CN114785288B - Amplifier power supply circuit of balance bridge and bridge amplifying circuit - Google Patents
Amplifier power supply circuit of balance bridge and bridge amplifying circuit Download PDFInfo
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- CN114785288B CN114785288B CN202210694587.5A CN202210694587A CN114785288B CN 114785288 B CN114785288 B CN 114785288B CN 202210694587 A CN202210694587 A CN 202210694587A CN 114785288 B CN114785288 B CN 114785288B
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/30—Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier
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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
- H02M3/00—Conversion of dc power input into dc power output
Abstract
The invention discloses an amplifier power supply circuit of a balance bridge and a bridge amplifying circuit, comprising: the input end of the isolation switch power supply circuit is connected with the bridge excitation power supply of the balance bridge, and the isolation switch power supply circuit is used for boosting the bridge excitation of the balance bridge by using the isolation switch power supply of the switch power supply circuit to obtain boosting electric energy; the linear voltage stabilizing circuit is used for linearly stabilizing the boosted electric energy to obtain a preset number of groups of power supply electric energy, and supplying power to the amplifier connected with the balance bridge by using the power supply electric energy; the invention adopts an isolation power supply and linear voltage stabilization mode, directly takes electricity from the bridge excitation power supply to supply power to the amplifier of the balance bridge, so that the amplifier does not need external power supply, the power supply difficulty of the amplifier of the balance bridge is reduced, and the circuit complexity and the number of power supply sources of the bridge amplifying circuit are simplified; and an isolating switch power supply can be utilized, the occurrence of loop current is avoided, and the measurement accuracy is improved.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to an amplifier power supply circuit of a balance bridge and an amplifier circuit.
Background
The balance bridge (such as a Wheatstone bridge) is a high-precision measuring bridge, has wide application in various measuring fields, and is an important measuring circuit.
The amplifier of the existing balance bridge (such as a Wheatstone bridge) is generally placed at the acquisition side and is used for supplying power in a centralized way; if the balance is required to be arranged at the bridge end of the balance, separate power supply is required. In the conventional bridge amplifying circuit shown in fig. 1, the bridge output is amplified by a low-noise programmable amplifier (AD 8221), so that the interference and error of signals in transmission are reduced; its power supply needs two sets of power supplies: bridge excitation and signal ground, amplifier supply + Vs, -Vs, signal ground; therefore, not only is the power supply complicated, but also when the amplifier power supply and the bridge power supply are grounded, the ground levels of the two power supplies are inconsistent, loop current can occur, and measurement errors can be caused.
Therefore, how to simplify the circuit complexity and the number of power supplies of the bridge amplifying circuit, avoid the occurrence of loop current, and improve the measurement accuracy is a problem which needs to be solved urgently nowadays.
Disclosure of Invention
The invention aims to provide an amplifier power supply circuit of a balance bridge and an amplifier circuit, so that the circuit complexity and the number of power supply sources of the bridge amplifying circuit are simplified, the occurrence of loop current is avoided, and the measurement accuracy is improved.
In order to solve the above technical problem, the present invention provides an amplifier power supply circuit of a balance bridge, including:
the isolation switch power supply circuit is used for boosting the bridge excitation of the balance bridge by utilizing the isolation switch power supply of the switch power supply circuit to obtain boosting electric energy;
and the input end of the linear voltage stabilizing circuit is connected with the output end of the isolating switch power supply circuit and is used for linearly stabilizing the boosted electric energy to obtain the power supply electric energy of a preset number of groups and supplying power to the amplifier connected with the balance bridge by using the power supply electric energy.
Optionally, the isolation switching power supply circuit includes: a choke coil;
the ground end and the output end of the bridge excitation power supply are respectively connected with the first input end and the second input end of the choke coil, and the first output end and the second output end of the choke coil are respectively connected with the negative input end and the positive input end of the isolating switch power supply.
Optionally, the isolation switch power supply circuit further includes: a first capacitor, a second capacitor and a first electrolytic capacitor;
wherein, the common end of the first output end of the bridge excitation power supply and the first input end of the choke coil is connected with the first end of the first capacitor, and the common end of the second output end of the bridge excitation power supply and the second input end of the choke coil is connected with the second end of the first capacitor; the first end of the second capacitor is connected with the first output end of the choke coil, the common end of the first end of the second capacitor and the first output end of the choke coil is connected with the cathode of the first electrolytic capacitor, and the cathode of the first electrolytic capacitor is connected with the negative input end of the isolating switch power supply; the second end of the second capacitor is connected with the second output end of the choke coil, the common end of the second capacitor and the second output end of the choke coil is connected with the anode of the first electrolytic capacitor, and the anode of the first electrolytic capacitor is connected with the positive input end of the isolating switch power supply.
