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Fairchild
Fairchild

ML4819 Datasheet

Power Factor and PWM Controller Combo


ML4819 Datasheet Preview


May 1997
ML4819
Power Factor and PWM Controller “Combo”
GENERAL DESCRIPTION
The ML4819 is a complete boost mode Power factor
Controller (PFC) which also contains a PWM controller.
The PFC circuit is similar to the ML4812 while the PWM
controller can be used for current or voltage mode control
for a second stage converter. Since the PWM and PFC
circuits share the same oscillator, synchronization of the
two stages is inherent. The outputs of the controller IC
provide high current (>1A peak) and high slew rate to
quickly charge and discharge MOSFET gates. Special care
has been taken in the design of the ML4819 to increase
system noise immunity.
The PFC section is of the peak current sensing boost type,
using a current sense transformer or current sensing
MOSFETs to non-dissipatively sense switch current. This
gives the system overall efficiency over average current
sensing control method.
The PWM section includes cycle by cycle current limiting,
precise duty cycle limiting for single ended converters,
and slope compensation.
BLOCK DIAGRAM
FEATURES
s Two 1A peak current totem-pole output drivers
s Precision buffered 5V reference (±1%)
s Large oscillator amplitude for better noise immunity
s Precision duty cycle limit for PWM section
s Current input gain modulator improves noise immunity
s Programmable Ramp Compensation circuit
s Over-Voltage comparator helps prevent output
“runaway”
s Wide common mode range in current sense
compensators for better noise immunity
s Under-Voltage Lockout circuit with 6V hysteresis
10 RT
OSC
20 CT
12 RAMP COMP
SLOPE
COMPENSATION
1 ISENSE A
POWER FACTOR
+ CONTROLLER
5V –
3 GM OUT
2 OVP
5V
+
4 EA OUT A
5 INV A
5V
+
ERROR
AMP
IEA
ISINE
6
GND
19
GAIN MODULATOR
IMULT
PWM
CONTROLLER
R
SQ
R
SQ
DUTY CYCLE 7
ILIM 11
1V
ISENSE B 9
0.7V
PWM B 8
VCC
OUT B
14
PGND B 13
UNDER
VOLTAGE
LOCKOUT
VREF 18
VCC 15
VCC
OUT A 16
PGND A 17
REV. 1.0 10/10/2000
Page 1

ML4819
PIN CONFIGURATION
ML4819
20-Pin PDIP
ISENSE A
OVP
GM OUT
EA OUT A
INV A
ISINE
DUTY CYCLE
PWM B
ISENSE B
RT
1 20
2 19
3 18
4 17
5 16
6 15
7 14
8 13
9 12
10 11
TOP VIEW
CT
GND
VREF
PGND A
OUT A
VCC
OUT B
PGND B
RAMP COMP
ILIM
PIN DESCRIPTION
PIN NAME
1 ISENSE A
FUNCTION
Input form the PFC current sense
transformer to the PWM comparator
(+). Current Limit occurs when this
point reaches 5V.
2 OVP
Input to Over-Voltage comparator.
3 GM OUT
Output of Gain Modulator. A resistor
to ground on this pin converts the
current to a voltage.
4 EA OUT A Output of error amplifier.
5 INV A
Inverting input to error amplifier.
6 ISINE
Current Multiplier input.
7 DUTY CYCLE PWM controller duty cycle is limited
by setting this pin to a fixed voltage.
8 PWM B
Error voltage feedback input.
9 ISENSE B
Input for Current Sense resistor for
current mode operation or for
Oscillator ramp for voltage mode
operation.
10 RT
Oscillator timing resistor pin. A 5V
source across this resistor sets the
charging current for CT
PIN NAME
11 ILIM
FUNCTION
Cycle by cycle PWM current limit.
Exceeding 1V threshold on this pin
terminates the PWM cycle.
12 RAMP COMP Buffered output from the Oscillator
Ramp (CT). A resistor to ground sets a
current, 1/2 of which is sourced on
pins 9 and 11.
13 GND B
Return for the high current totem pole
output of the PWM controller.
14 OUT B
PWM controller totem pole output.
15 VCC
16 OUT A
Positive Supply for the IC.
PFC controller totem pole output.
17 GND A
Return for the high current totem pole
output of the PFC controller.
18 VREF
Buffered output for the 5V voltage
reference
19 GND
Analog signal ground.
20 CT
Timing Capacitor for the Oscillator.
2 REV. 1.0 10/10/2000
Page 2

