High-side common-mode current signal acquisition circuit

Abstract

The utility model belongs to the field of electronic technology, and discloses a high-side common-mode current signal acquisition circuit, which consists of a load power switch MOS (Metal Oxide Semiconductor) tube circuit, a voltage-regulator tube operational amplifier power supply circuit, a sampling voltage circuit and an operational amplifier signal conditioning circuit, the load power switch MOS tube circuit is used for supplying power to a load; the voltage-regulator tube operational amplifier power supply circuit is used for generating stabilized voltage and supplying power to the positive and negative ends of a power supply of an operational amplifier; the sampling voltage circuit is used for sampling the load current of the high side and converting the load current into a voltage signal for conditioning by a post-stage circuit; the operational amplifier signal conditioning circuit is used for converting a power supply signal of the sampling resistor into a current signal of the bias resistor, so that the phenomenon that the negative end of a power line floats on the ground due to the fact that overcurrent is not found in time due to the fact that the resistor is serially connected to a low side in a traditional airborne current acquisition circuit is solved; the problems that a common operational amplifier cannot bear high-side common-mode voltage, an integrated current acquisition chip is high in price and the like are solved, the device cost is saved, and the high common-mode problem of the operational amplifier is solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the electronic technology class field especially, and it relates to a high side common mode current signal acquisition circuit. BACKGROUND

[0002] Current signal acquisition is a kind of common acquisition signal in the power-on transient and steady monitoring of airborne equipment, and the commonly used current acquisition signal types include load high side sampling / low side sampling, as shown in the drawing. Figure 1 For example, the SSPC machine power relay load current parameter and the torque size measurement parameter of DC motor are current signals, and the working state of load and the torque size of DC motor can be monitored by measuring the size of current.

[0003] The traditional low side current signal acquisition circuit is shown in the drawing. Figure 2 The current acquisition circuit uses low end negative line mode to connect into precision sampling resistance, the voltage U size of sampling resistance is measured, and then the voltage is divided by the size of precision resistance R, so that the size of sampling current I can be obtained. The circuit has the advantages of simple sampling circuit, no need to bear the high voltage influence of high side voltage of power line positive end, and stable and reliable acquisition. However, if the power supply is suddenly overvoltage or the load current is overloaded, the abnormal current value of the sampling resistance connected in the low side can be monitored only after the sudden high voltage or overload current has flowed through the device and has worked for a period of time, which causes the device damage. At the same time, the ground line is connected with resistance, which causes the voltage difference between the negative pole of source end power supply signal and load power ground signal due to the connection of current sampling resistance, and causes the floating ground phenomenon, which affects the sampling accuracy.

[0004] The differential current acquisition circuit is a kind of sampling circuit for current acquisition in high side, that is, the sampling resistance is connected between the positive end of power line and the positive end of load, the differential acquisition circuit of operational amplifier is obtained by connecting the voltage attenuation (r1>r2, and the amplification factor is r2 / r1, since r1>r2, only attenuation circuit can be made, and the attenuation is within the supply voltage of operational amplifier) of the same phase and opposite phase end of differential operational amplifier to the supply voltage of operational amplifier, and then the voltage of sampling resistance is obtained by the differential acquisition circuit of operational amplifier, and the sampling current size is obtained, as shown in the drawing. Figure 3 The advantages of the circuit are that the circuit does not need high side high power operational amplifier condition, and the device cost is low. However, the obvious disadvantage of the circuit is that the circuit can only attenuate the current signal but cannot amplify it, and the differential acquisition circuit of operational amplifier is not like the internal zero circuit of instrument amplifier, and the design does not have internal zero circuit, so four voltage dividing resistors must be in high precision error minimum, otherwise, if the resistance values are not symmetrical, it will bring great error influence, and the SOD AD for voltage reading and a follower for impedance matching with AD acquisition are also needed, which will cause output offset and bring greater acquisition error.

