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4707 Dey Road Liverpool, N.Y. 13088

(315) 701-6751

M.S.KENNEDY CORP.

ISO 9001 CERTIFIED BY DSCC

75 VOLT 20 AMP MOSFET

H-BRIDGE PWM MOTOR

DRIVER/AMPLIFIER

4225

The MSK 4225 is a complete H-Bridge circuit to be used for DC brushed motor control or Class D switchmode amplifi-
cation. All of the drive/control circuitry for the lowside and highside switches are internal to the circuit. The 45KHz PWM
circuitry is internal as well, leaving the user to only provide an analog signal for the motor speed/direction, or audio signal for
switchmode audio amplification. The MSK 4225 is constructed in a space efficient plastic power package that can be
directly bolted to a heatsink.

DESCRIPTION:

EQUIVALENT SCHEMATIC

TYPICAL APPLICATIONS

PIN-OUT INFORMATION

1
2
3
4
5
6
7
8
9

Rev. B 11/04

FEATURES:

Low RDS(ON) 0.013

Typical

Low Cost Complete H-Bridge

20 Amp Capability, 75 Volt Maximum Rating

Self-contained Smart Lowside/Highside Drive Circuitry

Internal 45KHz PWM Generation, Shoot-through Protection

Isolated Case Allows Direct Heatsinking

Logic Level Disable Input

Logic Level High Side Enable Input for Special Modulation or Function

NC
VCC
HEN
DIS
NC
INPUT
NC
GND
GND
NC

RSENSE A
RSENSE A
OUTPUT A
OUTPUT A
V+
V+
OUTPUT B
OUTPUT B
RSENSE B
RSENSE B

Each MOSFET I

=20A

Each MOSFET I

=20A 3

Each MOSFET I

=20A Intrinsic Diode 3

Intrinsic Diode

Each MOSFET V+=70V

Analog Input=6V

Output A,B=50% Duty Cycle

Output A=100% Duty Cycle High

Output B=100% Duty Cycle High

Input Voltage LO

Input Voltage HI

Input Current (DISABLE=0V)

Input Voltage LO

Input Voltage HI

Input Current (HEN=0V)

=100

OUTPUT CHARACTERISTICS

RDS (ON) 1 4

VDS(ON) Voltage

Instantaneous Forward Voltage

Reverse Recovery Time 1

Leakage Current

PWM Frequency

Vcc SUPPLY CHARACTERISTICS

Quiescent Bias Current

Vcc Voltage Range 1

INPUT SIGNAL CHARACTERISTICS 1

Analog Input Voltage

LOGIC CONTROL INPUTS 1

SWITCHING CHARACTERISTICS 1

Rise Time

Fall Time

Dead Time

V+
V

OUT

ABSOLUTE MAXIMUM RATINGS

Parameter

ELECTRICAL SPECIFICATIONS

Units

KHz

Max.

0.013

0.52

1.3

280

0.8

135

0.8

270

MSK 4225

Typ.

0.45

1.0

170

100

Min.

2.7

Test Conditions 2

NOTES:

Guaranteed by design but not tested. Typical parameters are representative of actual device performance but are for reference only.

Vcc=+12V, V+=28V, RSENSE A,B=Ground, DIS=0V, HEN=N/C unless otherwise specified.

Measured using a 300µS pulse with a 2% Duty Cycle.

On Resistance is specified for the Internal MOSFET for Thermal Calculations. It does not include the package pin resistance.

Tc= +25°C Unless Otherwise Specified

Disable Input

HEN Input

Rev. B 11/04

High Voltage Supply
Logic Supply
Continuous Output Current
Peak Output Current
Output Voltage Range
Thermal Resistance
(Output Switches @ 125°C)

75V
16V

20A
40A

GND -2V min. to V + max.

3.0°C/W

Storage Temperature Range
Lead Temperature Range
(10 Seconds)
Case Operating Temperature
MSK4225
Junction Temperature

-55°C to +125°C

300°C

-40°C to +85°C

+150°C

APPLICATION NOTES

VCC - Is the low voltage supply for powering internal logic
and drivers for the lowside and highside MOSFETS.
The supplies for the highside drivers are derived from this
voltage.

