CM6903/4
Low Pin Count PFC/PWM C
ONTROLLER
C
OMBO
GENERAL DESCRIPTION
The CM6903/4 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
CM6903/4 includes circuits for the implementation of a
leading edge, input current shaping technique “boost” type
PFC and a trailing edge, PWM.
!
The CM6903’s PFC and PWM operate at the same
frequency, 67kHz. The PFC frequency of the CM6904 is
automatically set at half that of the 134kHz PWM. 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 IAC pin to do the automatic slope
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: CM6903 (10ms), CM6904 (5ms)
Precision PWM 1.5V current limit for current mode
operation
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
PIN CONFIGURATION
SIP-09 (Z09)
Front View
1
SOP-16 (S16)
Top View
PFC OUT
GN D
GN D
I
SEN SE
VEAO
V
FB
I
AC
NC
NC
NC
PW M O UT
NC
V
CC
NC
DC I
LIM IT
NC
16
15
14
13
12
11
10
9
DC ILIMIT
PWMOUT
ISENSE
VEAO
IPC Power Supply
UPS
Battery Charger
DC Motor Power Supply
Monitor Power Supply
Telecom System Power Supply
Distributed Power
PFCOUT
2
GND
VCC
VFB
IAC
3
4
5
6
7
8
1
2
3
4
5
6
7
8
9
2002/12/16
Preliminary
Rev. 0.4
Champion Microelectronic Corporation
Page 1
CHAMP [ CHAMPION MICROELECTRONIC CORP. ]