Optionally, the isolation switch power supply circuit further includes: a third capacitor, a fourth capacitor, a second electrolytic capacitor, a third electrolytic capacitor and first magnetic beads;
the first end of the third capacitor is connected with the cathode of the first electrolytic capacitor, the common end of the first end of the third capacitor and the cathode of the first electrolytic capacitor is connected with the cathode of the second electrolytic capacitor, and the cathode of the second electrolytic capacitor is connected with the negative input end of the isolating switch power supply; the first end of the fourth capacitor is connected with the anode of the first electrolytic capacitor, the common end of the first end of the fourth capacitor connected with the anode of the first electrolytic capacitor is connected with the anode of the third electrolytic capacitor, and the anode of the second electrolytic capacitor is connected with the positive input end of the isolating switch power supply; the second end of the third capacitor is connected with the second end of the fourth capacitor, the anode of the second electrolytic capacitor is connected with the cathode of the third electrolytic capacitor, the second end of the third capacitor is connected with the anode of the second electrolytic capacitor, and the common end of the second end of the third capacitor and the anode of the second electrolytic capacitor is connected to a system ground which is grounded through the first magnetic bead.
Optionally, the amplifier power supply circuit further includes: a power supply polarity detection circuit;
the power polarity detection circuit comprises a current-limiting resistor and a diode; the cathode of the diode is connected with the second output end of the choke coil, and the anode of the diode is connected with the first output end of the choke coil through the current limiting resistor.
Optionally, when the preset number is 2, the linear voltage stabilizing circuit includes: the device comprises a second magnetic bead, a first voltage stabilizing chip, a second voltage stabilizing chip, a third voltage stabilizing chip, a fourth voltage stabilizing chip, a first voltage dividing circuit and a second voltage dividing circuit;
the grounding end of the isolating switch power supply is connected to an analog ground through the second magnetic bead, the positive output end of the isolating switch power supply is connected with the input end of the first voltage stabilizing chip, and the negative output end of the isolating switch power supply is connected with the input end of the second voltage stabilizing chip; the output end of the first voltage stabilizing chip is connected with the anode of the third voltage stabilizing chip through the first voltage dividing circuit, and the output end of the second voltage stabilizing chip is connected with the cathode of the fourth voltage stabilizing chip through the second voltage dividing circuit; the grounding end of the first voltage stabilizing chip, the grounding end of the second voltage stabilizing chip, the cathode of the third voltage stabilizing chip and the anode of the fourth voltage stabilizing chip are all connected to an analog ground; the output end of the first voltage stabilizing chip and the common end connected with the first voltage dividing circuit, the output end of the second voltage stabilizing chip and the common end connected with the second voltage dividing circuit output a group of power supply electric energy, and the anode of the third voltage stabilizing chip and the common end connected with the first voltage dividing circuit, and the cathode of the fourth voltage stabilizing chip and the common end connected with the second voltage dividing circuit output another group of power supply electric energy.
Optionally, the linear voltage stabilizing circuit further includes: the first inductor, the second inductor, the fifth capacitor, the sixth capacitor, the fourth electrolytic capacitor and the fifth electrolytic capacitor;
the positive output end of the isolating switch power supply is connected with the input end of the first voltage stabilizing chip through the first inductor, the common end of the first inductor connected with the input end of the first voltage stabilizing chip is connected with the first end of the fifth capacitor, and the common end of the first end of the fifth capacitor connected with the input end of the first voltage stabilizing chip is connected with the anode of the fourth electrolytic capacitor; the negative output end of the isolating switch power supply is connected with the input end of the second voltage stabilizing chip through the second inductor, the common end of the second inductor connected with the input end of the second voltage stabilizing chip is connected with the first end of the sixth capacitor, and the common end of the first end of the sixth capacitor connected with the input end of the second voltage stabilizing chip is connected with the cathode of the fifth electrolytic capacitor; and the second end of the fifth capacitor, the second end of the sixth capacitor, the cathode of the fourth electrolytic capacitor and the anode of the fifth electrolytic capacitor are all connected to a simulated ground.
