A satellite solid-state power distribution switch based on giant magnetoresistance effect

Abstract

The present invention relates to the field of giant magnetoresistance effect technology, and in particular to a satellite solid-state power distribution switch based on giant magnetoresistance effect. The GMR bridge measurement circuit is used to generate a differential voltage signal V by changing the resistance value of the GMR resistor under the action of a control current. diff ; Secondary power supply circuit, used to directly draw power from the satellite bus to provide a stable voltage supply for other circuits inside the distribution switch; Voltage conditioning and comparison circuit, receiving the differential voltage signal V output by the GMR bridge measurement circuit diff , amplifying and converting it into an electrical signal suitable for comparison, and then generating an ON / OFF control signal; the power distribution circuit receives the ON / OFF control signal output by the voltage conditioning and comparison circuit, and realizes the function of powering on or off the load by controlling the switching state of the power MOS tube. The solid-state power distribution switch combines the magnetic memory function of GMR with the satellite power distribution function. The switch has the characteristics of lightness and miniaturization, and can replace the existing satellite magnetic latching relay.

Description

Technical Field

[0001] The present invention relates to the technical field of giant magnetoresistance effect, and in particular to a satellite solid-state power distribution switch based on giant magnetoresistance effect. Background Art

[0002] The Giant Magneto-Resistance (GMR) effect is a physical phenomenon found in certain magnetic materials (usually thin-film materials with layered structures). Specifically, it refers to the phenomenon in which the resistivity of a magnetic material changes significantly when an external magnetic field is applied compared to when no external magnetic field is applied. A research team led by French scientist A. Fert first discovered the GMR effect in a [Fe(3nm) / Cr(0.9nm)]40 superlattice thin film. This discovery quickly became a key research topic in sensing technology. GMR sensors have been widely used in various fields due to their high sensitivity, wide operating temperature range, excellent resistance to mechanical shock and vibration, and stable operating point shift over time.

[0003] In the industrial control field, GMR sensors are used to measure information such as the angular velocity of gear rotation and the displacement of objects, demonstrating their unique advantages in precision measurement. In the military field, GMR sensors are used even more extensively, including ultra-micro magnetic field detection, geomagnetic field detection, and aerospace magnetic field orientation detection, demonstrating their stability and reliability in complex environments.

[0004] Traditional satellite solid-state power distribution systems have the defect of not having the function of maintaining status during power outages. That is, after the satellite bus loses power, the distribution system cannot maintain the state before the power outage, which brings many inconveniences in practical applications. Summary of the Invention

[0005] The present invention provides a satellite solid-state power distribution switch based on giant magnetoresistance effect, which aims to solve the problem that traditional satellite solid-state power distribution systems do not have a power-off retention function by introducing the GMR effect and combining it with innovative circuit design.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: The present invention provides a satellite solid-state power distribution switch based on the giant magnetoresistance effect, comprising: a GMR bridge measurement circuit for generating a differential voltage signal V by changing the resistance of the GMR resistor under the action of a control current; diff The secondary power supply circuit is used to directly draw power from the satellite bus to provide a stable voltage supply for other circuits inside the distribution switch; the voltage conditioning and comparison circuit receives the differential voltage signal V output by the GMR bridge measurement circuit diff, amplifying and converting it into an electrical signal suitable for comparison, thereby generating an ON / OFF control signal; the power distribution circuit receives the ON / OFF control signal output by the voltage conditioning and comparison circuit, and realizes the function of powering on or off the load by controlling the switching state of the power MOS tube; wherein, the GMR bridge measurement circuit includes a precision constant current source and a GMR-based bridge. The GMR-based bridge includes four GMR resistors. By controlling the forward or reverse pulse of the current, the resistance value of the GMR resistor is changed, thereby generating a positive or negative differential voltage signal.

