Three-wire direct-current water pump control circuit with FG signal feedback

Abstract

The utility model relates to the field of water pump control circuits, in particular to a three-wire direct-current water pump control circuit with FG signal feedback, which comprises a three-wire direct-current water pump, an FG end of the three-wire direct-current water pump outputs pulse signals corresponding to the rotating speed of the water pump; a control chip U1; the signal conditioning module comprises a diode D1 and a resistor R1, the anode of the diode D1 is directly connected to the FG end, and the cathode of the diode D1 is connected to the FG pin through the resistor R1; the power supply filtering module comprises a resistor R2, an inductor L1 and an inductor L2, one end of the resistor R2 is connected to the power supply VDD, the other end of the resistor R2 is connected to the FG pin, meanwhile, the DO pin is connected to the power supply VDD through the inductor L1, and the DOB pin is connected to the power supply VDD through the inductor L2. A diode D1 is directly connected with an FG end and is connected to an FG pin through a resistor R1, so that positive and negative voltage clamping of an FG signal is formed, the impact of abnormal voltage on a control chip U1 is prevented, and the stability of signal input is guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to water pump control circuit field especially a kind of three-wire direct current water pump control circuit with FG signal feedback. BACKGROUND

[0002] In the traditional ice maker water pump control scheme, the following technical means are usually adopted, but there are significant defects FG signal processing is insufficient: most circuits directly input water pump FG signal into control chip by resistance voltage division, but no protection is provided for possible negative pulse or voltage overshoot (such as motor reverse electromotive force) generated at FG end, resulting in damage to control chip or signal misjudgment.

[0003] Power interference leads to misoperation: power surge and high-frequency noise generated when water pump motor starts and stops are coupled to control chip through VDD line, triggering reset or false triggering of water shortage alarm.

[0004] Water shortage protection mechanism is single: existing schemes mostly use audible and visual alarm but keep power on, and water pump continuously idles in water shortage state, resulting in impeller wear or motor burnout. SUMMARY

[0005] To solve the above problems, the utility model provides a kind of three-wire direct current water pump control circuit with FG signal feedback, the anode of diode D1 is directly connected to FG end, the cathode is connected to FG pin through resistance R1, forms the positive and negative voltage clamping of FG signal, prevents the impact of abnormal voltage on control chip U1, guarantees the stability of signal input.

[0006] To achieve the above purpose, the utility model adopts the technical scheme that a kind of three-wire direct current water pump control circuit with FG signal feedback, comprising:

[0007] Three-wire direct current water pump, the FG end output of three-wire direct current water pump corresponds with the pulse signal of water pump speed;

[0008] Control chip U1 is provided with FG pin, DO pin, DOB pin and GND pin;

[0009] Signal conditioning module includes diode D1, resistance R1, wherein the anode of diode D1 is directly connected to the FG end, and the cathode of diode D1 is connected to FG pin through resistance R1;

[0010] Power filter module includes resistance R2, inductance L1, inductance L2, wherein one end of resistance R2 is connected to power supply VDD, the other end of resistance R2 is connected to FG pin, and DO pin is connected to power supply VDD through inductance L1, and DOB pin is connected to power supply VDD through inductance L2.

[0011] Further, the diode D1 is a transient suppression diode, and the reverse breakdown voltage is 1.2-1.5 times of the peak voltage of the FG end pulse signal; the resistance R1 is 50Ω-500Ω, for limiting the reverse current of the FG end.

[0012] Further, the resistance R2 is 2.2kΩ-10kΩ; the inductance L1 and the inductance L2 are both 22μH-100μH; the resistance R2, the inductance L1 and the inductance L2 jointly constitute a π type filter network, and the ripple voltage of the VDD end is suppressed to below 50mV.

