8 10 R2
Supersedes 6 11 R1
FULL-FEATURED POWER MODULE FOR HIGH-VOLTAGE
DIRECT DRIVE OF 3-PHASE BRUSHLESS DC MOTORS
FEATURES
•
Fully integrated 3-Phase Brushless DC Motor Control Subsystem
includes power stage, non-isolated driver stage, and controller stage
•
Rugged IGBT Power Output Stage with Soft Recovery Diode
•
25A Average Phase Current with 300V Maximum Bus Voltage
•
Internal Precision Current Sense Resistor (6W max. dissipation)
•
Speed and Direction Control of Motor
•
Brake Input for Dynamic Braking of Motor
•
Overvoltage/Coast Input for Shutdown of All Power Switches
•
Soft Start for Safe Motor Starting
•
Unique Lightweight Hermetic Ceramic-to-Metal Sealed Module (CERMOD
TM
)
•
(4.255" x 2.475" x .74")
APPLICATIONS
•
Fans and Pumps
•
Hoists
•
Actuator Systems
DESCRIPTION
The OM9369CM is one of a series of versatile, integrated three-phase brushless DC motor
controller/driver subsystems housed in a CERMOD
TM
. The OM9369CM is best used as a two
quadrant speed controller for controlling/driving fans, pumps, and motors in applications which require
small size. Typical size brushless DC motors that the OM9369CM can effectively control range from
fractional HP up to several HP. The OM9369CM is ideal for use on DC distribution busses up to and
including 270Vdc. Many integral control features provide the user much flexibility in adapting the
OM9369CM to specific system requirements.
The small size of the complete subsystem is ideal for aerospace, military, and high-end industrial
applications.
OM9369CM
205 Crawford Street, Leominster, MA 01453 USA (978) 534-5776 FAX (978) 537-4246
Visit Our Web Site at www.omnirel.com
25 Amp. Push-Pull 3-Phase Brushless
DC Motor Controller/Driver Module
in a Ceramic-to-Metal Sealed Module
P R E L I M I N A R Y
COMMUTATION TRUTH TABLE
This table shows the Phase Output state versus
the state of the Hall-Effect and Direction Inputs.
Please note that the OM9369CM Hall-Effect
Inputs are Grey-encoded; that is, only one input
is allowed to change from one input state to
another at a time.
The commutation coding shown reflects Hall-
Effect sensors that are spaced at 120
°
mechanical increments. Also, internal
protection logic disables all three Phase
Outputs when the Hall-Effect Inputs are set to
an illegal condition (i.e. all logic low or all logic
high).
2.1 - 2
SIMPLIFIED BLOCK DIAGRAM
OM9369CM
VCC (1)
Ground (20)
EA1+ (5)
Hall_1 (23)
Hall_2 (22)
Hall_3 (21)
Direction (25)
OV_Coast (18)
Tach_Out (16)
V_Motor (B)
Phase_A (E)
Phase_C (C)
EA1- (3)
EA1_Out (9)
EA2+ (4)
EA2- (7)
EA2_Out (8)
PWM_In (10)
Osc (11)
+5V_Ref (6)
Quad_Sel (15)
I_Sense (12)
ISH (13)
ISL (14)
CSL (27)
CSH (26)
Phase_B (D)
Pwr_Gnd (A)
Delay (2)
RC_Brake (17)
Speed_In (24)
SStart (19)
R/C
R/C
Filter
High-Side/
Low-Side
Drivers
with Bootstrap
and Charge Pump
High-Side/
Drivers
Low-Side
with Bootstrap
Low-Side
with Bootstrap
and Charge Pump
High-Side/
Drivers
and Charge Pump
Startup
Circuit
Vcc
Tach_Out
Tach_Out
V_Ref
Vcc
V_Ref
Quad_Sel
OV_Coast
Quad_Sel
OV_Coast
ISH
ISL
ISH
ISL
Delay
Delay
RC_Brake
RC_Brake
SStart
SStart
+
-
+
-
R_Sense
UC1625
RC_OSC
25
GND
15
E/A_IN(+)
1
E/A_OUT
27
PWM_IN
26
E/A_IN(-)
28
VREF
2
H1
8
H2
9
H3
10
DIR
6
RC_BRAKE
21
QUAD_SEL
22
OV_COAST
23
VCC
19
PWR_VCC
11
SSTART
24
PUA