[0007] Furthermore, the precision constant current source of the GMR bridge measurement circuit includes a three-terminal adjustable voltage regulator V11, a resistor R14, a resistor R4 and a transistor V6. The resistor R14 and the three-terminal adjustable voltage regulator V11 are connected in series to ground, the resistor R4 is connected to the adjustment terminal of the three-terminal adjustable voltage regulator V11 and grounded, the base and collector of the transistor V6 are connected to the two ends of the resistor R14, and the reference voltage V generated by V11 is V11. ref , used to generate a stable constant current source I, flowing through a bridge composed of four GMR resistors, (1).

[0008] Furthermore, in the bridge composed of the GMR resistors, the magnetic induction resistances of GMR1 and GMR3 change in the same direction, and the magnetic induction resistances of GMR2 and GMR4 change in the same direction. SIG+ and V SIG- The two ends generate different voltages, which in turn generate a differential voltage signal V diff , , (2) (3).

[0009] Where: R GMR1 ~R GMR4 are the resistance values ​​of the giant magnetoresistors GMR1~GMR4, I is the constant current value 1mA generated by the constant current source, V ref It is the reference voltage generated by V11.

[0010] The calculation formula for differential voltage is, (4).

[0011] Substituting formulas (2) and (3) into (4), we can obtain the differential voltage of the bridge: (5).

[0012] Furthermore, the secondary power supply circuit includes a three-terminal adjustable voltage regulator V14, a resistor R37, a resistor R39, a transistor V12, a transistor V13, a capacitor C5, a resistor R40, a resistor R41, a resistor R42, a resistor R43, and a resistor R44.

[0013] A resistor R37 is connected in series with the three-terminal adjustable voltage regulator V14. Resistors R37 and R39 are connected in series between the base and collector of the transistor V12. R37 functions as a current limiter. The collector of the transistor V12 is connected to the collector of the transistor V13, and the emitter of the transistor V12 is connected to the base of the transistor V13.

[0014] The emitter of the transistor V13 is connected in series with resistors R42 and R44 to ground; resistors R41 and R43 are connected in series and in parallel with resistors R42 and R44; resistor R40 is connected between the base and emitter of the transistor V13; capacitor C5 is connected to pins 1 and 2 of the three-terminal adjustable voltage regulator V14, and pins 2 and 3 of the three-terminal adjustable voltage regulator V14 are connected to resistor R43.

[0015] The reference voltage V generated by pin 2 of the three-terminal adjustable voltage regulator V14 ref , the calculation formula of the secondary power supply voltage Vo, (6) Through R42 and R44, V o The partial pressure is obtained, (7).

[0016] Furthermore, the voltage conditioning and comparison circuit includes a voltage conditioning amplifier circuit and a comparison circuit. The voltage conditioning amplifier circuit amplifies the differential voltage signal generated by the GMR bridge measurement circuit and compares it with the reference voltage through the comparison circuit to generate V ON / OFF Control signal, V ON / OFF The control signal is used to control the switching state of the power MOS tube in the power distribution circuit.

[0017] Furthermore, the voltage conditioning amplifier circuit includes an operational amplifier N1A, an operational amplifier N2A, and an operational amplifier N1B. The operational amplifier N1A and the resistor R27 form a voltage follower to send the reference voltage to the differential amplifier.

[0018] Op amp N1B, op amp N2A, resistors R15, R18, R20, R26 and R28 form a differential amplifier circuit to measure the V diff Voltage amplification, according to the characteristics of "virtual short" and "virtual disconnection" of the op amp, V amp The calculation formula is: (8), Under different control current directions, V amp There are two voltage values.

[0019] Furthermore, V amp Enter the comparison circuit, which includes a three-terminal adjustable voltage regulator V10, a transistor V8, a resistor R1, a resistor R17, a resistor R21 and a resistor R30. ampThe resistor R1 enters the 2nd pin of the three-terminal adjustable voltage regulator V10. The resistor R1 is used to limit the reference current of the three-terminal adjustable voltage regulator V10. amp Compared with the reference voltage, two states appear.

[0020] (1) When V amp > reference voltage, the three-terminal adjustable voltage regulator V10 is in low resistance state, at this time the emitter-base voltage V eb calculate, (9).

