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
CM6800
L
OW
S
TART-
U
P
C
URRENT
PFC/PWM C
ONTROLLER
C
OMBO
PIN DESCRIPTION
Pin No.
1
Symbol
IEAO
Description
PFC transconductance current error amplifier output
Operating Voltage
Min.
Typ.
Max.
Unit
0
4.25
V
2
I
AC
PFC gain control reference input
0
1
mA
3
I
SENSE
Current sense input to the PFC current limit comparator
-5
0.7
V
4
V
RMS
Input for PFC RMS line voltage compensation
0
6
V
5
SS
Connection point for the PWM soft start capacitor
0
8
V
6
V
DC
PWM voltage feedback input
0
8
V
7
RAMP 1
(RTCT)
Oscillator timing node; timing set by RT CT
1.2
3.9
V
8
When in current mode, this pin functions as the current sense
input; when in voltage mode, it is the PWM input from PFC
(PWM RAMP) output (feed forward ramp).
RAMP 2
DC I
LIMIT
PWM current limit comparator input
0
6
V
9
0
1
V
10
GND
Ground
11
PWM OUT
PWM driver output
0
VCC
V
12
PFC OUT
PFC driver output
0
VCC
V
13
V
CC
Positive supply
10
15
18
V
14
V
REF
Buffered output for the internal 7.5V reference
7.5
V
15
V
FB
PFC transconductance voltage error amplifier input
PFC transconductance voltage error amplifier output
0
2.5
3
V
16
VEAO
0
6
V
2008/10/23
Rev. 2.1
Champion Microelectronic Corporation
Page 2
CM6800
L
OW
S
TART-
U
P
C
URRENT
PFC/PWM C
ONTROLLER
C
OMBO
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum ratings are those values beyond which the device could be permanently damaged.
Parameter
V
CC
IEAO
I
SENSE
Voltage
PFC OUT
PWMOUT
Voltage on Any Other Pin
I
REF
I
AC
Input Current
Peak PFC OUT Current, Source or Sink
Peak PWM OUT Current, Source or Sink
PFC OUT, PWM OUT Energy Per Cycle
Junction Temperature
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 10 sec)
Thermal Resistance (θ
JA
)
Plastic DIP
Plastic SOIC
Power Dissipation (PD) T
A
<50℃
Min.
0
-5
GND – 0.3
GND – 0.3
GND – 0.3
Max.
20
7.5
0.7
VCC + 0.3
VCC + 0.3
VCC + 0.3
10
1
1
1
1.5
150
Units
V
V
V
V
V
V
mA
mA
A
A
μ
J
℃
℃
℃
℃
℃/W
℃/W
mW
-65
-40
150
125
260
80
105
800
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply Vcc=+15V, R
T
= 30.16kΩ, C
T
=1000pF, T
A
=Operating Temperature Range (Note 1)
Symbol
Parameter
Test Conditions
Voltage Error Amplifier (g
mv
)
Input Voltage Range
Transconductance
Feedback Reference Voltage
Input Bias Current
Output High Voltage
Output Low Voltage
Sink Current
Source Current
Open Loop Gain
Power Supply Rejection Ratio
11V < V
CC
< 16.5V
Current Error Amplifier (g
mi
)
Input Voltage Range
Transconductance
Input Offset Voltage
Output High Voltage
Output Low Voltage
V
NONINV
= V
INV
, VEAO = 3.75V
at room temp
-1.5
50
-25
4.0
4.25
1.0
1.2
85
0.7
100
25
V
V
FB
= 3V, VEAO = 6V
V
FB
= 1.5V, VEAO = 1.5V
30
50
50
Note 2
V
NONINV
= V
INV
, VEAO = 3.75V
at room temp
0
50
2.45
-1.0
5.8
70
2.5
-0.05
6.0
0.1
-35
40
60
60
0.4
-20
6
90
2.55
V
CM6800
Min.
Typ.
Max.
Unit
μ
mho
V
μ
A
V
V
μ
A
μ
A
dB
dB
μ
mho
mV
V
V
2008/10/23
Rev. 2.1
Champion Microelectronic Corporation
Page 4
CM6800
L
OW
S
TART-
U
P
C
URRENT
PFC/PWM C
ONTROLLER
C
OMBO
ELECTRICAL CHARACTERISTICS
(Conti.)
Unless otherwise stated, these specifications apply
Vcc=+15V, R
T
= 30.16kΩ, C
T
=1000pF, T
A
=Operating Temperature Range (Note 1)
CM6800
Min.
35
60
11V < V
CC
< 16.5V
PFC OVP Comparator
Threshold Voltage
Hysteresis
Low Power Detect Comparator
Threshold Voltage
VCC OVP Comparator
Threshold Voltage
Hysteresis
Tri-Fault Detect
Fault Detect HIGH
Time to Fault Detect HIGH
Fault Detect LOW
PFC I
LIMIT
Comparator
Threshold Voltage
(PFC I
LIMIT
V
TH
– Gain Modulator
Output)
Delay to Output (Note 4)
Threshold Voltage
Delay to Output (Note 4)
OK Threshold Voltage
Hysteresis
GAIN Modulator
I
AC
= 100
μ
A, V
RMS
=0, V
FB
= 1V
at room temp
I
AC
= 100
μ
A, V
RMS
= 1.1V, V
FB
= 1V
Gain (Note 3)
at room temp
I
AC
= 150
μ
A, V
RMS
= 1.8V, V
FB
= 1V
at room temp
I
AC
= 300
μ
A, V
RMS
= 3.3V, V
FB
= 1V
Bandwidth
Output Voltage =
3.5K*(I
SENSE
-I
OFFSET
)
at room temp
I
AC
= 100
μ
A
I
AC
= 250
μ
A, V
RMS
= 1.1V, V
FB
= 1V
Overdrive Voltage = 100mV
V
IN
OK Comparator
2.35
0.95
2.45
1.2
2.55
1.4
V
V
Overdrive Voltage = -100mV
DC I
LIMIT
Comparator
0.95
1.0
250
1.05
V
ns
-1.10
20
-1.00
100
250
-0.90
V
mV
ns
V
FB
=V
FAULT DETECT LOW
to
V
FB
=OPEN.470pF from V
FB
to GND
0.4
0.5
0.6
V
2.65
2.75
2
2.85
4
V
ms
17.5
1.40
17.9
1.5
18.5
1.65
V
V
0.2
0.3
0.4
V
2.70
230
2.77
2.85
290
V
mV
60
Typ.
-65
75
70
75
Max.
-35
Symbol
Sink Current
Parameter
Test Conditions
I
SENSE
= +0.5V, IEAO = 4.0V
I
SENSE
= -0.5V, IEAO = 1.5V
Unit
Source Current
Open Loop Gain
Power Supply Rejection Ratio
μ
A
μ
A
dB
dB
0.70
1.80
0.90
0.25
0.84
2.00
1.00
0.32
10
0.95
2.20
1.10
0.40
MHz
0.95
V
0.84
0.90
2008/10/23
Rev. 2.1
Champion Microelectronic Corporation
Page 5
PCB设计
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