CIRRUS SA12

���������������������������������
����
� � � � � � � � � � � � � � �
��������������������������������������������������������������
FEATURE
•
•
•
•
•
•
•
HIGH FREQUENCY SWITCHING — 200 kHz
WIDE SUPPLY RANGE—16-200V
15A CONTINUOUS TO 65°C CASE
3 PROTECTION CIRCUITS
ANALOG OR DIGITAL INPUTS
SYNCHRONIZED OR EXTERNAL OSCILLATOR
FLEXIBLE FREQUENCY CONTROL
APPLICATIONS
•
•
•
•
•
REACTIVE LOADS
LOW FREQUENCY SONAR
LARGE PIEZO ELEMENTS
OFF-LINE DRIVERS
C-D WELD CONTROLLER
12-PIN POWER DIP
PACKAGE STYLE CR
EXTERNAL CONNECTIONS
DESCRIPTION
��������
The SA12 is a pulse width modulation amplifier that can
supply 3000W to the load. An internal 400kHz oscillator requires no external components. The clock input stage divides
the oscillator frequency by two, which provides the 200 kHz
switching frequency. External oscillators may also be used to
lower the switching frequency or to synchronize multiple amplifiers. Current sensing is provided for each half of the H-bridge
giving amplitude and direction data. A shutdown input turns
off all four drivers of the H-bridge output. A high side current
limit and the programmable low side current limit protect the
amplifier from shorts to supply or ground in addition to load
shorts. The H-bridge output MOSFETs are protected from
thermal overloads by directly sensing the temperature of the
die. The 12-pin hermetic MO-127 power package occupies
only 3 square inches of board space.
BLOCK DIAGRAM AND TYPICAL APPLICATION
TORQUE MOTOR DRIVER
��� ��
����
������
�
��
�������
����
�
��
���������
�
�
���
�����
�
�
�
�
������
�������
������
���
�����
���������
��������������������������������������������������������������������
�������������������������������������������������������
��������������������������������������
��������������������������������������������������������
����������
�
���
������
�������
�
��
�
� ���
�
���
���
��������� �
�������
� ���
��
���
����
���������
�������
�����
�
�����
���
�����
�����
�����
��
��
��
��������
�������
�
�
�
�
���������
���������
��
�����
������
��
���������
������
��
��
APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected]
1
SA12
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, +VS
SUPPLY VOLTAGE, VCC
POWER DISSIPATION, internal
TEMPERATURE, pin solder - 10s
TEMPERATURE, junction3
TEMPERATURE, storage
OPERATING TEMPERATURE RANGE, case
INPUT VOLTAGE, +PWM
INPUT VOLTAGE, –PWM
INPUT VOLTAGE, ILIM
SPECIFICATIONS
PARAMETER
CLOCK (CLK)
CLK OUT, high level4
CLK OUT, low level4
FREQUENCY
RAMP, center voltage
RAMP, P-P voltage
CLK IN, low level4
CLK IN, high level4
OUTPUT
TOTAL RON4
EFFICIENCY, 10A output
SWITCHING FREQUENCY
CURRENT, continuous4
CURRENT, peak4
POWER SUPPLY
VOLTAGE, VS
VOLTAGE, VCC
CURRENT, VCC
CURRENT, VCC, shutdown
CURRENT, VS
TEST CONDITIONS2
MIN
IOUT ≤ 1mA
IOUT ≤ 1mA
4.8
0
392
CAUTION
400
5
4
MAX
UNITS
5.3
.4
408
V
V
kHz
V
V
V
V
.9
5.4
.4
VS = 200V
OSC in ÷ 2
65°C case
Full temperature range
Full temperature range
IOUT = 0
196
15
20
16
14
97
200
120
15
No Load
90
THERMAL3
RESISTANCE, junction to case
RESISTANCE, junction to air
TEMPERATURE RANGE, case
4.
TYP
0
3.7
ILIM/SHUTDOWN
TRIP POINT
INPUT CURRENT
NOTES: 1.
2.
3.
