L4990A SGS-Thomson-Microelectronics, L4990A Datasheet

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L4990A

Manufacturer Part Number
L4990A
Description
PRIMARY CONTROLLER
Manufacturer
SGS-Thomson-Microelectronics
Datasheet

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L4990AD
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DESCRIPTION
This primary controller I.C., developed in BCD60II
technology, has been designed to implement off
BLOCK DIAGRAM
July 1999
FOR POWER MOSFET (1A)
BLE PULSE SUPPRESSION
LIMIT
TION WITH RE-START DELAY
ING OF CURRENT SENSE
CURRENT-MODE CONTROL PWM
SWITCHING FREQUENCY UP TO 1MHz
LOW START-UP CURRENT < 0.45mA
HIGH-CURRENT OUTPUT DRIVE SUITABLE
FULLY LATCHED PWM LOGIC WITH DOU-
PROGRAMMABLE DUTY CYCLE
100% AND 50% MAXIMUM DUTY CYCLE
PROGRAMMABLE SOFT START
PRIMARY OVERCURRENT FAULT DETEC-
PWM UVLO WITH HYSTERESIS
IN/OUT SYNCHRONIZATION
DISABLE LATCHED
INTERNAL 100ns LEADING EDGE BLANK-
PACKAGE: DIP16 AND SO16W
ISEN
RCT
DIS
DC
SS
2
3
14
13
7
2.5V
1.2V
OVER CURRENT
+
+
+
-
-
-
DIS
1V
BLANKING
TIMING
SYNC
1
T
PWM
R
SOFT-START
FAULT
SGND
2R
12
15
DC-LIM
16V/10V
25V
VREF OK
CLK
line or DC-DC power supply applications using a
fixed frequency current mode control.
Based on a standard current mode PWM control-
ler this device includes some features as pro-
grammable soft start, IN/OUT synchronization,
disable (to be used for over voltage protection
and for power management), precise maximum
Duty Cycle Control, 100ns (typ) leading edge
blanking on current sense, pulse by pulse current
limit and overcurrent protection with soft start in-
tervention.
8
DIS
V
CC
+
-
MULTIPOWER BCD TECHNOLOGY
ORDERING NUMBERS: L4990/L4990A(DIP16)
S
R
COMP
6
Q
PRIMARY CONTROLLER
PWM UVLO
DIP16
E/A
+
-
2.5V
Vref
13V
D98IN1002
L4990D/L4990AD (SO16W)
4
VREF
10
11
9
5
SO16W
L4990A
V
OUT
PGND
VFB
C
L4990
1/24

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L4990A Summary of contents

Page 1

... July 1999 PRIMARY CONTROLLER MULTIPOWER BCD TECHNOLOGY DIP16 ORDERING NUMBERS: L4990/L4990A(DIP16) line or DC-DC power supply applications using a fixed frequency current mode control. Based on a standard current mode PWM control- ler this device includes some features as pro- grammable soft start, IN/OUT synchronization, ...

Page 2

... L4990 - L4990A ABSOLUTE MAXIMUM RATINGS Symbol V Supply Voltage (I < 50mA) (*) Output Peak Pulse Current OUT Analog Inputs & Outputs (6,7) Analog Inputs & Outputs (1,2,3,4,5,15,14 13) P Power Dissipation @ T tot T Junction Temperature, Operating Range j T Storage Temperature, Operating Range stg (*) maximum package power dissipation limits must be observed ...

Page 3

... 2mA 2.7V sink 0.5mA 2.3V sou rce FB V > 4V 2.3V COMP 1.1V 2.7V COMP sen 0.92 COMP 2.85 VSS = 0. L4990 - L4990A Typ. Max. Unit 5.0 5.075 0.4 mV/ C 5.0 5.125 V 30 150 mA 0.2 0.5 V 300 315 kHz 300 321 kHz 295 310 ...

Page 4

... L4990 - L4990A ELECTRICAL CHARACTERISTICS (continued.) Symbol Parameter OUTPUT SECTION V Output Low Voltage OL V Output High Voltage OH V Output Clamp Voltage OUT CLAMP Collector Leakage Fall Time Rise Time UVLO Saturation SUPPLY SECTION V Startup voltage CCON V Minimum Operating Voltage CCOFF V Voltage After Turn-on Hysteresis ...

Page 5

... DC. If this pin is floating the maximum duty cycle de- pends on DC-LIM status. Synchronization A SYNC pin eases Synchronization of the IC to the external world ( e.g. another IC working in Figure 1. Quiescent current vs. input voltage 7.6V and Y = 8.4V for L4990A SC= d isa bled ...

Page 6

... L4990 - L4990A Figure 3. Quiescent current vs. input voltage 9 Vref Rt = 4.5Kohm 7.5 7 igure 5. Quiescent current vs. input voltage and switching frequency. Iq [mA 1nF 100 ...

Page 7

... Figure 14. Switching frequency vs. temperature. fsw (KHz) 320 310 100pF 300 220pF 470pF 290 1nF 280 30 40 -50 -25 0 L4990 - L4990A Vcc = 15V 0.4 0.6 0.8 1 1.2 Isourc e [A] 600 800 1,000 1,200 1,400 Vpin10 [mV] Rt= 4.5Kohm 1nF Vcc = 15V, V15=Vref 100 ...

Page 8

... L4990 - L4990A Figure 15. Switching frequency vs. temperature. fsw (KHz) 320 Rt= 4.5Kohm 1nF 310 Vcc = 15V, V15= 0 300 290 280 -50 - Figure 17. Maximum Duty Cycle vs Vpin3. DC Control Voltage V pin3 [V] 3.5 V15 = 2 4.5Kohm , Ct = 1nF 1 Duty C y cle [% ] Figure 19 ...

