reomendations of CI for PPM

[Miguelrgp]

Please give me recomendations of PPM Ci's for servo applications. NOt the 555
Thanks

 

[D.A.(Tony)Stewart]

If we assume an average servo pulse of 1500ms, the following average refresh rates apply -

Servos In Each Bank Average Servo Position Time To Cycle Through Servos Average Refresh Rate
1 1500 1500 666.6666667
2 1500 3000 333.3333333
3 1500 4500 222.2222222
4 1500 6000 166.6666667
5 1500 7500 133.3333333
6 1500 9000 111.1111111
7 1500 10500 95.23809524
8 1500 12000 83.33333333
9 1500 13500 74.07407407
10 1500 15000 66.66666667

Not sure what you expect. Command Intervals can be generated with a clock and counter.

 

[Miguelrgp]

Recommendation for IC to Generate PPM, like the 555.

I ecpect a recomendation of what IC use, like the 555 to obtain PPM

 

[BrunoARG]

Re: Recommendation for IC to Generate PPM, like the 555.

I would recommend you to use a 2 opamp VCO (voltage controlled oscilator) which can vary its frequency (generating PPM) when different voltages are in the input.

It's not a single IC but a simple circuit with easy calcules.

Depending of the frequency and the transistors used you can reach higher frequencies. If your output is a square wave, then your only problem will be the non-linearity of the circuit, as I said, whenever the frequency is so high.

If you are interested on this method tell me so I tell you how to calculate it.

 

[BradtheRad]

Re: Recommendation for IC to Generate PPM, like the 555.

Since you mention the 555 IC, its use with PPM is discussed at this website.

https://electriclubs.blogspot.com/2011/06/pulse-position-modulation-ppm-using-555.html