Circuit applied to underwater power supply protection and current detection - Google Patents

Circuit applied to underwater power supply protection and current detection Download PDF

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Publication number
CN111953195A
CN111953195A CN202010973925.XA CN202010973925A CN111953195A CN 111953195 A CN111953195 A CN 111953195A CN 202010973925 A CN202010973925 A CN 202010973925A CN 111953195 A CN111953195 A CN 111953195A
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China
Prior art keywords
capacitor
pin
resistor
protection
chip
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CN202010973925.XA
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Chinese (zh)
Inventor
杨文才
蔡笃思
高怀宁
辛永智
李志远
张少伟
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Institute of Deep Sea Science and Engineering of CAS
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Institute of Deep Sea Science and Engineering of CAS
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Priority to CN202010973925.XA priority Critical patent/CN111953195A/en
Publication of CN111953195A publication Critical patent/CN111953195A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • 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
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
    • G01R19/16571—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters

Abstract

The invention provides a circuit applied to underwater power supply protection and current detection, wherein a positive voltage input pin of a protection chip is connected with one end of a sampling resistor and a direct current input power supply, a sampling current input pin of the protection chip is connected with the other end of the sampling resistor and a drain electrode of an N-MOS (N-metal oxide semiconductor) tube, a grid driving output pin of the protection chip is connected with a grid electrode of the N-MOS tube, and an output feedback pin of the protection chip is connected with a source electrode of the N-MOS tube; a first voltage division node in the voltage division device is connected with an under-voltage locking pin of the protection chip, and a second voltage division node in the voltage division device is connected with the over-voltage locking pin of the protection chip; and a high potential input pin and a low potential input pin of the instrument amplifier chip are respectively connected with two ends of the sampling resistor. Compared with the prior art, the invention has the beneficial effects that: the circuit has high function integration level, and the circuit structure is simplified on the premise of not sacrificing performance, so that the circuit is suitable for deep-sea high-voltage environment.

Description

Circuit applied to underwater power supply protection and current detection
Technical Field
The invention relates to the technical field of electronic circuit design, in particular to a circuit applied to underwater power supply protection and current detection.
Background
In the process of developing deep sea electronic equipment, one of the development and design criteria is as follows: the electronic equipment is required to be small in size and light in weight under the condition of ensuring that the performance is not sacrificed. This requires that the electronic equipment be able to be housed in a small, non-pressure-resistant compartment, while the electronic equipment itself is also able to withstand pressure.
In the prior art, a high-power protection circuit and a current detection circuit are designed independently in an overall circuit, and high-power inductors, capacitors, resistors and other devices are generally required to be arranged on the peripheries of the two independently arranged circuits. However, the high-power protection circuit and the current detection circuit in the prior art have obvious defects, and the defects are that the high-power protection circuit and the current detection circuit in the prior art are not suitable for being used in an underwater high-voltage environment, and particularly, the high-power inductor, the capacitor and the resistor used in the high-power protection circuit and the current detection circuit in the prior art have large volumes, and the packaging form cannot resist high voltage, so that the high-power protection circuit and the current detection circuit cannot be used in a voltage-. Meanwhile, the high-power circuit needs extra measures for heat dissipation, so that the occupied area of the circuit is large, the integration level is not high, and the requirement on economy in deep sea application is not met.
Therefore, it is urgently needed to develop a circuit which can be applied underwater and integrates a high-power supply protection function and a high-current detection function.
