L5994_02 STMICROELECTRONICS [STMicroelectronics], L5994_02 Datasheet

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FEATURE DUAL PWM CONTROLLERS ADJUSTABLE 1.9V to 5.3V(Section1) 1.6V to 3.5V(Section2) AUXILIARY DRIVER FOR LINEAR REGULATOR CURRENT MODE CONTROL USING A LOW SENSE RESISTOR DUAL SYNC RECTIFIERS DRIVERS "ONE SHOT" FEATURE (L5994A only) 96% EFFICIENCY ACHIEVABLE 50 A@12V STAND BY ...

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L5994 - L5994A DESCRIPTION (continued) The device produces an adjustable regulated voltage in both sections and a linear regulated voltage with an external bipolar such as for PCMCIA applications. The auxiliary linear driver is able to source ...

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BLOCK DIAGRAM + SLOPE ERROR SUMMING - 6 I1SNS + 5 V1SNS - 7 COMP1 + - VREF 1 H1STRAP 32 H1GATE Hside LOGIC AND 31 H1SRC SHOOT- REG5 THROUGH CONTROL 30 R1GATE Lside PREG5 29 LINEAR 4 REGULATOR W5SW ...

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L5994 - L5994A ELECTRICAL CHARACTERISTICS (continued) Symbol Parameter V Over voltage threshold ON 5 V1SNS Under voltage threshold ON V1SNS SECTION 2 PWM CONTROLLER V V2SNS feedback voltage 2out V -V Overcurrent Threshold current Pulse skipping ...

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ELECTRICAL CHARACTERISTICS (continued) Symbol Parameter V Output low voltage OL LINEAR REGULATOR DRIVER SECTION I Driver current max V VFBLIN threshold ref V Input voltage range DRLIN I Bias Current FBLIN V Input voltage clamp CP “One Shot” activation threshold ...

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L5994 - L5994A PIN DESCRIPTION N° Name 1 H1STRAP Section 1 bootstrap capacitor connection. A bootstrap capacitor must be connected between this pin and pin H1SRC to supply the H1GATE driver. 2 Vin Device supply voltage. 3 SREG5 Internal logic ...

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PIN DESCRIPTION (continued) N° Name 21 VDRLIN Linear regulator driver connection. It must be connected to the base pin of an external PNP transistor and, through a resistor, to its emitter in order to supply the internal driver ...

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L5994 - L5994A the oscillator and the internal supply and differ for the pre-set output voltages. Each converter can be turned on and off independently: RUN1 and RUN2 are control inputs which disable the relevant section when a low logic ...

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That turns off the low-side MOSFET (synchronous rectifier) and, when the low-side gate voltage falls below 0.3V to prevent cross-conduction, turns on the high-side one, thus allowing energy to be drawn from the input source and stored in ...

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L5994 - L5994A Although the Schottky might appear to be redundant not in a system where a very high efficiency is re- quired. In fact, its lower threshold prevents the lossy body-diode of the synchronous rectifier MOSFET from ...

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Protections Each converter is fully protected against fault conditions. A monitoring system checks for overvoltages of the output, quickly disabling the interested converter in case such an event occurs. This condition is latched and to allow the device to start ...

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L5994 - L5994A works in order to obtain a voltage on the VFBLIN pin of about 2.5V. In this way, the minimum regulated voltage is of 2.5V, obtained connecting directly the VFBLIN pin to the output, while the maximum is ...

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The 5V regulator is always active, even if both PWM regulators are disabled, as long as power is applied to the chip. The 2.5V reference voltage generator, provides comparison levels for threshold detection and device operation allowed to ...

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L5994 - L5994A Power management The device is provided with some control pins suitable to perform some functions which are commonly used or sometimes required in battery-operated equipment. Besides, it features controlled timing sequences in case of turn-on/off and device ...

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Inductor To define the inductor necessary to determine firstly the inductance value. Its minimum value is given by: and a value L > L should be selected. Core geometry selection is connected to the requirements of the ...

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L5994 - L5994A Power MOSFET's and Schottky Diodes Since the gate drivers of the device are powered bus , the use of logic-level MOSFET's is highly rec- ommended, especially for high current applications. Their breakdown voltage V ...

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Input Capacitors A pulsed current (with zero average value) flows through the input capacitor of a buck converter. The AC com- ponent of this current is quite high and dissipates a considerable amount of power on the ESR of the ...

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L5994 - L5994A thus both should be considered 3.1 10 RPP X If specification on the output ripple under pulse-skipping condition is also given, C with it as well. Further constraints on the minimum output capacitance can ...

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Transformer Catch Diode (L5994A only) The diode which steers the current generated by the secondary winding of the +5.1V transformer should be a fast-recovery one, with a breakdown voltage greater than: with a certain safety margin. The diode has to ...

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L5994 - L5994A side and power traces on the other side. 7) Use heavy copper traces: this will reduce their resistance, increasing overall efficiency and will improve their heat-sinking ability. L5994 Evaluation Kit The L5994 Evaluation kit is a fully ...

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The electrical schematic, illustrated in fig. 7, shows that some pull-up/down resistor are added to the compo- nents strictly needed in a real application. Along with a quad dip-switch, they allow to set manually the logic sig- nals that control ...

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L5994 - L5994A Component list Table shows the complete L5994/ L5994A Evaluation Kit parts list. Critical components characteristics are given in detail. Resistors R1,R2,R3, R7,R8 R9,R15 R10,R11,R12,R13,R14 R16 R17,R18,R19,R20 R21,R22,R23,R24 R25 R26 R27 R28 R33,R34 Capacitors C1,C4 C2,C6 ...

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Figure 8. PCB and component layout L5994 - L5994A 23/26 ...

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L5994 - L5994A Figure 9. Demo Board Efficiency vs Output Current EFF. (%) Vin=6V 90 Vin=20V 80 Vin=15V 0.001 0.005 0.01 0.05 0.1 Figure 10. Demo Board Efficiency vs Output Current EFF. (%) Vin=6V 90 Vin=20V 80 ...

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DIM. MIN. TYP. MAX. MIN. A 1.60 A1 0.05 0.15 0.002 A2 1.35 1.40 1.45 0.053 B 0.30 0.37 0.45 0.012 C 0.09 0.20 0.004 D 9.00 D1 7.00 D3 5.60 e 0.80 E 9.00 E1 7.00 E3 5.60 ...

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L5994 - L5994A 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 ...