Version 1.6 - May 28, 2012
5
require external filtering or voltage regulation. It may be used directly with a 6V-28V battery or
other voltage source. Connections can be made using either the screw terminal or solder
pads or both.
3. Application Configurations
When connected, as an
H-bridge
the MegaMoto is suitable for driving DC brushed motors
both forward and reverse with variable speed. It may also be used to drive other bi-directional
loads such as Peltier junctions, bi-directional solenoids, electromagnets and other DC loads.
Pulse-width modulation may be applied to the inputs of the MegaMoto to vary the average
voltage applied to the load. Thus the MegaMoto supports both variable speed and direction of
a single load. Since the MegaMoto supports 100% ON and OFF periods for the inputs, you
may use binary signals to activate the power chips if variable speed is not needed.
When connected in
half-bridge
mode the MegaMoto may be used for driving uni-directional
loads such as lamps, heaters, solenoids or DC motors in one direction. The true half-bridge
configuration of the power MOSFETs in the power chips allow for efficient driving of loads with
variable speed.
Both half-bridges may operate independently or they can be ganged together in parallel to
support approximately double the current of the H-bridge or single half-bridge configuration.
When driving DC motors it is important to understand the power switch configuration within
the BTS7960B chip. As long as the enable line is held logic high, the motor terminals (MA
and MB) are connected either to the BAT + or BAT - terminal through their respective power
device. In an H-bridge configuration when both PWMA and PWMB are at the same logic level
the load will be shorted through both the power chip switches and one battery rail. This
provides a strong “braking” action to the motor. To turn off all power switches the Enable line
must be pulled low. This is a freewheeling “coast” condition for the load.
Following are some common configurations:
H-bridge Mode Example
Figure 4. MegaMoto H-bridge mode