18
PUC
16
PUB
17
PDC
12
PDB
13
PDA
14
ISENSE_1
4
ISENSE_2
5
SPEED_IN
7
ISENSE
3
TACH_OUT
20
DIGITAL INPUTS
PHASE OUTPUTS
Dir
H1
H2
H3
A
B
C
1
0
0
1
Hi-Z
Sink
Source
1
0
1
1
Sink
Hi-Z
Source
1
0
1
0
Sink
Source
Hi-Z
1
1
1
0
Hi-Z
Source
Sink
1
1
0
0
Source
Hi-Z
Sink
1
1
0
1
Source
Sink
Hi-Z
0
1
0
1
Sink
Source
Hi-Z
0
1
0
0
Sink
Hi-Z
Source
0
1
1
0
Hi-Z
Sink
Source
0
0
1
0
Source
Sink
Hi-Z
0
0
1
1
Source
Hi-Z
Sink
0
0
0
1
Hi-Z
Source
Sink
X
0
0
0
Hi-Z
Hi-Z
Hi-Z
X
1
1
1
Hi-Z
Hi-Z
Hi-Z
2.1 - 3
OM9369CM
ABSOLUTE MAXIMUM RATINGS
Motor Supply Voltage, V
m
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 Vdc
Peak Motor Supply Voltage V
m pK
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 Vdc
Average Phase Output Current, I
o
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Amperes DC*
Peak Phase Output Current, I
om
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Amperes Peak**
Control Supply Voltage, V
cc
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
+
18 V
Logic Input Voltage
(Note 1
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to +8 V
Reference Source Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -30 mAdc
Error Amplifier Input Voltage Range, (EA1+/EA1-) . . . . . . . . . . . . . . . . . . . . -0.3 Vdc to 10 Vdc
Error Amplifier Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±8 mAdc
Spare Amplifier Input Voltage (EA2+/EA2-). . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 Vdc to 10 Vdc
Spare Amplifier Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±8 mAdc
Current Sense Amplifier Input Voltage (ISH/ISL) . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to +6 Vdc
Current Sense Amplifier Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±10 mAdc
Tachometer Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±10 mAdc
PWM Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 0.3 Vdc to +6 Vdc
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to +150° C
Storage Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65° C to +150° C
Power Switch Junction-to-Case Thermal Resistance, R
θ
jc
. . . . . . . . . . . . . . . . . . . . . . 0.48°C/W
Package Isolation Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600 Vrms
Lead Soldering Temperature . . . . . . . . . . . . . 300°C, 10 seconds maximum, 0.125” from case
* Tcase = 25° C
** Tcase = 25° C, Maximum pulse width = 10mSec
RECOMMENDED OPERATING CONDITIONS
(Tcase = 25° C)
Motor Power Supply Voltage, V
m
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + 2 7 0 Vdc
Average Phase Output Current, I
O
With Internal Current Sense Resistor
(Note 2)
Each Power Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A
Control Supply Voltage, V
cc
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Vdc ±10%
Logic Low Input Voltage, V
il
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8 Vdc (max)
Logic High Input Voltage, V
ih
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 Vdc (min)
Note 1: Logic Inputs: Direction, Hall Inputs (H1...H3) Overvoltage - Coast, Speed, and Quad Select.
Note 2: The internal 5m
Ω
current sense resistor is limited to 6 Wdc power dissipation. Other values are available.
Please contact the factory for more information.
PARAMETER
SYMBOL
CONDITIONS (NOTE 1)
MIN.
TYP.
MAX.