OUTPUT B - Is the output pin for the other half of the
bridge. Increasing the input voltage causes increasing
duty cycles at this output.

OUTPUT A - Is the output pin for one half of the bridge.
Decreasing the input voltage causes increasing duty cycles
at this output.

RSENSE A - Is the connection for the bottom of the A half
bridge. This can have a sense resistor connection to the
V+ return ground for current limit sensing, or can be con-
nected directly to ground. The maximum voltage on this
pin is ±2 volts with respect to GND.

RSENSE B - Is the connection for the bottom of the B half
bridge. This can have a sense resistor connection to the
V+ return ground for current limit sensing, or can be con-
nected directly to ground. The maximum voltage on this
pin is ±2 volts with respect to GND.

GND - Is the return connection for the input logic and Vcc.

INPUT - Is an analog input for controlling the PWM pulse
width of the bridge. A voltage lower than Vcc/2 will pro-
duce greater than 50% duty cycle pulses out of OUTPUT
A. A voltage higher than Vcc/2 will produce greater than
50% duty cycle pulses out of OUTPUT B.

DISABLE - Is the connection for disabling all 4 output
switches. DISABLE high overrides all other inputs. When
taken low, everything functions normally. An internal
pullup to Vcc will keep DISABLE high if left unconnected.

HEN - Is the connection for enabling the high side output
switches. When taken low, HEN overrides other inputs
and the high side switches remain off. When HEN is high
everything functions normally. An internal pullup to Vcc
will keep HEN high if left unconnected.

This is a diagram of a typical application of the MSK4225. The
design Vcc voltage is +12 volts and should have a good low ESR
bypass capacitor such as a tantalum electrolytic. The analog input
can be an analog speed control voltage from a potentiometer, other
analog circuitry or by microprocessor and a D/A converter. This
analog input gets pulled by the current control circuitry in the proper
direction to reduce the current flow in the bridge if it gets too high.
The gain of the current control amplifier will have to be set to
obtain the proper amount of current limiting required by the sys-
tem.

Current sensing is done in this case by a 0.1 ohm sense resis-
tor to sense current from both legs of the bridge separately. It is
important to make the high current traces as big as possible to keep
inductance down. The storage capacitor connected to the V+ and
the module should be large enough to provide the high energy
pulse without the voltage sagging too far. A low ESR ceramic
capacitor or large polypropylene capacitor will be required. Mount
the capacitor as close to the module as possible. The connection
between GND and the V+ return should not be carrying any motor
current. The sense resistor signal is common mode filtered as nec-
essary to feed the limiting circuitry for the microprocessor. This
application will allow full four quadrant torque control for a closed
loop servo system.

A snubber network is usually required, due to the inductance in
the power loop. It is important to design the snubber network to
suppress any positive spikes above 70V and negative spikes be-
low -2V with respect to ground.

*There are certain inductive load situations that can possibly cause
a momentary shoot-through or cross-conduction condition in the
MSK4225. This shoot-through is approximately 100nSec long
and can be several amps, depending on the layout and impedence
of the bypassing circuit. Most bypassing and current sensing filter-
ing will usually eliminate the effects. However, in the case where it
is still present, or the sense resistor trace lengths are long, reverse-
biased ultra-fast recovery diodes or power schottky diodes from
RSENSE A and RSENSE B to power ground will minimize or elimi-
nate the situation.

V+ - Is the higher voltage H-bridge supply. The MOSFETS
obtain the drive current from this supply pin. The voltage
on this pin is limited by the drive IC. The MOSFETS are
rated at 75 volts. Proper by-passing to GND with suffi-
cient capacitance to suppress any voltage transients, and
to ensure removing any drooping during switching, should
be done as close to the pins of the module as possible.

MSK 4225 PIN DESCRIPTIONS

TYPICAL SYSTEM OPERATION

Rev. B 11/04

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: MSK4225G