C2472, C2473 and C24 74 Datasheet
RDFC Controllers for Offline Applications
Product data
Page 1 of 18
DS-1423-0709C
© Cambridge Semiconductor Ltd 2007
26-Sep-2007
ADVANTAGES
Low system component count
High average efficiency
Low standby power consumption
EMI compliance without extra components
High isolation & surge voltage withstand
High power density in very small size
FEATURES
Highly integrated CMOS controller IC
Low cost package options
Drive suitable for low cost bipolar power transistors
Resonant switching for high efficiency and low EMI
Frequency optimised for power circuit parasitics
Protection against overload, over-temperature and under-voltage
APPLICATIONS
External AC/DC charger/adaptor (single voltage input) e.g. cordless phones, portable electric tools.
Embedded PSU (single voltage input) e.g. set-top boxes, DVD players, audio products, domestic appliances.
OVERVIEW
The C2472, C2473 and C2474 controllers use CamSemi’s Resonant Discontinuous Forward Converter
(RDFC) topology to create a high efficiency, low cost alternative to line-frequency transformer PSUs. By
operating in resonant mode, EMI is greatly reduced, enabling the replacement of linear PSUs in demanding
applications such as audio products and cordless phone chargers. The C2472, C2473 and C2474 controllers
also offer overload protection which is usually associated with more expensive switch mode solutions.
Resonance
sensing
Vdd
regulator
Switch
saturation
sensing
Current
sensing
RDFC
Control
Vdd
VDD
COL
CS
GND
BAS
AUX
Base
drive
Figure 1: Block Diagram of the C2472, C2473 and C2474 Controller ICs
C2474PW1
PDIP-8
C2472PX2
SOT23-6
C2473PX1
SOP-8
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