Pwm ic

[ronv]

I want to build a little RC car. It will be a breadboard project so I would like to minimize wiring. Does anyone know a nice PWM IC where you can input a control voltage and get out PWM from 0 to 100%? It would be nice if it could run off 12 volts, but not a must.

 

[RoboWanabe]

i dnt no about an IC but i no you can use a micro to do that. i used the psoc.

 

[shortbus=]

How about a 555 Schmitt trigger into a LM339? The Schmitt trigger out-put on one 339 input and the variable voltage to the other gives a PWM out-put from the 339. This link shows it better than I can explain it; Fig. 5.3; https://forum.allaboutcircuits.com/blog.php?bt=678

 

[ronv]

How about a 555 Schmitt trigger into a LM339?

That would work, but I had hoped to find the saw tooth and the comparator all in one package.
Have to keep looking. Maybe it's not fancy enough to warrant a chip.

I thought about a micro, but I'll already have some hardware so I thought just one more chip?

 

[jpanhalt]

The TPIC2101 from TI may help you. At least it will create the PWM from a voltage. Then you will probably (but not necessarily) need a mosfet or bridge driver chip.

John

 

[nickelflippr]

I want to build a little RC car. It will be a breadboard project so I would like to minimize wiring. Does anyone know a nice PWM IC where you can input a control voltage and get out PWM from 0 to 100%? It would be nice if it could run off 12 volts, but not a must.

How is the RC receiver putting out a variable voltage in the first place? What IC, or receiver model, is involved, is it using PPM?

 

[ronv]

How is the RC receiver putting out a variable voltage in the first place? What IC, or receiver model, is involved, is it using PPM?

I'm was going to use a pulse width to voltage converter to convert the 1 to 2 ms pulses from the receiver to a dc voltage to set the level of the pwm.

 

[ronv]

The TPIC2101 from TI may help you. At least it will create the PWM from a voltage.

Something like this is what I am looking for. I'll browse thru some automotive IC's to see if I can find a simple one. I might even find one with a motor driver as part of the chip.

 

[nickelflippr]

@ronv

I'm was going to use a pulse width to voltage converter to convert the 1 to 2 ms pulses from the receiver to a dc voltage to set the level of the pwm.

I think most all the commercial RC ESC's use a micro to do that. If it was easier or cheaper to do it some other way, I would expect them to do so.

The Tamiya tracked wheel kit, dual gear motor, microcontroller, and a SN754410 dual H-Bridge chip,or two , makes for a budget RC tank.

 

[ronv]

I'm a microprocessor illiterate so I'm searching for a hardware solution. I guess someday I will learn how to speak PIC.

 

[nickelflippr]

If you end up with small motors like the Tamiya dual gearbox setup, then PWM'ing the motors is about worthless, and not worth messing with.

 

[4pyros]

The Tamiya tracked wheel kit, dual gear motor, microcontroller, and a SN754410 dual H-Bridge chip,or two , makes for a budget RC tank.

Kent; Do you have more info on that?

 

[nickelflippr]

Kent; Do you have more info on that?

Yes, I posted to my new Blog https://www.electro-tech-online.com/blogs/nickelflippr/187-rc-tank-project.html

 

[4pyros]

Thanks Kent.

 

[k7elp60]

I want to build a little RC car. It will be a breadboard project so I would like to minimize wiring. Does anyone know a nice PWM IC where you can input a control voltage and get out PWM from 0 to 100%? It would be nice if it could run off 12 volts, but not a must.

Here is a circuit I have recently built that works quite well, times are 93%on and 13%off. The P channel mosfet will control several amps. The IC is a 555 Q1 is IRF4905. If you want the other values let me know.

 

[ronv]

I'm thinking if I give up reverse I could use a pwm fan controller. Any thoughts?

 

[4pyros]

The chips are out thare;
**broken link removed**

 

[4pyros]

Here is some more;
**broken link removed**

 

[4pyros]

It seems most of the recevers just use shift registers;
**broken link removed**

 

[Dragon Tamer]

In higher end radio systems I think they use a one shot to create a an output. I'm not entirely sure so you may want to double check on that one.

I do know that to have an effective system you will need a carier frequency and an operating frequency. The carier frequency in off the shelf toys is 27 or 49MHz though 27MHz seems to be more popular. To have the system work with more than one channel you will need a PWM signal for each channel.

I'm going to stop helping now becuase I'm entering areas where I'm unsure of what is going on.