ETC2 AC243E.F8A.G.LF.W Current mode pwm contoller Datasheet

Power Management AAC242/243
AAC242/243
PRELIMINARY DATA
Current Mode PWM Contoller
DESCRIPTION
The AAC242 and AAC243 are part of AAI’s new
family of specialty products for Power Management
applications. The AAC242 and AAC243 are high
performance integrated circuits designed for Off-line
or DC to DC converters using peak current mode
control. The AAC24X has a current sense of 250mV
in comparison to 1V for AAC14X parts.
In offline AC designs the startup is improved by the
low start-up current of the family. The integrated
soft-start function adds to the easy of using the
AAC24X parts in offline applications.
The AAC242 and AAC243 are identical except for the
Under Voltage Lockout. The AAC242 has UVLOon
threshold of 16V and off of 10V making it easy to use
in offline supplies where startup requirements for
energy storage is necessary. For applications using
lower supply voltages the AAC243 has UVLOon of
8.4V and UVLOoff of 7.6V.
FEATURES
• Low Start-up current
• Pulse by pulse current limiting
• On board voltage reference
•
•
•
•
•
•
•
•
Under Voltage Lockout with hysteresis
The greater than 1A output driver is ideal for driving
MOSFETs and low power IGBTs. Rise and fall times
are typically less that 30ns with a 1000pF load. The
improvements in switching speed can provide
improvements in efficiency, higher operating
frequency and over current protection.
•
100ns leading edge current blanking for reduced
filtering
•
250mV current sense
The AAC24X family has a minimum pulse width of
0.4% allowing operation at very low power without
pulse skipping or erratic operation. The narrower
pulse width capibilities enhances operation at higher
frequencies and voltages.
View of the AAC24X shown from the top.
The AAC24X family is offered in DIP and SMD
packages. The packages are industry standards and
are ROHS compliant.
Extended temperature is
standard with the AAC24X family.
© Copyright 2010- ASIC Advantage, Inc.
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Simple oscillator circuit
Over Voltage protection zener
High current output driver
Less than 30ns rise and fall times
Operation to over 1MHz
Peak Current Mode control
Integrated
Cycles)
Soft-Start
Function
(~330
Clock
PIN CONFIGURATION: 8-Lead DIP and SOIC8
AADS00012 / R127B
COMP 1
8
VFB AAC242
ISENSE AAC243
5
Rt/Ct 4
-
Preliminary
-
VREF
VCC
OUT
GND
October 2010
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Power Management AAC242/243
BLOCK DIAGRAM
8 Vcc
UVLO
34V
5.00VREF
5V
REF
5 GND
REF
OK
2.5V
OSC
4 Rt/Ct
Error
Amp
OUTPUT 6
11R
2R
+
S
2 Vf b
Vref 7
DVR
-
R
1V
R
+
Q
Current Sense
Comparator
1 COMP
3 Isense
Open Loop Test Circuit
V+
A
Rt
4.7K
100K
1
2N3904
2
1K
3
4
4.7K
5K
Vref
FB
Vcc
Isense
R/C
0.1uF
8
COMP
OUT
GND
7
1K/1W
6
OUTPUT
5
0.1uF
Ct
MAXIMUM RATINGS
PARAMETER
PARAMETERS
UNITS
CONDITIONS
Low impedance source
Supply Voltage (Vcc – Ground)
MIN.
0
MAX.
30
V
Vfb and Isense Amp Inputs
-0.3
5.5
V
±1
A
1200
mW
DIP
1000
mW
SOIC8
150
°C
Output Current
Power Dissipation
Operating Junction Temperature
Operating Ambient Temperature
-40
105
°C
Operating Ambient Temperature
-40
125
°C
Storage Temperature Range
-65
150
°C
300
°C
Lead Temperature (10 Second)
© Copyright 2010- ASIC Advantage, Inc.
–
AADS00012 / R127B
-
Preliminary
Extended industrial temp. rated
devices
Automotive temp. rated devices
Soldering
-
October 2010
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Power Management AAC242/243
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, T=25C, Vcc=15V, RT = 10KΩ, CT = 3300pF.