UNITS
Power Output Section
IGBT Leakage Current
Ices
Vce = 600Vdc
300
uA
Vge = 0V
IGBT c-e Saturation Voltage
Vce(sat)
Ic = 50Adc
3.2
V
Vge = 15V
Diode Leakage Current
Ir
Vr = 600Vdc
100
uA
Diode Forward Voltage
Vf
If = 37A
1.7
V
Diode Reverse Recovery Time
trr
Io = 1A, di/dt = -100A/usec,
50
ns
Vr = 30V
Control Section
Control Supply Current
Icc
Vcc over operating range
100
mA
Control Turn-On Threshold
Vcc(+)
Tc over operating range
9.45
V
Driver Turn-On Threshold
Vcc(+)
Tc over operating range
13.0
V
Reference Section
Output Voltage
Vref
4.9
5.0
5.1
V
Output Voltage
Vref
Tc over operating range
4.7
5.0
5.3
V
Output Current
Io
---
---
30
mA
Load Regulation
Iload = 0mA to -20mA
-40
-5
mV
Short Circuit Current
Isc
Tc over operating range
50
100
150
mA
Error Amplifier / Spare Amplifier Sections
EA1 / EA2 Input Offset Current
Ios
V(pin 3) = V(pin 5) = 0V
-30
-3
0
nA
V(pin 4) = V(pin 7) = 0V
EA1 / EA2 Input Bias Current
Iin
V(pin 3) = V(pin 5) = 0V
-50
-45
0
nA
V(pin 4) = V(pin 7) = 0V
Input Offset Voltage
Vos
0V < Vcommon-mode < 3V
7
mV
Amplifier Output Voltage Range
--
0
6
V
PWM Comparator Section
PWM Input Current
Iin
V(pin 10) = 2.5V
0
3.0
30
uA
Current-Sense Amplifier Section
ISH / ISL Input Current
Iin
V(pin 13) = V(pin 14) = 0V
-850
-320
0
uA
Input Offset Current
Ios
V(pin 13) = V(pin 14) = 0V
+/-2
+/-12
uA
Peak Current Threshold Voltage
Vpk
V(pin 13) = 0V, V(pin 14)
0.14
0.20
0.26
V
Varied to Threshold
Over Current Threshold Voltage
Voc
V(pin 13) = 0V, V(pin 14)
0.26
0.30
0.36
V
Varied to Threshold
ISH / ISL Input Voltage Range
--
(Note 2)
-1
2
V
Amplifier Voltage Gain
Av
V(pin 13) = 0.3V, V(pin 14)
1.75
1.95
2.15
V/V
= 0.5V to 0.7V
Amplifier Level Shift
--
V(pin 13) = V(pin 14) = 0.3V
2.4
2.5
2.65
V
Logic Input Section
H1, H2, H3 Low Voltage Threshold
Vil
Tc over operating range
0.8
1.0
1.2
V
H1, H2, H3 High Voltage Threshold
Vih
Tc over operating range
1.6
1.9
2.0
V
H1, H2, H3 Input Current
Iin
Tc over operating range,
-400
-250
-120
uA
V(pin 21, 22 or 23) = 0Vdc
Quad Select / Direction
Threshold Voltage
Vth
Tc over operating range
0.8
1.4
2.0
V
Quad Select Voltage Hysteresis
Vh
70
mV
Direction Voltage Hysteresis
Vh
0.6
V
Quad Select Input Current
Iin
-30
50
150
uA
Direction Input Current
Iin
-30
-1
30
uA
Overvoltage / Coast Input Section
Overvoltage / Coast Inhibit
Threshold Voltage
Vth
Tc over operating range
1.65
1.75
1.85
V
Overvoltage / Coast Restart
Threshold Voltage
Vth
Tc over operating range
1.55
1.65
1.75
V
Overvoltage / Coast Hysteresis Voltage Vh
0.05
0.10
0.15
V
Overvoltage / Coast Input Current
Iin
-10
-1
0
uA
2.1 - 4
OM9369CM
ELECTRICAL CHARACTERISTICS
Parameter
Symbol
Conditions (Note 1)
MIN.
TYP.
MAX.
