Voltage-stabilizing power supply circuit of flow meter

Abstract

The utility model relates to the technical field of flow meters, in particular to a voltage-stabilizing power supply circuit of a flow meter, which comprises a filter circuit, a voltage-stabilizing chip circuit, a voltage regulating circuit, a current regulating circuit and a load, wherein the filter circuit is used for carrying out noise filtering on the direct-current voltage source; the voltage stabilizing chip circuit provides reference voltage values of power supply voltage and power supply current of a load; the voltage regulating circuit obtains the power supply voltage of the load according to the reference voltage value of the voltage stabilizing chip circuit; and the current adjusting circuit obtains the power supply current of the load according to the reference voltage value of the voltage stabilizing chip circuit. The compatible voltage-stabilizing power supply circuit is designed, the current and the voltage input into the flowmeter can be adjusted according to the type of the flowmeter by adjusting different adjustable resistors, and the compatibility is high.

Description

Technical Field

[0001] The utility model relates to the technical field of flow meters, in particular to a voltage-stabilizing power supply circuit of a flow meter. Background Art

[0002] Various types of flow meters are usually used in water treatment equipment to monitor the operation of the water treatment equipment.

[0003] Flow meters can be used for water quality monitoring, control, metering and billing according to their functions. The stability of the flow meter's power supply plays a vital role in its service life.

[0004] In addition, due to the wide variety of flow meters, there are large differences in the input voltage and current of different flow meters. The existing flow meter power supplies are usually adapted by design. When there are too many power supplies, it causes waste of resources and poor power supply compatibility.

[0005] The power supply circuit and flow meter with publication number CN219086835U provide a flow meter power supply circuit, the output voltage of which is constant at 3.3V and is not adjustable, and the output current is also not adjustable. Utility Model Content

[0006] In order to overcome the problems existing in the prior art, the utility model designs a voltage-stabilizing power supply circuit with compatibility. By adjusting the adjustable resistor, the current and voltage input to the flow meter can be adjusted according to the model of the flow meter, and the compatibility is strong.

[0007] The technical solution adopted by the utility model is as follows: a voltage-stabilized power supply circuit of a flow meter, comprising: a filter circuit, a voltage-stabilized chip circuit, a voltage regulating circuit, a current regulating circuit and a load; wherein,

[0008] The filter circuit is used to filter the noise of the DC voltage source;

[0009] The voltage stabilizing chip circuit provides a reference voltage value for the load supply voltage and supply current;

[0010] The voltage regulating circuit obtains the supply voltage of the load according to the reference voltage value of the voltage stabilizing chip circuit;

[0011] The current regulating circuit obtains the supply current of the load according to the reference voltage value of the voltage stabilizing chip circuit.

[0012] As a preferred implementation manner of the utility model, it also includes a ripple current control circuit, and the ripple current control circuit is used to adjust the ripple current.

[0013] As a preferred implementation of the present utility model, the filter circuit includes a capacitor C1.

[0014] As a preferred embodiment of the utility model, the voltage stabilizing chip circuit includes: a voltage stabilizing chip U1, a resistor R1, a resistor R4, a diode D1 and a capacitor C2, the resistor R1 is connected in parallel between pins 1 and 2 of U1, the pin 2 of the voltage stabilizing chip U1 is also connected in series with the resistor R4 and the diode D1, and the pin 2 of the voltage stabilizing chip U1 is also connected to the capacitor C2.

[0015] As a preferred embodiment of the utility model, the voltage regulating circuit includes: resistors R2 and R3, pin 3 of the voltage stabilizing chip U1 is connected to one end of the resistors R2 and R3 respectively, and the other end of R3 is connected to the positive electrode of the diode D1.

[0016] As a preferred embodiment of the utility model, the current regulating circuit includes: a resistor R5, one end of which is connected to pin 4 of U1, and the other end is connected to pin 5 of the voltage regulator chip U1 and the lower end of the resistor R2.

[0017] As a preferred embodiment of the utility model, the ripple current control circuit includes: an inductor L1, a capacitor C3, and a diode D2, one end of L1 is connected to R5 and pin 5 of U1 and the lower end of R2 respectively, the other end of L1 is connected to C3, the lower end of C3 is connected to the positive electrode of D2, and the negative electrode of D2 is connected to pin 5 of U1; the other end of L1 is also connected to the positive electrode of D1 and the lower end of R3.

[0018] As a preferred implementation of the present utility model, the model of the voltage regulator chip U1 is AP5216.

