CM6800A
L
OW
S
TART-
U
P
C
URRENT
PFC/PWM C
ONTROLLER
C
OMBO
GENERAL DESCRIPTION
The CM6800A 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
of the industry-standard ML4824, CM6800A
includes circuits for the implementation of leading edge,
average current, “boost” type power factor 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.
CM6800A 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 2.25V instead of 1.5V(ML4800).
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
2009/08/10
Rev. 1.6
Champion Microelectronic Corporation
Page 1
CM6800A
L
OW
S
TART-
U
P
C
URRENT
PFC/PWM C
ONTROLLER
C
OMBO
PIN DESCRIPTION
Pin No.
Symbol
Description
Operating Voltage
Min.
0
Typ.
Max.
4.25
Unit
V
1
IEAO
PFC transconductance current error amplifier output
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
RAMP 1
(RTCT)
RAMP 2
PWM voltage feedback input
0
8
V
7
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).
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
2009/08/10
Rev. 1.6
Champion Microelectronic Corporation
Page 2
CM6800A
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
150
125
260
80
105
800
Units
V
V
V
V
V
V
mA
mA
A
A
μ
J
℃
℃
℃
℃
℃/W
℃/W
mW
-65
-40
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply Vcc=+15V, R
T
= 30.16kΩ, C
T
= 1000pF, T
A
=Operating Temperature Range (Note 1)
CM6800A
Min.
0
V
NONINV
= V
INV
, VEAO = 3.75V
at room temp
Note 2
50
2.45
-1.0
5.8
V
FB
= 3V, VEAO = 6V
V
FB
= 1.5V, VEAO = 1.5V
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
30
50
50
70
2.5
-0.05
6.0
0.1
-35
40
60
60
0.4
-20
Typ.
Max.
6
90
2.55
Symbol
Parameter
Test Conditions
Voltage Error Amplifier (g
mv
)
Unit
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
V
μ
mho
V
μ
A
V
V
μ
A
μ
A
dB
dB
μ
mho
mV
V
V
2009/08/10
Rev. 1.6
Champion Microelectronic Corporation
Page 4
CM6800A
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)
CM6800A
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
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
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
2.16
0.9
2.25
1.1
2.36
1.3
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
300
V
mV
60
Typ.
-65
75
70
75
Max.
-35
Symbol
Sink Current
Parameter
Test Conditions
I
SENSE
= +0.6V, IEAO = 4.0V
I
SENSE
= -0.6V, 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
Gain (Note 3)
Bandwidth
Output Voltage =
3.5K*(I
SENSE
-I
OFFSET
)
0.84
0.90
2009/08/10
Rev. 1.6
Champion Microelectronic Corporation
Page 5
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