No. Remove the zener diode and connect a schottky diode, cathode to the 5V supply, anode to the inverter input, as an input clamping diode.

Thanks. Is that mean you are clamping the inverter input to the 5V supply which doesn't go beyond 5V right. Can I use 1N4001 as a schottky?

 

The circuit from post #1 appears to be a motor driver circuit.
Why do you need a 5V pulse from this circuit?
Why not use the signal already labeled as CLK1 1kHz?

What are you trying to do?

 

The circuit from post #1 appears to be a motor driver circuit.
Why do you need a 5V pulse from this circuit?
Why not use the signal already labeled as CLK1 1kHz?

What are you trying to do?

1. Yes, it is the motor driver circuit. I've updated my post.
2. 5V pulse to drive the motor
3. I am using the 5v signal but it is getting dropped 3.8V at the voltage divider output.

 

With correction...

 

With correction...

View attachment 139386

Thanks But I am wondering did you see my updated post (I have attached some extra information) will this circuit works for my requirement?

 

Could anyone help me please. Thank in advance.

Try arranging your thoughts in paragraphs so they're easier to follow.

You can't switch a voltage regulator and expect it to settle within 10's of nS.

 

1. Yes, it is the motor driver circuit. I've updated my post.
2. 5V pulse to drive the motor
3. I am using the 5v signal but it is getting dropped 3.8V at the voltage divider output.

You didn't answer my question.
Why do you want to use the signal?
What is wrong with using the original signal directly into a 74HC14?

 

You didn't answer my question.
Why do you want to use the signal?
What is wrong with using the original signal directly into a 74HC14?

1. To drive the stepper motor. is what you are looking for?
2. Original signal gets inverted while transmission and I am seeing an inverted pulse

 

1. To drive the stepper motor. is what you are looking for?
2. Original signal gets inverted while transmission and I am seeing an inverted pulse

Then cascade two 74HC14 inverters to create a non-inverting buffer.

 

When you have it connected that way, does the input pin on the inverter (which should be electrically equivalent to the voltage divider output) still show the expected voltage?

If the inverter input is correct and you get no output response, that's one issue.

If the voltage divider output drops to 0V as soon as you connect it to the inverter input, that's a very different problem.

1. Yes it is showing 4.98V at the inverter input.
2. inverter input stays at 5V only there is no pulse response.
3. No the voltage divider doesn't drops to 0V when I connect to the inverter input

 

Here's an example from the internet of clamping diodes. This one includes two, one for preventing too high of input, the other for too low.

View attachment 139381

Thanks. It could be great if the clamping diode is through hole one and it is a simple circuit with fewer components. Why we need the amplifier? shall I just use the 1N5177?

 

Thanks. It could be great if the clamping diode is through hole one and it is a simple circuit with fewer components. Why we need the amplifier? shall I just use the 1N5177?

Sorry, didn't mean to confuse things: I wasn't suggesting you need the amplifier. You just need to connect a Schottky diode from input pin to VCC, as described earlier by AlbertHall, instead of using a zener to ground. You may also want to include a second Schottky from input to ground to protect against negative voltage spikes. The example I found just happened to show clamping diodes protecting an op-amp instead of clamping diodes protecting an inverter. The concept is the same, but the components are different. I just thought an example schematic might help.

 

Sorry, didn't mean to confuse things: I wasn't suggesting you need the amplifier. You just need to connect a Schottky diode from input pin to VCC, as described earlier by AlbertHall, instead of using a zener to ground. You may also want to include a second Schottky from input to ground to protect against negative voltage spikes. The example I found just happened to show clamping diodes protecting an op-amp instead of clamping diodes protecting an inverter. The concept is the same, but the components are different. I just thought an example schematic might help.

Yes, thanks for your help

 

1. Yes it is showing 4.98V at the inverter input.
2. inverter input stays at 5V only there is no pulse response.
3. No the voltage divider doesn't drops to 0V when I connect to the inverter input

I just thought of something. What are you doing with all the unused pins on your hex inverter? Unused outputs are fine, but unused inputs need to be tied to VCC or ground. If left floating, they can oscillate wildly, creating noise, heat, and other issues.

On a related note, do you have a decoupling cap on your inverter VCC input?

Am I right in thinking that, at this point in testing, the 5V supply is only powering the inverter? You haven't yet hooked up the motor driver chip and motor, right?

If you could upload a picture of your setup, particularly the inverter wiring, that might be helpful.

 

I just thought of something. What are you doing with all the unused pins on your hex inverter? Unused outputs are fine, but unused inputs need to be tied to VCC or ground. If left floating, they can oscillate wildly, creating noise, heat, and other issues.

On a related note, do you have a decoupling cap on your inverter VCC input?

Am I right in thinking that, at this point in testing, the 5V supply is only powering the inverter? You haven't yet hooked up the motor driver chip and motor, right?

If you could upload a picture of your setup, particularly the inverter wiring, that might be helpful.

Thanks for your suggestions. The motor is working.

 

Thanks for your suggestions. The motor is working.

I'm confused. Do you mean that everything is working now? If so, how did you get it fixed? What was the problem?

Or do you just mean that the motor is also connected to the circuit when you're testing the inverter, but that the inverter is still not responding properly to inputs?

 

I'm confused. Do you mean that everything is working now? If so, how did you get it fixed? What was the problem?

Or do you just mean that the motor is also connected to the circuit when you're testing the inverter, but that the inverter is still not responding properly to inputs?

Yes, the motor circuit was connected before but it wasn't receiving the pulse because the inverter wasn't generating any pulse. As per your suggestion, I have connected the inverter other inputs to ground, used Schottky to clamp at VCC and placed decoupling cap to the VCC. I am getting a 5V pulse to the motor now. But still, I need to verify some other things to double check.

 

Yes, the motor circuit was connected before but it wasn't receiving the pulse because the inverter wasn't generating any pulse. As per your suggestion, I have connected the inverter other inputs to ground, used Schottky to clamp at VCC and placed decoupling cap to the VCC. I am getting a 5V pulse to the motor now. But still, I need to verify some other things to double check.

Excellent! Glad to hear you're making progress.

 

Excellent! Glad to hear you're making progress.

Thanks

 

Hi all

This is the latest schematic which is working fine to run the motor. I have noticed that it consumes 30mA when there is no pulse (20mA for the motor). There shouldn't be any current draw when there is no pulse. Could anyone suggest me please with the modifications I can do that there is no current consumption if there is no pulse?