Disclosure of Invention
In view of this, in order to solve the problem that the high-power protection circuit and the current detection circuit in the prior art are not suitable for the deep sea environment, the invention provides a circuit for underwater power protection and current detection, which comprises a protection chip, a sampling resistor, an N-MOS tube, a voltage divider and an instrument amplifier chip, wherein a positive voltage input pin of the protection chip is connected with one end of the sampling resistor and a direct current input power supply, a sampling current input pin of the protection chip is connected with the other end of the sampling resistor and a drain electrode of the N-MOS tube, a gate drive output pin of the protection chip is connected with a gate of the N-MOS tube, and an output feedback pin of the protection chip is connected with a source electrode of the N-MOS tube; the voltage divider is connected with the direct-current input power supply, a first voltage dividing node in the voltage divider is connected with an under-voltage locking pin of the protection chip, and a second voltage dividing node in the voltage divider is connected with an over-voltage locking pin of the protection chip; the instrumentation amplifier chip is used for detecting current, and a high potential input pin and a low potential input pin of the instrumentation amplifier chip are respectively connected with two ends of the sampling resistor.
Preferably, the direct current input power supply further comprises a first diode and a second diode, wherein the first diode and the second diode are TVS diodes, the first diode is connected in parallel with the voltage divider, and a cathode of the first diode is connected with the direct current input power supply; and the cathode of the second diode is connected with a sampling current input pin of the protection chip.
Preferably, the voltage divider further comprises a first capacitor and a second capacitor, and the first capacitor, the second capacitor and the voltage divider are connected in parallel; the first capacitor is a ceramic capacitor, the positive electrode of the first capacitor is connected with a direct current input power supply, and the other end of the first capacitor is grounded; the first capacitor and the second capacitor are used for filtering direct current input.
Preferably, the protection circuit further comprises a fourth capacitor and a fifth capacitor, the fourth capacitor and the fifth capacitor are arranged in parallel, the positive electrode of the fourth capacitor is connected with the output feedback pin of the protection chip, and the other end of the fourth capacitor is grounded; the fourth capacitor and the fifth capacitor are used for filtering the output of the protection chip.
Preferably, the voltage divider is a series resistance voltage divider, which includes a first resistor, a second resistor and a third resistor sequentially connected in series, the first voltage dividing node is disposed between the first resistor and the second resistor, and the second voltage dividing node is disposed between the second resistor and the third resistor; the other end of the first resistor is connected with the direct current input power supply, and the other end of the third resistor is grounded.
Preferably, the protection circuit further comprises a fourth resistor and a sixth capacitor, wherein one end of the fourth resistor is connected with the power limit setting pin of the protection chip, and the other end of the fourth resistor is grounded; one end of the sixth capacitor is connected with the time sequence capacitor pin of the protection chip, the other end of the sixth capacitor is grounded, and the ground pin of the protection chip is grounded.
Preferably, the protection circuit further comprises a third capacitor and a fifth resistor, wherein one end of the third capacitor C3 is connected to the positive voltage input pin of the protection chip, and the other end is grounded; and two ends of the fifth resistor are respectively connected with a power normal indication signal pin and an output feedback pin of the protection chip.
Preferably, a high potential input pin and a low potential input pin of the instrumentation amplifier chip are connected with the sampling resistor through an input filter network, and the input filter network includes a seventh capacitor, a tenth resistor and an eleventh resistor; two ends of the seventh capacitor are respectively connected with a high potential input pin and a low potential input pin of the instrumentation amplifier chip; one end of the tenth resistor is connected with a low-potential input pin of the instrumentation amplifier chip, and the other end of the tenth resistor is connected with one low-potential end of the sampling resistor; one end of the eleventh resistor is connected with a high potential input pin of the instrumentation amplifier chip, and the other end of the eleventh resistor is connected with one high potential end of the sampling resistor.
Preferably, a first reference voltage input pin and a second reference voltage input pin of the instrumentation amplifier chip are both connected to an input reference voltage; the grounding pin of the instrumentation amplifier chip is grounded; an eighth capacitor is arranged between the grounding pin and the second reference voltage input pin; and a voltage output pin of the instrumentation amplifier chip and an AD (analog-to-digital) converter.
Preferably, the protection chip is an LM5069 chip; the instrumentation amplifier chip is an INA240A2D chip.