[0013] The utility model has the advantages that:

[0014] 1. The anode of the diode D1 is directly connected with the FG end, and the cathode is connected with the FG pin through the resistance R1, forming the positive and negative voltage clamping of the FG signal, preventing the impact of abnormal voltage (such as the reverse electromotive force of the water pump) on the control chip U1, and guaranteeing the stability of signal input. Moreover, the FG end and the FG pin are electrically isolated through the series connection of D1 and R1, and the direct conduction of high-frequency noise to the control chip is blocked.

[0015] 2. The combination of the resistance R2 and the inductance L1 and L2 forms independent filter branches at the VDD power supply end and the DO / DOB pin respectively: R2 is connected in series between VDD and the FG pin, and the high-frequency fluctuation of the power bus is suppressed; the DO and DOB pins are connected to VDD through L1 and L2, and the switching noise of the driving signal loop is filtered by using the inductance characteristics.

[0016] 3. The DO and DOB pins of the control chip U1 are connected with VDD through the inductance L1 and L2, realizing the complementary signal output, and avoiding the power disturbance caused by the sudden change of the driving signal by using the transient current suppression effect of the inductance. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a kind of circuit diagram of three-wire DC water pump control circuit with FG signal feedback. DETAILED DESCRIPTION

[0018] Please refer to Figure 1 The utility model relates to a kind of three-wire DC water pump control circuit with FG signal feedback, comprising:

[0019] Three-wire DC water pump, the FG end output of three-wire DC water pump corresponds with the pulse signal of the speed of water pump rotation;

[0020] Control chip U1, with FG pin, DO pin, DOB pin and GND pin;

[0021] The signal conditioning module includes a diode D1 and a resistor R1, wherein the anode of the diode D1 is directly connected to the FG terminal, and the cathode of the diode D1 is connected to the FG pin through the resistor R1;

[0022] The power filter module includes a resistor R2, an inductor L1 and an inductor L2, wherein one end of the resistor R2 is connected to the power supply VDD, the other end of the resistor R2 is connected to the FG pin, the DO pin is connected to the power supply VDD through the inductor L1, and the DOB pin is connected to the power supply VDD through the inductor L2.

[0023] The FG terminal of the three-wire DC water pump can output a pulse signal corresponding to the speed, and the control chip U1 receives the pulse signal of the water pump through the FG pin and monitors the signal frequency in real time. When the detected frequency is lower than the preset threshold, the DO pin outputs a high-level alarm signal, and the DOB pin outputs a low-level to cut off the power supply of the water pump.

[0024] The diode D1 protects the circuit from transient overvoltage, and its reverse breakdown voltage is 1.2-1.5 times the peak voltage of the FG terminal pulse signal. The resistor R1 limits the reverse current to prevent circuit damage. The resistor R2 (2.2kΩ-10kΩ) and the inductors L1 and L2 (22μH-100μH) form a π-type filter network, which suppresses the ripple voltage at the power supply VDD terminal to below 50mV, ensuring the stable operation of the control chip.

[0025] The control chip monitors the pump speed in real time, and immediately alarms and cuts off the power supply when an abnormality is found, effectively preventing the fault from expanding. Moreover, the power filter module significantly reduces power supply noise, providing a stable working environment for the control chip and improving the stability and reliability of the overall circuit. The circuit structure is simple, standard electronic components and control chips are used, and it is easy to install, debug and troubleshoot. The circuit realizes precise monitoring of the water pump speed through the FG signal feedback mechanism, combined with efficient power filtering and signal conditioning design, ensuring stable operation and timely protection of the system, and has high practical value.

[0026] Further, the diode D1 is a transient suppression diode, and its reverse breakdown voltage is 1.2-1.5 times the peak voltage of the FG terminal pulse signal; the resistance value of the resistor R1 is 50Ω-500Ω, used to limit the reverse current of the FG terminal.

[0027] When an abnormal overvoltage occurs in the circuit, D1 quickly conducts, leading the overvoltage to ground, protecting the control chip U1 and other components from damage. Under normal pulse signals, D1 maintains high impedance and does not affect signal transmission, ensuring that the control chip U1 can accurately receive the pulse signal from the FG terminal.

