DC Motor Drivers
Will
why H-Bridges were needed for motor control. Is it possible to get the same
functionality from two opamps? The setup I envision is one opamp on either
side of a DC motor, with one sourcing the current and the other sinking it.
Common sources for power and ground on opamps. Will this
blow up/catch fire/sit there and do nothing? Alternatively, does anyone know
of a smaller motor driver chip than the PowerSO20 version of STMicroelectronics
L298P? I need to drive a total of three DC motors at less than 1 amp apiece.
Source voltage for the chips is ~7.2 volts and the chip should accept 0-5v
digital inputs.
-Will
Johan Vannebo
Johan
"Will" <lark...@aol.com> wrote in message
news:5faf6114.01060...@posting.google.com...
Douglas W. Jones,201H MLH,3193350740,3193382879
by lark...@aol.com (Will):
> I am trying to reduce the size of my motor driver circuit and was
> wondering why H-Bridges were needed for motor control.
They aren't needed.
> Is it possible to get the same functionality from two opamps?
Certainly! The advantage of the H-bridge is that it requires only
one polarity of power supply, while op-amps require both positive and
negative supply rails.
If you look at the output driver stage of a power op-amp, you'll see
that it involves a complementary transistor pair. If you look at each
half of an H-bridge, you'll see that it involves a transistor pair.
In fact, the two circuits don't differ in complexity by that much,
except that the H-bridge is not designed for linear operation, while
the op-amp is designed for linear application, and is therefore more
complex.
Doug Jones
jo...@cs.uiowa.edu
http://www.cs.uiowa.edu/~jones/step/
Dennis D Fishermann
You may also want to check out the National Semiconductor "Boomer"
series audio amplifiers. They are easy to use and almost bomb proof.
ie short circuit and overheat protected.
Dennis