200V
16V
250W1
300°C
150°C
–65 to +150°C
–55 to +125°C
0 to +11V
0 to +11V
0 to +10V
Full temperature range, for each die
Full temperature range
Meets full range specifications
204
Ω
%
kHz
A
A
200
16
80
50
200
V
V
mA
mA
mA
110
100
mV
nA
1
°C/W
°C/W
°C
12
–25
+85
Each of the two active output transistors can dissipate 125W.
Unless otherwise noted: TC = 25°C, VS, VCC at typical specification.
Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power
dissipation to achieve high MTTF. For guidance, refer to the heatsink data sheet.
Guaranteed but not tested.
The SA12 is constructed from MOSFET transistors. ESD handling procedures must be observed.
The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush,
machine, or subject to temperatures in excess of 850°C to avoid generating toxic fumes.
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
2
�����������
���������������
�
��
��
��
��
��
��
���
���
����������������������
�������������
��
������������������������
��
��
�
�
�
�
���
���
���
���
���
�����������������������������
�����������������
��
������������������
�
���
�
��������������������������
���
��
��
��
���
���
���
��
��
���
���
�����������������������
���������������������
���������
������������
�
�
�
�����������������
�
�����������������������
���
���
������
���������
��
��
��
�
�
������������������������������������
�������������������������������������
���
��������
���������
��
��� ��� � �� �� �� ��� ���
������������������������
����
����
����
����
��� ��� � �� �� �� ��� ���
����������������������
��
���
��
��
��
��
�
�� �� �� ��� ��� ��� ��� ���
�������
������������������
����
��
����
�
�����
�
�
�����
�
�
�
��
���
�
��
���
���
�����������������������������
�����
�
��
�����
������������������������
���������������
���������������
��
�����
���
�����
��
�����
����
��
���
��������������������������
��
��
�����
�����������������������
��
��
�����
�������������������������������������
��
�������������������������
�������������
������������������������������������
��
�������������������������
���
���
�������������������������
��������������
���
�
SA12
����������������������������
�������������������������������
TYPICAL PERFORMANCE
GRAPHS
���
�����
����
�����
�
�
�
��
��
�������������������
���������������������
��
��
��
��
��
��
���
���
���
����������������������������
�������������������������
���
��
��
��
��
���
��
���
��
���
����������������������������
APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected]
3
OPERATING
CONSIDERATIONS
SA12
GENERAL
CLOCK CIRCUIT AND RAMP GENERATOR
The clock frequency is internally set to a frequency of approximately 400kHz. The CLK OUT pin will normally be tied to
the CLK IN pin. The clock is divided by two and applied to an
RC network which produces a ramp signal at the –PWM/RAMP
pin. An external clock signal can be applied to the CLK IN pin
for synchronization purposes. If a clock frequency lower than
400kHz is chosen an external capacitor must be tied to the
–PWM/RAMP pin. This capacitor, which parallels an internal
capacitor, must be selected so that the ramp oscillates 4 volts
p-p with the lower peak 3 volts above ground.
PWM INPUTS
The full bridge driver may be accessed via the pwm input
comparator. When +PWM > -PWM then A OUT > B OUT. A
motion control processor which generates the pwm signal can
drive these pins with signals referenced to GND.
PROTECTION CIRCUITS
A fixed internal current limit senses the high side current.
Should either of the outputs be shorted to ground the high
side current limit will latch off the output transistors. The temperature of the output transistors is also monitored. Should a
fault condition raise the temperature of the output transistors
to 165°C the thermal protection circuit will latch off the output
transistors. The latched condition can be cleared by either
recycling the Vcc power or by toggling the I LIMIT/SHDN input
with a 10V pulse. See Figures A and B. The outputs will remain
off as long as the shutdown pulse is high (10V).
When supply voltage is over 100V, these circuits may not
protect the FET switches in the case of short circuits directly
at the pins of the amplifier. However, a small inductance between the amplifier and the short circuit will limit current rise
time and the protection circuits will be effective. A pair of 12
inch wires is adequate inductance.
