OM9375 Datasheet, PDF (6/12 Pages) List of Unclassifed Manufacturers – 25 Amp. Push-Pull 3-Phase Brushless DC Motor Controller/Driver Module in a Power Flatpack

PIN DESCRIPTIONS / FUNCTIONALITY
VCC (Pin 1) -- The Vcc Supply input provides bias
voltage to all of the internal control electronics within
the OM9375, and should be connected to a nominal
+15Vdc power source. High frequency bypass
capacitors (10uF polarized in parallel with 0.1uF
ceramic are recommended) should be connected as
close as possible to pin 1 and Ground (pin 19).
ERROR AMPLIFIER (EA1- Input, Pin 2; EA1+
Input, Pin 4; EA1 Output, Pin 8) -- The Error
Amplifier is an uncommitted LM158-type operational
amplifier, providing the user with many external
control loop compensation options. This amplifier is
compensated for unity gain stability, so it can be
used as a unity gain input buffer to the internal PWM
comparator when pin 2 is connected to pin 8. The
output of the Error Amplifier is internally connected
to the PWM comparator's "-" input, simplifying
external layout connections.
+5V REFERENCE OUTPUT (Pin 5) -- This output
provides a temperature-compensated, regulated
voltage reference for critical external loads. It is
recommended that this pin be used to power the
external Hall-effect motor position sensors. By
design, the +5V reference must be in regulation
before the remainder of the control circuitry is
activated. This feature allows the Hall-effect sensors
to become powered and enabled before any Phase
Output is enabled in the OM9375, preventing
damage at turn-on. High-frequency bypass
capacitors (10uF polarized in parallel with 0.1uF
ceramic are recommended) should be connected as
close as possible to pin 5 and Ground (pin 19).
SPARE AMPLIFIER (EA2- Input, Pin 6; EA2+
Input, Pin 3; EA2 Output, Pin 7) -- The Spare
Amplifier is an uncommitted LM158-type operational
amplifier, and in addition to the internal error
amplifier, provides the user with additional external
control loop compensation options. This amplifier is
also compensated for unity gain stability and it can
be used as a unity gain input buffer when pin 6 is
connected to pin 7. If the Spare Amplifier is unused,
pin 3 should be connected to Ground, and pin 6
should be connected to pin 7.
PWM INPUT (Pin 9) -- This pin is connected to the
"+" input of the internal PWM comparator. The PWM
output clears the internal PWM latch, which in turn
commands the Phase Outputs to chop. For voltage-
mode control systems, pin 9 may be connected to
the Oscillator Timing Input, pin 10.
OM9375
OSCILLATOR TIMING INPUT (Pin 10) -- The Oscillator
Timing Input sets a fixed PWM chopping frequency by
means of an internal resistor (Rosc), whose value is set
to 75kΩ, connected from pin 10 to the +5V Reference
Output, and an internal capacitor (Cosc), whose value
is 1800pF, connected from pin 10 to Ground. In custom
applications, the recommended range of values for
Rosc is 10kΩ to 100kΩ, and for Cosc is 0.001uF to
0.01uF, and the maximum operating frequency should
be kept below 20kHz. The approximate oscillator
frequency is:
fo =
2
[Hz]
(Rosc x Cosc)
The voltage waveform on pin 10 is a ramp whose
magnitude is approximately 1.2Vp-p, centered at
approximately 1.6Vdc. In addition to the voltage-mode
PWM control, pin 10 may be used for slope
compensation in current-mode control applications.
ISENSE (Pin 11) -- This pin is connected to the output
of the internal current-sense amplifier. It drives a peak-
current (cycle-by-cycle) comparator which controls
Phase Output chopping, and a fail-safe current
comparator which, in the event of an output overcurrent
condition, activates the soft-start feature and disables
the Phase Outputs until the overcurrent condition is
removed. The magnitude of the voltage appearing at pin
11 is dependent upon the voltages present at the
current-sense amplifier inputs, ISH and ISL:
V(Isense) = 2.5V + [2 x ABS (ISH - ISL)] [Volts]
CURRENT SENSE INPUTS (ISH, Pin 12; ISL, pin 13)
-- These inputs to the current-sense amplifier are
interchangeable and they can be used as differential
inputs. The differential voltage applied between pins 12
and 13 should be kept below +/-0.5Vdc to avoid
saturation.
QUAD SELECT INPUT (Pin 14) -- This input is used to
set the OM9375 in a half control or full control chopping
regime. When driven with a logic low level, the OM9375
is in the half control mode, whereby only the three lower
(pull-down) power switches associated with the Phase
Outputs are allowed to chop. Alternately, when driven
with a logic high level, the OM9375 is in the full control
mode, where all six power switches (pull-up and pull-
down) associated with the Phase Outputs are chopped
by the PWM. During motor braking, changing the logic
state of the Quad Select Input has no effect on the
operation of the OM9375.
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