L4990 SGS-Thomson-Microelectronics, L4990 Datasheet
L4990
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L4990 Summary of contents
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... 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, ...
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... 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 ...
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... 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 ...
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... 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 ...
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... 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 ...
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... 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 ...
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... 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 ...
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... 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 ...
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... As a master, the pin delivers positive pulses dur- ing the ramp-down of the oscillator (see pin 2). In slave operation the circuit is edge triggered. Refer to fig see how it works. When several IC Figure 20. Synchronizing the L4990. SYNC SYNC 1 1 L4981A ...
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... VFB (pin 5). Compensation networks to- wards ground are not possible since the L4990 E voltage mode amplifier (low output im- (5) pedance). See application ideas for some exam- ext ple of compensation techniques ...
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... 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 ...
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... The peculiarity of this circuit is its ability to mantain the same sink capability (typically, 20mA @ 1V) from the start-up threshold. CC When the threshold is exceeded and the L4990 starts operating, V REFOK fig. 26) and the circuit is disabled then possible to omit the ”bleeder” resistor ...
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... 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 ...
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... 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 ...
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... As to this point, the L4990 turns out to be particu- larly useful since it allows to set any maximum duty cycle greater (and lower) than 50% with very good precision ...
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... 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 ...
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... 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 ...
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... 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 this task by putting two pins at disposal for sepa- rate current returns of bias (SGND) and switch drive currents (PGND) The matter is complex and only few important points will be here reminded ...
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... 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 ...
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... 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 ...
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... PGND SGND Figure 43. Voltage mode operation. REFERENCES [1] Efficient active Clamp for Off-line Applications using L4990 and L6380 (N.Tricomi, G. Gattavari, 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 ...
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... 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 ...
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... 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 ...
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... 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 ...