MC44603 Datasheet, PDF (1/24 Pages) ON Semiconductor – MIXED FREQUENCY MODE GREENLINE PWM CONTROLLER

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MC44603
Advance Information
Mixed Frequency Mode
GreenLine™ PWM Controller:
Fixed Frequency, Variable Frequency,
Standby Mode
The MC44603 is an enhanced high performance controller that is
specifically designed for off–line and dc–to–dc converter applications. This
device has the unique ability of automatically changing operating modes if
the converter output is overloaded, unloaded, or shorted, offering the
designer additional protection for increased system reliability. The MC44603
has several distinguishing features when compared to conventional SMPS
controllers. These features consist of a foldback facility for overload
protection, a standby mode when the converter output is slightly loaded, a
demagnetization detection for reduced switching stresses on transistor and
diodes, and a high current totem pole output ideally suited for driving a power
MOSFET. It can also be used for driving a bipolar transistor in low power
converters (< 150 W). It is optimized to operate in discontinuous mode but
can also operate in continuous mode. Its advanced design allows use in
current mode or voltage mode control applications.
Current or Voltage Mode Controller
• Operation up to 250 kHz Output Switching Frequency
• Inherent Feed Forward Compensation
• Latching PWM for Cycle–by–Cycle Current Limiting
• Oscillator with Precise Frequency Control
High Flexibility
• Externally Programmable Reference Current
• Secondary or Primary Sensing
• Synchronization Facility
• High Current Totem Pole Output
• Undervoltage Lockout with Hysteresis
Safety/Protection Features
• Overvoltage Protection Against Open Current and Open Voltage Loop
• Protection Against Short Circuit on Oscillator Pin
• Fully Programmable Foldback
• Soft–Start Feature
• Accurate Maximum Duty Cycle Setting
• Demagnetization (Zero Current Detection) Protection
• Internally Trimmed Reference
GreenLine Controller: Low Power Consumption in Standby Mode
• Low Startup and Operating Current
• Fully Programmable Standby Mode
• Controlled Frequency Reduction in Standby Mode
• Low dV/dT for Low EMI Radiations
MIXED FREQUENCY MODE
GREENLINE PWM*
CONTROLLER:
VARIABLE FREQUENCY,
FIXED FREQUENCY,
STANDBY MODE
* PWM = Pulse Width Modulation
16
1
P SUFFIX
PLASTIC PACKAGE
CASE 648
16
1
DW SUFFIX
PLASTIC PACKAGE
CASE 751G
(SOP–16L)
PIN CONNECTIONS
VCC 1
VC 2
Output 3
Gnd 4
Foldback Input 5
Overvoltage
Protection (OVP)
6
Current Sense Input 7
Demag Detection 8
16 Rref
15
RFrequency
Standby
14
Voltage Feedback
Input
13 Error Amp Output
12 RPower _Standby
11
Soft–Start/Dmax/
Voltage Mode
10 CT
9 Sync Input
(Top View)
ORDERING INFORMATION
Device
Operating
Temperature Range Package
GreenLine is a trademark of Motorola, Inc.
MC44603P
Plastic DIP–16
TA = –25° to +85°C
MC44603DW
SOP–16L
This document contains information on a new product. Specifications and information herein
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© Motorola, Inc. 1996
Rev 0
1