The A3977 specifies 1.6 volts to one pin to run with 1.0 AMP of motor current.
I hope I'm not hijacking this thread but I've been wondering about a related question. Basically when driving high currents, is it better to smooth the PWM before the current amplifying transistor or after?Here are my thoughts:If you do it before the transistor (i.e. to the base of the transistor) you don't need a big cap, but you are running in the "active" region (i.e. unsaturated) so it is burning energy and you are relying on a specific hopefully nearly linear Hfe transistor curve.Also, if you do it after, some wire is carrying high current PWM... would that emit undesireable RF?Cheers!Andrew
Well I would filter before the high current driver. This is because the capacitor is much smaller and so the circuit is more reliable and has a longer life. It is easer to deal with the heat generated by a linear buffer than the life time of a large capacitor switching gob loads of current.
" Its retail price in 1978 was $1295.00. According to the average historical price of gold, it would have listed for an equivalent of $8199.42 in 2010"http://en.wikipedia.org/wiki/Pioneer_SX-1980