MC44602 Datasheet, PDF (1/18 Pages) Motorola, Inc – HIGH PERFORMANCE CURRENT MODE CONTROLLER

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High Performance
Current Mode Controller
MC44602
The MC44602 is an enhanced high performance fixed frequency current
mode controller that is specifically designed for off–line and high voltage
dc–to–dc converter applications. This device has the unique ability of
changing operating modes if the converter output is overloaded or shorted,
offering the designer additional protection for increased system reliability.
The MC44602 has several distinguishing features when compared to
conventional current mode controllers. These features consist of a foldback
amplifier for overload detection, valid load and demag comparators with a
fault latch for short circuit detection, thermal shutdown, and separate high
current source and sink outputs that are ideally suited for driving a high
voltage bipolar power transistor, such as the MJE18002, MJE18004, or
MJE18006.
Standard features include an oscillator with a sync input, a temperature
compensated reference, high gain error amplifier, and a current sensing
comparator. Protective features consist of input and reference undervoltage
lockouts each with hysteresis, cycle–by–cycle current limiting, a latch for
single pulse metering, and a flip–flop which blanks the output off every other
oscillator cycle, allowing output deadtimes to be programmed from 50% to
70%. This device is manufactured in a 16 pin dual–in–line heat tab package
for improved thermal conduction.
• Separate High Current Source and Sink Outputs Ideally Suited for
Driving Bipolar Power Transistors: 1.0 A Source, 1.5 A Sink
• Unique Overload and Short Circuit Protection
• Thermal Protection
• Oscillator with Sync Input
• Current Mode Operation to 500 kHz Output Switching Frequency
• Output Deadtime Adjustable from 50% to 70%
• Automatic Feed Forward Compensation
• Latching PWM for Cycle–By–Cycle Current Limiting
• Input and Reference Undervoltage Lockouts with Hysteresis
• Low Startup and Operating Current
Vref
16
Sync Input
7
RT/CT
8
Compensation
1
Voltage Feedback–Input
3
Simplified Block Diagram
Vref
Undervoltage
Lockout
5.0V
Reference
VCC
Undervoltage
Lockout
Short Circuit
Detection
Oscillator
Error
Amplifier
Flip Flop
and
Latching
PWM
Foldback
Amplifier
Thermal
Gnd 9
15 ^VCC
Load Detect Input
2
14 ^VC
Source Output
11
Sink Output
10
Sink Ground
4, 5, 12, 13
Current Sense Input
6
HIGH PERFORMANCE
CURRENT MODE
CONTROLLER
SEMICONDUCTOR
TECHNICAL DATA
16
1
P2 SUFFIX
PLASTIC PACKAGE
CASE 648C
DIP (12 + 2 + 2)
PIN CONNECTIONS
Compensation 1
Load Detect Input 2
Voltage Feedback Input 3
4
Sink Gnd
5
16 Vref
15 VCC
14 VC
13
Sink Gnd
12
Current Sense Input 6
Sync Input 7
RT/CT 8
11 Source Output
10 Sink Output
9 Gnd
(Top View)
ORDERING INFORMATION
Operating
Device Temperature Range
Package
MC44602 TA = – 25 to 85°C DIP (12 + 2 + 2)
MOTOROLA ANALOG IC DEVICE DATA
© Motorola, Inc. 1996
Rev 0
1