PARAMETER
PARAMETERS
UNITS
MIN.
TYP.
MAX.
4.95
5.00
5.05
V
Line Regulation
6
15
mV
Load Regulation
3
25
mV
CONDITIONS
REFERENCE SECTION
Output Voltage
Temperature Stability
Total Output Variation
0.2
4.9
5.1
Long Term Stability
Output Short Circuit Current
5
12V<Vcc<25V
mV/°C
0C to 130C
V
Line, Load, and Temperature
mV
Ta=125°C for 1000 hours
-30
-50
-60
mA
47
52
57
KHz
Ta=25°C
Frequency Change with Voltage
0.2
1
%
12<Vcc<25V
Frequency Change with Temp.
1
%
Tlow<Ta<Thigh
1.65
Vpp
OSCILLATOR SECTION
Frequency Initial Accuracy
Oscillator Voltage Swing
ERROR AMPLIFIER SECTION
Voltage Feedback Input
2.45
2.5
Input Bias Current
2.55
V
-1
µA
Vout=2.5V
Open Loop Voltage Gain
90
dB
Unity Gain Bandwidth
10
MHz
Tj=25°C
Power Supply Rejection Ratio
70
dB
12V<Vcc<25V
Output Current Sink
12
mA
Output Current Source
-1
mA
Output Voltage Swing High
6
V
Output Voltage Swing Low
0.8
V
Maximum Duty Cycle
97
%
Minimum Duty Cycle
0.4
%
PULSE WIDTH MODULATION SECTION
Before drop out
CURRENT SENSE SECTION
Voltage Gain
11.4
12.0
12.6
V
Maximum Input Signal
242
250
258
mV
Power Supply Rejection Ratio
70
dB
Input Bias Current
-10
µA
Time Delay to Output
300
nS
© Copyright 2010- ASIC Advantage, Inc.
–
AADS00012 / R127B
-
Preliminary
-
October 2010
3/8
Power Management AAC242/243
PARAMETER
PARAMETERS
MIN.
TYP.
UNITS
CONDITIONS
MAX.
OUTPUT SECTION
Voltage Out Low
0.4
V
Isink = 20mA
Voltage Out Low
2.2
V
Isink = 200mA
Voltage Out High
13.5
14
V
Isink = 20mA
Voltage Out High
12.5
13.5
V
Isink = 200mA
1.1
V
Vcc=6V, Isink = 1mA
Voltage Out UVLO
Voltage Output Rise Time
30
50
ns
CL=1000pF
Voltage Output Fall Time
30
50
ns
CL=1000pF
Current Output Source Peak
1.2
A
Current Output Sink Peak
0.7
A
UNDER-VOLTAGE LOCKOUT SECTION
Voltage Start Threshold (142)
15
16
17
V
Voltage Start Threshold (143)
7.8
8.4
9
V
Voltage Turnoff Threshold (142)
9
10
11
V
Voltage Turnoff Threshold (143)
7
7.6
8.2
V
Zener Clamp Voltage
30
34
V
Icc≤25mA
TOTAL DEVICE SECTION
Start-up Supply Current
0.4
Operating Supply Current
0.6
mA
11
mA
The improved switching performance increases the high peak current associated with internal and external
capacitances and will require careful grounding and PCB trace routing. Bypass and timing capacitors should be of
high quality and located carefully with short traces. The reference capacitor must be located very close to the IC
with minimum trace lengths. A single point ground should be located at pin 5 ground. The use of a good ground
plane is recommended. Under certain conditions of high peak currents it may be advisable to isolate the Vref pin
from the bypass capacitor with a resistor to prevent interaction of the high current with the internal oscillator
operation.
Charge and discharge times are given by the following formulas:
TC=0.55RtCt
TD=RtCtLn[(0.0063Rt-2.7)/(0.0063Rt-4)]
Frequency =( TC+ TD)-1
Oscillator simplified circuit.
