Current output circuit of ultrasonic liquid level sensor

Abstract

The utility model discloses a current output circuit of an ultrasonic liquid level sensor, which comprises a power supply, a reference current source, a distributed current mirror network, a dynamic current sharing control module and an output stage and load interface, the reference current source, the distributed current mirror network, the dynamic current-sharing control module and the output stage and load interface are all electrically connected with the power supply, the distributed current mirror network is electrically connected with the reference current source and the dynamic current-sharing control module, and the dynamic current-sharing control module is electrically connected with the output stage and load interface. According to the utility model, the reference current, the distributed current mirror image network and the dynamic current sharing control module are matched, so that the output current can be uniformly and effectively shunted through the combination of rough adjustment current sharing and forced current sharing, and the condition that the stable use of the ultrasonic liquid level sensor is influenced by deviation from a set value due to non-uniform current shunting is reduced; the use stability is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to ultrasonic liquid level sensor technical field especially relates to a current output circuit of ultrasonic liquid level sensor. BACKGROUND

[0002] The current output circuit of ultrasonic liquid level sensor is used to provide stable current output, protect equipment from damage, the current output circuit in the prior art is greatly influenced by load difference in the use process, when multiple outputs share the same current source, the load impedance difference of each channel can lead to uneven current distribution, when the load of certain channel suddenly drops, other channels can deviate from the set value due to current shunting, thereby affecting the stable use of ultrasonic liquid level sensor, cannot satisfy the use demand, for this, the present application proposes a current output circuit of ultrasonic liquid level sensor. UTILITY MODEL CONTENT

[0003] The utility model discloses a current output circuit of ultrasonic liquid level sensor to solve the shortcoming in prior art.

[0004] In order to realize the above-mentioned purpose, the utility model discloses a technical scheme as follows:

[0005] A current output circuit of ultrasonic liquid level sensor, including power, reference current source, distributed current mirror network, dynamic current sharing control module and output stage and load interface, reference current source, distributed current mirror network, dynamic current sharing control module and output stage and load interface all are connected with power electrically, and distributed current mirror network is connected with reference current source and dynamic current sharing control module electrically, and dynamic current sharing control module and output stage and load interface are connected electrically.

[0006] Preferably, the reference current source includes an operational amplifier U1, one end of the resistor R1 is electrically connected to the pin 1 of the operational amplifier U1, one end of the resistor R2 is electrically connected to the pin 2 of the operational amplifier U1, the other end of the resistor R2 is electrically connected to one end of the thermistor R3 and the anode of the diode D1, the cathode of the diode D1 is electrically connected to one end of the capacitor C1 and one end of the resistor R4, the other end of the capacitor C1 is electrically connected to the other end of the thermistor R3, the pin 3 of the operational amplifier U1 is electrically connected to the pin 1 of the MOSFET transistor, and the pin 2 of the MOSFET transistor is electrically connected to the other end of the resistor R4.

[0007] Preferably, the distributed current mirror network comprises a triode Q1 and a triode Q2, one end of a resistor R5 is electrically connected to the collector of the triode Q1, one end of a resistor R6 and one end of a resistor R7 are electrically connected to the base of the triode Q1, the other end of the resistor R6 is electrically connected to the other end of the resistor R5, the other end of the resistor R7 is electrically connected to one end of a capacitor C2, the other end of the capacitor C2 is electrically connected to the emitter of the triode Q2, the base of the triode Q2 is electrically connected to the anode of a diode D1, the cathode of the diode D1 is electrically connected to the emitter of the triode Q1, one end of a resistor R8 is electrically connected to the emitter of the triode Q1, the other end of the resistor R8 is electrically connected to the collector of the triode Q2, one end of a resistor R9 is electrically connected to the collector of the triode Q2, the other end of the resistor R8 and the other end of the resistor R9 are electrically connected, and the collector of the triode Q1 and the one end of the resistor R5 are electrically connected to pin 3 of the MOSFET transistor.

[0008] Preferably, the dynamic current sharing control module comprises a chip U2, one end of a resistor R10 is electrically connected to pin 1 and pin 2 of the chip U2, pin 3, pin 4 and pin 5 of the chip U2 are grounded, one end of a resistor R11 is electrically connected to pin 7 of the chip U2, the other end of the resistor R11 is electrically connected to pin 6 of the chip U2, the anode of a diode D2 is electrically connected to pin 8 of the chip U2, the cathode of the diode D2 is electrically connected to pin 2 of the MOSFET transistor, one end of a capacitor C3 is electrically connected to pin 1 of the MOSFET transistor, the other end of the capacitor C3 is electrically connected to the other end of the resistor R11, the other end of the resistor R10 is electrically connected to the other end of the resistor R9, pin 3 of the MOSFET transistor and an output stage are electrically connected to a load interface.