Compared with the prior art, the invention has the beneficial effects that:
the circuit applied to underwater power supply protection and current detection integrates the functions of high-power supply protection and large-current detection, and greatly simplifies the circuit structure on the premise of not sacrificing the performance. Thereby making the circuit suitable for deep sea high voltage environment. When the circuit is applied, the characteristic of low temperature in deep sea can be utilized, so that additional heat dissipation measures are not additionally arranged, the size and the weight of related electronic equipment are further effectively reduced, and the circuit has higher economical efficiency on underwater electronic equipment.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a circuit diagram of a circuit applied to underwater power supply protection and current detection in the present invention.
Reference numerals:
protection chip U1, instrumentation amplifier chip U2, sampling resistor RsenseThe voltage divider comprises an N-MOS transistor Q1, a voltage divider 100, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a tenth resistor R10, an eleventh resistor R11, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a first diode D1, a second diode D2, the voltage divider 100 and an input filter network 200.
Detailed Description
The above and further features and advantages of the present invention are described in more detail below with reference to the accompanying drawings.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention.
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
Example one
The embodiment of the invention provides a circuit for underwater power supply protection and current detection, which comprises a protection chip U1 and a sampling resistor RsenseThe device comprises an N-MOS tube Q1, an instrumentation amplifier chip U2 and a voltage divider 100.
The structure formed by the protection chip U1 and the discrete components of the peripheral capacitor and the resistor provides a high-power supply protection function.
The instrumentation amplifier chip U2 detects the sampling resistance RsenseThe voltage change across the terminals measures the current. The structure formed by the instrumentation amplifier chip U2 and the discrete components of the peripheral capacitor and resistor provides a high-current detection function.
Positive voltage input pin and sampling resistor R of protection chip U1senseOne end of which is connected with a direct current input power supply.
Sampling current input pin and sampling resistor R of protection chip U1senseThe other end of the N-MOS transistor is connected with a drain electrode D of an N-MOS transistor Q1.
The gate drive output pin of the protection chip U1 is connected to the gate G of the N-MOS transistor Q1.
An output feedback pin of the protection chip U1 is connected with a source S and a load of the N-MOS transistor Q1. The other end of the load is grounded.
High potential input pin and sampling resistor R of instrument amplifier chip U2senseThe high potential end is connected with the positive voltage input pin of the protection chip U1. Low potential input pin and sampling resistor R of instrument amplifier chip U2senseThe low potential is connected to one end, namely, the sampling current input pin of the protection chip U1.
One end of the voltage divider 100 is connected to the dc input power source, and the other end is grounded. A first voltage division node and a second voltage division node are arranged in the voltage division device. The first voltage division node is higher than the second voltage division node. The first voltage division node is connected with an undervoltage locking pin of the protection chip U1. The second voltage division node is connected with an overvoltage locking pin of the protection chip U1.
The invention has the beneficial effects that: the invention provides a high-power supply protection and large current detection circuit, which integrates the functions of high-power supply protection and large current detection together in a form of multiplexing peripheral discrete elements. Greatly simplifying the circuit complexity. The invention integrates a high-power (less than or equal to 3000W) protection circuit and a high-current (-100A to +100A) detection circuit, and can further realize the configuration of a peripheral circuit by utilizing a ceramic capacitor resistor capable of withstanding voltage.
The circuit is mainly applied to electronic equipment under the deep sea pressure-resistant condition, and because the electronic equipment works under the pressure-resistant condition, the working environment temperature of the electronic equipment is balanced with the deep sea environment temperature, the high-power protection circuit can be radiated by utilizing the deep sea (the water depth of 500m is less than or equal to 10 ℃) low-temperature environment. By utilizing the characteristic of low deep sea temperature (less than or equal to 10 ℃), when the current exceeds 30A, additional heat dissipation measures are not required, the volume and the weight of the electronic equipment are effectively reduced, and the underwater electronic equipment has higher economy; under the condition of input current less than 30A, the device can work normally at normal temperature. Therefore, under the condition of not reducing the performance, the occupied volume of the circuit is greatly reduced, and the economy of deep sea application is improved.