[0019] Beneficial effects of the utility model:

[0020] 1. By adjusting the resistance of variable resistors R2 and R3, the output voltage can be adjusted;

[0021] 2. By adjusting the resistance of the variable resistor R5, the output voltage can be adjusted;

[0022] 3. Adjust the output ripple current by adjusting the resistance of the variable inductor L1;

[0023] 4. By adjusting the resistance of the variable resistor R3, the line loss of the load is compensated;

[0024] 5. The voltage-stabilized power supply circuit of the flow meter has a simple structure and strong compatibility, and can be adjusted according to the model of the flow meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a logic block diagram of the voltage-stabilized power supply circuit of the flow meter of the utility model;

[0026] Figure 2 This is a detailed circuit diagram of the voltage-stabilized power supply of the flow meter of the utility model. DETAILED DESCRIPTION

[0027] The utility model is now described in further detail with reference to the accompanying drawings.

[0028] like Figure 1 A voltage-stabilizing power supply circuit for a flow meter includes: a filter circuit, a voltage-stabilizing chip circuit, a voltage regulating circuit, a current regulating circuit, a ripple current control circuit and a load; wherein the output end of the filter circuit is connected to the input end of the voltage-stabilizing chip circuit, the output ends of the current regulating circuit and the voltage regulating circuit are connected to the input end of the voltage-stabilizing chip circuit, the output end of the voltage-stabilizing chip circuit is connected to the input end of the ripple current control circuit, and the ripple current control circuit is connected to the load;

[0029] The input end of the filter circuit is a DC voltage source, which includes a battery pack, a photovoltaic panel or an AC voltage source. When the input is an AC voltage source, an AC-DC conversion module is required, such as 220V AC to 48V DC; the filter circuit is used to filter the noise of the DC voltage source; there are often electromagnetic interference sources in water treatment equipment, and there are usually pulse signals in the electromagnetic interference. The pulse signals will affect the service life of the voltage stabilizing chip circuit, so the DC input voltage of the voltage stabilizing chip circuit is stabilized through the filter circuit.

[0030] The voltage stabilizing chip circuit is used to provide a reference voltage value for the load's supply voltage and supply current;

[0031] The voltage regulating circuit obtains the supply voltage of the load according to the reference voltage value of the voltage stabilizing chip circuit;

[0032] The current regulating circuit obtains the supply current of the load according to the reference voltage value of the voltage stabilizing chip circuit;

[0033] The ripple current control circuit is used to adjust the ripple current.

[0034] like Figure 2 As shown, the filter circuit includes: a polarized capacitor C1, the upper end of C1 is respectively connected to a DC voltage source and pin 1 of a voltage regulator chip U1.

[0035] The voltage stabilizing chip circuit includes: a voltage stabilizing chip U1, a resistor R1, a resistor R4, a diode D1 and a capacitor C2. Resistor R1 is connected in parallel between pins 1 and 2 of U1. Pin 2 of the voltage stabilizing chip U1 is also connected in series with resistors R4 and D1. Pin 2 of the voltage stabilizing chip U1 is also connected to capacitor C2.

[0036] The voltage regulating circuit includes: resistors R2 and R3. Pin 3 of the voltage stabilizing chip U1 is connected to one end of the resistors R2 and R3 respectively. The other end of the resistor R2 is grounded. The other end of the resistor R3 is connected to the positive electrode of the diode D1.

[0037] The current regulating circuit includes: a resistor R5, one end of which is connected to the 4th pin of U1.

[0038] The ripple current control circuit includes: an inductor L1, a capacitor C3, and a diode D2. One end of L1 is connected to R5 and pin 5 of U1 and the lower end of resistor R2 respectively, and the other end of L1 is connected to C3. The other end of L1 is also the output end of voltage Vout and current Iout. The lower end of C3 is connected to the positive electrode of diode D2, and the negative electrode of D2 is connected to pin 5 of U1; the other end of L1 is also connected to the positive electrode of D1 and the lower end of R3.

[0039] Capacitor C2 uses a low ESR capacitor to allow chip U1 to work in a low noise and low ripple environment. The capacitor can use an electrolytic capacitor; the low ESR capacitor will absorb the input switching current and requires a sufficient ripple current rating.

[0040] Inductor L1 is an adjustable power inductor, which is used to provide a constant current to the flow meter load. This process easily leads to an increase in the inductor ripple current, which can be reduced by increasing the inductance.

[0041] R6 is a dummy load resistor, which outputs a dummy load current of 3-6mA.

[0042] Models of each chip: The model of the voltage regulator chip U1 is AP5216, the diode D1 is 1N4001, and the diode D2 is SS310.

[0043] Working principle:

[0044] When the operating current of the voltage regulator chip U1 provided by the startup resistor R1 is designed to be within 4-8mA, the output feedback power supply resistors R4 and D1 can be omitted, and the operating current calculation formula is Idd = (Vin-5V) / R1; therefore, when you want to omit R4 and D1, the input voltage should not be in a wide voltage range.