Page 9

... R T RCT OSC T T (b) D97IN494A 3V, then is quickly internally discharged. As the ) and a ca- T voltage has dropped starts being charged again + - L4990 - L4990A VREF 4 L4981A (SLAVE) SYNC 1 L4990 SYNC OSC C OSC (c) SYNC 600 A CLK ...

Page 10

... L4990 - L4990A The frequency can be established with the aid of fig. 13 diagrams or considering the approximate relationship osc C 0.693 where K is defined as: T 90, V VREF 160 V GND/OPEN 15 and is linked to the duration of the falling edge of the sawtooth ...

Page 11

... The oscillation frequency appearing on the soft- I Qpk(max) start capacitor in case of permanent fault, referred ’hiccup” period, is approximately given by: T 4.5 hic T ON(min) I OUT Since the system tries restarting each hiccup cy- cle, there is not any latchoff risk. SHORT D97IN496 L4990 - L4990A SSC SSD 7V time 11/24 ...

Page 12

... L4990 - L4990A Figure25.Turn-on and turn-offspeeds adjustment Rg’ ( 13V 13 10 DRIVE & CONTROL OUT Rg L4990 11 PGND D97IN497A ”Hiccup” keeps the system in control in case of short circuits but does not eliminate power com- ponents overstress during pulse-by-pulse limita- tion (from ...

Page 13

... R will be slightly higher. The halving of frequency can be used to reduce losses at light load in all those systems that must comply with requirements regarding energy con- sumption (e.g. monitor displays). L4990 - L4990A could be re- sense TO PWM LOGIC TO FAULT LOGIC ...

Page 14

... L4990 - L4990A Figure 29. Half duty cycle option. V15=GND V5=V13=GND t c V15=VREF V5=V13=GND t c DEMONSTRATION BOARD To evaluate the device performance, a demon- stration board has been realized. Despite its sim- plicity, it exploits most of the features of the L4990. The board embodies an application based on the ...

Page 15

... Output ripple Minimum load Transition Volt. R12 R20 C8 R19 D4 R13 R21 D3 R14 OUT R24 ISEN 13 R11 11 SGND PGND C11 R23 C14 L4990 - L4990A = out out Effic (V) Effic 83.7 14.53 84.3 82.5 14.55 84.9 81.4 14.57 85.2 76 14.59 81 270 Vac 30mV 0.5A out Vac ...

Page 16

... L4990 - L4990A Table 3. Components List of the Fig. 30 AC-DC adaptor electric schematic. Component Reference Resistors R1 R2 R3, R14 R8, R9 R10 R11 R12, R13 R15 R16 R17 R19 R20, R21 R22 R23 R24 Capacitors C6, C15 C7, C14 C8 C9 C10 C11 C12 ...

Page 17

... Figure 31. AC-DC adaptor PCB layout (1.25 :1 scale) - Component Side. Figure 32. AC-DC adaptor PCB layout (1.25 :1 scale) - Back Side. L4990 - L4990A 17/24 ...

Page 18

... L4990 - L4990A Layout hints. Generally speaking a proper cir- cuitboard layout is vital for correct operation but is not an easy task. Careful component placing, cor- rect traces routing, appropriate traces widths and, in case of high voltages, compliance with isolation distances are the major issues. The L4990 eases ...

Page 19

... COMP Error Amp compensation circuit for stabilizing current-mode boost and flyback topologies operating with continuous inductor current OUT ISEN 13 11 PGND D97IN506 + 2.5V 1.3mA + VFB 2.5V 1.3mA + VFB L4990 - L4990A SGND SGND D97IN507 19/24 ...

Page 20

... L4990 - L4990A Figure 37. Feedback with optocoupler 6 L4990 5 VFB Figure 38. Slope compensation techniques V REF RCT L4990 I SLOPE ISEN SGND SENSE OPTIONAL Figure 39. Protection against overvoltage/feedbackdisconnection (latched) R START DIS L4990 SGND PGND D97IN510 20/24 COMP TL431 D97IN508 V REF ...

Page 21

... C. Adragna, PCIM96 - NURBERG). [2] 25W Off-Line Autoranging Battery Charger with L4990 (AN889) [3] 300W Secondary Controlled Two-Switch Forward Converter with L4990 (AN890) [4] SMPS with L4990 for Multisync Monitors (AN891) [5] High performance VRM using L4990A, for Pentium Pro Figure 41. Device shutdown on overcurrent 4 14 L4990 ...

Page 22

... L4990 - L4990A mm DIM. MIN. TYP. MAX. MIN. a1 0.51 0.020 B 0.77 1.65 0.030 b 0 8.5 e 2.54 e3 17.78 F 7.1 I 5.1 L 3.3 Z 1.27 22/24 inch OUTLINE AND MECHANICAL DATA TYP. MAX. 0.065 0.020 0.010 0.787 0.335 0.100 0.700 0.280 0.201 0.130 0.050 DIP16 ...

Page 23

... TYP. A 2.35 2.65 0.093 A1 0.1 0.3 0.004 B 0.33 0.51 0.013 C 0.23 0.32 0.009 D 10.1 10.5 0.398 E 7.4 7.6 0.291 e 1.27 0.050 H 10 10.65 0.394 h 0.25 0.75 0.010 L 0.4 1.27 0.016 K 0 (min.)8 (max OUTLINE AND MECHANICAL DATA MAX. 0.104 0.012 0.020 0.013 0.413 0.299 0.419 0.030 0.050 SO16 Wide L4990 - L4990A C 23/24 ...

Page 24

... L4990 - L4990A Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice ...

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