[0021] Where V in The satellite bus input voltage is typically 28V. m is the voltage regulation value of the three-terminal adjustable voltage regulator V10, and V is calculated eb , transistor V8 is saturated and turned on, the emitter-collector voltage of V8 is Vec, then the output voltage of the comparator is V ON / OFF =V in -V ec .

[0022] (2) V amp When the reference voltage is less than the reference voltage, the three-terminal adjustable voltage regulator V10 is in high impedance state, V m ≈28V; at this time, V8 is cut off and the output voltage of the comparator V ON / OFF =0.

[0023] Furthermore, the power distribution circuit includes a P-type MOS transistor V7, a transistor V9, a voltage regulator V5, a resistor R11, a resistor R16, a resistor R19, a resistor R29, a resistor R35, a resistor RL and a capacitor C2.

[0024] By V ON / OFF The control signal controls the on or off of the transistor V9, and controls the source-gate voltage V of the MOS tube V7 through the voltage divider of the resistors R11 and R19. SG , realizing the switch control of MOS tube V7.

[0025] Capacitor C2 increases the slow start time of MOS tube V7 and enhances the capacitive load capacity.

[0026] The resistor R16 is connected in series to the gate of the MOS tube V7 to prevent the MOS tube V7 from oscillating during the switching process.

[0027] The resistor RL is the satellite load. When the MOS tube V7 is turned on, the voltage V _OUT is 27V~28V, the specific value depends on the voltage drop of the cable and MOS tube; when the MOS tube V7 is turned off, the voltage of the load RL V _OUT is 0.

[0028] Furthermore, (1) when the control current is in the forward direction, V ON / OFF The base current I flowing through transistor V9 b The calculated value of (10).

[0029] The maximum collector current formula of a transistor is: (11).

[0030] The dynamic amplification factor β of transistor V9 is 100, then I b Much greater than I cmax / β, the transistor V9 works in the saturated conduction state, at this time the source-gate voltage V SG The calculation formula is: (12).

[0031] V th is the turn-on voltage of MOS tube V7, V SG >V th MOS tube V7 is saturated and turned on, and V SD 、V _OUT , realize power distribution output.

[0032] (2) When the control current is reversed, V ON / OFF =0, transistor V9 is cut off, V SG =0, MOS tube V7 is cut off, and the power distribution is shut down.

[0033] Furthermore, the distribution switch has a power-off holding function. When the control current is forward, the distribution switch is turned on and supplies power to the load. Even if the control current is removed or the satellite bus is powered on again after being powered off, the distribution switch remains on; when the control current is reverse, the distribution switch is disconnected and stops supplying power to the load. Even if the control current is removed or the satellite bus is powered on again after being powered off, the distribution switch remains off.

[0034] The beneficial effects achieved by the present invention are as follows: the present invention is a satellite solid-state distribution switch based on the giant magnetoresistance effect, which combines the magnetic memory function of GMR with the satellite distribution function. The switch has the characteristics of being lightweight and miniaturized and can replace the existing satellite magnetic latching relay.

[0035] The invention discloses a satellite solid-state power distribution switch based on giant magnetoresistance effect. The circuit generates a 1mA constant current source, and the signal is converted into an electrical signal through a bridge composed of four GMRs.

[0036] The present invention discloses a satellite solid-state power distribution switch based on the giant magnetoresistance effect. The switch directly draws power from a 28V busbar through a secondary power supply circuit, eliminating the need for external secondary power supplies such as 5V and ±12V, thereby saving satellite power supply resources.

[0037] The present invention discloses a satellite solid-state power distribution switch based on the giant magnetoresistance effect, a voltage conditioning and comparison circuit, and a single-power operational amplifier and a three-terminal adjustable voltage regulator. The circuit converts the GMR resistance change into a switching signal of a MOS tube, and the circuit is simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0039] Figure 1 It shows the composition and connection relationship of the distribution switch.

[0040] Figure 2 This is the principle of a solid-state power distribution switch.