Optionally, the linear voltage stabilizing circuit further includes: a seventh capacitor, an eighth capacitor, a sixth electrolytic capacitor and a seventh electrolytic capacitor;
the common end of the anode of the third voltage stabilizing chip connected with the first voltage dividing circuit is connected with the first end of the seventh capacitor, and the common end of the first end of the seventh capacitor connected with the anode of the third voltage stabilizing chip is connected with the anode of the sixth electrolytic capacitor; a common end of the cathode of the fourth voltage stabilizing chip, which is connected with the second voltage dividing circuit, is connected with a first end of the eighth capacitor, and a common end of the first end of the eighth capacitor, which is connected with the cathode of the fourth voltage stabilizing chip, is connected with an anode of the seventh electrolytic capacitor; and the second end of the seventh capacitor, the second end of the eighth capacitor, the cathode of the sixth electrolytic capacitor and the anode of the seventh electrolytic capacitor are all connected to a simulated ground.
Optionally, the first voltage dividing circuit and the second voltage dividing circuit are voltage dividing circuits with three resistors connected in parallel.
The present invention also provides a bridge amplifying circuit, comprising: the balance bridge, the amplifier connected with the balance bridge and the amplifier power supply circuit of the balance bridge.
The invention provides an amplifier power supply circuit of a balance bridge, which comprises: the isolation switch power supply circuit is used for boosting the bridge excitation of the balance bridge by utilizing the isolation switch power supply of the switch power supply circuit to obtain boosting electric energy; the linear voltage stabilizing circuit is used for linearly stabilizing the boosted electric energy to obtain a preset number of groups of power supply electric energy, and supplying power to the amplifier connected with the balance bridge by using the power supply electric energy;
therefore, the invention adopts the mode of isolating the power supply and linearly stabilizing the voltage, directly takes electricity from the bridge excitation power supply to supply power to the amplifier of the balance bridge, so that the amplifier does not need external power supply, the power supply difficulty of the amplifier of the balance bridge is reduced, and the circuit complexity and the number of power supply sources of the bridge amplifying circuit are simplified; and the isolation switch power supply can be utilized, the influence on the bridge excitation power supply is reduced, the loop current is avoided, and the measurement accuracy is improved. In addition, the invention also provides a bridge amplifying circuit which also has the beneficial effects.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a circuit diagram of a conventional bridge amplifier circuit;
fig. 2 is a schematic diagram of an amplifier power supply circuit of a balance bridge according to an embodiment of the present invention;
FIG. 3 is a schematic circuit diagram of an isolated switching power supply circuit of an amplifier power supply circuit of another balance bridge according to an embodiment of the present invention;
FIG. 4 is a schematic circuit diagram of a power polarity detection circuit of an amplifier power supply circuit of another balance bridge according to an embodiment of the present invention;
fig. 5 is a schematic circuit diagram of a linear voltage stabilizing circuit of an amplifier power supply circuit of another balance bridge according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 2, fig. 2 is a schematic diagram of an amplifier power supply circuit of a balance bridge according to an embodiment of the present invention. The amplifier supply circuit may include:
the isolation switch power supply circuit 10 is used for boosting the bridge excitation of the balance bridge by using the isolation switch power supply of the switch power supply circuit 10 to obtain boosting electric energy;
and the linear voltage stabilizing circuit 20, the input end of which is connected with the output end of the isolating switch power supply circuit 10, is used for linearly stabilizing the boosted electric energy to obtain the power supply electric energy of a preset number of groups and supplying power to the amplifier connected with the balance bridge by using the power supply electric energy.
It can be understood that if a linear voltage stabilization mode is directly adopted, the bridge is used for exciting and stabilizing voltage to supply to an amplifier power supply of a balance bridge, the bridge exciting power supply generally has only 8-12V (single-side power supply), the linear voltage stabilization loss is generally 1-3V, the voltage is lower after voltage stabilization, and the power supply requirement of the amplifier is not easily met; on the other hand, if the common ground is forcibly arranged at the middle point, the virtual ground is unstable once the current is unbalanced, and the working point of the amplifier circuit is influenced; and the amplifier often needs multiunit power supply, and the direct adoption linear voltage regulation often the power efficiency is extremely low. Therefore, in the embodiment, a mode of isolating switch power supply + linear voltage stabilization is adopted, the bridge is excited to pass through the isolating switch power supply to form the isolating power supply required by the amplifier of the balance bridge, and then the isolating power supply is linearly supplied to the amplifier in a voltage stabilization manner, at the moment, the ground of the amplifier is floating, and no loop current is generated when the ground of the amplifier is grounded together with the bridge excitation power supply, so that the measurement accuracy is ensured.