Units
Soft-Start Section
Soft-Start Pull-Up Current
Ip
V(pin 19) = 0V
-16
-10
-5
uA
Soft-Start Discharge Current
Id
V(pin 19) = 2.5V
0.1
0.4
3.0
mA
Soft-Start Reset Threshold Voltage
Vth
0.1
0.2
0.3
V
Tachometer/Brake Section
Tachometer Output High Level
Voh
Tc o
ver operating range
4.7
5.0
5.3
V
(Pin 16) 10k
Ω
to 2.5 V
Tachometer Output Low Level
Vol
Tc o
ver operating range
(Pin 16) 10k
Ω
to 2.5 V
0.2
V
Tachometer On-Time
ton
85
100
140
us
Tachometer On-Time Variation
--
Tc o
ver operating range
0.1
%
Brake/Tach Timing Input Current
Iin
V (pin 17) = oV
-4.0
-1.9
mA
Brake/Tach Timing
Threshold Voltage
Vth
Tc o
ver operating range
0.8
1.0
1.2
V
Brake/Tach Timing
Voltage Hysteresis
Vh
0.09
V
Speed Input Threshold Voltage
Vth
Tc o
ver operating range
220
257
290
mV
Speed Input Current
Iin
-30
-5
30
uA
Oscillator Section
Oscillator Frequency
fo
Measured at pin 11
13.5
14.8
20.0
kHz
SPECIFICATION NOTES:
1. All parameters specified for Ta = 25
°
C, Vcc = 15Vdc, Rosc = 75K
Ω
(to Vref), Cosc = 1800 pF, and all Phase Outputs unloaded (Ta ~ Tj). All negative currents shown
are sourced by (flow from) the pin under test.
2. Either ISH or ISL may be driven over the range shown.
3. Bold parameters tested at -55
°
C, 25
°
C, 125
°
C.
PIN#
NAME
PIN#
NAME
1
VCC
24
Speed Input
2
Delay
25
Direction Input
3
EA1 “-” Input
26
CSH
4
EA2 “+” Input
27
CSL
5
EA1 “+” Input
28
(No Connection)
6
+5V Reference Output
A
Motor Return
7
EA2 “-” Input
B
Vmotor
8
EA2 Output
C
Phase C Output
9
EA1 Output
D
Phase B Output
10
PWM Input
E
Phase A Output
11
Oscillator Timing Input
(Base)
(No Connection)
12
Isense
13
ISH
14
ISL
15
Quad Select Input
16
Tachometer Output
17
Brake/Tach Timing Input
18
Overvoltage/Coast Input
19
Soft-Start Input
20
Ground
21
H3 Input
22
H2 Input
23
H1 Input
2.1 - 5
OM9369CM
PINOUT
output clears the internal PWM latch, which in turn
commands the Phase Outputs to chop. For voltage-
mode control systems, pin 10 may be connected to the
Oscillator Timing Input, pin 11.
OSCILLATOR TIMING INPUT (Pin 11) -- The Oscillator
Timing Input sets a fixed PWM chopping frequency by
means of an internal resistor (Rosc), whose value is set
to 75k
Ω
, connected from pin 11 to the +5V Reference
Output, and an internal capacitor (Cosc), whose value
is 1800pF, connected from pin 11 to Ground. In custom
applications, the recommended range of values for
Rosc is 10k
Ω
to 100k
Ω
, and for Cosc is 0.001uF to
0.01uF, and the maximum operating frequency should
be kept below 20kHz. The approximate oscillator
frequency is:
2
fo = (Rosc x Cosc)
[Hz]
The voltage waveform on pin 11 is a ramp whose
magnitude is approximately 1.2Vp-p, centered at
approximately 1.6Vdc. In addition to the voltage-mode
PWM control, pin 11 may be used for slope
compensation in current-mode control applications.
ISENSE (Pin 12) -- 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
12 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 13; ISL, pin 14)
-- These inputs to the current-sense amplifier are
interchangeable and they can be used as differential
inputs. The differential voltage applied between pins 13
and 14 should be kept below +/-0.5Vdc to avoid
saturation.
