OM9375 International Rectifier Corp., OM9375 Datasheet - Page 9
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OM9375
Manufacturer Part Number
OM9375
Description
25 Amp. Push-pull 3-phase Brushless Dc Motor Controller/driver Module In A Power Flatpack
Manufacturer
International Rectifier Corp.
Datasheet
1.OM9375.pdf
(12 pages)
OM9375
APPLICATIONS
Start-Up Conditions
The
controller/driver is designed to drive fractional to
integral horsepower motors.
operation, it is necessary to ensure that the high-side
bootstrap capacitors are charged during initial start-
up. However, the method(s) used to ensure this may
be dependent upon the application.
some applications may only require that OV_COAST
(pin 17) be connected to ground, either via a hardwire
connection or via a switch (Enable/Disable), before
applying
controller/driver is forced into brake mode for
approximately 200 sec (all high-side drivers are
disabled and all low-side drivers are enabled).
This may not be adequate for other applications;
RC_BRAKE (pin 16) may have to be momentarily
connected to ground via a switch, either manually or
electronically (ref. Figure 3).
component values shown in Figure 3, RC_BRAKE is
pulled low for approximately 300 mSec after applying
Vcc at pin1.
Modes of Operation
Figures 4 and 5, shown on the following pages,
provide schematic representations of typical voltage-
mode and current-mode applications for the OM9375
controller/driver.
Figure 4 represents the implementation of a typical
voltage-mode controller for velocity control. A voltage
or speed command is applied to the noninverting input
of the error amplifier which is configured as a voltage
follower. The output of the error amplifier is compared
to a pulse width modulated ramp, and since motor
speed is nearly proportional to the average phase
Test/Inspection
Precap Visual Inspection
Temperature Cycle
Mechanical Shock
Hermeticity (Fine and Gross Leak)
Pre Burn-In Electrical
Burn-In (160 hours)
Final Electrical Test
Group A Testing
Final Visual Inspection
OM9375
Vcc.
3-phase
When
brushless
Vcc
Note that with the
To ensure proper
is
applied,
For example,
DC
motor
-55°C, +25°C,
the
2.1 - 9
+125°C
100%
100%
100%
100%
100%
100%
100%
100%
SFB
output voltage, the speed is controlled via duty cycle
control.
tachometer output can be connected to the inverting
input of the error amplifier via a loop compensation
network.
Figure 4 also shows the implementation of the cycle-
by-cycle current limit/overcurrent protection feature of
the OM9375. The load current is monitored via the
controller’s internal sense resistor. The current sense
signal is filtered and fed into the current sense amplifier
where the absolute value of ISH-ISL is multiplied by two
and biased up by 2.5 volts. The output of the current
sense amplifier is compared to a fixed reference, thus
providing cycle-by-cycle current limiting and/or
overcurrent protection as necessary. The typical peak
current threshold (ISH-ISL) is 0.20 volts; the typical
over current threshold (ISH-ISL) is 0.30 volts.
Figure 5 represents the implementation of a typical
current-mode controller for torque control. The load
current is monitored via the controller’s internal sense
resistor. The current sense signal is filtered and fed
into the current sense amplifier where the absolute
value of ISH-ISL is multiplied by two and biased up by
2.5 volts. Besides the implementation of the cycle-by-
cycle current limit/overcurrent protection feature of the
OM9375 discussed in the preceding paragraph, the
output of the current sense amplifier is fed into the error
amplifier which is configured as a differential amplifier.
An error signal representing the difference between the
current command input and the value of the amplified
current sense signal is produced. Then it is compared
to a pulse width modulated ramp and since torque is
nearly proportional to the average phase output
current, the torque is controlled via duty cycle control.
If a speed feedback loop is required, the
+25°C
100%
100%
100%
N.A.
N.A.
N.A.
N.A.
N.A.
SF
+25°C
100%
100%
SPP
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.