[0041] Figure 3 This is the schematic diagram of the GMR bridge measurement circuit.

[0042] Figure 4 This is the circuit principle of solid-state power distribution switch.

[0043] Figure 5 This is the principle of voltage conditioning and comparison circuit.

[0044] Figure 6 This is the schematic diagram of the power distribution circuit.

[0045] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0047] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if the meaning of "and / or" appearing in the full text is to include three parallel schemes, taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0049] like Figures 1 to 5 As shown, the present invention provides a satellite solid-state switch based on the giant magnetoresistance effect. It includes a GMR bridge measurement circuit, a secondary power supply circuit, a voltage conditioning and comparison circuit, and a power distribution circuit. The satellite power supply and distribution system provides a bidirectional pulse control current to generate positive and reverse magnetic fields, thereby changing the GMR resistance and generating a differential signal. The differential signal passes through the voltage conditioning and comparison circuit to convert the weak signal of the mV level into an amplified signal of about 2.5V, and then passes through the voltage comparator to output the ON / OFF signal. The ON / OFF signal is input as the input of the power distribution circuit, and drives the MOS tube through the driving circuit, thereby realizing 28V switch control to power the load. The composition and connection relationship of the distribution switch are shown in the figure. Figure 1 shown.

[0050] This invention implements a solid-state switch with memory function through a purely hardware circuit, independently of software. This converts the magnetic memory of the GMR into the switch memory of the power MOS transistor. When a positive pulse control current is input, the power distribution switch is on and has a power-off hold function. When a negative pulse control current is input, the power distribution switch is off and has a power-off hold function.

[0051] The distribution switch operates as follows: When the control current is positive, the bridge circuit formed by the four GMR resistors generates a 150mV differential voltage. This differential voltage, after voltage conditioning and comparison circuitry, produces a DC voltage of approximately 3.1V. This voltage, passing through the comparator circuit, generates an ON / OFF signal of approximately 27.9V. The ON / OFF signal passes through the distribution circuit, where it is divided down and controls the P-type MOS transistor to turn on, resulting in a distribution output voltage of 28V. When the control current is negative, the bridge circuit formed by the four GMR resistors generates a -150mV differential voltage. This differential voltage, after voltage conditioning and comparison circuitry, produces a DC voltage of approximately 1.9V. This voltage, passing through the comparator circuit, generates a 0V ON / OFF signal. The ON / OFF signal passes through the distribution circuit, controls the P-type MOS transistor to turn off, and the distribution output voltage is 0.

[0052] The principle of solid-state distribution switch is as follows Figure 2 As shown in the figure, it consists of four parts: GMR bridge measurement circuit, secondary power supply circuit, voltage conditioning and comparison circuit, and power distribution circuit. Each part is discussed in detail below.

[0053] The schematic diagram of the GMR bridge measurement circuit is as follows: Figure 3 As shown. It mainly consists of a precision constant current source and a GMR-based bridge. The precision constant current source consists of a three-terminal adjustable voltage regulator V11, resistors R14, R4 and transistor V6. R14 is used to limit the regulated current I of V14. KA , making I KA The maximum value is 28V / 10k=2.8mA, and the reference voltage V generated by V11 ref =2.5V, voltage accuracy is 0.5%, constant current value calculation of constant current source, (1).

[0054] According to Kirchhoff's current law, the total current flowing through the GMR bridge is 1mA. The GMR-based bridge consists of GMR1~GMR4, where the magnetic induction resistance of GMR1 and GMR3 changes in the same direction, and the magnetic induction resistance of GMR2 and GMR4 changes in the same direction. The low value resistance of GMR at room temperature is 5kΩ, the high value resistance is 5.3kΩ, and the resistance change rate is 6%. That is, when the control current is a forward pulse, the resistance of GMR1 and GMR3 is 5kΩ, and the resistance of GMR2 and GMR4 is 5.3kΩ; when the control current is a reverse pulse, the resistance of GMR1 and GMR3 is 5.3kΩ, and the resistance of GMR2 and GMR4 is 5kΩ. The constant current flowing through the bridge is 1mA, then in the two bridge arms V SIG+ and V SIG- The different voltages generated at the ends are calculated using the formula: (2), (3), where: R GMR1 ~R GMR4are the resistance values ​​of the giant magnetoresistors GMR1~GMR4, I is the constant current value 1mA generated by the constant current source, V ref It is the reference voltage generated by V11.

