August 2000
PRELIMINARY
ML4802
PFC/PWM Controller Combo with Green Mode
GENERAL DESCRIPTION
The ML 4802 is a controller for power factor corrected,
switched mode power supplies that offers Green Mode
operation and reduced start-up and operating currents.
Green Mode is an efficiency improving circuit feature
which operates automatically in low power situations.
This feature helps meet the demands of Energy Star™
programs.
Power Factor Correction (PFC) offers the use of lower cost
bulk capacitors, reduces power line loading and stress on
the switching FETs. The ML4802 includes circuits for the
implementation of a leading edge, average current,
“boost” type power factor corrector and a trailing edge
Pulse Width Modulator (PWM).
The PFC frequency of the ML4802 is automatically
synchronized to be one half that of the PWM. This
technique allows the user to design with smaller PWM
components while maintaining the optimum operating
frequency for the PFC. 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 brown-out protection.
s
s
FEATURES
Internally synchronized PFC and PWM in one IC
Green Mode maximizes efficiency during low power
standby operation
Low supply current
(Start-up 200µA typ., operating 5.5mA typ.)
Average current continuous boost leading edge PFC
High efficiency trailing edge PWM can be configured
for current mode operation
Reduced ripple current in the storage capacitor
between the PFC and PWM sections
PFC overvoltage comparator eliminates output
“runaway” due to load removal
Current fed gain modulator for improved noise
immunity
Overvoltage protection, UVLO, and soft start
s
s
s
s
s
s
s
BLOCK DIAGRAM
VEAO
16
IEAO
1
POWER FACTOR CORRECTOR
+
VCC
13
VEA
VFB
15
2.5V
IAC
VRMS
ISENSE
RAMP 1
2
4
3
8
GAIN
MODULATOR
1.8kΩ
-
+
–
1.8kΩ
+
IEA
PFC
CONTROLLER
8V
2.75V
-
OVP
7.5V
REFERENCE
14 VREF
-1V
+
-
PFC ILIMIT
PFC
OUTPUT
DRIVER
12 PFC OUT
÷2
VFB
OSCILLATOR
DC LIMIT
VDC
GREEN
MODE
CONTROLLER
RT/CT 7
RAMP 2
9
8V
VLS
1.25V
-
GREEN
MODE
VDC
6
VCC
25µA
+
VIN OK
-
+
DC ILIMIT
+
VFB
2.43V
-
+
SS
5
8V
1.5V
-
PWM
OUTPUT
DRIVER
11 PWM OUT
PULSE WIDTH MODULATOR
1
ML4802
PIN CONFIGURATION
ML4802
16-Pin PDIP (P16)
16-Pin Narrow SOIC (S16N)
IEAO
IAC
ISENSE
VRMS
SS
VDC
RT/CT
RAMP 1
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VEAO
VFB
VREF
VCC
PFC OUT
PWM OUT
GND
RAMP 2
TOP VIEW
PIN DESCRIPTION
PIN
NAME
FUNCTION
PIN
NAME
FUNCTION
1
2
3
4
5
6
7
8
IEAO
IAC
ISENSE
VRMS
SS
VDC
RT/CT
RAMP 1
PFC current error amplifier output
PFC gain control reference input
9
10
RAMP 2
GND
PWM current feedback/overcurrent
limit input
Ground
Current sense input to the PFC current
limit comparator
Input for PFC RMS line voltage
compensation
Connection point for the PWM soft start
capacitor
PWM feedback voltage input
11
12
13
14
15
PWM OUT PWM driver output
PFC OUT
VCC
VREF
VFB
VEAO
PFC driver output
Positive supply input
Buffered output for the internal 7.5V
reference
PFC voltage error amplifier input
PFC voltage error amplifier output
Connection for master (PWM) oscillator
frequency setting components
PFC ramp input
16
2
Datasheet
August 2000
ML4802
ABSOLUTE MAXIMUM RATINGS
Absolute maximum ratings are those values beyond which
the device could be permanently damaged. Absolute
maximum ratings are stress ratings only and functional
device operation is not implied.
