33932 Datasheet, PDF (12/21 Pages) Freescale Semiconductor, Inc – 5.0 A Throttle Control H-Bridge

FUNCTIONAL DESCRIPTION
FUNCTIONAL PIN DESCRIPTION
ENABLE INPUT/DISABLE INPUT 2 (EN/D2))
The EN/D2 pin performs the same function as D1 pin,
when it goes to a logic LOW the outputs are immediately tri-
stated. It is also used to place the device in a Sleep Mode so
as to consume very low currents. When the EN/D2 pin
voltage is a logic LOW state, the device is in the Sleep Mode.
The device is enabled and fully operational when the EN pin
voltage is logic HIGH. An internal pull-down resistor
maintains the device in Sleep Mode in the event EN is driven
through a high-impedance I/O or an unpowered
microcontroller, or the EN/D2 input becomes disconnected.
FEEDBACK (FB)
The 33932 has a feedback output (FB) for “real time”
monitoring of H-bridge high-side output currents to facilitate
closed-loop operation for motor speed and torque control.
The FB pin provides current sensing feedback of the
H-bridge high side drivers. When running in the forward or
reverse direction, a ground-referenced 0.24% of load current
is output to this pin. Through the use of an external resistor to
ground, the proportional feedback current can be converted
to a proportional voltage equivalent and the controlling
microcontroller can “read” the current proportional voltage
with its analog-to-digital converter (ADC). This is intended to
provide the user with only first-order motor current feedback
for motor torque control. The resistance range for the linear
operation of the FB pin is 100 Ω < R_FB < 300 Ω.
If PWM-ing is implemented using the disable pin input
(only D1), a small filter capacitor (~1.0 µF) may be required
in parallel with the R_FB resistor to ground for spike
suppression.
33932
12
Analog Integrated Circuit Device Data
Freescale Semiconductor