ML4819
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.
Supply Voltage (VCC) ................................................. 35V
Output Current, Source or Sink (RAMP COMP)
DC ....................................................................... 1.0A
Output Energy (capacitive load per cycle) ................... 5µJ
Multiplier ISINE Input (ISINE) ................................... 1.2mA
Error Amp Sink Current (GM OUT) ........................ 10mA
Oscillator Charge Current ........................................ 2mA
Analog Inputs (ISENSE A, EA OUT A, INV A)
............................................................... –0.3V to 5.5V
Junction Temperature ............................................. 150°C
Storage Temperature Range ..................... –65°C to 150°C
Lead Temperature (soldering 10 sec.) ..................... 260°C
Thermal Resistance (θJA)
Plastic DIP or SOIC ......................................... 60°C/W
OPERATING CONDITIONS
Temperature Range
ML4819C .................................................. 0°C to 70°C
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, RT = 14k, CT = 1000pF, TA = Operating Temperature Range, VCC = 15V (Notes 1, 2).
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
OSCILLATOR
Initial Accuracy
Voltage Stability
Temperature Stability
TJ = 25°C
12V < VCC < 18V
90 97 104 kHz
0.2 %
2%
Total Variation
Line, temp.
88 106 kHz
Ramp Valley
0.9 V
Ramp Peak
4.3 V
RT Voltage
Discharge Current (PWM B open)
DUTY CYCLE LIMIT COMPARATOR
TJ = 25°C, VOUT A = 2V
VOUT A = 2V
4.8 5.0 5.2
V
7.5 8.4 9.3 mA
7.2 8.4 9.5 mA
Input Offset Voltage
–15 15 mV
Input Bias Current
–2 –10 µA
Duty Cycle
REFERENCE
VDUTY CYCLE = VREF/2
43 45 49 %
Output Voltage
Line Regulation
Load Regulation
Temperature Stability
TJ = 25°C, IO = 1mA
12V < VCC < 25V
1mA < IO < 20mA
4.95
5.00
2
8
0.4
5.05
20
25
V
mV
mV
%
Total Variation
Line, load, temperature
4.9
5.1 V
Output Noise Voltage
10Hz to 10kHz
50 µV
Long Term Stability
Short Circuit Current
ERROR AMPLIFIER
TJ = 125°C, 1000 hours, (Note 1)
VREF = 0V
5 25 mV
–30 –85 –180 mA
Input Offset Voltage
–15 15 mV
Input Bias Current
–0.1 –1.0
µA
Open Loop Gain
PSRR
Output Sink Current
1 < VEA OUT A < 5V
12V < VCC < 25V
VEA OUT A = 1.1V, VINV A = 5.2V
60 75
60 90
2 12
dB
dB
mA
Output Source Current
VEA OUT A = 5.0V, VINV A = 4.8V
–0.5 –1.0
mA
REV. 1.0 10/10/2000
3
Page 3

ML4819
ELECTRICAL CHARACTERISTICS (Continued)
PARAMETER
CONDITIONS
ERROR AMPLIFIER (continued)
Output High voltage
Output Low Voltage
Unity Gain Bandwidth
IEA OUT A = –0.5mA, VINV A = 4.8V
IEA OUT A = 2mA, VINV A = 5.2V
GAIN MODULATOR
ISINE Input Voltage
Output Current (GM OUT)
Bandwidth
ISINE = 500µA
ISINE = 500µA, INV A = VREF –20mV
ISINE = 500µA, INV A = VREF + 20mV
ISINE = 1mA, INV A = VREF – 20mV
PSRR
SLOPE COMPENSATION CIRCUIT
12V < VCC < 25V
RAMP COMP Voltage
IOUT (ISENSE A or ISENSE B)
OVP COMPARATOR
IRAMP COMP = 100µA (Note 3)
Input Offset Voltage
Output Off
Hysteresis
Output On
Input Bias Current
Propagation Delay
ISENSE COMPARATORS
Input Common Mode Range
Input Offset Voltage
Input Bias Current
Input Offset Current
ISENSE A
ISENSE B
Propagation Delay
ILIMIT (A) Trip Point
ILIM COMPARATOR
ILIMIT Trip Point
Input Bias Current
VOVP = 5.5V
Propagation Delay
OUTPUT DRIVERS
Output Voltage Low
Output Voltage High
Output Voltage Low in UVLO
Output Rise/Fall Time
IOUT = –20mA
IOUT = –200mA
IOUT = 20mA
IOUT = 200mA
IOUT = –1mA, VCC = 8V
CL = 1000pF
MIN
6.5
0.4
460
900
45
–15
100
–0.2
–15
0.4
–3
4.8
.95
13
12
TYP
7.0
0.7
1.0
0.7
495
0
990
200
70
VC(T) – 1
48
120
–0.3
150
0.7
–3
0
150
5
1.0
–2
150
0.1
1.6
13.5
13.4
0.1
50
MAX
1.0
0.9
505
10
1005
51
15
140
–3
5.5
15
0.9
–10
3
5.2
1.05
–10
0.4
2.2
0.8
UNITS
V
V
MHz
V
µA
µA
µA
kHz
dB
V
µA
mV
mV
µA
ns
V
mV
V
µA
µA
ns
V
V
µA
ns
V
V
V
V
V
ns
4 REV. 1.0 10/10/2000
Page 4
Part Number ML4819
Manufactur Fairchild
Description Power Factor and PWM Controller Combo
Total Page 15 Pages
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