[0028] When the circuit is abnormal, R1 limits the size of the reverse current, preventing the control chip U1 from being damaged by excessive current. In cooperation with D1, it ensures stable transmission of pulse signals to the control chip U1, while suppressing high-frequency noise and improving signal quality. D1 and R1 form a "voltage-current" double protection mechanism, D1 limits the voltage, and R1 limits the current, which together improves the anti-interference ability of the circuit and ensures the stability and reliability of the circuit. Standard electronic components such as transient suppression diodes and current-limiting resistors are used to balance performance and cost, ensuring the economy and practicality of the circuit.

[0029] Further, the resistance R2 has a resistance value of 2.2kΩ-10kΩ; the inductance L1 and the inductance L2 each have an inductance value of 22μH-100μH; the resistance R2, the inductance L1 and the inductance L2 together constitute a π-type filter network that suppresses the ripple voltage at the VDD terminal to below 50mV.

[0030] By reasonably selecting the parameters of the resistance R2 and the inductances L1 and L2, the π-type filter network can effectively filter signals within a certain frequency range, suppressing the ripple voltage at the VDD terminal to below 50mV. By filtering out low-frequency ripples and high-frequency noise in the DC power supply, a relatively pure DC voltage is output, improving the stability of the power supply. The π-type filter network can effectively filter out ripples and noise in the power supply, ensuring that the control chip U1 and other circuit components receive stable power supply.

[0031] The overall effect is that the control chip U1 can monitor the operating state of the water pump in real time, and immediately output an alarm signal once an abnormality or potential failure is detected, so that timely measures can be taken for repair or replacement. This real-time monitoring and alarm mechanism can significantly improve the reliability and safety of the water pump operation, reducing downtime and maintenance costs due to failures. When the water pump has abnormal speed or fails, the control chip U1 can automatically cut off the power supply to the water pump, preventing the failure from expanding or causing more serious consequences. Through real-time monitoring, alarm and protection mechanisms, the control chip U1 can ensure that the water pump works stably under normal operating conditions, while quickly protecting key components under abnormal conditions.

[0032] The above embodiments only describe the preferred embodiments of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by ordinary engineering and technical personnel in the field shall fall within the protection scope determined by the claims of the present application.

Claims

1. A three-wire DC water pump control circuit with FG signal feedback, characterized in that, The application relates to a three-wire direct-current water pump, a control chip U1, a signal conditioning module and a power filter module. The three-wire direct-current water pump comprises an FG end output corresponding to a pulse signal of water pump rotating speed; The control chip U1 is provided with an FG pin, a DO pin, a DOB pin and a GND pin; The signal conditioning module comprises a diode D1 and a resistor R1, wherein the anode of the diode D1 is directly connected to the FG end, and the cathode of the diode D1 is connected to the FG pin through the resistor R1; The power filter module comprises a resistor R2, an inductor L1 and an inductor L2, wherein one end of the resistor R2 is connected to a power supply VDD, the other end of the resistor R2 is connected to the FG pin, the DO pin is connected to the power supply VDD through the inductor L1, and the DOB pin is connected to the power supply VDD through the inductor L2.

2. The three-wire DC water pump control circuit with FG signal feedback according to claim 1, characterized in that: The diode D1 is a transient suppression diode, the reverse breakdown voltage of which is 1.2-1.5 times the peak voltage of the FG end pulse signal; and the resistance value of the resistor R1 is 50-500 ohms.

3. The three-wire DC water pump control circuit with FG signal feedback according to claim 1, characterized in that: The resistance value of the resistor R2 is 2.2-10 kohms; the inductance values of the inductor L1 and the inductor L2 are both 22-100 mu H; and the resistor R2, the inductor L1 and the inductor L2 jointly form a pi-type filter network, which suppresses the ripple voltage at the VDD end to below 50 mV.

Images