[0055] The differential voltage is calculated as follows: (4). Substituting formulas (2) and (3) into (4), we can obtain the differential voltage of the bridge, (5), and put the numerical value into Formula 5 to obtain the calculated value, as shown in Table 1.

[0056] Table 1 Control current and differential voltage calculation table

[0057]

[0058] Solid-state power distribution switch circuit principle Figure 4 As shown, the solid-state power distribution switch requires a 10V voltage to power the operational amplifier. In order to save satellite power distribution resources, a three-terminal adjustable voltage regulator is used to form a precision high-current series voltage regulator to generate a +10V voltage. R37 acts as a current limiter to make I KA The maximum value is 28V / 10k=2.8mA. The reference voltage V generated by pin 2 of V14 ref =2.5V. V12 and V13 form a Darlington structure, so that the current of +10V reaches 200mA, which meets the power supply requirements of the op amp.

[0059] The calculation formula of the secondary power supply voltage Vo is: (6), where R41 = 30k, with an accuracy of 0.1%, R43 = 10k, with an accuracy of 0.1%, and the reference voltage V ref =2.5V, substitute into formula 6, and we get V o =10V.

[0060] Through R42 and R44 to V o The partial pressure is: (7), where R42 = 30k, accuracy is 0.1%, R44 = 10k, accuracy is 0.1%, V o =10V, substitute into formula 7 to get V ref_2.5V =2.5V.

[0061] The voltage conditioning and comparison circuit consists of a voltage conditioning amplifier circuit and a comparison circuit. The GMR bridge measurement circuit generates V diff The voltage is amplified and conditioned by the voltage conditioning and comparison circuit, and then enters the comparison circuit to generate V on / off Voltage. Circuit principle is as follows Figure 5 shown.

[0062] The voltage conditioning amplifier circuit consists of op amps N1A, N2A, and N1B and corresponding resistors. N1A and R27 form a voltage follower, feeding the 2.5V reference voltage into the differential amplifier. The 2.5V reference serves two purposes: first, to provide a bias for the differential voltage, improving the signal's anti-interference capability; second, to condition the amplified differential voltage to around 2.5V, facilitating resolution by the comparison circuit. N1B, N2A, R15, R18, R20, R26, and R28 form a differential amplifier circuit, converting the V generated by the GMR bridge measurement circuit to diff The voltage (as shown in Table 1) is amplified to a voltage that can be recognized by the comparison circuit. According to the characteristics of the op amp "virtual short" and "virtual open", V amp The calculation formula is as follows, (8), where R15 = 100k, R18 = 100k, R20 = 100k, V ref_2.5V =2.5V, V SIG+ and V SIG- They are the two bridge arm voltages of the GMR bridge, and their calculated values ​​are shown in Table 1 (V diff =V SIG+ - V SIG- ). Combining Table 1 and Formula 8, when the control current direction is different, the two states are as follows: 1) When the control current is forward, V SIG+ -V SIG- =0.15V, substituting into formula 8, we get V amp =4×0.15+2.5=3.1V;2) When the control current is reversed, V SIG+ -V SIG- =-0.15V, substituting into formula 8, we get V amp =4×(-0.15)+2.5=1.9V. Based on the above calculation, we can get the control current direction and V amp The calculation table is shown in Table 2.

[0063] Table 2 Control current and V amp Calculation table

[0064]

[0065] It can be seen from Table 2 that under different control current directions, V amp There are two voltage values, 3.1V and 1.9V. amp Enter the comparison circuit, which consists of a three-terminal adjustable voltage regulator V10, a transistor V8, resistors R1, R17, R21 and R30. amp It enters pin 2 of V10 through resistor R1, which is used to limit the reference current of V10. amp Compared with the reference voltage 2.5V, two states appear.