Specifically, for the specific circuit structure of the isolation switch power supply circuit 10 in this embodiment, the specific circuit structure can be set by a designer according to a practical scenario and a user requirement, for example, because the noise of the isolation switch power supply is very large, the noise can be fed back to an input power supply (a bridge excitation power supply), and the measurement accuracy is reduced, so that the isolation switch power supply circuit 10 in this embodiment may include not only the isolation switch power supply but also a choke coil, so as to reduce the noise fed back to the bridge excitation power supply by using the choke coil; the current protection can be realized by using the choke coil, the volume of the system is reduced, and for example, the 1.5A instantaneous current and the 0.5A working current choke coil are used for protecting the input current of the system; as shown in fig. 3, the isolated switching power supply circuit 10 may include: a choke (L26); the grounding end (PGND) and the output end (D1) of the bridge excitation power supply are respectively connected with the first input end (1) and the second input end (2) of the choke coil, and the first output end (4) and the second output end (3) of the choke coil are respectively connected with the negative input end (-Vin) and the positive input end (+ Vin) of the isolation switch power supply (U7).
Further, the isolated switching power supply circuit 10 provided in this embodiment may further include a reverse feed-in blocking circuit, which is used to reduce the energy fed back to the bridge excitation power supply by the isolated switching power supply noise; as shown in fig. 3, the choke coil (L26), the first capacitor (C127), the second capacitor (C128) and the first electrolytic capacitor (C129) may form a filter circuit (i.e., a reverse feeding blocking circuit) to eliminate the feedback of the series mode noise of the isolated switching power supply (U7) to the two terminals (PGND and D1) of the bridge excitation power supply. That is to say, as shown in fig. 3, the isolated switching power supply circuit 10 provided in this embodiment may further include: a first capacitor (C127), a second capacitor (C128) and a first electrolytic capacitor (C129); wherein, the common end of the first output end (PGND) of the bridge excitation power supply and the first input end of the choke coil is connected with the first end of the first capacitor, the common end of the second output end (D1) of the bridge excitation power supply and the second input end of the choke coil is connected with the second end of the first capacitor; the first end of the second capacitor is connected with the first output end of the choke coil, the common end of the first end of the second capacitor and the first output end of the choke coil is connected with the cathode of the first electrolytic capacitor, and the cathode of the first electrolytic capacitor is connected with the negative input end of the isolating switch power supply; the second end of the second capacitor is connected with the second output end of the choke coil, the common end of the second capacitor and the second output end of the choke coil is connected with the anode of the first electrolytic capacitor, and the anode of the first electrolytic capacitor is connected with the positive input end of the isolating switch power supply.
Further, the isolation switch power supply circuit 10 provided in this embodiment may further include a virtual ground filtering circuit, configured to perform virtual ground filtering on the input of the isolation switch power supply, and common the virtual ground with a system ground through a magnetic bead, so as to reduce signal interference fed back to the bridge excitation power supply and reduce the influence of the switching power supply noise on the balance excitation power supply; that is to say, in this embodiment, the noise return channel of the isolation switch power supply can be realized by setting the virtual ground filter circuit, the virtual ground filter is adopted at the input end of the isolation switch power supply, and the virtual ground is grounded through the magnetic beads and the system ground, so that not only can the noise of the isolation switch power supply be returned to the power supply through the system power supply ground, and the interference fed back to the bridge excitation signal is reduced, but also a noise energy release channel is provided for the isolation power supply, and the influence of the noise on the balance excitation power supply is reduced; as shown in fig. 3, a filter circuit to the virtual ground common point (i.e., a virtual ground filter circuit) composed of the third capacitor (C122), the second electrolytic capacitor (C121), the fourth capacitor (C130) and the third electrolytic capacitor (C131) provides a noise return path for U7, so that the interference of noise to the bridge excitation power supply can be further reduced, and the power can be taken from the bridge excitation power supply.