Example two
The difference between this embodiment and the first embodiment is:
preferably, the voltage divider is a series resistance voltage divider, and includes a first resistor R1, a second resistor R2, and a third resistor R3, the first resistor R1, the second resistor R2, and the third resistor R3 are sequentially connected in series, a first voltage dividing node is disposed between the first resistor R1 and the second resistor R2, and a second voltage dividing node is disposed between the second resistor R2 and the third resistor R3. A first resistor R1The other end of the second switch is connected with a direct current input power supply. The other end of the third resistor R3 is connected to ground. The first resistor R1, the second resistor R2 and the third resistor R3 divide the voltage of the DC input power supply inputTo the protection chip U1.
The first capacitor C1, the second capacitor C2, the first diode D1 and the voltage divider are connected in parallel. Namely, the positive electrode of the first capacitor C1 is connected to the dc input power source, and the negative electrode thereof is grounded. One end of the second capacitor C2 is connected to the dc input power supply, and the other end is grounded. The anode of the first diode D1 is grounded, and the cathode is connected with a direct current input power supply.
The first capacitor C1 and the second capacitor C2 are used for filtering the direct current input power supply. The capacitor is a ceramic chip capacitor capable of resisting underwater pressure, and preferably, the capacitance value of the first capacitor C1 is 47uF, and the pressure resistance value is 100V. The second capacitor C2 has a capacitance of 0.1-0.22 uF and a withstand voltage of 100V.
Preferably, the first diode D1 is a TVS diode, which performs an overvoltage clamp when its input voltage exceeds a clamping voltage, and protects the rear protection chip U1 from overvoltage surge. Further preferably, the TVS diode clamping voltage does not exceed 75V.
The circuit provided by the invention further comprises a fourth capacitor C4, a fifth capacitor C5, a fourth capacitor C4 and a fifth capacitor C5 which are used for filtering the direct current power supply output by the protection chip U1. The cathode of the fourth capacitor C4 and the other end of the fifth capacitor C5 are both grounded. One end of the fifth capacitor C5 and the anode of the fourth capacitor C4 are both connected to the output feedback pin of the protection chip U1. The capacitor is a ceramic chip capacitor capable of resisting underwater pressure, and preferably, the capacitance value of the fourth capacitor C4 is 47uF, and the pressure resistance value is 100V. The capacitance of the fifth capacitor C5 is 0.1-0.22 uF and the withstand voltage is 100V.
The circuit provided by the invention further comprises a fourth resistor R4 and a sixth capacitor C6. One end of the fourth resistor R4 is connected with the power limit setting pin of the protection chip U1, and the other end is grounded. One end of the sixth capacitor C6 is connected to the timing capacitor pin of the protection chip U1, and the other end is grounded. The ground pin of the protection chip U1 is grounded.
The circuit provided by the invention further comprises a fifth resistor R5, and two ends of the fifth resistor R5 are respectively connected with the power normal indication signal pin and the output feedback pin of the protection chip U1.
The circuit provided by the invention also comprises a third capacitor C3. One end of the third capacitor C3 is connected to the dc input power supply, and the other end is connected to ground.
The protection chip U1 sets corresponding threshold value through peripheral capacitance and resistance discrete component, controls the conduction of N-MOS pipe Q1 to achieve the purpose of power protection. Selecting proper sampling resistor RsenseAnd Q1, the circuit provided by the invention can meet the voltage input of 9-75V and the current detection capability of +/-100A.
The protection chip U1 detects the voltage of the undervoltage locking pin and the overvoltage locking pin to determine the threshold values of the high-voltage locking protection and the low-voltage locking protection, and the protection chip U1 closes the grid electrode of the N-MOS tube to prohibit the power supply output when the threshold values are exceeded.
Wherein the high voltage locking threshold VuvloRepresented by the formula:
Figure BDA0002685073450000061
wherein the low voltage locks the threshold value VovloRepresented by the formula:
Figure BDA0002685073450000062
v in the above two formulasinThe voltage of the direct current input power supply.