[0066] (1) When Vamp>2.5V, V10 is in low resistance state, Vm=2.0V, and the emitter-base voltage of V8 is V eb calculate, (9), where V in The satellite bus input voltage is typically 28V. m is the voltage regulation value of the three-terminal adjustable voltage regulator V10, R17=1k, R21=9.1k, and put it into formula 9 to get V eb =2.57V, transistor V8 is saturated and turned on, V8's emitter-collector voltage Vec=0.3V, then the comparator's output voltage V ON / OFF =V in -V ec =28-0.3=27.7V.

[0067] (2) V amp When <2.5V, V10 is in high impedance state, V m ≈28V; at this time, V8 is cut off and the output voltage of the comparator V ON / OFF =0.

[0068] The power distribution circuit is mainly composed of P-type MOS tubes, transistors, voltage regulator tubes and resistors and capacitors. Figure 6 shown.

[0069] By V ON / OFF Controls the on / off of transistor V9 and controls the source-gate voltage V of MOS tube V7 through the voltage divider R11 and R19. SG , to realize the switch control of MOS tube. The voltage regulator value of voltage regulator V5 is generally set to 12V, which protects the source-gate voltage V of MOS tube V7. SG Working within the safe voltage range, the capacitor C2 is set to 0.1uF to increase the slow start time of the MOS tube V7 and enhance the capacitive load capacity. R16 is connected in series with the gate of the MOS tube V7 to prevent the MOS tube V7 from oscillating during the switching process. RL is a satellite load. When the MOS tube V7 is turned on, the voltage of the load RL is V _OUT is 27~28V, the specific value depends on the voltage drop of the cable and MOS tube; when the MOS tube V7 is turned off, the voltage of the load RL V _OUT is 0.

[0070] According to the calculation results in Section 3.3, when the control current direction is different, V ON / OFF There are two results. When the control current is forward, V ON / OFF =27.7V; when the control current is reverse, V ON / OFF =0, V ON / OFF Control the opening and closing of the MOS tube. The calculation process is as follows: (1) When the control current is positive, V ON / OFF=27.7V, the base current I flowing through transistor V9 b The calculated value of (10), where R29 = 20k, R35 = 10k, V BE =0.7V, and substituting it into formula 10, we get I b ≈1.3mA. The maximum collector current formula of the transistor is, (11), where R11=5.1k, R19=10k, V in =28V, and substituting it into formula 11, we get I cmax =1.85mA, the dynamic amplification factor β of transistor V9 is 100, then I b Much greater than I cmax / β, that is, the transistor V9 works in the saturated conduction state, V ce ≈0.3V, at this time the source-gate voltage of the MOS tube is V SG The calculation formula is, (12), where R11 = 5.1k, R19 = 10k, V in =28V, V ce =0.3V, and substituting it into formula 12, we get V SG =9.4V, V th Is the turn-on voltage of the MOS tube, generally 2~4V, V SG >V th MOS tube V7 is saturated and turned on, V SD ≈0.1V, V _OUT ≈27.9V, achieving power distribution output. (2) When the control current is reversed, V ON / OFF =0, transistor V9 is cut off, V SG =0, MOS tube V7 is cut off, V _OUT ≈0, realizing power distribution shutdown.

[0071] Based on the above analysis, the calculated values ​​of the control current and the power distribution state are shown in Table 3. That is, when the control current is in the forward direction, the power distribution state is on, and after power is turned off and then on again, the power distribution state remains on; when the control current is in the reverse direction, the power distribution state is off, and after power is turned off and then on again, the power distribution state remains off.

