CM6903/4
Low Pin Count PFC/PWM CONTROLLER COMBO
GENERAL DESCRIPTION
FEATURES
The CM6903/4 is a space-saving PFC-PWM controller for ꢀ
power factor corrected, switched mode power supplies that
Patent Number #5,565,761, #5,747,977, #5,742,151,
#5,804,950, #5,798,635
offers very low start-up and operating currents. For the
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Pin to pin compatible with FAN6903/4
power supply less than 500Watt, its input current shaping ꢀ
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
PFC performance could be very close to CM6800 or
ML4800 architecture.
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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
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leading edge, input current shaping technique “boost” type ꢀ
PFC and a trailing edge, PWM.
PFCOVP, PFC VCCOVP, Precision -1V PFC ILIMIT,
Tri-Fault Detect comparator to meet UL1950
No bleed resistor required
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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
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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
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down the PFC section in the event of a sudden decrease in ꢀ
load. The PFC section also includes peak current limiting
VINOK Comparator to guarantee to enable PWM when
PFC reach steady state
for enhanced system reliability.
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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
SIP-09 (Z09)
SOP-16 (S16)
Top View
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Desktop PC Power Supply
AC Adaptor
Front View
1
2
3
4
5
6
7
8
NC
16
15
14
13
12
11
10
9
Internet Server Power Supply
IPC Power Supply
PFCOUT
NC
GND
GND
PWMOUT
UPS
Battery Charger
DC Motor Power Supply
Monitor Power Supply
Telecom System Power Supply
Distributed Power
NC
VCC
NC
ISENSE
VEAO
1
2
3
4
5
6
7
8
9
VFB
IAC
DC ILIMIT
NC
NC
2002/12/16 Preliminary Rev. 0.4
Champion Microelectronic Corporation
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