[0005] The novel IC integrated circuit chip collects high side, and the current collecting chip with high precision and high common mode voltage has the advantages that the noninverting input and inverting input of the operational amplifier are specially treated and can bear very high common mode voltage, but the obvious disadvantage is high price, and generally one chip can only collect one high side high common mode voltage signal, the packaging area of the chip is large, and a large printed board area is occupied. Practical new type content

[0006] The technical problem solved by the utility model is: the utility model aims at providing a high side high common mode current signal collecting circuit, which can solve the phenomenon that the low side resistance in the traditional airborne current collecting circuit causes overcurrent discovery not in time and the power line negative end floating ground, solve the problems that the ordinary operational amplifier cannot bear high side common mode voltage and the integrated current collecting chip is expensive, save the device cost, and solve the high common mode problem of the operational amplifier.

[0007] The technical scheme of the utility model:

[0008] A high side common mode current signal collecting circuit, the circuit is composed of a load power switch MOS tube circuit, a voltage stabilizing tube operational amplifier power supply circuit, a sampling voltage circuit and an operational amplifier signal conditioning circuit.

[0009] The load power switch MOS tube circuit is used for supplying power to the load.

[0010] The voltage stabilizing tube operational amplifier power supply circuit is used for generating a stabilized voltage and supplying power to the positive and negative terminals of the operational amplifier.

[0011] The sampling voltage circuit is used for sampling the load current of the high side and converting it into a voltage signal for conditioning by the subsequent circuit.

[0012] The operational amplifier signal conditioning circuit is used for converting the power signal of the sampling resistor into a current signal of the bias resistor.

[0013] Further,

[0014] The load power switch MOS tube circuit is composed of a MOS control tube and a 28V power supply in series.

[0015] The gate of the MOS control tube is connected with an external control signal CTRL, the source is connected with the positive pole of the 28V power supply, and the drain is connected with the negative pole of the 28V power supply.

[0016] Further,

[0017] The voltage stabilizing tube operational amplifier power supply circuit is composed of a first voltage stabilizing tube and a current limiting resistor in series, the positive pole of the first voltage stabilizing tube is connected with the power negative terminal of the operational amplifier, and the negative pole of the first voltage stabilizing tube is connected with the power positive terminal of the operational amplifier.

[0018] Further,

[0019] One end of the sampling resistor is connected to the source of the MOS control tube, and the other end is connected to the positive end of the load.

[0020] Further,

[0021] The operational amplifier conditioning circuit comprises an operational amplifier, a cross-resistance, a first shunt resistor, a second shunt resistor, a third shunt resistor, a PMOS tube, and a bias resistor.

[0022] The output end of the operational amplifier is connected to the gate of the PMOS tube, the source of the PMOS tube is connected to one end of the cross-resistance, and the other end of the cross-resistance is connected to the source of the MOS control tube.

[0023] One end of the first shunt resistor is connected to one end of the cross-resistance, and the other end is connected to the negative end of the operational amplifier; the second shunt resistor is connected to the negative end of the operational amplifier and the source of the MOS control tube, respectively; and the third shunt resistor is connected to the positive end of the operational amplifier and one end of the sampling resistor, respectively.

[0024] The drain of the PMOS tube is connected to the ground through the bias resistor.

[0025] Further,

[0026] The operational amplifier conditioning circuit further comprises a second stabilizing tube, wherein the negative electrode of the second stabilizing tube is connected to the drain of the PMOS tube, and the positive electrode of the second stabilizing tube is connected to the ground.

[0027] The utility model discloses a novel high side high common mode current signal acquisition circuit, through resistance, capacitor, stabilizing tube, operational amplifier etc. discrete component, builds a kind of airborne high side high common mode current signal acquisition circuit, can carry out real-time monitoring to the high side current of load on machine, and the input pin of operational amplifier resists high side high common mode voltage, and saves the cost of device. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is high low side sampling circuit schematic diagram;

[0029] Figure 2 It is traditional low side sampling signal schematic diagram;

[0030] Figure 3 It is high side differential current acquisition circuit schematic diagram;

[0031] Figure 4 It is the structure schematic diagram of high side common mode current signal acquisition circuit provided by the utility model;

[0032] Figure 5The utility model provides a MOS switch power supply circuit is provided.

[0033] Figure 6 The utility model provides an operational amplifier power supply circuit diagram is provided.

[0034] Figure 7 The utility model provides a sampling resistance current voltage conversion circuit diagram.