1
2
Rt
3
4
COMP
Vref
FB
Vcc
Isense
OUT
R/C
GND
8
7
6
5
Ct
© Copyright 2010- ASIC Advantage, Inc.
–
AADS00012 / R127B
-
Preliminary
-
October 2010
4/8
Power Management AAC242/243
Dead/delay time verses Ct
Delay in µs
Rt resistance in KΩ
Oscillator Frequency as a function of Rt and Ct
Ct Capacitance in nF
Oscillator frequency in KHz
Peak current is set by the internal comparator with a fixed limit of 0.250V. Raising the current sense pin (3) to
0.250V or higher will cause a termination of the output pulse regardless of the error amplifier output. The peak
current is normally determined when the current sense pin exceeds the error amplifier conditioned output. Peak
current is determined by the formula:
ISENSE(PK) = 0.250V/RS
In some cases where leading edge switching transients exceed the 100ns blanking, a small RC filter will be required.
RC filter
1
2
3
R
Rsense
© Copyright 2010- ASIC Advantage, Inc.
–
C
4
COMP
Vref
FB
Vcc
Isense
OUT
R/C
GND
AADS00012 / R127B
-
8
7
6
5
Preliminary
-
October 2010
5/8
Power Management AAC242/243
In cases where duty cycle exceeds 50% slope compensation is required. This can be implemented by adding a buffer
transistor to the oscillator circuit and using a resistive summing circuit to provide the ramp necessary for slope
compensation.
Slope compensation
Rt
2N3904
1
Rslope
2
3
R
Rsense
4
C
COMP
Vref
FB
Vcc
Isense
OUT
R/C
GND
8
7
6
5
Ct
Shut down circuits depend on the desired function. A transistor can be used to allow control on and off of the PWM
or an SCR can be used to latch off the PWM.
Shutdown circuits
100K
1
2
3
4
shutdown
COMP
Vref
FB
Vcc
Isense
OUT
R/C
GND
100K
8
7
2
6
3
5
4
shutdown
COMP
Vref
FB
Vcc
Isense
OUT
R/C
GND
8
7
6
5
2N3904
2N3904
© Copyright 2010- ASIC Advantage, Inc.
1
–
AADS00012 / R127B
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Preliminary
-
October 2010
6/8
Power Management AAC242/243
Ordering Information
Ordering PN(1)
AAC242E‐D8A‐G‐LF
Subgroup
Controller
Description
Current Mode,
Offline Thresholds
Temp. Range
Ext. Industrial
Package
8‐Pin DIP
Packing Type
Tube
AAC242A‐D8A‐G‐LF
Controller
AAC242E‐S8A‐G‐LF
Packing Qty
50
Current Mode,
Offline Thresholds
Automotive
8‐Pin DIP
Tube
50
Controller
Current Mode,
Offline Thresholds
Ext. Industrial
8‐Pin SOIC
Tube
98
AAC242E‐S8A‐G‐LF‐TR
Controller
Current Mode,
Offline Thresholds
Ext. Industrial
8‐Pin SOIC
13” T&R (2)
2500
AAC242A‐S8A‐G‐LF
Controller
Current Mode,
Offline Thresholds
Automotive
8‐Pin SOIC
Tube
98
AAC242A‐S8A‐G‐LF‐TR
Controller
Current Mode,
Offline Thresholds
Automotive
8‐Pin SOIC
13” T&R (2)
2500
AAC242E‐F8A‐G‐LF‐W
Controller
Current Mode,
Offline Thresholds
Ext. Industrial
3mmx3mm
8‐Pin DFN
Waffle Pack
TBD
AC242E‐F8A‐G‐LF‐TR
Controller
Current Mode,
Offline Thresholds
Ext. Industrial
3mmx3mm
8‐Pin DFN
T&R (2)
TBD
AAC242A‐F8A‐G‐LF‐W
Controller
Current Mode,
Offline Thresholds
Automotive
3mmx3mm
8‐Pin DFN
Waffle Pack
TBD
AC242A‐F8A‐G‐LF‐TR
Controller
Current Mode,
Offline Thresholds
Automotive
3mmx3mm
8‐Pin DFN
T&R (2)
TBD
AAC243E‐D8A‐G‐LF
Controller
Current Mode,
Battery Level Thresholds
Ext. Industrial
8‐Pin DIP
Tube
50
AAC243A‐D8A‐G‐LF
Controller
Current Mode,
Battery Level Thresholds
Automotive
8‐Pin DIP
Tube
50
AAC243E‐S8A‐G‐LF
Controller
Current Mode,
Battery Level Thresholds
Ext. Industrial
8‐Pin SOIC
Tube
98
AAC243E‐S8A‐G‐LF‐TR
Controller
Current Mode,
Battery Level Thresholds
Ext. Industrial