QUAD SELECT INPUT (Pin 15) -- This input is used to
set the OM9369CM in a half control or full control
chopping regime. When driven with a logic low level, the
OM9369CM 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 OM9369CM 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 OM9369CM.
PIN DESCRIPTIONS / FUNCTIONALITY
VCC (Pin 1) -- The Vcc Supply input provides bias
voltage to all of the internal control electronics within
the OM9369CM, 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 20).
DELAY (Pin 2) -- This pin must be connected to the
Brake/Tach Timing Input pin (pin 17) to ensure that
the high-side bootstrap capacitors are charged
during initial startup.
ERROR AMPLIFIER (EA1- Input, Pin 3; EA1+
Input, Pin 5; EA1 Output, Pin 9) -- 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 3 is connected to pin 9. The
output of the Error Amplifier is internally connected
to the PWM comparator's "-" input, simplifying
external layout connections.
+5V REFERENCE OUTPUT (Pin 6) -- 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 OM9369CM, 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 20).
SPARE AMPLIFIER (EA2- Input, Pin 7; EA2+
Input, Pin 4; EA2 Output, Pin 8) -- 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 7 is
connected to pin 8. If the Spare Amplifier is unused,
pin 4 should be connected to Ground, and pin 7
should be connected to pin 8.
PWM INPUT (Pin 10) -- This pin is connected to the
"+" input of the internal PWM comparator. The PWM
2.1 - 6
OM9369CM
TACHOMETER OUTPUT (Pin 16) -- This output
provides a fixed width 5V pulse when any Hall-effect
Input (1, 2 or 3) changes state. The pulse width of the
Tachometer Output is set internally in the OM9369CM
to 113
µ
s (nominal). The average value of the output
voltage on pin 16 is directly proportional to the motor's
speed, so this output may be used (with an external
averaging filter) as a true tachometer output, and fed
back to the Speed Input (pin 24) to sense the actual
motor speed.
Note: Whenever pin 16 is high, the internal Hall-effect
position latches are inhibited (i.e. "latched"), to reject
noise during the chopping portion of the commutation
cycle, and this makes additional commutations
impossible. This means that in order to prevent false
commutation at a speed less than the desired
maximum speed, the highest speed as observed at the
Tachometer Output should be set above the expected
maximum value.
BRAKE / TACH TIMING INPUT (Pin 17) -- The
Brake/Tach Timing Input is a dual-purpose input.
Internal to the OM9369CM are timing components tied
from pin 17 to Ground (a 51k
Ω
resistor and a 3300pF
capacitor). These components set the minimum pulse
width of the Tachometer Output to 113
µ
s, and this time
may be adjusted using external components,
according to the equation:
T(tach) = 0.67 x (Ct + 3300pf) x
(
Rt x 51k
Ω
)
(µs)
Rt + 51k
Ω
The recommended range of external resistance (to
Ground) is 15k
Ω
to
∞
, and the range of external
capacitance (to Ground) is 0pF to 0.01uF. With each
Tachometer Output pulse, the capacitor tied to pin 17
is discharged from approximately 3.33V to
approximately 1.67V by an internal timing resistor. The
Brake / Tach Timing Input has another function. If this
pin is pulled below the brake threshold voltage, the
OM9369CM will enter the brake mode. The brake
mode is defined as the disabling of all three high-side
(pull-up) drivers associated with the Phase Outputs,
and the enabling of all three low-side (pull-down)
drivers.
OVERVOLTAGE / COAST INPUT (Pin 18) -- This
input may be used as a shutdown or an enable/disable
input to the OM9369CM. Also, since the switching
inhibit threshold is so tightly defined, this input can be
directly interfaced with a resistive divider which senses
the voltage of the motor supply, Vm, for overvoltage
conditions. A high level (greater than the inhibit
threshold) on pin 18 causes the coast condition to
occur, whereby all Phase Outputs revert to a Hi-Z state
and any motor current which flowed prior to the
Overvoltage / Coast command is commutated via the
power "catch" rectifiers associated with each Phase
Output.
