ML4819CS Micro Linear, ML4819CS Datasheet

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ML4819CS

Manufacturer Part Number
ML4819CS
Description
Power Factor and PWM Controller Combo
Manufacturer
Micro Linear
Datasheet
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
19
10
20
12
1
3
2
4
5
6
Power Factor and PWM Controller “Combo”
R
C
RAMP COMP
OVP
GND
I
GM OUT
EA OUT A
I
INV A
T
T
SENSE
SINE
A
5V
5V
GAIN MODULATOR
+
+
COMPENSATION
ERROR
AMP
SLOPE
OSC
5V
I
MULT
+
POWER FACTOR
CONTROLLER
I
EA
* Some Packages Are Obsolete
FEATURES
CONTROLLER
R
S
Two 1A peak current totem-pole output drivers
Precision buffered 5V reference (±1%)
Large oscillator amplitude for better noise immunity
Precision duty cycle limit for PWM section
Current input gain modulator improves noise immunity
Programmable Ramp Compensation circuit
Over-Voltage comparator helps prevent output
“runaway”
Wide common mode range in current sense
compensators for better noise immunity
Under-Voltage Lockout circuit with 6V hysteresis
R
S
PWM
Q
Q
+
+
+
LOCKOUT
VOLTAGE
V
V
UNDER
CC
CC
1V
DUTY CYCLE
0.7V
PGND B
PGND A
I
PWM B
SENSE
OUT A
OUT B
I
LIM
V
V
REF
CC
B
11
14
13
18
15
16
17
7
9
8
ML4819*
May 1997
1

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ML4819CS Summary of contents

Page 1

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 ...

Page 2

ML4819 PIN CONFIGURATION PIN DESCRIPTION PIN NAME FUNCTION Input form the PFC current sense SENSE transformer to the PWM comparator (+). Current Limit occurs when this point reaches 5V. 2 OVP Input to Over-Voltage comparator ...

Page 3

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 (V ) ................................................. 35V CC Output Current, ...

Page 4

ML4819 ELECTRICAL CHARACTERISTICS PARAMETER ERROR AMPLIFIER (continued) Output High voltage Output Low Voltage Unity Gain Bandwidth GAIN MODULATOR I Input Voltage SINE Output Current (GM OUT) Bandwidth PSRR SLOPE COMPENSATION CIRCUIT RAMP COMP Voltage ...

Page 5

ELECTRICAL CHARACTERISTICS PARAMETER UNDER-VOLTAGE LOCKOUT Start-Up Threshold Shut-Down Threshold V Good Threshold REF SUPPLY Supply Current Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst-case test conditions. Note raised above the Start-Up Threshold ...

Page 6

ML4819 15V 100 f , OSCILLATOR FREQUENCY (kHz) OSC MAX DUTY CYCLE Figure 2. Oscillator Timing Resistance vs. Frequency 0 SOURCE SATURATION ...

Page 7

SLOPE COMPENSATION Slope compensation is accomplished by adding 1/2 of the current flowing out of pin 12 to pin 1 (for the PFC section and pin 9 (for the PWM section). The amount of slope compensation is equal to (I ...

Page 8

ML4819 0 –4.0 –8.0 –12 –16 –20 – REFERENCE SOURCE CURRENT (mA) REF Figure 11. Reference Load Regulation APPLICATIONS POWER FACTOR SECTION The power factor section in the ML4819 is similar to the power ...

Page 9

Figure 12. Typical Application, 180W Power Factor Corrected 12V Output Power Supply ML4819 9 ...

Page 10

ML4819 then 100mA LDRY Step 3: The value of the inductance can now be found using previously calculated data INDRY ON MAX ( ) DRY ( ) OSC ...

Page 11

The value of R (pin 3) depends on the selection (pin 6). V 260 1 414 . IN MAX PEAK ( ) SINE PEAK ( ) ...

Page 12

ML4819 OVERVOLTAGE PROTECTION (OVP) COMPONENTS The OVP loop should be set so that there is no interaction with the voltage control loop. Typically it should be set to a level where the power components are safe to operate. Ten to ...

Page 13

OSC OSC SLOPE COMP RSC 2 + DUTY CYCLE – I LIM + – SENSE – 0. PWM B – Figure 15. Voltage Mode Configuration CONSTRUCTION AND LAYOUT TIPS High frequency power ...

Page 14

ML4819 Component Values/Bill of Materials for Figure 12 Reference Description C1, C3 0.6µF, 630V Film (250 VAC) C2 330µF 25V Electrolytic C4 6800pF 1KV Ceramic C5, C6 1000pF C7 10µF 35V C8, C11, C13, C15, C16 1µF Ceramic C9, C20, ...

Page 15

... MIN) ORDERING INFORMATION PART NUMBER ML4819CP ML4819CS (Obsolete) © Micro Linear 1997 is a registered trademark of Micro Linear Corporation Products described in this document may be covered by one or more of the following patents, U.S.: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376; Japan: 2598946; 2619299. Other patents are pending. ...

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