4707 Dey Road Liverpool, N.Y. 13088
(315) 701-6751
M.S.KENNEDY CORP.
ISO 9001 CERTIFIED BY DSCC
4252
30 AMP, 75V, H-BRIDGE
MOSFET BRUSHED
MOTOR CONTROLLER
FEATURES:
75 Volt Motor Supply Voltage
30 Amp Output Switch Capability
100% Duty Cycle High Side Conduction Capable
Shoot-Through/Cross Conduction Protection
"Real" Four Quadrant Torque Control Capability
Good Accuracy Around the Null Torque Point
MIL-PRF-38534 CERTIFIED
DESCRIPTION:
The MSK 4252 is a complete H-bridge MOSFET Brushed Motor Control System in an electrically isolated hermetic
package. The hybrid is capable of 30 amps of output current and 75 volts of DC bus voltage. It has the normal features for
protecting the bridge. Included is all the bridge drive circuitry, and all the current sensing and analog circuitry necessary for
closed loop current mode (torque) control. When PWM'ing, the transistors are modulated in locked anti-phase mode for the
tightest control and the most bandwidth. Provisions for applying different compensation schemes are included. The MSK
4252 has good thermal conductivity of the MOSFET's due to isolated substrate/package design that allows direct heat
sinking of the hybrid without insulators.
EQUIVALENT SCHEMATIC
TYPICAL APPLICATIONS
Brushed DC Motor Control
Servo Control
Fin Actuator Control
Voice Coil Control
Gimbal Control
AZ-EL Control
1
PRELIMINARY Rev. - 2/05
Typ.
60
16
25
3
0.33
5.0
-
12
8
13
6.5
275
POWER SUPPLY REQUIREMENTS
+Vcc
-Vcc
PWM
Free Running Frequency
CONTROL
Transconductance
Current Monitor
ERROR AMP
Input Voltage Range
Slew Rate
Output Voltage Swing
Gain Bandwidth Product
Large Signal Voltage Gain
75V
13.5V
+16V
-18V
30A
50A
High Voltage Supply
Current Command Input
Continuous Output Current
Peak Output Current
@ +15V
@ -15V
30 Amps Output
30 Amps Output
mA
mA
KHz
Amp/Volt
V/Amp
mAmp
mAmp
Volts
V/Sec
Volts
MHz
V/mV
ABSOLUTE MAXIMUM RATINGS
V+
V
IN
+Vcc
-Vcc
I
OUT
I
PK
1.5C/W
-65C to +150C
+300C
-40C to +125C
-55C to +125C
+150C
JC
T
ST
T
LD
T
C
T
J
Parameter
ELECTRICAL SPECIFICATIONS
Units
Max.
85
35
28
3.6
0.40
35.0
-
-
-
-
-
-
MSK 4252
Typ.
60
16
25
3
0.33
5.0
-
12
8
13
6.5
275
Test Conditions
Min.
-
-
22
2.4
0.26
-
-
11
6.5
12
-
175
Thermal Resistance @ 125C
Storage Temperature Range
Lead Temperature Range
(10 Seconds)
Case Operating Temperature
MSK4252
MSK4252H/E
Junction Temperature
All Ratings: Tc=+25C Unless Otherwise Specified
2
Max.
85
35
26.5
3.3
0.38
25.0
50.0
-
-
-
-
-
MSK 4252H/E
Min.
-
-
23.5
2.7
0.28
-
-
11
6.5
12
-
175
1,2,3
1,2,3
4,5,6
4,5,6
4,5,6
4
5,6
-
-
-
-
-
-
-
-
-
-
-
-
-
-
NOTES:
1
Guaranteed by design but not tested. Typical parameters are representative of actual device
performance but are for reference only.
2
Industrial grade and "E" suffix devices shall be tested to subgroups 1 and 4 unless otherwise specified.
3
Military grade devices ("H" Suffix) shall be 100% tested to Subgroups 1, 2, 3 and 4.
4
Subgroups 5 and 6 testing available upon request.
