
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.
2002/12/16
Preliminary
Rev. 0.4
Champion Microelectronic Corporation
Page 1
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
PIN CONFIGURATION
!
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
SIP-09 (Z09)
Front View
D
V
P
P
G
I
V
V
I
1
2
3
4
5
6
7
8
9
SOP-16 (S16)
Top View
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PFCOUT
GND
GND
I
SENSE
VEAO
V
FB
I
AC
NC
NC
NC
PWMOUT
NC
V
CC
NC
DC I
LIMIT
NC