8‐Pin SOIC
13” T&R (2)
2500
AAC243A‐S8A‐G‐LF
Controller
Current Mode,
Battery Level Thresholds
Automotive
8‐Pin SOIC
Tube
98
AAC243A‐S8A‐G‐LF‐TR
Controller
Current Mode,
Battery Level Thresholds
Automotive
8‐Pin SOIC
13” T&R (2)
2500
AC243E‐F8A‐G‐LF‐W
Controller
Current Mode,
Battery Level Thresholds
Ext. Industrial
3mmx3mm
8‐Pin DFN
Waffle Pack
TBD
AAC243E‐F8A‐G‐LF‐TR
Controller
Current Mode,
Battery Level Thresholds
Ext. Industrial
3mmx3mm
8‐Pin DFN
T&R (2)
TBD
AC243A‐F8A‐G‐LF‐W
Controller
Current Mode,
Battery Level Thresholds
Automotive
3mmx3mm
8‐Pin DFN
Waffle Pack
TBD
AAC243A‐F8A‐G‐LF‐TR
Controller
Current Mode,
Battery Level Thresholds
Automotive
3mmx3mm
8‐Pin DFN
T&R (2)
TBD
(1) Only RoHS/Lead‐Free Packaging is normally offered.
(2) T&R ‐ Tape and Reel
Package Dimensions and Marking
The AAC242 and AAC243 are available in a plastic 8-pin DIP or SOIC package. Refer to the latest version of
specification AAPS001 (ASIC Advantage’s “Package Numbering, Marking, and Outline Standard”, available at
www.asicadvantage.com) for specific information concerning the package dimensions and package marking.
© Copyright 2010- ASIC Advantage, Inc.
–
AADS00012 / R127B
-
Preliminary
-
October 2010
7/8
Power Management AAC242/243
The following is a brief overview of certain terms and conditions of sale of product. For a full and complete copy of all
the General Terms and Conditions of Sale, visit our webpage http://www.asicadvantage.com/terms.htm.
LIMITED WARRANTY
The product is warranted that it will conform to the applicable specifications and be free of defects for one year.
Buyer is responsible for selection of, use of and results obtained from use of the product. Buyer indemnifies and
holds ASIC Advantage, Inc. harmless for claims arising out of the application of ASIC Advantage, Inc.’s products to
Buyer’s designs. Applications described herein or in any catalogs, advertisements or other documents are for
illustrative purposes only.
CRITICAL APPLICATIONS
Products are not authorized for use in critical applications including aerospace and life support applications. Use of
products in these applications is fully at the risk of the Buyer. Critical applications include any system or device
whose failure to perform can result in significant injury to the user.
LETHAL VOLTAGES
Lethal voltages could be present in the applications. Please comply with all applicable safety regulations.
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ASIC Advantage, Inc. retains all intellectual property rights in the products. Sale of products does not confer on
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notice to the products at any time. Buyer agrees not to use or disclose ASIC Advantage Inc.’s proprietary information
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- IN-PLUG® is a registered trademark of ASIC Advantage, Inc.
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For the latest datasheet updates, visit our web page: http://www.asicadvantage.com.
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Websites: http://www.asicadvantage.com
© Copyright 2010- ASIC Advantage, Inc.
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AADS00012 / R127B
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Preliminary
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October 2010
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