Rendering demonstration of solenoid valve PWM drive circuit_Basic hardware circuit diagram explanation

Circuit diagram:

Circuit function:

When the controller outputs PWM pulses, the solenoid valve works; when there is no PWM output, the solenoid valve does not work.

Circuit breakdown:

The entire circuit can be divided into two parts according to the optocoupler:

The left side is the optocoupler input part, which is also the input part of the PWM signal of the entire circuit; the right side is the optocoupler output part, which is also the driving part of the solenoid valve.

These two parts are isolated by optocoupler, and the grounds on both sides are different.

The working process of the entire circuit:

When there is no PWM signal input to the optocoupler, the optocoupler light-emitting diode is cut off, and the phototransistor of the optocoupler is also in a cut-off state. Q1 is an NMOS and is also in a cut-off state. The solenoid valve has no current and does not work.

When the optocoupler has a PWM signal input, the optocoupler light-emitting diode is turned on, and the triggering phototransistor is also turned on. The 24V power supply divides the voltage through the resistor R1, the CE pole of the phototransistor, and the resistor R3 to make the gate of the NMOS IRF540N high level, triggering the MOS tube to conduct, current flows through the solenoid valve coil, and the solenoid valve triggers action.

Diode D1 is the bleeder diode of the solenoid valve to prevent the NMOS from being damaged by high voltage. Capacitor C1 plays a filtering role, but it also increases the switching loss of the MOS tube.

Notice:

During actual production, attention should be paid to the solenoid valve drive, and the MOS tube should be in a switching state to prevent it from heating up seriously.

-The Electronic Components Purchasing Network (www, oneyac, com) is a local component catalog distributor. It adopts the "small batch, spot, sample" sales model and is committed to meeting customers' procurement needs for multiple models, high quality, and fast delivery. Self-built and efficient intelligent warehousing, with over 50,000 self-operated inventories, provides one-stop genuine spot procurement, personalized solutions, option substitution and other diversified services. (This article is compiled from the Internet for the purpose of disseminating useful information and knowledge. If there is any infringement, please contact the administrator to delete it)

Circuit diagram:

Circuit function analysis:

This circuit can not work during the day and emit flashing lights at night to issue a warning and pay attention to safety.

Circuit working process:

Before analyzing the circuit, let us first understand the pin functions of CD4013:

1. Before the circuit is connected, there is no charge on the capacitors C1 and C2. After the circuit is powered on and it is night, the photoresistor RG assumes a large resistance state. Pin 3 of CD4013 will receive a high level, and the initial states of pins 4 and 6 are low level. According to the truth table of CD4013, Q=D=0,/Q=1 at this time.

2. When /Q=1, capacitor C1 starts to be charged through resistor R1. As the capacitor charging voltage gradually rises, the potential of the SD pin of CD4013 also slowly rises. When SD is high level, Q outputs 1, /Q outputs 0, and capacitor C1 quickly discharges through diode D3, causing SD to return to low level.

3. After Q outputs a high level, the transistor is turned on and the light-emitting diode D5 is lit. At the same time, capacitor C2 starts to charge through resistor R2, and the potential of the RD pin slowly rises. When RD is high level, Q outputs low level and /Q outputs high level. Capacitor C2 quickly discharges through diode D4, causing RD to return to low level.

4. Then capacitor C1 starts charging again, and the above process is repeated.

5. When it is daytime, RG is in a small resistance state, and pin 3 is at low level. At the same time, through the clamping effect of diodes D1 and D2, SD and RD are pulled down to low level.

expand:

The fun of electronics is to draw inferences from one example and replace the output part of the above circuit, Q1 and D5, with other components, and it will be another light-controlled circuit.

-The Electronic Components Purchasing Network (www, oneyac, com) is a local component catalog distributor. It adopts the "small batch, spot, sample" sales model and is committed to meeting customers' procurement needs for multiple models, high quality, and fast delivery. Self-built and efficient intelligent warehousing, with over 50,000 self-operated inventories, provides one-stop genuine spot procurement, personalized solutions, option substitution and other diversified services. (This article is compiled from the Internet for the purpose of disseminating useful information and knowledge. If there is any infringement, please contact the administrator to delete it)