5
Subgroup 1, 4 T
A
= T
C
= +25C
2, 5 T
A
= T
C
= +125C
3, 6 T
A
= T
C
= -55C
6
This is to be used for MOSFET thermal calculation only.
7
Measurements do not include offset current at 0V current command.
8 Continuous operation at or above absolute maximum ratings may adversly effect the device
performance and/or life cycle.
3
2
nSec
nSec
Amps
Volts
Volts
Volts
nSec
Sec
OUTPUT
Rise Time
Fall Time
Leakage Current
Voltage Drop Across Bridge (1 Upper and 1 Lower)
Voltage Drop Across Bridge (1 Upper and 1 Lower)
Drain-Source On Resistance (Each MOSFET)
Diode VSD
trr
Dead Time
-
-
750
0.3
0.6
0.026
2.6
-
-
100
100
-
-
-
-
-
280
2
-
-
-
-
-
-
-
-
-
100
100
-
-
-
-
-
280
2
-
-
-
-
-
-
-
-
-
-
-
750
1
1.83
0.026
2.6
-
-
7
Group A
5
Subgroup
4
7
6
1
1
1
1
1
1
1
1
1
1
1
1
@ 0 Volts Command
Output Offset
1
8
@ 64V, +150C Junction
@ 30 Amps
@30Amps, +150C Junction
@ 30 Amps, 150C Junction
@ 30 Amps, Each FET
IF=30 Amps, di/dt=100A/S
PRELIMINARY Rev. - 2/05
APPLICATION NOTES
IN
MSK 4252 PIN DESCRIPTIONS
AV+, BV+ - are the power connections from the hybrid to
the bus. All pins for the motor voltage supply should be con-
nected together to share the current through the pins in the
hybrid. The external wiring to these pins should be sized
according to the RMS current required by the motor. A high
quality monolithic ceramic capacitor for high frequencies and
enough bulk capacitance for keeping the V+ supply from
drooping should bypass these pins. 470F minimum is rec-
ommended. Capacitors should be placed as close to these
pins as practical. The addition of high quality ceramic capaci-
tance will help with noise issues.
OUTPUT A, OUTPUT B- are the connections to the motor
phase windings from the bridge output. The wiring to these
pins should be sized according to the required current by the
motor. There are no short circuit provisions for these out-
puts. Shorts to V+ or gound from these pins must be avoided
or the bridge will be destroyed.
RTN - is the power return connection from the module to the
bus. All internal ground returns connect to this point inside
the hybrid. All capacitors from the V+ bus should connect to
this point as close as possible. All external V+ return con-
nections should be made as close to these pins as possible.
Wiring sizing to this pin should be made according to the
required current.
GND - is the return point for the low powered circuitry inside
the hybrid. All GND pins should be tied together. All capaci-
tors for bypassing the + and -15V supplies should be tied at
this point, as close to the pins as possible. Any ground plane
connections for low powered and analog citcuitry outside the
hybrid should be tied to this point.
+15VIN - is the input for applying +15 volts to run the low
power section of the hybrid. Both pins should be used to-
gether for optimum operation. These pins should be bypassed
with a 10F capacitor and a 0.1F capacitor as close to these
pins as possible.
-15VIN - is the input for applying -15 volts to run the low
power section of the hybrid. Both pins should be used to-
gether for optimum operation. These pins should be bypassed
with a 10F capacitor and a 0.1F capacitor as close to these
pins as possible.
SENSE RESISTOR + - is the top of the sense resistor for
sensing the bridge current and closing the loop. The bottom
of the sense resistor is RTN. All RSENSE A and RSENSE B
pins should be connected to this point, with connectios being
as short as possible.
RSENSE A, RSENSE B - are the power pins for the bottom
of the bridge. Both of these pins are to be connected to sense
resistor +, with connections being as short as possible.
DIS - is a pin for externally disabling the output bridge. A TTL
logic low will enable the bridge and a TTL high will disable it.
It is internally pulled up by a 100Amp pull-up.
