Can you guys help me see if my circuit can normally realize pwm3.3v control 12v and is it adjustable?

nicai2

Can you guys help me see if my circuit can normally realize pwm3.3v control 12v and is it adjustable? [Copy link]

 

Guys, help me take a look, thanks.

tagetage

Is the OUT output terminal connected to a relay?

maychang

The PWM signal at DCF_CH1 can control the output of Q7, but the control may be very slow.

maychang

The second floor asked you whether the OUT terminal was connected to a relay. He was suspicious because there was a diode connected from the output terminal to the power supply terminal.

If the Q7 load is a relay, there is no need for PWM at all. Just give a switching signal to the left end of R52.

beyond_笑谈

Is an inductive load connected between VIN and JDQ1_OUT? The switching frequency of PWM cannot be too high, and the on/off speed of the optocoupler needs to be considered.

nicai2

tagetage posted on 2024-10-23 13:36 Is the OUT output terminal connected to a relay?

It is not directly connected to the electric push rod. The electric push rod uses 12v voltage.

nicai2

beyond_笑谈Published on 2024-10-23 15:21 Is an inductive load connected between VIN and JDQ1_OUT? The switching frequency of PWM cannot be too high, and the on/off speed of the optocoupler needs to be considered

Ok thanks, I'll consider it.

nicai2

maychang posted on 2024-10-23 14:39 The PWM signal at DCF_CH1 can control the output of Q7, but the control may be very slow.

It doesn't have to be fast because the push rod moves slowly.

nicai2

maychang posted on 2024-10-23 14:58 The second floor asked you whether the OUT terminal is connected to a relay. He suspected that there was a diode connected from the output terminal to the power supply terminal. If the Q7 load is a relay, ...

For relays, just high and low levels will do. Haha. To control a 12v electric push rod, you can buy one on Taobao.

tagetage

You want to control the electric actuator, why didn't you say it in the original post? I think your circuit is OK, but you need to pay attention to the PWM frequency.

nicai2

tagetage posted on 2024-10-23 17:34 You want to control the electric push rod, why didn't you say it in the original post? ? Your circuit looks OK to me, but you need to pay attention to the PWM frequency.

Thank you for your answer. It’s mainly because this is my first time posting and I have no experience. The pwm frequency cannot be too high, right? Or can it not change too quickly?

tagetage

nicai2 posted on 2024-10-24 11:01 Thank you for your answer. It's my first time posting and I have no experience. The pwm frequency can't be too high, right? Or can it not change too fast?

The higher the PWM frequency, the better the regulation effect, but the operating frequency of the optocoupler and MOS must be considered.

振动试验仪器

Speaking of electric push rods, I did one five years ago. It was used to push a platform up. It was a paper feeding platform for a printing press. The height to be raised was very small, so I used an electric push rod as a power device. I used the square wave output of the vibration table amplifier to control the 24V power supply. In this way, the time for the electric push rod to be powered on once can be controlled within 20 microseconds, which can control a very small displacement.

The lifting platform was not completed in the end. There is an electric push rod in the middle of the lifting platform, and four guide columns. The lifting table is not flexible and stuck.

Now I think back, the thrust I chose was too small.

振动试验仪器

The electric push rod uses a millisecond square wave to control the output, which should be able to obtain a very small displacement output. Attention should be paid to the load capacity of the electric push rod at small displacement.

振动试验仪器

The standard configuration for driving MOS tubes: the push-pull circuit is not used, so the switching speed of the tube is very slow.

振动试验仪器

If it is controlled by square wave and the thrust is small, you can consider increasing the voltage of the square wave from 12V to 24, 36 or 48V. It will not work for a long time.

nicai2

Vibration Test Instrument Published on 2024-10-25 00:12 If it is controlled by square wave and the thrust is small, you can consider increasing the voltage of the square wave from 12V to 24, 36 or 48V. It will not work for a long time.

OK, thanks sir.

nicai2

Vibration Test Instrument Published on 2024-10-25 00:02 The electric push rod uses a millisecond square wave to control the output, which should be able to obtain a very small displacement output. Pay attention to the load capacity of the electric push rod at small displacement.

OK, I understand. Thanks for the answer.

xiaxingxing

maychang posted on 2024-10-23 14:58 The second floor asked you whether the OUT terminal is connected to a relay. He suspected that there was a diode connected from the output terminal to the power supply terminal. If the Q7 load is a relay, ...

Hello, how can there be an output voltage at the output terminal JDQ1_OUT? Isn't the output voltage "isolated" by D21? Where does the voltage come from to be transmitted to the output terminal? Thank you!

maychang

xiaxingxing posted on 2024-11-11 22:16 Hello, senior, how can there be an output voltage at the output end JDQ1_OUT? Isn't the output voltage "isolated" by D21? Where does the voltage come from?

The second poster suspected that the circuit diagram was not drawn completely, and suspected that there was a relay winding connected from JDQ1_OUT to VIN. If a relay winding was connected between JDQ1_OUT and VIN, there would certainly be output.