About 51 single chip microcomputer controls H bridge, 51 single chip microcomputer controls four DC

It should be that the bias resistor selection is not suitable.

To be honest, the motor drive is a difficult problem, because I have actually used it and found that the load characteristics of the H-bridge are very poor, with the increase of the current, the output voltage drops too much, the triode is seriously heated and cannot work normally, even if the special L298 or ULN2803 is used when the current is large, the heat is also very strong, it is recommended to directly use the relay or high-power thyristor.

Forward and reverse rotation is not a problem of current flow, and speed regulation is a problem of output voltage.

It is driven by an H-bridge motor consisting of 6 transistors. Typical kind. Two IO ports control the motor. Controlled with infrared. 01 forward, 10 reversed, 00 or 11 stopped.

The above design is no problem.

Two IO ports cannot output PWM at the same time, and a single output PWM is definitely OK.

Let's take a look at whether the single-chip microcomputer is pulled up when there is no load.

If there is, it is a problem with the drive.

If the no-load is not pulled up, it is a procedural problem.

Generally, the problem with the driver is that there is no current limiting resistor installed in the IO output.

I don't understand!

2003 does need to be connected to the optocoupler before, it is based on your circuit, it is mainly used to isolate the power supply by engaging in interference and solving voltage inconsistency.

If your stepper motor and the power supply of the control circuit board are on the same ground, I often think that there is no need to connect them, because the interference signal will also be transmitted to the control part through the ground wire.

If you want to connect, there must be a resistor between the 4N25 and 2003 inputs, and the current is limited! , 1k is OK, and it is better to connect a resistor to the input terminal of 1k resistor and 2003, and the other end of the resistor is grounded, so that in the case that 4N25 does not work, the 2003 input terminal is grounded through the resistor.

Inside the 2003 is a set of Darlington tubes, which you can understand as a triode with a high magnification, and the control pole you use is its base, so it can work when it has voltage. However, when in use, it is still necessary to ensure that it provides more than 2V, otherwise it may not be very reliable.

The last question I don't understand, what does it mean to withstand a voltage of 4n25? They are connected in series, so at most they can withstand the current! This can be solved by stringing 1k resistors above!

Two L298N, a total of 4 H bridges, can control 4 DC motors forward and reverse, and can regulate the speed If you only need forward or reverse rotation, you can pay attention to one point with ULN2003: when using 298N, you need to add a freewheeling diode protection chip, ULN2003 comes with a freewheeling diode.

Microcontrollers (microcontrollers) is a kind of integrated circuit chip, which is a small and perfect microcomputer system composed of a small and perfect microcomputer system composed of a silicon wafer that uses ultra-large-scale integrated circuit technology to integrate the best processor CPU, random access RAM, read-only memory ROM, a variety of IO ports and interrupt systems, timer counters and other functions (which may also include display drive circuits, pulse width modulation circuits, analog multiplexers, AD converters and other circuits) into a silicon waferIt is widely used in the field of industrial control. From the 80s of the last century, from the 4-bit and 8-bit single-chip microcomputers at that time, to the current 300m high-speed single-chip microcomputer.

It depends on the peripherals and the degree of control: is the motor to be speed adjustable and forward and reverse? Do you have a requirement for speed response?

The simple method is to control the drive equipment through 4 DA outputs after being conditioned by op amp; If the driver is an H-bridge built by MOSFET, it should be controlled by PWM, which requires the MCU to have an enhanced multi-channel PWM output function, otherwise it will be much more troublesome.

One. Motor speed control module. Our design idea is to first generate a square wave with adjustable duty cycle (there are many methods, one is to use 555 to form a multivibrator.

Second, the single-chip microcomputer can be used to generate PWM square wave) +4 power device composed of H-bridge circuit to drive the DC motor to rotate. Of course, there are also many drive solutions, such as transistors.

The PCB has no network and is not easy to see, so it is better to have a schematic.

Check whether the initial configuration of the IO port is low.