That is to say, as shown in fig. 3, the isolated switching power supply circuit 10 provided in this embodiment may further include: a third capacitor (C122), a fourth capacitor (C130), a second electrolytic capacitor (C121) and a third electrolytic capacitor (C131); the first end of the third capacitor is connected with the cathode of the first electrolytic capacitor, the common end of the first end of the third capacitor, which is connected with the cathode of the first electrolytic capacitor, is connected with the cathode of the second electrolytic capacitor, and the cathode of the second electrolytic capacitor is connected with the negative input end of the isolating switch power supply; the first end of the fourth capacitor is connected with the anode of the first electrolytic capacitor, the common end of the first end of the fourth capacitor, which is connected with the anode of the first electrolytic capacitor, is connected with the anode of the third electrolytic capacitor, and the anode of the second electrolytic capacitor is connected with the positive input end of the isolating switch power supply; the second end of the third capacitor is connected with the second end of the fourth capacitor, the anode of the second electrolytic capacitor is connected with the cathode of the third electrolytic capacitor, the second end of the third capacitor is connected with the anode of the second electrolytic capacitor, and the common end of the second end of the third capacitor and the anode of the second electrolytic capacitor is connected to a System Ground (SGND); accordingly, as shown in fig. 3, the isolated switching power supply circuit 10 may further include: a first magnetic bead (L28); and the system ground connected with the second end of the third capacitor, the second end of the fourth capacitor, the anode of the second electrolytic capacitor and the cathode of the third electrolytic capacitor is Grounded (GND) through the first magnetic bead.
In addition, in the isolated switching power supply circuit 10 shown in fig. 3, the first capacitor (C127), the second capacitor (C128), the first electrolytic capacitor (C129), the choke coil (L26), the third capacitor (C122), the fourth capacitor (C130), the second electrolytic capacitor (C121), and the third electrolytic capacitor (C131) may jointly form an energy storage device, so as to realize a long-line starting function; when the long line is started, the bridge excitation power supply firstly charges the energy accumulator; when the voltage is higher than the starting voltage of the isolation switch power supply, the energy accumulator can release partial current after being charged, the starting current of the bridge excitation power supply is reduced, and the isolation switch power supply is assisted to start, so that the voltage drop of the bridge excitation power line is reduced, and long-line start is realized.
Specifically, the feedback noise of the isolation switch power supply is generally 30-50 millivolts, and if the power is directly taken, the equivalent noise of the amplifier input of 30-50 uV can be brought by calculating according to the voltage suppression ratio of 80 dB; by adopting the isolated switch power supply circuit 10 shown in fig. 3, the input equivalent noise of the amplifier can be less than 1uV, and the power-taking feedback noise is reduced by more than 95%.
Further, the amplifier power supply circuit provided in this embodiment may further include: the power polarity detection circuit is used for detecting the power polarity of a bridge excitation power supply connected to the power supply circuit of the amplifier to realize reverse connection protection; as shown in fig. 4, the power polarity detection circuit may include: a current limiting resistor (R91) and a diode (D3); the polarity detection of the power supply is realized by using a diode, when the bridge excitation power supply is correctly connected, VCC + is positive, and VCC-is negative voltage, the diode is cut off, and the current is almost 0; when the bridge excitation power supply is connected in error, the diode is conducted, and the input current of the bridge excitation power supply is controlled by the current limiting resistor. For example, the power polarity detection circuit may be disposed behind the choke, and as shown in fig. 3, the cathode of the diode of the power polarity detection circuit may be connected to the second output terminal (3) of the choke (L26), and the anode of the diode is connected to the first output terminal (4) of the choke through the current limiting resistor of the power polarity detection circuit; by the resistance value configuration of the current-limiting resistor, the input negative voltage can be very small, and the isolation switch power supply is protected from being damaged, so that reverse connection protection is realized.
It should be noted that, for the specific circuit configuration setting of the linear voltage stabilizing circuit 20 in this embodiment, the setting may be set by a designer according to a practical scenario and a user requirement, for example, the setting is performed according to the amount of power supply energy (i.e. a preset amount) required by the amplifier of the bridge, and if the preset amount is 2, as shown in fig. 5, the linear voltage stabilizing circuit 20 may include: the magnetic bead voltage stabilizing circuit comprises a second magnetic bead (L29), a first voltage stabilizing chip (U6), a second voltage stabilizing chip (U10), a third voltage stabilizing chip (U8), a fourth voltage stabilizing chip (U9), a first voltage dividing circuit (a voltage dividing circuit consisting of R146, R147 and R148) and a second voltage dividing circuit (a voltage dividing circuit consisting of R149, R150 and R151); the ground terminal (GND) of the isolating switch power supply is connected to an Analog Ground (AGND) through the second magnetic bead, the positive output terminal (+ 18V) of the isolating switch power supply is connected with the input terminal (VIN) of the first voltage stabilizing chip, and the negative output terminal (-18V) of the isolating switch power supply is connected with the input terminal (VOUT) of the second voltage stabilizing chip; the output end of the first voltage stabilizing chip is connected with the anode (+ V) of the third voltage stabilizing chip through a first voltage dividing circuit, and the output end of the second voltage stabilizing chip is connected with the cathode (-V) of the fourth voltage stabilizing chip through a second voltage dividing circuit; the grounding end of the first voltage stabilizing chip, the grounding end (GND) of the second voltage stabilizing chip, the cathode of the third voltage stabilizing chip and the anode of the fourth voltage stabilizing chip are all connected to the analog ground; the output end of the first voltage stabilizing chip is connected with the common end of the first voltage dividing circuit, the output end of the second voltage stabilizing chip is connected with the common end of the second voltage dividing circuit to output a group of power supply electric energy, and the anode of the third voltage stabilizing chip is connected with the common end of the first voltage dividing circuit and the cathode of the fourth voltage stabilizing chip is connected with the common end of the second voltage dividing circuit to output another group of power supply electric energy. That is, as shown in fig. 3 and 5, the ground inside the amplifier and the ground of the bridge excitation power supply are all connected in common by 100 ohm beads, the output of the switch power supply is isolated, and two sets of power supply energy (± 15V and ± 2.5V) are output to the amplifier after linear voltage stabilization through the first voltage stabilization chip (U6), the second voltage stabilization chip (U10), the third voltage stabilization chip (U8) and the fourth voltage stabilization chip (U9) for use by the amplifier.