2.1 - 7
OM9369CM
SOFT-START INPUT (Pin 19) -- The Soft-Start input is
internally connected to a 10
µ
A (nominal) current source,
the collector of an NPN clamp/discharge transistor, and a
voltage comparator whose soft-start/restart threshold is
0.2Vdc (nominal). An external capacitor is connected
from this pin to Ground (pin 20). Whenever the Vcc
supply input drops below the turn-on threshold,
approximately 9Vdc, or the sensed current exceeds the
over-current threshold, approximately 0.3V at the current
sense amplifier, the soft-start latch is set. This drives the
NPN clamp transistor which discharges the external soft-
start capacitor. When the capacitor voltage drops below
the soft-start/restart threshold and a fault condition does
not exist, the soft-start latch is cleared; the soft-start
capacitor charges via the internal current source.
In addition to discharging the soft-start capacitor, the
clamp transistor also clamps the output of the error
amplifier internal to the controller IC, not allowing the
voltage at the output of the error amplifier to exceed the
voltage at pin 19, regardless of the inputs to the amplifier.
This action provides for an orderly motor start-up either at
start-up or when recovering from a fault condition.
GROUND (Pin 20) -- The voltages that control the
OM9369CM are referenced with respect to this pin. All
bypass capacitors, timing resistors and capacitors, loop
compensation components, and the Hall-effect filter
capacitors must be referenced as close as possible to pin
20 for proper circuit operation. Additionally, pin 20 must
be connected as close as physically possible to the Motor
Return, pin A.
HALL-EFFECT INPUTS (H1, Pin 23; H2, Pin 22; H3, Pin
21) -- Each input has an internal pull-up resistor to the
+5V Reference. Each input also has an internal 180pF
noise filter capacitor to Ground. In order to minimize the
noise which may be coupled from the motor commutation
action to these inputs, it is strongly recommended that
additional external filter capacitors, whose value is in the
range of 2200pF, be connected from each Hall-Effect
Input pin to Ground. Whatever capacitor value is used,
the rise/fall times of each input must be guaranteed to be
less than 20us for proper tachometer action to occur.
Motors with 60 degree position sensing may be used if
one or two of the Hall-effect sensor signals is inverted
prior to connection to the Hall-Effect Inputs.
SPEED INPUT (Pin 24) - This pin is connected to the “+”
input of a voltage comparator, whose threshold is
0.25Vdc. As long as the Speed Input is less than 0.25V,
the direction latch is transparent. When the Speed Input
is greater than 0.25V, then the direction latch inhibits all
changes in direction. It is recommended, especially while
operating in the half control mode, that the Tachometer
Output is connected to the Speed Input via a low-pass
filter, such that the direction latch is transparent only
when the motor is spinning very slowly. In this case,
the motor has too little stored energy to damage the
power devices during direction reversal.
DIRECTION INPUT (Pin 25) - This input is used to
select the motor direction. This input has an internal
protection feature: the logic-level present on the
Direction Input is first loaded into a direction latch, then
shifted through a two-bit shift register before
interfacing with the internal output phase driver logic
decoder. Also, protection circuitry detects when the
input and the output of the direction latch or the 2-bit
shift register are different, and inhibits the Phase
Outputs (i.e. Hi-Z) during those times. This feature
may be used to allow the motor to coast to a safe
speed before a direction reversal takes place. Power
stage cross-conduction (current "shoot-through" from
Vmotor to Ground through simultaneously enabled
pull-up and pull-down drivers) is prevented by the shift
register as it is clocked by the PWM oscillator, so that
a fixed delay of between one and two PWM oscillator
clock cycles occurs. This delay or "dead-time"
guarantees that power-stage cross-conduction will not
occur.
CURRENT SENSE OUTPUTS (CSH, Pin 26; CSL,
Pin 27) - The Current Sense Outputs produce a
differential voltage equal to the motor current times the
sense resistance value (5m
Ω
nominal). There is an
internal 1000pF filter capacitor across pins 26 and 27,
and two 100
Ω
series resistors, one between each pin
and each end of the current sense resistor. To
configure the current sense amplifier for cycle-by-cycle