User Manual

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 (EA or EB) is held logic high, the motor
terminal (M1 or M2) is connected either to the B+ or B- terminal through the device. In an H-
bridge configuration when both PA and PB are at the same logic level the load will be shorted
through both the top switches and the positive battery rail or the bottom switches and the
negative rail. This provides a strong “braking” action to the motor. To turn off both power
switches the Enable (EA and/or EB) line must be pulled low. This is a freewheeling “coast”
condition for the load.
4. Features
The Simple-H uses the Infineon BTS7960B as its power-switching element. This chip
contains two low-resistance complimentary MOSFET switching elements along with protection
and driver circuits. Each BTS7960B thus contains a complete half-bridge and all needed
driver circuits including robust protection features. The device features self-protection from
over temperature, over current and over and under voltage conditions. As mentioned above
the two half-bridge chips may be connected either as an H-bridge or as two independent half-
bridges. This flexibility makes the Simple-H suitable for driving a wide variety of DC loads.
The Simple-H features a current sense output from each half-bridge power chip. This output
is a voltage proportional to the current flowing through the chip. The voltage output is
approximately 0.075V per Ampere of current. When jumpered for individual current readings
the CA and CB outputs reflect the current passing through the M1 and M2 motor terminals
respectively. When jumpered for combined current output the CA output reflects the
combined current flowing through both power chips. However, the current reading may not be
negative so in an H-bridge configuration only the one power chip passing current in the
positive direction (high-side switch on) will present an output; the other chip presents no
voltage output. So in combined current mode the current output is correctly proportional to the
current passing through the H-bridge.
5. Driving the Simple-H
IMPORTANT you cannot simply connect the battery voltage to the EA, EB, PA and PB
inputs through a switch. The maximum voltage level on these inputs is 6V.
Connecting them directly to the battery voltage will damage the unit.
The fan and the +/- positions on the screw terminal block are directly connected to the
B+ and B- battery terminals. These are provided for convenience connections to the
main battery. DO NOT ATTACH AN EXTERNAL BATTERY OR VOLTAGE SOURCE TO
THESE. The Simple-H is completely self-powered and the main battery connection is
all that is needed.
The EA/EB and PA/PB inputs are inputs which control the output of the power chips in the
Simple-H. The Simple-H inputs must be driven by 3V-5V logic-level signals. These voltage
levels are compatible with nearly all microprocessors and controllers. Note, however that the
Simple-H is not optically isolated from the command inputs so in the unlikely event of a total
power chip failure it is possible that the full battery voltage could be applied to the command
input pins. Protection devices are installed to limit the damage but users are advised to take
precautions to protect the device controlling the Simple-H.