In addition, the overcurrent protection threshold I of the protection chip U1limRepresented by the formula:
Figure BDA0002685073450000063
sampling resistor RsenseThe specific resistance values of the first resistor R1, the second resistor R2 and the third resistor R3 can be flexibly set according to actual requirements.
The value of the sixth capacitor C6 determines the maximum time t allowed for the current limit when a fault exceeding a set threshold occursflt，tfltRepresented by the formula:
Figure BDA0002685073450000064
in addition, the protection chip U1 provides programmable power protection for the N-MOS transistor Q1, ensuring that the power dissipation of the N-MOS transistor Q1 itself does not exceed its rated value. The threshold of the power protection is specifically determined by the performance parameters of the N-MOS transistor Q1, and the protection chip U1 programs the power threshold P through the fourth resistor R4lim，PlimRepresented by the formula:
Figure BDA0002685073450000065
wherein, VDSIs a typical value for the source-drain voltage of the N-MOS transistor Q1.
Preferably, the protection chip U1 is an LM5069 chip, and the 1 st pin of the LM5069 chip is a SENSE pin, i.e., a sampling current input pin; the 2 nd pin is a VIN pin, namely a positive voltage input pin; the 3 rd pin is a UVLO pin, namely an undervoltage locking pin; the 4 th pin is an OVLO pin, namely an overvoltage locking pin; the 4 th pin is a GND pin, i.e., a ground pin. The 6 th pin is a TIMER pin, i.e., a timing capacitor pin. The 7 th pin is a PWR pin, i.e., a power limit setting pin. The 8 th pin is a PGD pin, i.e., a power ok indicator signal pin. The 9 th pin is an OUT pin, i.e., an output feedback pin. The 10 th pin is a GATE pin, i.e., a GATE drive output pin.
The circuit applied to power supply protection and current detection under water in the invention further comprises an input filter network 200 and a second diode D2.
Preferably, the high potential input pin and the low potential input pin of the instrumentation amplifier chip U2 pass through the input filter network 200 and the sampling resistor RsenseAnd (4) connecting. The input filter network 200 includes a seventh capacitor C7, a tenth resistor R10, and an eleventh resistor R11. Two ends of the seventh capacitor C7 are connected to a high potential input pin and a low potential input pin of the instrumentation amplifier chip U2, respectively. One end of a tenth resistor R10 is connected with a low potential input pin of the instrumentation amplifier chip U2, and the other end is connected with a sampling resistor RsenseOne end of low potentialAnd (4) connecting. One end of an eleventh resistor R11 is connected with a high potential input pin of an instrumentation amplifier chip U2, and the other end of the eleventh resistor R11 is connected with a sampling resistor RsenseOne end of the high potential is connected.
Preferably, the tenth resistor R10 and the eleventh resistor R11 have the same resistance value, and the resistance value range is 2-5 omega. The capacitance value of the seventh capacitor C7 is selected to be 0.01-0.1 uF.
The anode of the second diode D2 is grounded, the cathode thereof is connected with the sampling resistor RsenseOne end of the low potential is connected. Preferably, the second diode D2 is a TVS diode that is over-voltage clamped when its input voltage exceeds the clamping voltage, protecting the back-end instrumentation amplifier chip U2 from over-voltage surges. Further preferably, the TVS diode clamping voltage does not exceed 75V.
In addition, a first reference voltage input pin and a second reference voltage input pin of the instrumentation amplifier chip U2 are both connected to input reference voltage. The ground pin of instrumentation amplifier chip U2 is grounded. An eighth capacitor C8 is disposed between the ground pin and the second reference voltage input pin. The power supply pin of the instrumentation amplifier chip U2 is connected to a power supply, preferably, the power supply voltage is + 3.3V. And a voltage output pin of the instrumentation amplifier chip U2 and an AD analog-to-digital converter.
