CM6824
L
OW
S
TART-
U
P
C
URRENT
PFC/PWM C
ONTROLLER
C
OMBO
GENERAL DESCRIPTION
The CM6824 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, CM6824 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.
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FEATURES
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Patent Filed #5,565,761, #5,747,977, #5,742,151,
#5,804,950, #5,798,635
Pin to pin compatible with ML4800 and FAN6800/1
Additional folded-back current limit for PWM section.
23V Bi-CMOS process
VIN OK guaranteed 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 (100µA 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
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
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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
VEAO
V
FB
V
R EF
V
CC
PFC OUT
PW M OUT
GND
DC I
LIM IT
16
15
14
13
12
11
10
9
IEAO
I
AC
I
SENSE
V
RMS
SS
V
DC
RAMP1
RAMP2
2002/09/20
Preliminary
Rev. 1.1
Champion Microelectronic Corporation
Page 1
CM6824
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
RAMP 2
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
20
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
2002/09/20
Preliminary
Rev. 1.1
Champion Microelectronic Corporation
Page 2
CM6824
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
Min.
0
-5
GND – 0.3
GND – 0.3
GND – 0.3
Max.
23
4.5
0.7
VCC + 0.3
VCC + 0.3
VREF + 0.3
10
1
1
1
1.5
150
150
125
260
80
105
Units
V
V
V
V
V
V
mA
mA
A
A
µJ
℃
℃
℃
℃
℃/W
℃/W
-65
-40
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply Vcc=+15V, R
T
= 52.3kΩ, C
T
= 470pF, T
A
=Operating Temperature Range (Note 1)
CM6824
Min.
0
V
NONINV
= V
INV
, VEAO = 3.75V
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
Input Bias Current
Output High Voltage
Output Low Voltage
V
NONINV
= V
INV
, VEAO = 3.75V
-1.5
130
-12
-1.0
4.0
-0.5
4.25
0.65
1.0
195
0.7
310
12
V
µmho
mV
µA
V
V
30
50
50
85
2.5
-0.5
6.0
0.1
-35
40
60
60
0.4
-20
Typ.
Max.
5
120
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
µmho
V
µA
V
V
µA
µA
dB
dB
2002/09/20
Preliminary
Rev. 1.1
Champion Microelectronic Corporation
Page 4
CM6824
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
= 52.3kΩ, C
T
= 470pF, T
A
=Operating Temperature Range (Note 1)
CM6824
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
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)
Threshold Voltage
Hysteresis
GAIN Modulator
I
AC
= 100µA, V
RMS
= V
FB
= 0V
Gain (Note 3)
I
AC
= 100µA, V
RMS
= 1.1V, V
FB
= 0V
I
AC
= 150µA, V
RMS
= 1.8V, V
FB
= 0V
I
AC
= 300µA, V
RMS
= 3.3V, V
FB
= 0V
Bandwidth
Output Voltage =
3.5K*(I
SENSE
-I
OFFSET
)
Initial Accuracy
Voltage Stability
Temperature Stability
Total Variation
Ramp Valley to Peak Voltage
PFC Dead Time (Note 4)
CT Discharge Current
V
RAMP2
= 0V, V
RAMP1
= 2.5V
500
6.5
Line, Temp
68
2.5
700
10.5
I
AC
= 100µA
I
AC
= 250µA, V
RMS
= 1.1V, V
FB
= 0V
Oscillator
T
A
= 25℃
11V < V
CC
< 16.5V
66
1
2
84
75.5
kHz
%
%
kHz
V
ns
mA
0.70
0.36
1.20
0.55
0.14
0.55
1.80
0.80
0.20
10
0.80
0.90
0.66
2.24
1.01
0.26
MHz
V
Overdrive Voltage = 100mV
V
IN
OK Comparator
2.35
0.8
2.45
1.0
2.55
1.2
V
V
Overdrive Voltage = -100mV
DC I
LIMIT
Comparator
0.95
1.0
250
1.05
V
ns
-1.10
80
-1.00
200
250
-0.90
V
mV
ns
19
1.40
19.4
1.5
20
1.65
V
V
0.4
0.5
0.6
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
µA
µA
dB
dB
Source Current
Open Loop Gain
Power Supply Rejection Ratio
2002/09/20
Preliminary
Rev. 1.1
Champion Microelectronic Corporation
Page 5
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