[0072] Table 3 Control current and V amp Calculation table

[0073]

[0074] The above descriptions are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present description and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A satellite solid-state power distribution switch based on giant magnetoresistance effect, characterized in that: include: The GMR bridge measurement circuit is used to generate a differential voltage signal V by changing the resistance of the GMR resistor under the action of the control current. diff ; The secondary power supply circuit is used to directly draw power from the satellite bus to provide a stable voltage supply for other circuits inside the power distribution switch; The voltage conditioning and comparison circuit receives the differential voltage signal V output by the GMR bridge measurement circuit. diff , amplifying it and converting it into an electrical signal suitable for comparison, thereby generating an ON / OFF control signal; The power distribution circuit receives the ON / OFF control signal output by the voltage conditioning and comparison circuit, and realizes the function of supplying power or cutting off power to the load by controlling the switching state of the power MOS tube; (1) When the control current is forward, V ON / OFF The base current I flowing through transistor V9 b The calculated value of is as follows, The maximum collector current formula of a transistor is as follows: The dynamic amplification factor β of transistor V9 is 100, then I b Much larger than I cmax / β, the transistor V9 works in the saturated conduction state, at this time the source-gate voltage V SG The calculation formula is as follows, V in is the satellite bus input voltage, V th is the turn-on voltage of MOS tube V7, V SG >V th MOS tube V7 is saturated and turned on, and V SD 、V _OUT , realize power distribution output; (2) When the control current is reversed, V ON / OFF =0, transistor V9 is cut off, V SG =0, MOS tube V7 is cut off, and the power distribution is shut down; The power distribution circuit includes a P-type MOS tube V7, a triode V9, a voltage regulator tube V5, a resistor R11, a resistor R16, a resistor R19, a resistor R29, a resistor R35, a resistor RL and a capacitor C2; By V ON / OFF The control signal controls the on or off of the transistor V9, and controls the source-gate voltage V of the MOS tube V7 through the voltage division of the resistors R11 and R19. SG , realize the switch control of MOS tube V7; Capacitor C2 increases the slow start time of MOS tube V7 and enhances the capacitive load capacity; Resistor R16 is connected in series to the gate of MOS tube V7 to prevent MOS tube V7 from oscillating during the switching process; The resistor RL is the satellite load. When the MOS tube V7 is turned on, the voltage V _OUT is 27V~28V, the specific value depends on the voltage drop of the cable and the MOS tube; when the MOS tube V7 is turned off, the voltage V _OUT is 0; The distribution switch has a power-off holding function. When the control current is in the forward direction, the distribution switch is turned on and supplies power to the load. Even if the control current is removed or the satellite bus is powered on again after being powered off, the distribution switch remains on. When the control current is in the reverse direction, the distribution switch is turned off and stops supplying power to the load. Even if the control current is removed or the satellite bus is powered on again after being powered off, the distribution switch remains off. The GMR bridge measurement circuit includes a precision constant current source and a GMR-based bridge. The GMR-based bridge includes four GMR resistors. By controlling the forward or reverse pulse of the current, the resistance of the GMR resistor is changed to generate a positive or negative differential voltage signal.

2. A satellite solid-state power distribution switch based on giant magnetoresistance effect according to claim 1, characterized in that: The precision constant current source of the GMR bridge measurement circuit includes a three-terminal adjustable voltage regulator V11, a resistor R14, a resistor R4 and a transistor V6. The resistor R14 and the three-terminal adjustable voltage regulator V11 are connected in series to ground, the resistor R4 is connected to the adjustment end of the three-terminal adjustable voltage regulator V11 to ground, the base and collector of the transistor V6 are connected to the two ends of the resistor R14, and the reference voltage V generated by V11 is ref , used to generate a stable constant current source I, flowing through a bridge composed of four GMR resistors, 3. A satellite solid-state power distribution switch based on giant magnetoresistance effect according to claim 2, characterized in that: The bridge composed of the GMR resistors, wherein the magnetic induction resistances of GMR1 and GMR3 change in the same direction, and the magnetic induction resistances of GMR2 and GMR4 change in the same direction, in the two bridge arms V SIG+ and V SIG- The two ends generate different voltages, which in turn generate a differential voltage signal V diff , Where: R GMR1 ~R GMR4 are the resistance values ​​of giant magnetoresistors GMR1~GMR4 respectively, I is the constant current value 1mA generated by the constant current source, V ref is the reference voltage generated by V11; The differential voltage is calculated as follows: V diff =V SIG+ -V SIG- (4) Substituting formula (2) and (3) into (4), we can obtain the differential voltage of the bridge:

4. A satellite solid-state power distribution switch based on giant magnetoresistance effect according to claim 3, characterized in that: The secondary power supply circuit includes a three-terminal adjustable voltage regulator V14, a resistor R37, a resistor R39, a transistor V12, a transistor V13, a capacitor C5, a resistor R40, a resistor R41, a resistor R42, a resistor R43, and a resistor R44; A three-terminal adjustable voltage regulator V14 is connected in series with a resistor R37, a resistor R37 and a resistor R39 are connected in series between the base and collector of the transistor V12, R37 plays a current limiting role, the collector of the transistor V12 is connected to the collector of the transistor V13, and the emitter of the transistor V12 is connected to the base of the transistor V13; The emitter of the transistor V13 is connected in series with resistors R42 and R44 to ground; resistors R41 and R43 are connected in series and then connected in parallel with resistors R42 and R44; resistor R40 is connected between the base and emitter of the transistor V13; capacitor C5 is connected to pins 1 and 2 of the three-terminal adjustable voltage regulator V14, and pins 2 and 3 of the three-terminal adjustable voltage regulator V14 are connected to resistor R43; The reference voltage V generated by the 2nd foot of the three-terminal adjustable voltage regulator V14 ref ; The calculation formula for the secondary power supply voltage Vo is as follows: Through R42 and R44 to V o The partial pressure is obtained 5. A satellite solid-state power distribution switch based on giant magnetoresistance effect according to claim 4, characterized in that: The voltage conditioning and comparison circuit includes a voltage conditioning amplifier circuit and a comparison circuit. The voltage conditioning amplifier circuit amplifies the differential voltage signal generated by the GMR bridge measurement circuit and compares it with the reference voltage through the comparison circuit to generate V ON / OFF Control signal, V ON / OFF The control signal is used to control the switching state of the power MOS tube in the power distribution circuit.

6. A satellite solid-state power distribution switch based on giant magnetoresistance effect according to claim 5, characterized in that: The voltage conditioning amplifier circuit includes an operational amplifier N1A, an operational amplifier N2A and an operational amplifier N1B. The operational amplifier N1A and a resistor R27 form a voltage follower to send the reference voltage to the differential amplifier. Op amp N1B, op amp N2A, resistors R15, R18, R20, R26 and R28 form a differential amplifier circuit to measure the V generated by the GMR bridge measurement circuit. diff Voltage amplification, according to the characteristics of "virtual short" and "virtual disconnection" of the op amp, V amp The calculation formula is as follows, Under different control current directions, V amp There are two voltage values.

7. A satellite solid-state power distribution switch based on giant magnetoresistance effect according to claim 6, characterized in that: V amp Enter the comparison circuit, which includes a three-terminal adjustable voltage regulator V10, a transistor V8, a resistor R1, a resistor R17, a resistor R21 and a resistor R30. amp Enters pin 2 of the three-terminal adjustable voltage regulator V10 through resistor R1. Resistor R1 is used to limit the reference current of the three-terminal adjustable voltage regulator V10. amp Compared with the reference voltage, two states appear: (1) When V amp > reference voltage, the three-terminal adjustable regulator V10 is in a low-resistance state. At this time, the emitter-base voltage V eb The calculation is as follows, Where V in The satellite bus input voltage is typically 28V. m is the voltage value of the three-terminal adjustable voltage regulator V10, and V eb , transistor V8 is saturated and turned on, the emitter-collector voltage of V8 is V ec , then the comparator output voltage V ON / OFF =V in -V ec ; (2) V amp When the reference voltage is less than the reference voltage, the three-terminal adjustable voltage regulator V10 is in high impedance state, V m ≈28V; at this time, V8 is cut off, and the output voltage of the comparator V ON / OFF =0.

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