VCC .......................................................................... 18V
ISENSE Voltage ................................................–3V to 5V
Voltage on Any Other Pin .... GND – 0.3V to VCC + 0.3V
IREF ....................................................................... 20mA
IAC Input Current ................................................... 10mA
PeakCurrent, Source or Sink
PFC OUT, PWM OUT ....................................... 500mA
PFC OUT, PWM OUT Energy Per Cycle .................. 1.5µJ
Junction Temperature .............................................. 150°C
Storage Temperature Range ..................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ..................... 260°C
Thermal Resistance (qja)
Plastic DIP ....................................................... 80°C/W
Plastic SOIC ................................................... 105°C/W
OPERATING CONDITIONS
Temperature Range
ML4802CX ................................................. 0°C to 70°C
ML4802IX .............................................. –40°C to 85°C
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, VCC = 15V, RT = 29.4kW, RRAMP1 = 15.4kW, CT = 270pF, CRAMP1 = 620pF,
TA = Operating Temperature Range (Note 1)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
VOLTAGE ERROR AMPLIFIER
Input Voltage Range
Transconductance
Feedback Reference Voltage
Input Bias Current
Output High Voltage
Output Low Voltage
Source Current
Sink Current
Open Loop Gain
PSRR
CURRENT ERROR AMPLIFIER
Input Voltage Range
Transconductance
Input Offset Voltage
Input Bias Current
Output High Voltage
Output Low Voltage
Source Current
Sink Current
Open Loop Gain
PSRR
11V < VCC < 16.5V
DVIN
= ±0.5V, VOUT = 6V
DVIN
= ±0.5V, VOUT = 1.5V
-40
40
60
60
6.0
VNON INV = VINV, VEAO = 3.75V
-1.5
50
–5
100
3
-0.5
6.7
0.65
-70
70
75
75
1.0
-150
150
2
150
10
-1.0
V
µ
11V < VCC < 16.5V
DVIN
= ±0.5V, VOUT = 6V
DVIN
= ±0.5V, VOUT = 1.5V
–1
–1
50
50
Note 2
6.0
VNON INV = VINV, VEAO = 3.75V
0
20
2.4
35
2.5
-0.5
6.7
0.2
–2.5
–2.5
60
60
0.5
–4
–4
5
50
2.6
-1.0
V
µ
V
µA
V
V
µA
µA
dB
dB
mV
µA
V
V
µA
µA
dB
dB
August 2000
Datasheet
W
W
3
ML4802
ELECTRICAL CHARACTERISTICS
(Continued)
SYMBOL
OVP COMPARATOR
Threshold Voltage
Hysteresis
PFC ILIMIT COMPARATOR
Threshold Voltage
DPFC
ILIMIT Threshold - Gain Modulator Output
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
2.65
175
2.75
250
2.85
325
V
mV
–0.9
120
–1
220
150
–1.1
V
mV
Delay to Output
DC ILIMIT COMPARATOR
Threshold Voltage
Input Bias Current
Delay to Output
VIN OK COMPARATOR
Threshold Voltage
Hysteresis
GAIN MODULATOR
Gain (Note 3)
IAC = 100µA, VRMS = VFB = 0V
IAC = 50µA, VRMS = 1.2V, VFB = 0V
IAC = 50µA, VRMS = 1.8V, VFB = 0V
IAC = 100µA, VRMS = 3.3V, VFB = 0V
Bandwidth
Output Voltage
OSCILLATOR
Initial Accuracy
Voltage Stability
Temperature Stability
Total Variation
Ramp Valley to Peak Voltage
Dead Time
CT Discharge Current
GREEN MODE
VGMT-L
Green Mode Threshold Low
VGMT = VDC –VLS
VGMT = VDC –VLS
70
360
PFC Only
VRAMP 2 = 0V, VRAMP 1 = 2.5V
260
3.5
Line, Temp
182
TA = 25ºC
11V < VCC < 16.5V
188
IAC = 100µA
IAC = 250µA, VRMS = 1.15V,
VFB = 0V
0.6
0.6
1.8
0.8
0.2
2.33
0.8
1.4
300
ns
1.5
±0.3
150
1.6
±1
300
V
µA
ns
2.43
1.0
2.55
1.2
V
V
0.8
2
1
0.3
10
0.75
1.05
2.80
1.25
0.4
MHz
0.9
V
200
1
2
212
kHz
%
%
218
2.5
400
5.5
7.5
kHz
V
ns
mA
275
580
1.25
mV
mV
V
VGMT-H Green Mode Threshold High
VLS
Level Shift
4
Datasheet
August 2000
ML4802
ELECTRICAL CHARACTERISTICS
(Continued)
SYMBOL
REFERENCE
Output Voltage
Line Regulation
Load Regulation
Temperature Stability
Total Variation
Long Term Stability
PFC
Minimum Duty Cycle
Maximum Duty Cycle
Output Low Voltage
VIEAO > 4.0V
VIEAO < 1.2V
IOUT = –20mA
IOUT = –100mA
IOUT = –10mA, VCC = 11V
Output High Voltage
IOUT = 20mA
IOUT = 100mA
Rise/Fall Time
PWM
DC
VOL
Duty Cycle Range
Output Low Voltage
IOUT = –20mA
IOUT = –100mA
IOUT = –10mA, VCC = 11V
VOH
Output High Voltage
IOUT = 20mA
IOUT = 100mA
Rise/Fall Time
SUPPLY
Start-up Current
Operating Current
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
Note 1:
Limits are guaranteed by 100% testing, sampling, or correlation with worst-case test conditions.
Note 2:
Includes all bias currents to other circuits connected to the VFB pin.
Note 3:
Gain = K x 5.3V; K = (IMULO - IOFFSET) x IAC x (VEAO - 1.5V)
-1
.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
TA = 25ºC, I(VREF) = 1mA
11V < VCC < 16.5V
1mA < I(VREF) < 10mA
7.4
7.5
2
2
0.4
7.6
30
20
V
mV
mV
%
Line, Load, Temp
TJ = 125ºC, 1000 Hours
7.35
5
7.65
25
V
mV
0
85
90
0.4
0.7
0.8
VCC - 0.8
VCC - 2.0
50
0.8
2.0
1.5
%
%
V
V
V
V
V
ns
CL = 1000pF
0-44
0-47
0.4
0.7
0.8
0-50
0.8
2.0
1.5
%
V
V
V
V
V
VCC - 0. 8
VCC - 2.0
50
CL = 1000pF
ns
VCC = 12V, CL = 0
VCC = 14V, CL = 0
12
2.5
200
5
13
2.8
350
7
14
3.1
µA
mA
V
V
August 2000
Datasheet
5
Embedded System
京公网安备 11010802033920号
EEWORLD