CURRENT COMMAND (+,-) - are differential inputs for con-
trolling the module in current mode. Scaled at 3 amps per volt
of input command, the bipolar input allows both forward and
reverse current control capability regardless of motor direc-
tion. The maximum operational command voltage should be
10 volts for 30 amps of motor current. Going beyond
10 volts of command voltage will force the bridge to conduct
more than the desired maximum current. There is internal
current limiting that will ultimately limit the absolute maximum
current being output by the bridge. The input impedance is
approximately 3.75K
for each pin.
CURRENT MONITOR - is a pin providing a current viewing
signal for external monitoring purposes. This is scaled at 3
amps of motor current per volt output, up to a maximum of
10 volts, or 30 amps. Going beyond the 10 volt maxi-
mum may result in clipping of the waveform peaks.
E/A OUT - is the current loop error amplifier output. It is
brought out for allowing various loop compensation circuits
to be connected between this and E/A-.
E/A- - is the current loop error amplifier inverting input. It is
brought out for allowing various loop compensation circuits
to be connected between this and E/A OUT.
3
PRELIMINARY Rev. - 2/05
BUS VOLTAGE FILTER CAPACITORS
The size and placement of the capacitors for the DC bus has a direct bearing on the amount of noise filtered and also on the size
and duration of the voltage spikes seen by the bridge. What is being created is a series RLC tuned circuit with a resonant
frequency that is seen as a damped ringing every time one of the transistors switches. For the resistance, wire resistance, power
supply impedance and capacitor ESR all add up for the equivalent lumped resistance in the circuit. The inductance can be figured
at about 30 nH per inch from the power supply. Any voltage spikes are on top of the bus voltage and the back EMF from the
motor. All this must be taken into account when designing and laying out the system. If everything has been minimized, there is
another solution. A second capacitance between 5 and 10 times the first capacitor and it should either have some ESR or a
resistor can be added in series with the second capacitor to help damp the voltage spikes.
Be careful of the ripple current in all the capacitors. Excessive ripple current, beyond what the capacitors can handle, will
destroy the capacitors.
15VIN FILTER CAPACITORS
It is recommended that about 10 F of capacitance (tantalum electrolytic) for bypassing the + and -15V inputs be placed as close
to the module pins as practical. Adding ceramic bypass capacitors of about 0.1 F or 1 F will aid in suppressing noise transients.
GENERAL LAYOUT
Good PC layout techniques are important. Ground planes for the analog circuitry must be used and should be tied back to the
small signal grounds, pins 10 and 11. The high power ground (RTN) pin 18 gets tied back to the small signal ground internally. DO
NOT connect these grounds externally. A ground loop will result.
LOW POWER STARTUP
When starting up a system utilizing the MSK 4252 for the first time, there are a few things to keep in mind. First, because of the
small size of the module, short circuiting the output phases either to ground or the DC bus will destroy the bridge. The current
limiting and control only works for current actually flowing through the bridge. The current sense resistor has to see the current
in order for the electronics to control it. If possible, for startup use a lower voltage and lower current power supply to test out
connections and the low current stability. With a limited current supply, even if the controller locks up, the dissipation will be
limited. By observing the E/A OUT pin which is the error amp output, much can be found out about the health and stability of the
system. An even waveform with some rounded triangle wave should be observed. As current goes up, the DC component of the
waveform should move up or down. At full current (with a regular supply) the waveform should not exceed +9 volts positive peak,
or -9 volts negative peak. Some audible noise will be heard which will be the commutation frequency. If the motor squeals, there
is instability and power should be removed immediately unless power dissipation isn't excessive due to limited supply current. For
compensation calculations, refer to the block diagram for all information to determine the amplifier gain for loop gain calculations.
For the power up sequence, 15 volts should be powered at the same time or before the V+ voltage is applied.
APPLICATION NOTES CONTINUED
4
PRELIMINARY Rev. - 2/05
MSK4252 TEST CIRCUIT
5
PRELIMINARY Rev. - 2/05
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