Specifically, the first voltage dividing circuit and the second voltage dividing circuit may each be a voltage dividing circuit formed by connecting three resistors in parallel, as shown in fig. 5, the first voltage dividing circuit may be a voltage dividing circuit formed by connecting a first resistor (R146), a second resistor (R147) and a third resistor (R148) in parallel, and the second voltage dividing circuit may be a voltage dividing circuit formed by connecting a fourth resistor (R149), a fifth resistor (R150) and a sixth resistor (R151) in parallel; the first voltage dividing circuit and the second voltage dividing circuit may be a voltage dividing circuit formed by connecting two resistors in parallel or a voltage dividing circuit formed by connecting more resistors in parallel, which is not limited in this embodiment.
Further, as shown in fig. 5, the linear voltage regulating circuit 20 provided in this embodiment may further include: the first inductor (L27), the second inductor (L30), the fifth capacitor (C134), the sixth capacitor (C139), the fourth electrolytic capacitor (C132) and the fifth electrolytic capacitor (C138) are used for improving the stability of the power supply electric energy output by the first voltage stabilizing chip (U6) and the second voltage stabilizing chip (U10); the positive output end of the isolating switch power supply is connected with the input end of the first voltage stabilizing chip through the first inductor, the common end of the first inductor connected with the input end of the first voltage stabilizing chip is connected with the first end of the fifth capacitor, and the common end of the first end of the fifth capacitor connected with the input end of the first voltage stabilizing chip is connected with the anode of the fourth electrolytic capacitor; the negative output end of the isolating switch power supply is connected with the input end of the second voltage stabilizing chip through a second inductor, the common end of the second inductor connected with the input end of the second voltage stabilizing chip is connected with the first end of a sixth capacitor, and the common end of the first end of the sixth capacitor connected with the input end of the second voltage stabilizing chip is connected with the cathode of a fifth electrolytic capacitor; the second end of the fifth capacitor, the second end of the sixth capacitor, the cathode of the fourth electrolytic capacitor and the anode of the fifth electrolytic capacitor are all connected to the analog ground.
Further, as shown in fig. 5, the linear voltage regulating circuit 20 provided in this embodiment may further include: a seventh capacitor (C126), an eighth capacitor (C137), a sixth electrolytic capacitor (C125) and a seventh electrolytic capacitor (C133) to improve the stability of the power supply energy output by the third voltage stabilization chip (U8) and the fourth voltage stabilization chip (U9)); the common end of the anode of the third voltage stabilizing chip, which is connected with the first voltage dividing circuit, is connected with the first end of the seventh capacitor, and the common end of the first end of the seventh capacitor, which is connected with the anode of the third voltage stabilizing chip, is connected with the anode of the sixth electrolytic capacitor; the common end of the cathode of the fourth voltage stabilizing chip, which is connected with the second voltage dividing circuit, is connected with the first end of the eighth capacitor, and the common end of the first end of the eighth capacitor, which is connected with the cathode of the fourth voltage stabilizing chip, is connected with the anode of the seventh electrolytic capacitor; the second end of the seventh capacitor, the second end of the eighth capacitor, the cathode of the sixth electrolytic capacitor and the anode of the seventh electrolytic capacitor are all connected to the analog ground.