Due to the fact that the input voltage ranges of the U1 and the U2 are the same, in the circuit topology, the U1 and the U2 share the D1 and the D2 for input clamp protection.
Detection output voltage V of instrument amplifier chip U2isenseAnd the detected current IsenseThe following linear formula is satisfied:
Visense＝Vref+G×Rsense×Isense；
in the formula IsenseFor the current to be detected, RsenseThe resistance of the sampling resistor is shown, wherein G is the amplification factor of U2, which can be selected, for example, 50, 100 or 200. VrefIs the input reference voltage of U2. The measurement precision of the related current detection is less than or equal to 1 percent, and the measurement range Visense∈[Vref，+3.3V]。
Preferably, instrumentation amplifier chip U2 is an INA240A2D chip. The 1 st pin of the INA240A2D chip is a low potential input pin, i.e., an IN-pin. The 2 nd pin is a ground pin, i.e., a GND pin. The 3 rd pin is a second reference voltage input pin, i.e., the REF2 pin. The 4 th pin is a null pin, namely an NC pin. The 5 th pin is a voltage output pin, i.e., an OUT pin. The 6 th pin is a power supply pin, namely a VS pin. The 7 th pin is a first reference voltage input pin, i.e., the REF1 pin. The 8 th pin is a high input pin, i.e., an IN + pin.
The whole circuit design is divided into two functions of high-power supply protection and large-current detection, the peripheries of U1 and U2 are integrated by multiplexing a small number of discrete components, and the multiplexed small number of discrete components comprise sampling resistors RsenseA first diode D1 and a second diode D2.
U1 and U2 share one sampling resistor RsenseU1 provides a high power supply protection function, and U2 is an instrumentation amplifier for detecting current. Through the combination of peripheral discrete components, the U1 provides high-voltage locking, low-voltage locking and overcurrent protection for a load, and the U2 provides high-voltage locking, low-voltage locking and overcurrent protection for the load through a sampling resistor RsenseWeak voltage signals at two ends are subjected to current-voltage linear conversion, so that the measuring current is output to obtain a corresponding voltage value VisenseThen, the current is digitally converted by an AD converter and then transmitted to the MCU, and the MCU can calculate the current value according to a preset linear mathematical relation.
Since the U2 is used for current detection for a non-isolated Hall chip, the possibility exists that the chip is damaged when the current exceeds the measured value. However, since the U1 has an overcurrent protection function, the U2 does not need an additional overcurrent protection design, thereby simplifying the current detection circuit part.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will 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 substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.

Claims (10)

1. A circuit applied to underwater power supply protection and current detection is characterized by comprising a protection chip, a sampling resistor, an N-MOS (N-metal oxide semiconductor) tube, a voltage divider and an instrument amplifier chip, wherein a positive voltage input pin of the protection chip is connected with one end of the sampling resistor and a direct current input power supply, a sampling current input pin of the protection chip is connected with the other end of the sampling resistor and a drain electrode of the N-MOS tube, a grid driving output pin of the protection chip is connected with a grid electrode of the N-MOS tube, and an output feedback pin of the protection chip is connected with a source electrode of the N-MOS tube; the voltage divider is connected with the direct-current input power supply, a first voltage dividing node in the voltage divider is connected with an under-voltage locking pin of the protection chip, and a second voltage dividing node in the voltage divider is connected with an over-voltage locking pin of the protection chip; the instrumentation amplifier chip is used for detecting current, and a high potential input pin and a low potential input pin of the instrumentation amplifier chip are respectively connected with two ends of the sampling resistor.
2. The circuit for protection and current detection of a power supply under water as claimed in claim 1, further comprising a first diode and a second diode, said first diode and said second diode being TVS diodes, said first diode being arranged in parallel with a voltage divider means, said first diode having its cathode connected to said dc input power supply; and the cathode of the second diode is connected with a sampling current input pin of the protection chip.