[0035] Figure 8 The utility model provides an operational amplifier conditioning circuit.

[0036] Figure 9 The utility model provides a high side common mode current signal acquisition circuit's real object analog figure. Specific implementation

[0037] The utility model technical scheme is in detail below the combination of drawing.

[0038] The utility model embodiment provides a high side common mode current signal acquisition circuit, as Figure 4 And Figure 9 As shown in the circuit is composed of load power switch MOS pipe circuit, voltage stabilizing tube operational amplifier power supply circuit, sampling voltage circuit, operational amplifier signal conditioning circuit.

[0039] The load power switch MOS pipe circuit is used for supplying power to the load.

[0040] The voltage stabilizing tube operational amplifier power supply circuit is used to generate a stabilized voltage to supply power to the positive and negative terminals of the operational amplifier.

[0041] The sampling voltage circuit is used to sample the load current of the high side and convert it into a voltage signal for conditioning by the subsequent circuit.

[0042] The operational amplifier signal conditioning circuit is used to convert the power signal of the sampling resistor into a current signal of the bias resistor.

[0043] The load power switch MOS pipe circuit is composed of a MOS control tube and a 28V power supply in series.

[0044] The gate of the MOS control tube is connected to an external control signal CTRL, the source is connected to the positive pole of the 28V power supply, and the drain is connected to the negative pole of the 28V power supply.

[0045] The voltage stabilizing tube operational amplifier power supply circuit is composed of a first voltage stabilizing tube and a current limiting resistor in series, the positive pole of the first voltage stabilizing tube is connected to the power supply negative terminal of the operational amplifier, and the negative pole of the first voltage stabilizing tube is connected to the power supply positive terminal of the operational amplifier.

[0046] One end of the sampling resistor is connected to the source of the MOS control tube, and the other end is connected to the positive end of the load.

[0047] The operational amplifier conditioning circuit comprises an operational amplifier, a cross resistor, a first shunt resistor, a second shunt resistor, a third shunt resistor, a PMOS tube, and a bias resistor.

[0048] The output end of the operational amplifier is connected to the gate of the PMOS tube, the source of the PMOS tube is connected to one end of the cross resistor, and the other end of the cross resistor is connected to the source of the MOS control tube.

[0049] One end of the first shunt resistor is connected to one end of the cross resistor, and the other end is connected to the negative end of the operational amplifier; the second shunt resistor is connected to the negative end of the operational amplifier and the source of the MOS control tube, respectively; and the two ends of the third shunt resistor are connected to the positive end of the operational amplifier and one end of the sampling resistor, respectively.

[0050] The drain of the PMOS tube is connected to the ground through the bias resistor.

[0051] The operational amplifier conditioning circuit further comprises a second zener diode, the negative electrode of the second zener diode is connected to the drain of the PMOS tube, and the positive electrode of the second zener diode is connected to the ground.

[0052] Referring to Figure 4 , a high-side common-mode current signal acquisition circuit comprises a load power supply switch MOS tube circuit, a zener diode operational amplifier power supply circuit, a sampling voltage circuit, and an operational amplifier signal conditioning circuit. The working process is as follows:

[0053] When the airborne power supply supplies DC power, the MOS tube is first controlled to control whether the 28V power supply supplies power to the load. When the pilot or the main control board controller needs to supply power to the airborne DC load, the MOS tube is opened to allow the airborne load to work, as shown in Figure 5 When the CTRL signal outputs a high level, the MOS tube is turned on, the 28V power supply is turned on, and the load works.

[0054] The zener diode operational amplifier power supply circuit utilizes the breakdown voltage stabilization characteristic of the zener diode and utilizes the current limiting resistor to divide voltage and limit current, so as to protect the zener diode from being damaged and generate a stabilized voltage to supply power to the positive and negative ends of the operational amplifier, thereby improving the common-mode voltage input range of the operational amplifier and enabling the operational amplifier to withstand 28V voltage, as shown in Figure 6 .

[0055] The sampling resistor voltage sampling circuit utilizes a high-precision sampling resistor to sample the high-side load current and convert it into a voltage signal for conditioning by the subsequent circuit, as shown in Figure 7The current signal flows through the sampling resistor, is converted into a voltage signal, and the voltage signal is divided by the sampling resistor value to convert the current value.

