MSA240 Datasheet, PDF (1/5 Pages) Cirrus Logic – PULSE WIDTH MODULATION AMPLIFIER

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MSMAS2A42400
Pulse Width Modulation Amplifiers
FEATURES
• LOW COST
• HIGH VOLTAGE - 100 VOLTS
• HIGH OUTPUT CURRENT - 20 AMPS
• 2kW OUTPUT CAPABILITY
• VARIABLE SWITCHING FREQUENCY
APPLICATIONS
• BRUSH MOTOR CONTROL
• MRI
• MAGNETIC BEARINGS
• CLASS D SWITCHMODE AMPLIFIER
DESCRIPTION
The MSA240 is a surface mount constructed PWM amplifier
that provides a cost effective solution in many industrial applica-
tions. The MSA240 offers outstanding performance that rivals
many much more expensive hybrid components. The MSA240
is a complete PWM amplifier including an oscillator, comparator,
error amplifier, current limit comparators, 5V reference, a smart
controller and a full bridge output circuit.The switching frequency
is user programmable up to 50 kHz. The MSA240 is built on a
thermally conductive but electrically insulating substrate that
can be mounted to a heatsink.
TYPICAL APPLICATION
58-pin DIP
PACKAGE STYLE KC
CONTROL
SIGNAL
SINGLE POINT GND @ 26
20
CLK/2 OUT
RRAMP ₁
RRAMP IN
24
CLK OUT
ROSC ₂₂
ROSC
19 _{+5V REF OUT}
13 _+IN
28 2,18,26 23
58
AC
BACK
SIG DIG PWR
GND RET GND
PLATE
35-39
A OUT
PWM AMPLIFIER
17 E/A OUT
B OUT ^49-53
16 E/A -IN
15 E/A +IN
2.5V
Is B
54-57
Is A
40-43
EQUIVALENT CIRCUIT DIAGRAM
VCC 29
5V REF
OUT
19
SIGNAL
GND
26
18
2
23
ILIM B 7
ILIM A/SHDN 10
ROSC 22
5V
REF
SIGNAL
GND
SIGNAL
GND
200mV
DIGITAL
RETURN
+
1K
-
.01F
+
1K
-
2.68K
.01F
2200pF ^OSC
CLK OUT 24
SMART
CONTROLLER
E/A OUT 17
E/A -IN 16
-
E/A +IN 15
+IN 13
RRAMP IN 1
+
5.36K
R2
+
R3
-
CLK/2 OUT 20
CLK IN 21
CLK/2
2200pF
AC BACK
PLATE
28
1F
APEX TP 27
PWR
GND
58
BACK PLATE
A1
Rs A
Rs B
2.5V
30-34
+Vs
44-48
+Vs
TORQUE MOTOR CONTROL
With the addition of a few external components the MSA240
becomes a motor torque controller. In the MSA240 the source
terminal of each low side MOSFET driver is brought out for
Q1
Q2
35-39
current sensing via R_SA and R_SB. A1 is a differential amplifier
that amplifies the difference in currents of the two half bridges.
A OUT _{This signal is fed into the internal error amplifier that mixes the}
D1
current signal and the control signal. The result is an input
Q3
49-53
signal to the MSA240 that controls the torque on the motor.
B OUT _{EXTERNAL CONNECTIONS}
D2
Q4
54-57
I SENSE B
40-43
I SENSE A
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
VIEW FROM
COMPONENT SIDE
R_RAMP
R_OSC
SINGLE
POINT
GND
C1
C2+
C3
58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29
PWR I_SENSE B
GND
B OUT
+Vs
I_SENSE A
A OUT
+Vs
VCC
NOTES: C2 IS ELECTROLYTIC ≥10UF PER AMP OUTPUT CURRENT
C1,3 HIGH QUALITY CERAMIC ≥1.0UF
ALL +Vs MUST BE TIED TOGETHER
ALL SIG GND PINS MUST BE TIED TOGETHER
SINGLE POINT GROUND @ PIN 26
MSA2_ht4_tp0_:U_{//www.cirrus.com}
Copyright © Cirrus Logic, Inc. 2009
(All Rights Reserved)
MAY 2009₁
APEX − MSA240UREVD