[0009] Preferably, the model of the operational amplifier U1 is OPA2188.

[0010] Preferably, the output stage and the load interface are used for driving the load and isolating external interference.

[0011] Preferably, the chip U2 is used for collecting currents of channels, and the resistor R10 and the resistor R11 are sampling resistors.

[0012] Compared with the prior art, the utility model has the advantages of:

[0013] The utility model discloses a reference current, distributed current mirror network and dynamic current sharing control module cooperate with each other, can be combined to the current of output even effective shunt through coarse adjustment current sharing and forced current sharing, reduces the situation that the stable use of ultrasonic liquid level sensor is influenced because the current shunt is uneven and deviates from the set value, improves the use stability. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A block diagram of a current output circuit of an ultrasonic liquid level sensor is provided in the utility model;

[0015] Figure 2 A circuit diagram of a reference current source in the current output circuit of the ultrasonic liquid level sensor is provided in the utility model;

[0016] Figure 3 A circuit diagram of a distributed current mirror network in the current output circuit of the ultrasonic liquid level sensor is provided in the utility model;

[0017] Figure 4 A circuit diagram of a dynamic current equalization control module in the current output circuit of the ultrasonic liquid level sensor is provided in the utility model. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the utility model will be apparently and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments.

[0019] Referring to Figures 1-4 A current output circuit of an ultrasonic liquid level sensor, comprising a power supply, a reference current source, a distributed current mirror network, a dynamic current equalization control module, and an output stage and a load interface, the reference current source, the distributed current mirror network, the dynamic current equalization control module, and the output stage and the load interface are electrically connected with the power supply, the distributed current mirror network is electrically connected with the reference current source and the dynamic current equalization control module, the dynamic current equalization control module and the output stage and the load interface are electrically connected, wherein the output stage and the load interface are used for driving the load and isolating external interference;

[0020] The reference current source comprises an operational amplifier U1, wherein the model number of the operational amplifier U1 is OPA2188, one end of a resistor R1 is electrically connected with pin 1 of the operational amplifier U1, one end of a resistor R2 is electrically connected with pin 2 of the operational amplifier U1, the other end of the resistor R2 is electrically connected with one end of a thermistor R3 and the anode of a diode D1, the cathode of the diode D1 is electrically connected with one end of a capacitor C1 and one end of a resistor R4, the other end of the capacitor C1 is electrically connected with the other end of the thermistor R3, pin 3 of the operational amplifier U1 is electrically connected with pin 1 of a MOSFET transistor, pin 2 of the MOSFET transistor is electrically connected with the other end of the resistor R4;

[0021] The distributed current mirror network comprises a triode Q1 and a triode Q2, one end of a resistor R5 is electrically connected to the collector of the triode Q1, one end of a resistor R6 and one end of a resistor R7 are electrically connected to the base of the triode Q1, the other end of the resistor R6 is electrically connected to the other end of the resistor R5, one end of a capacitor C2 is electrically connected to the other end of the resistor R7, the other end of the capacitor C2 is electrically connected to the emitter of the triode Q2, the positive electrode of a diode D1 is electrically connected to the base of the triode Q2, the negative electrode of the diode D1 is electrically connected to the emitter of the triode Q1, one end of a resistor R8 is electrically connected to the emitter of the triode Q1, the other end of the resistor R8 is electrically connected to the collector of the triode Q2, one end of a resistor R9 is electrically connected to the collector of the triode Q2, the other end of the resistor R8 is electrically connected to one end of the resistor R9, the collector of the triode Q1 and one end of the resistor R5 are both electrically connected to pin 3 of the MOSFET transistor;

[0022] The dynamic current sharing control module comprises a chip U2, one end of a resistor R10 is electrically connected to pin 1 and pin 2 of the chip U2, pin 3, pin 4 and pin 5 of the chip U2 are grounded, one end of a resistor R11 is electrically connected to pin 7 of the chip U2, the other end of the resistor R11 is electrically connected to pin 6 of the chip U2, the positive electrode of a diode D2 is electrically connected to pin 8 of the chip U2, the negative electrode of the diode D2 is electrically connected to pin 2 of the MOSFET transistor, one end of a capacitor C3 is electrically connected to pin 1 of the MOSFET transistor, the other end of the capacitor C3 is electrically connected to the other end of the resistor R11, the other end of the resistor R10 is electrically connected to the other end of the resistor R9, pin 3 of the MOSFET transistor and an output stage are electrically connected to a load interface, wherein the chip U2 is used for collecting currents of channels, the resistor R10 and the resistor R11 are both sampling resistors; the reference current, the distributed current mirror network and the dynamic current sharing control module are matched, the output current can be uniformly and effectively shared by combining coarse adjustment current sharing and forced current sharing, the situation that the ultrasonic liquid level sensor deviates from the set value due to uneven current sharing and affects stable use is reduced, and the use stability is improved.