[0056] The operational amplifier signal conditioning circuit uses a common operational amplifier for conditioning, utilizes the virtual break and virtual short characteristics of the operational amplifier, converts the voltage signal of the sampling resistor into a current signal of the bias resistor through the operational amplifier circuit conditioning, simultaneously utilizes the output pin of the operational amplifier to open the PMOS tube, utilizes the high-precision bias resistor to sample the voltage signal, and then supplies the voltage for the ADC to collect, and a stabilizing tube is connected in parallel with the high-precision sampling resistor to prevent the overvoltage signal from burning the ADC pin, as shown in Figure 8

[0057] The high-side common-mode current signal acquisition circuit provided by the utility model is composed of a load power switch MOS tube circuit, a stabilizing tube operational amplifier power supply circuit, a sampling voltage circuit and an operational amplifier signal conditioning circuit. The operational amplifier power supply adopts the voltage after the breakdown of the stabilizing tube to improve the common-mode voltage resistance characteristic of the operational amplifier, and the sampling conditioning circuit of the operational amplifier can amplify and reduce various current sampling circuits by adjusting the resistance value. In view of the multiple event signal types in the communication of airborne electronic equipment, the novel airborne current signal acquisition circuit can realize real-time monitoring of the current of the airborne load at the high side, can resist the high-side common-mode voltage, and can save the device cost.​

Claims

1. A high-side common-mode current signal acquisition circuit, characterized by, The circuit is composed of a load power switch MOS tube circuit, a voltage regulator operational power supply circuit, a sampling voltage circuit and an operational amplifier signal conditioning circuit. The load power switch MOS tube circuit is used for powering the load. The voltage regulator operational power supply circuit is used for generating a stable voltage to power the positive and negative terminals of the operational amplifier. The sampling voltage circuit is used for sampling the load current of the high side and converting it into a voltage signal for conditioning by the subsequent circuit. The operational amplifier signal conditioning circuit is used for converting the power signal of the sampling resistor into a current signal of the bias resistor.

2. The high-side common-mode current signal acquisition circuit according to claim 1, wherein the load power switch MOS tube circuit is composed of a MOS control tube and a 28V power supply in series. The gate of the MOS control tube is connected to an external control signal CTRL, the source is connected to the positive terminal of the 28V power supply, and the drain is connected to the negative terminal of the 28V power supply.

3. The high-side common-mode current signal acquisition circuit according to claim 2, wherein the voltage regulator operational power supply circuit is composed of a first voltage regulator and a current limiting resistor in series, the positive terminal of the first voltage regulator is connected to the power supply negative terminal of the operational amplifier, and the negative terminal of the first voltage regulator is connected to the power supply positive terminal of the operational amplifier.

4. The high-side common-mode current signal acquisition circuit according to claim 3, wherein one end of the sampling resistor is connected to the source of the MOS control tube, and the other end is connected to the positive terminal of the load.

5. The high-side common-mode current signal acquisition circuit according to claim 4, wherein the operational amplifier conditioning circuit comprises an operational amplifier, a cross-resistance, a first shunt resistor, a second shunt resistor, a third shunt resistor, a PMOS tube and a bias resistor. The output terminal of the operational amplifier is connected to the gate of the PMOS tube, the source of the PMOS tube is connected to one end of the cross-resistance, and the other end of the cross-resistance is connected to the source of the MOS control tube. One end of the first shunt resistor is connected to one end of the cross-resistance, and the other end is connected to the negative terminal of the operational amplifier; the second shunt resistor is connected to the negative terminal of the operational amplifier and the source of the MOS control tube, respectively; and the third shunt resistor is connected to the positive terminal of the operational amplifier and one end of the sampling resistor, respectively. The drain of the PMOS tube is connected to the ground through the bias resistor.

6. The high-side common-mode current signal acquisition circuit according to claim 5, wherein the operational amplifier conditioning circuit further comprises a second voltage regulator, the negative terminal of the second voltage regulator is connected to the drain of the PMOS tube, and the positive terminal of the second voltage regulator is connected to the ground. ​ ​ ​ ​ ​

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