In the embodiment of the invention, an isolation power supply and linear voltage stabilization mode is adopted, and the power is directly taken from the bridge excitation power supply to supply power to the amplifier of the balance bridge, so that the amplifier does not need external power supply, the power supply difficulty of the amplifier of the balance bridge is reduced, and the circuit complexity and the number of power supply sources of the bridge amplifying circuit are simplified; and the isolation switch power supply can be utilized, the influence on the bridge excitation power supply is reduced, the loop current is avoided, and the measurement accuracy is improved.
Based on the above embodiments, the embodiments of the present invention further provide a bridge amplifying circuit, and a bridge amplifying circuit described below and an amplifier power supply circuit of a balance bridge described above can be referred to with each other.
The embodiment of the invention provides a bridge amplifying circuit, which comprises: a balance bridge, an amplifier connected to the balance bridge, and an amplifier supply circuit for the balance bridge as provided in the above embodiments.
The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The bridge amplifying circuit disclosed in the embodiment corresponds to the amplifier power supply circuit of the balance bridge disclosed in the embodiment, so that the description is relatively simple, and the relevant points can be referred to the description of the amplifier power supply circuit part.
The amplifier power supply circuit and the amplifier circuit of the balance bridge provided by the invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, it is possible to make various improvements and modifications to the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (9)
1. An amplifier supply circuit for a balance bridge, comprising:
the isolation switch power supply circuit is used for boosting the bridge excitation of the balance bridge by utilizing the isolation switch power supply of the switch power supply circuit to obtain boosting electric energy;
the input end of the linear voltage stabilizing circuit is connected with the output end of the isolating switch power supply circuit and is used for linearly stabilizing the boosted electric energy to obtain a preset number of groups of power supply electric energy and supplying power to the amplifier connected with the balance bridge by using the power supply electric energy;
wherein, the isolation switch power supply circuit includes: a choke coil;
the ground end and the output end of the bridge excitation power supply are respectively connected with the first input end and the second input end of the choke coil, and the first output end and the second output end of the choke coil are respectively connected with the negative input end and the positive input end of the isolating switch power supply.
2. The amplifier supply circuit of a balance bridge according to claim 1, wherein the isolated switching power supply circuit further comprises: a first capacitor, a second capacitor and a first electrolytic capacitor;
wherein, the common end of the first output end of the bridge excitation power supply and the first input end of the choke coil is connected with the first end of the first capacitor, and the common end of the second output end of the bridge excitation power supply and the second input end of the choke coil is connected with the second end of the first capacitor; the first end of the second capacitor is connected with the first output end of the choke coil, the common end of the first end of the second capacitor and the first output end of the choke coil is connected with the cathode of the first electrolytic capacitor, and the cathode of the first electrolytic capacitor is connected with the negative input end of the isolating switch power supply; the second end of the second capacitor is connected with the second output end of the choke coil, the common end of the second capacitor and the second output end of the choke coil is connected with the anode of the first electrolytic capacitor, and the anode of the first electrolytic capacitor is connected with the positive input end of the isolating switch power supply.
3. The amplifier supply circuit of the balance bridge according to claim 2, wherein the isolated switching power supply circuit further comprises: a third capacitor, a fourth capacitor, a second electrolytic capacitor, a third electrolytic capacitor and first magnetic beads;
the first end of the third capacitor is connected with the cathode of the first electrolytic capacitor, the common end of the first end of the third capacitor and the cathode of the first electrolytic capacitor is connected with the cathode of the second electrolytic capacitor, and the cathode of the second electrolytic capacitor is connected with the negative input end of the isolating switch power supply; the first end of the fourth capacitor is connected with the anode of the first electrolytic capacitor, the common end of the first end of the fourth capacitor, which is connected with the anode of the first electrolytic capacitor, is connected with the anode of the third electrolytic capacitor, and the anode of the second electrolytic capacitor is connected with the positive input end of the isolating switch power supply; the second end of the third capacitor is connected with the second end of the fourth capacitor, the anode of the second electrolytic capacitor is connected with the cathode of the third electrolytic capacitor, the second end of the third capacitor is connected with the anode of the second electrolytic capacitor, and the common end of the second end of the third capacitor and the anode of the second electrolytic capacitor is connected to a system ground which is grounded through the first magnetic bead.
4. The amplifier supply circuit of a balance bridge according to claim 1, further comprising: a power supply polarity detection circuit;
the power polarity detection circuit comprises a current-limiting resistor and a diode; the cathode of the diode is connected with the second output end of the choke coil, and the anode of the diode is connected with the first output end of the choke coil through the current limiting resistor.