[0023] Working principle: when using, the resistance R2 and thermistor R3 in the reference current source are connected in series to form a voltage dividing network, and the output voltage is reduced through the diode D1 and injected into the MOSFET transistor through the resistance R4 when the temperature rises, the MOSFET transistor dynamically adjusts the voltage at the voltage dividing point, the pin 3 of the operational amplifier U1 receives the reference voltage output by the voltage dividing network, and outputs a stable reference current, the transistor Q1 and the transistor Q2 constitute a mirror current source, and the reference current is copied to each channel, the collector of the transistor Q2 converts the mirror current into a voltage signal through the resistance R9, controls the on-off state of the MOSFET transistor, realizes coarse adjustment of current sharing, the chip U2 in the dynamic current sharing control module monitors the current of each channel in real time, calculates the error, dynamically adjusts the on-resistance of the MOSFET transistor, and realizes forced current sharing, the current after current sharing is output to the load interface through the output stage for driving the load, so as to realize the purpose of uniform current distribution, and reduce the influence of uneven current distribution on the stable use of the ultrasonic liquid level sensor.

[0024] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A current output circuit for an ultrasonic liquid level sensor, characterized by, The power supply, the reference current source, the distributed current mirror network, the dynamic current sharing control module and the output stage and load interface are electrically connected, the distributed current mirror network is electrically connected with the reference current source and the dynamic current sharing control module, and the dynamic current sharing control module and the output stage and load interface are electrically connected.

2. A current output circuit for an ultrasonic liquid level sensor according to claim 1, wherein The reference current source comprises an operational amplifier U1, one end of a resistor R1 is electrically connected to a pin 1 of the operational amplifier U1, one end of a resistor R2 is electrically connected to a pin 2 of the operational amplifier U1, the other end of the resistor R2 is electrically connected to one end of a thermistor R3 and a positive electrode of a diode D1, a negative electrode of the diode D1 is electrically connected to one end of a capacitor C1 and one end of a resistor R4, the other end of the capacitor C1 is electrically connected to the other end of the thermistor R3, a pin 3 of the operational amplifier U1 is electrically connected to a pin 1 of a MOSFET transistor, and a pin 2 of the MOSFET transistor is electrically connected to the other end of the resistor R4.

3. A current output circuit for an ultrasonic liquid level sensor according to claim 2, wherein The distributed current mirror network comprises a triode Q1 and a triode Q2, one end of a resistor R5 is electrically connected to a collector of the triode Q1, one end of a resistor R6 and one end of a resistor R7 are electrically connected to a base of the triode Q1, the other end of the resistor R6 is electrically connected to the other end of the resistor R5, one end of a capacitor C2 is electrically connected to the other end of the resistor R7, the other end of the capacitor C2 is electrically connected to an emitter of the triode Q2, a positive electrode of the diode D1 is electrically connected to a base of the triode Q2, a negative electrode of the diode D1 is electrically connected to an emitter of the triode Q1, one end of a resistor R8 is electrically connected to the emitter of the triode Q1, the other end of the resistor R8 is electrically connected to a collector of the triode Q2, one end of a resistor R9 is electrically connected to the collector of the triode Q2, the other end of the resistor R8 and the one end of the resistor R9 are electrically connected, and the collector of the triode Q1 and the one end of the resistor R5 are electrically connected to a pin 3 of the MOSFET transistor.

4. The current output circuit of an ultrasonic liquid level sensor according to claim 1, wherein, The dynamic current sharing control module comprises a chip U2, one end of a resistor R10 is electrically connected to a pin 1 and a pin 2 of the chip U2, pins 3, 4 and 5 of the chip U2 are grounded, one end of a resistor R11 is electrically connected to a pin 7 of the chip U2, the other end of the resistor R11 is electrically connected to a pin 6 of the chip U2, a positive electrode of a diode D2 is electrically connected to a pin 8 of the chip U2, a negative electrode of the diode D2 is electrically connected to a pin 2 of the MOSFET transistor, one end of a capacitor C3 is electrically connected to a pin 1 of the MOSFET transistor, the other end of the capacitor C3 is electrically connected to the other end of the resistor R11, the other end of the resistor R10 is electrically connected to the other end of the resistor R9, a pin 3 of the MOSFET transistor and an output stage and load interface are electrically connected.

5. The current output circuit of an ultrasonic liquid level sensor according to claim 2, wherein, The model of the operational amplifier U1 is OPA2188.

6. The current output circuit of an ultrasonic liquid level sensor according to claim 1, wherein, The output stage and load interface is used for driving a load and isolating external interference.

7. The current output circuit of an ultrasonic liquid level sensor according to claim 4, wherein The chip U2 is used for collecting currents of channels, and the resistor R10 and the resistor R11 are sampling resistors.

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