CM6903B
Low Pin Count PFC/PWM C
ONTROLLER
C
OMBO
GENERAL DESCRIPTION
The CM6903B is a space-saving PFC-PWM controller for
power factor corrected, switched mode power supplies that
offers very low start-up and operating currents. For the
power supply less than 500Watt, its input current shaping
PFC performance could be very close to CM6800 or
ML4800 architecture.
Power Factor Correction (PFC) offers the use of smaller,
lower cost bulk capacitors, reduces power line loading and
stress on the switching FETs, and results in a power supply
fully
compliant
to
IEC1000-3-2
specifications.
The
CM6903B includes circuits for the implementation of a
leading edge, input current shaping technique “boost” type
PFC and a trailing edge, PWM.
The CM6903B’s PFC and PWM operate at the same
frequency, 67.5kHz. This higher frequency allows the user
to design with smaller PWM components while maintaining
the optimum operating frequency for the PFC. An PFC OVP
comparator shuts down the PFC section in the event of a
sudden decrease in load. The PFC section also includes
peak current limiting for enhanced system reliability.
FEATURES
Patent
Number
#5,565,761,
#5,747,977,
#5,742,151,
#5,804,950, #5,798,635
Pin to pin compatible with FAN6903/4
Enable lowest BOM for power supply with PFC
Internally synchronized PFC and PWM in one IC
Patented slew rate enhanced voltage error amplifier with
advanced input current shaping technique
Universal Line Input Voltage
CCM boost or DCM boost with leading edge modulation
PFC using Input Current Shaping Technique
Feedforward
compensation
PFCOVP, PFC VCCOVP, Precision -1V PFC ILIMIT,
Tri-Fault Detect comparator to meet UL1950
No bleed resistor required
Low supply currents; start-up: 100uA typical, operating
current: 2mA typical.
Synchronized leading PFC and trailing edge modulation
PWM to reduce ripple current in the storage capacitor
between the PFC and PWM sections and to reduce
switching noise in the system
VINOK Comparator to guarantee to enable PWM when
PFC reach steady state
High efficiency trailing-edge current mode PWM
UVLO, REFOK, and brownout protection
Digital PWM softstart: CM6903B (10ms)
Precision PWM 1.5V current limit for current mode
operation
IAC
pin
to
do
the
automatic
slope
24 Hours Technical Support---WebSIM
Champion provides customers an online circuit simulation tool
called WebSIM. You could simply logon our website at
www.champion-micro.com for details.
APPLICATIONS
Desktop PC Power Supply
AC Adaptor
Internet Server Power Supply
IPC Power Supply
UPS
Battery Charger
DC Motor Power Supply
Monitor Power Supply
Telecom System Power Supply
Distributed Power
PIN CONFIGURATION
SIP-09 (Z09)
Front View
2007/04/13 Rev1.0
Champion Microelectronic Corporation
Page 1
CHAMP [ CHAMPION MICROELECTRONIC CORP. ]