3. The circuit for underwater power supply protection and current sensing as claimed in claim 1, further comprising a first capacitor and a second capacitor, said first capacitor, said second capacitor and said voltage divider being disposed in parallel with each other; the first capacitor is a ceramic capacitor, the positive electrode of the first capacitor is connected with a direct current input power supply, and the other end of the first capacitor is grounded; the first capacitor and the second capacitor are used for filtering direct current input.
4. The circuit for underwater power supply protection and current detection as claimed in claim 1, further comprising a fourth capacitor and a fifth capacitor, wherein said fourth capacitor and said fifth capacitor are arranged in parallel, the anode of said fourth capacitor is connected to the output feedback pin of said protection chip, and the other end is grounded; the fourth capacitor and the fifth capacitor are used for filtering the output of the protection chip.
5. The circuit for underwater power supply protection and current sensing as claimed in claim 1, wherein said voltage divider means is a series resistive voltage divider means comprising a first resistor, a second resistor and a third resistor arranged in series in sequence, said first voltage dividing node being arranged between said first resistor and said second resistor, said second voltage dividing node being arranged between said second resistor and said third resistor; the other end of the first resistor is connected with the direct current input power supply, and the other end of the third resistor is grounded.
6. The circuit for underwater power supply protection and current detection as claimed in claim 1, further comprising a fourth resistor and a sixth capacitor, wherein one end of the fourth resistor is connected to a power limit setting pin of the protection chip, and the other end is grounded; one end of the sixth capacitor is connected with the time sequence capacitor pin of the protection chip, the other end of the sixth capacitor is grounded, and the ground pin of the protection chip is grounded.
7. The circuit for underwater power supply protection and current detection as claimed in claim 1, further comprising a third capacitor and a fifth resistor, wherein one end of said third capacitor C3 is connected to the positive voltage input pin of said protection chip, and the other end is connected to ground; and two ends of the fifth resistor are respectively connected with a power normal indication signal pin and an output feedback pin of the protection chip.
8. The circuit for underwater power supply protection and current detection as claimed in claim 1, wherein the high potential input pin and the low potential input pin of the instrumentation amplifier chip are connected to the sampling resistor through an input filter network, the input filter network including a seventh capacitor, a tenth resistor and an eleventh resistor; two ends of the seventh capacitor are respectively connected with a high potential input pin and a low potential input pin of the instrumentation amplifier chip; one end of the tenth resistor is connected with a low-potential input pin of the instrumentation amplifier chip, and the other end of the tenth resistor is connected with one low-potential end of the sampling resistor; one end of the eleventh resistor is connected with a high potential input pin of the instrumentation amplifier chip, and the other end of the eleventh resistor is connected with one high potential end of the sampling resistor.
9. The circuit for underwater power supply protection and current sensing as recited in claim 1 wherein the first reference voltage input pin and the second reference voltage input pin of the instrumentation amplifier chip are both connected to an input reference voltage; the grounding pin of the instrumentation amplifier chip is grounded; an eighth capacitor is arranged between the grounding pin and the second reference voltage input pin; and a voltage output pin of the instrumentation amplifier chip and an AD (analog-to-digital) converter.
10. The circuit for underwater power supply protection and current detection according to any of claims 1-9, wherein said protection chip is an LM5069 chip; the instrumentation amplifier chip is an INA240A2D chip.
CN202010973925.XA 2020-09-16 2020-09-16 Circuit applied to underwater power supply protection and current detection Pending CN111953195A (en)

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Application Number Priority Date Filing Date Title
CN202010973925.XA CN111953195A (en) 2020-09-16 2020-09-16 Circuit applied to underwater power supply protection and current detection

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114498592A (en) * 2021-12-17 2022-05-13 郑州中科集成电路与系统应用研究院 Surge suppressor with adjustable input range

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114498592A (en) * 2021-12-17 2022-05-13 郑州中科集成电路与系统应用研究院 Surge suppressor with adjustable input range

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