CURRENT LIMIT
Switching noise spikes will invariably be found at the I SENSE
pins. The noise spikes could trip the
�������
current limit threshold which is only
���������
100 mV. RFILTER and CFILTER should
��
be adjusted so as to reduce the
switching noise well below 100 mV
�������
to prevent false current
limiting. The sum of the
��������
������������ �
�������
������ DC level plus the noise
�����
peak will determine the
��������
������
current limiting value.
As in most switching
����������������������������
circuits it may be dif����������������������
ficult to determine the
true noise amplitude without careful attention to grounding
of the oscilloscope probe. Use the shortest possible ground
lead for the probe and connect exactly at the GND terminal of
the amplifier. Suggested starting values are CFILTER = .01uF,
RFILTER = 5k .
The required value of RLIMIT in voltage mode may be calculated by:
RLIMIT = .1 V / ILIMIT
where RLIMIT is the required resistor value, and ILIMIT is the
maximum desired current. In current mode the required value
of each RLIMIT is 2 times this value since the sense voltage is
divided down by 2 (see Figure B). If RSHDN is used it will further
divide down the sense voltage. The shutdown divider network
will also have an effect on the filtering circuit.
���������
Please read Application Note 30 on "PWM Basics". Refer
to Application Note 1 "General Operating Considerations" for
helpful information regarding power supplies, heat sinking and
mounting. Visit www.apexmicrotech.com for design tools that
help automate pwm filter design; heat sink selection; Apex’s
complete Application Notes library; Technical Seminar Workbook; and Evaluation Kits.
���������
There are two load current
�������
sensing pins, I SENSE A and ���������
I SENSE B. The two pins can
��
be shorted in the voltage
��������
mode connection but both ������������ ��������
������
�����
must be used in the current
������
��������
mode connection (see figures
A and B). It is recommended
that RLIMIT resistors be non-in- ����������������������������
����������������������
ductive. Load current flows in
the I SENSE pins. To avoid errors due to lead lengths connect
the I LIMIT/SHDN pin directly to the RLIMIT resistors (through
the filter network and shutdown divider resistor) and connect
the RLIMIT resistors directly to the GND pin.
��
BYPASSING
Adequate bypassing of the power supplies is required for
proper operation. Failure to do so can cause erratic and low
efficiency operation as well as excessive ringing at the outputs. The Vs supply should be bypassed with at least a 1µF
ceramic capacitor in parallel with another low ESR capacitor
of at least 10µF per amp of output current. Capacitor types
rated for switching applications are the only types that should
be considered. The bypass capacitors must be physically
connected directly to the power supply pins. Even one inch of
lead length will cause excessive ringing at the outputs. This is
due to the very fast switching times and the inductance of the
lead connection. The bypassing requirements of the Vcc supply
are less stringent, but still necessary. A .1µF to .47µF ceramic
capacitor connected directly to the Vcc pin will suffice.
MODULATION RANGE
The high side of the all N channel H-bridge is driven by a
bootstrap circuit. For the output circuit to switch high, the low
side circuit must have previously been switched on in order to
charge the bootstrap capacitor. Therefore, if the input signal to
the SA12 demands a 100% duty cycle upon start-up the output
will not follow and will be in a tri-state (open) condition. The
ramp signal must cross the input signal at some point to correctly determine the output state. After the ramp crosses the
input signal one time the output state will be correct thereafter.
In addition, if during normal operation the input signal drives
the SA12 beyond its linear modulation range (approximately
95%) the output will jump to 100% modulation.
This data
sheet has been carefullyCORPORATION
checked and is believed
to beNORTH
reliable, however,
no responsibility
is assumed ARIZONA
for possible inaccuracies
omissions.
All specificationsHOTLINE:
are subject to
notice.
APEX
MICROTECHNOLOGY
• 5980
SHANNON
ROAD • TUCSON,
85741 • orUSA
• APPLICATIONS
1 change
(800)without
546-2739
4
SA12U REV E SEPTEMBER 2004
© 2004 Apex Microtechnology Corp.