5. The amplifier supply circuit of the balance bridge according to any one of claims 1 to 4, wherein when the preset number is 2, the linear voltage regulating circuit comprises: the device comprises a second magnetic bead, a first voltage stabilizing chip, a second voltage stabilizing chip, a third voltage stabilizing chip, a fourth voltage stabilizing chip, a first voltage dividing circuit and a second voltage dividing circuit;
the grounding end of the isolating switch power supply is connected to an analog ground through the second magnetic bead, the positive output end of the isolating switch power supply is connected with the input end of the first voltage stabilizing chip, and the negative output end of the isolating switch power supply is connected with the input end of the second voltage stabilizing chip; the output end of the first voltage stabilizing chip is connected with the anode of the third voltage stabilizing chip through the first voltage dividing circuit, and the output end of the second voltage stabilizing chip is connected with the cathode of the fourth voltage stabilizing chip through the second voltage dividing circuit; the grounding end of the first voltage stabilizing chip, the grounding end of the second voltage stabilizing chip, the cathode of the third voltage stabilizing chip and the anode of the fourth voltage stabilizing chip are all connected to an analog ground; the output end of the first voltage stabilizing chip and the common end connected with the first voltage dividing circuit, the output end of the second voltage stabilizing chip and the common end connected with the second voltage dividing circuit output a group of power supply electric energy, and the anode of the third voltage stabilizing chip and the common end connected with the first voltage dividing circuit, and the cathode of the fourth voltage stabilizing chip and the common end connected with the second voltage dividing circuit output another group of power supply electric energy.
6. The amplifier supply circuit of a balance bridge according to claim 5, wherein the linear voltage regulating circuit further comprises: the first inductor, the second inductor, the fifth capacitor, the sixth capacitor, the fourth electrolytic capacitor and the fifth electrolytic capacitor;
the positive output end of the isolating switch power supply is connected with the input end of the first voltage stabilizing chip through the first inductor, the common end of the first inductor connected with the input end of the first voltage stabilizing chip is connected with the first end of the fifth capacitor, and the common end of the first end of the fifth capacitor connected with the input end of the first voltage stabilizing chip is connected with the anode of the fourth electrolytic capacitor; the negative output end of the isolating switch power supply is connected with the input end of the second voltage stabilizing chip through the second inductor, the common end of the second inductor connected with the input end of the second voltage stabilizing chip is connected with the first end of the sixth capacitor, and the common end of the first end of the sixth capacitor connected with the input end of the second voltage stabilizing chip is connected with the cathode of the fifth electrolytic capacitor; and the second end of the fifth capacitor, the second end of the sixth capacitor, the cathode of the fourth electrolytic capacitor and the anode of the fifth electrolytic capacitor are all connected to a simulated ground.
7. The amplifier supply circuit of a balance bridge according to claim 6, wherein the linear voltage regulating circuit further comprises: a seventh capacitor, an eighth capacitor, a sixth electrolytic capacitor and a seventh electrolytic capacitor;
the common end of the anode of the third voltage stabilizing chip connected with the first voltage dividing circuit is connected with the first end of the seventh capacitor, and the common end of the first end of the seventh capacitor connected with the anode of the third voltage stabilizing chip is connected with the anode of the sixth electrolytic capacitor; a common end of the cathode of the fourth voltage stabilizing chip, which is connected with the second voltage dividing circuit, is connected with a first end of the eighth capacitor, and a common end of the first end of the eighth capacitor, which is connected with the cathode of the fourth voltage stabilizing chip, is connected with an anode of the seventh electrolytic capacitor; and the second end of the seventh capacitor, the second end of the eighth capacitor, the cathode of the sixth electrolytic capacitor and the anode of the seventh electrolytic capacitor are all connected to a simulated ground.
8. The amplifier supply circuit according to claim 5, wherein the first voltage divider circuit and the second voltage divider circuit are voltage divider circuits with three resistors connected in parallel.
9. A bridge amplifier circuit, comprising: a balance bridge, an amplifier connected to the balance bridge and an amplifier supply circuit of a balance bridge according to any of claims 1 to 8.
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| JP5223874B2 (en) * | 2010-03-09 | 2013-06-26 | 株式会社村田製作所 | Isolated switching power supply |
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| CN110333002A (en) * | 2019-06-24 | 2019-10-15 | 青岛航天半导体研究所有限公司 | Platinum resistance temperature sensor isolating amplifier circuit and adjustment method |
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