CM6800
L
OW
S
TART-
U
P
C
URRENT
PFC/PWM C
ONTROLLER
C
OMBO
GENERAL DESCRIPTION
The CM6800 is a controller for power factor corrected,
switched mode power suppliers. Power Factor Correction
(PFC) allows the use of smaller, lower cost bulk
capacitors, reduces power line loading and stress on the
switching FETs, and results in a power supply that fully
compiles with IEC-1000-3-2 specifications. Intended as a
BiCMOS version
edge,
average
of the industry-standard ML4824,
current,
“boost”
type
power
factor
CM6800 includes circuits for the implementation of leading
correction and a trailing edge, pulse width modulator
(PWM). Gate-driver with 1A capabilities minimizes the
need for external driver circuits. Low power requirements
improve efficiency and reduce component costs.
An over-voltage comparator shuts down the PFC section
in the event of a sudden decrease in load. The PFC
section also includes peak current limiting and input
voltage brownout protection. The PWM section can be
operated in current or voltage mode, at up to 250kHz, and
includes an accurate 50% duty cycle limit to prevent
transformer saturation.
CM6800 includes an additional folded-back current limit
for PWM section to provide short circuit protection
function.
FEATURES
Patent Number #5,565,761, #5,747,977, #5,742,151,
#5,804,950, #5,798,635
Pin to pin compatible with ML4800 and FAN4800
Additional folded-back current limit for PWM section.
23V Bi-CMOS process
VIN OK turn on PWM at 2.5V instead of 1.5V
Internally synchronized leading edge PFC and trailing
edge PWM in one IC
Slew rate enhanced transconductance error amplifier for
ultra-fast PFC response
Low start-up current (100
μ
A typ.)
Low operating current (3.0mA type.)
Low total harmonic distortion, high PF
Reduces ripple current in the storage capacitor between
the PFC and PWM sections
Average current, continuous or discontinuous boost
leading edge PFC
VCC OVP Comparator, Low Power Detect Comparator
PWM configurable for current mode or voltage mode
operation
Current fed gain modulator for improved noise immunity
Brown-out control, over-voltage protection, UVLO, and
soft start, and Reference OK
APPLICATIONS
Desktop PC Power Supply
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
SOP-16 (S16) / PDIP-16 (P16)
Top View
1
2
3
4
5
6
7
8
IEAO
I
AC
I
SENSE
V
RMS
SS
V
DC
RAM P1
RAM P2
VEAO
V
FB
V
REF
V
CC
PFC OUT
PW M OUT
GND
DC I
LIMIT
16
15
14
13
12
11
10
9
2008/10/23
Rev. 2.1
Champion Microelectronic Corporation
Page 1
CHAMP [ CHAMPION MICROELECTRONIC CORP. ]
