CM6903/4
Low Pin Count PFC/PWM C
ONTROLLER
C
OMBO
PIN DESCRIPTION
Pin No.
1
2
3
4
5
6
7
8
9
Symbol
DC I
LIMIT
V
CC
PWM OUT
PFC OUT
GND
I
SENSE
VEAO
V
FB
IAC
Description
PWM current limit comparator input
Positive supply
PWM driver output
PFC driver output
Ground
Current sense input to the PFC current limit comparator
PFC transconductance voltage error amplifier output
-5
0
0
0
2.5
0.7
6
3
1
V
V
V
V
Min.
0
10
0
0
15
Operating Voltage
Typ.
Max.
1.5
23
VCC
VCC
Unit
V
V
V
V
PFC transconductance voltage error amplifier input
Feedforward input to do slope compensation and to start up
the system
BLOCK DIAGRAM
IAC
9
VREFOK
R1C
4K ohm
R1B
ISENSE
6
U1
-
2
VCC
+
.
R1A
100K ohm
400K ohm
+
.
.
OUT
-
.
SUM
+
S
R
R
Q
Q
+
ISENSEAMP
4
PFCCMP
VREF OK
PFCOUT
VFB
8
2.5V
-
gmv
.
+
VCC
.
.
.
RAMP
UVLO
.
UVLO
7
VEAO
VCC
17.9V
16.4V
-
-
+
.
FAULTB
VCC OVP
OSC
Tri-Fault
Detect
PFCCLKB
.
PWMCLK
.
PFCCLKB
PWMCLK
3
S
.
R
R
R
Q
Q
VREF OK
-
.
0.5V
+
VFB
VIN OK
-
+
+
PWMOUT
PFC OVP
+
2.75V
2.5V
-
-
.
2.45V
0.75V
1.5V
-
-
+
.
-
.
-1V
+
.
.
PWM CLK
10mS
PWMCMP
PFC ILIMIT
1V
.
SS
CM6903
fpfc= 67KHz
fpwm=67KHz
1
5
GND
CM6904
fpfc= 67KHz
fpwm=134KHz
DCILIMIT
2002/12/16
Preliminary
Rev. 0.4
Champion Microelectronic Corporation
Page 2
CHAMP [ CHAMPION MICROELECTRONIC CORP. ]
