Buffer driver, non-inverting, for 8 servos?

[zorgloub]

Hello,

What integrated Buffer driver(s) would you recommend to drive directly 8 servos at the output of the Picaxe, without inversion of the output signal?

Thanks

 

[AllyCat]

Hi,

Why do you want to add a non-inverting buffer? Its drive current capability will probably be no higher than the PICaxe pins; if you want to "protect" the PICaxe, then a resistor of perhaps 1k ohms in series with each output pin will probably be as good.

But if you want a "general purpose" HCMOS (5v) non-inverting buffer, then look at the 74HC244 . Or the 74HC540 might have a more convenient pinout (inputs along one side, outputs on the other); both are in 20-pin packages.

Cheers, Alan.

 

[zorgloub]

Hi Alan,
I was just wondering if a driver was really needed per servo?
But it is true that the control line (out Picaxe) is not significant and that the "power consumption" is, in fact, at the servo motor supply line.
Regards

 

[oracacle]

That's correct. In each servo there is a small controller that "decodes" the PWM signal. Logic input on controllers are normally high impedance messaging that only very tiny amounts of current can flow