[0045] The flowmeter as a load input current usually fluctuates within a certain range. For example, the operating current of a certain model of mass flowmeter is 0.5uA±0.05uA, and the operating voltage range is: 5V±0.1V; the maximum output current Iout of the voltage-stabilized power supply circuit can be adjusted by adjusting the variable resistor R5 between the CS pin and the VSS pin of U1. In order to make the output overcurrent Ics setting more accurate, the variable resistor R5 is selected to have an adjustment accuracy of 1%. The formula for the output current value Iout is:

[0046] Iout=Vcs / R5

[0047] The current sampling reference Vcs of the U1 chip is 200mV. When the maximum input current of the flow meter is limited to 0.5A, the adjustable resistor R5 is set to 400mΩ, and the current value can be controlled according to the change of the resistance value of the adjustable resistor R5.

[0048] R3 is the pull-up sampling resistor, R2 is the pull-down sampling resistor, and both R2 and R3 are adjustable resistors. The output voltage is set by adjusting R2 connected to the VFB pin of chip U1. The adjustment accuracy of R2 is 1%, and the formula for the output voltage value is:

[0049] Vout=(R3 / R2+1)*(VFB-Iout*R3).

[0050] Among them, R3 is a pull-up sampling resistor, R2 is a pull-down sampling resistor, and the voltage sampling reference VFB of the chip U1 is 1.2V; when R3=100KΩ, R2=30KΩ, Iout=0.5uA, the output voltage=4.98V.

[0051] The U1 chip is designed with an output line loss compensation function. If the voltage loss between the power supply and the flow meter load is very small, the pull-up resistor R3 can be set to a resistance value below 100KΩ; if there is a relatively long line from the power supply to the flow meter load, there will be a line loss voltage. The pull-up resistor R3 can be set to a resistance value above 100KΩ to effectively compensate for the line loss voltage of the output long line. For example, the line loss compensation function needs to adjust the pull-up resistor R3 according to the actual application.

[0052] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A voltage-stabilized power supply circuit for a flow meter, characterized in that: It includes a filter circuit, a voltage stabilizing chip circuit, a voltage regulating circuit, a current regulating circuit and a load; wherein, The filter circuit is used to filter the noise of the DC voltage source; The voltage stabilizing chip circuit provides a reference voltage value for the load supply voltage and supply current; The voltage regulating circuit is used to regulate the supply voltage of the load; The current regulation circuit is used to regulate the supply current of the load.

2. The voltage-stabilized power supply circuit of the flow meter according to claim 1, characterized in that: The filter circuit includes a capacitor C1.

3. The voltage-stabilized power supply circuit of the flow meter according to claim 2, characterized in that: The voltage stabilizing chip circuit includes: a voltage stabilizing chip U1, a resistor R1, a resistor R4, a diode D1 and a capacitor C2. Resistor R1 is connected in parallel between pins 1 and 2 of U1. Pin 2 of the voltage stabilizing chip U1 is also connected in series with resistor R4 and diode D1. Pin 2 of the voltage stabilizing chip U1 is also connected to capacitor C2.

4. The voltage-stabilized power supply circuit of the flow meter according to claim 3, characterized in that: The voltage regulating circuit includes: a resistor R2 and a resistor R3. Pin 3 of the voltage stabilizing chip U1 is connected to one end of the resistor R2 and one end of the resistor R3 respectively, and the other end of R3 is connected to the positive electrode of the diode D1.

5. The voltage-stabilized power supply circuit of the flow meter according to claim 4, characterized in that: The voltage regulating circuit includes: the current regulating circuit includes: a resistor R5, one end of R5 is connected to the 4th pin of U1, and the other end is connected to the pin 5 of the voltage stabilizing chip U1 and the lower end of the resistor R2.

6. The voltage-stabilized power supply circuit of the flow meter according to claim 1, characterized in that: The invention also comprises a ripple current control circuit, and the ripple current control circuit is used for adjusting the ripple current.

7. The voltage-stabilized power supply circuit of the flow meter according to claim 6, characterized in that: The ripple current control circuit includes: an inductor L1, a capacitor C3, and a diode D2. One end of the inductor L1 is connected to the resistor R5 and the pin 5 of the inductor U1 and the lower end of the resistor R2 respectively. The other end of L1 is connected to C3. The lower end of C3 is connected to the positive electrode of the diode D2. The negative electrode of D2 is connected to the pin 5 of the voltage regulator chip U1. The other end of the inductor L1 is also connected to the positive electrode of the diode D1 and the lower end of R3.

8. The voltage-stabilized power supply circuit of the flow meter according to claim 3, characterized in that: The model of the voltage regulator chip U1 is AP5216.

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