L5994A STMicroelectronics, L5994A Datasheet

IC CTRLR PS ADJ TRPL-OUT 32-TQFP

L5994A

Manufacturer Part Number
L5994A
Description
IC CTRLR PS ADJ TRPL-OUT 32-TQFP
Manufacturer
STMicroelectronics
Datasheet

Specifications of L5994A

Pwm Type
Current Mode
Number Of Outputs
3
Frequency - Max
345kHz
Duty Cycle
96%
Voltage - Supply
4.75 V ~ 25 V
Buck
Yes
Boost
No
Flyback
Yes
Inverting
No
Doubler
No
Divider
No
Cuk
No
Isolated
No
Operating Temperature
-40°C ~ 140°C
Package / Case
32-TQFP, 32-VQFP
Frequency-max
345kHz
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
497-5340
L5994A

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
L5994A
Manufacturer:
STMicroelectronics
Quantity:
10 000
Part Number:
L5994A
Manufacturer:
ST
0
FEATURE
Figure 1. System Block Diagram
April 2002
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 CONSUMPTION
4.75V TO 25V OPERATING SUPPLY VOLTAGE
EXCELLENT LOAD TRANSIENT RESPONSE
"PULSE SKIPPING" FUNCTION
OUTPUT UNDER VOLTAGE SHUTDOWN
ADAPTATIVE ANTI SHOOT-THROUGH
CONTROL
OVER/UNDER VOLTAGE DETECTION
POWER GOOD SIGNALS
SEPARATED DISABLE
THERMAL SHUTDOWN
25V
D98IN862
5V
to
SYNC
MANAGEMENT
SUPERVISOR
& SYSTEM
POWER
L5994
POWER SUPPLY CONTROLLER
SECTION
POWER
ADJUSTABLE TRIPLE OUTPUT
APPLICATIONS
DESCRIPTION
The device provides a dual PWM controller and a
linear driver controller that can support the complete
power management in mobile equipment with high
efficiency.
POWER GOOD
NOTEBOOK AND SUB NOTEBOOK
COMPUTERS
1.8V AND 2.5V I/O SUPPLY
WORDPAD
INTERNET APPLIANCE
3.39V REF
5.1V LDO
12V LDO
2.5V
1.8V
ORDERING NUMBERS: L5994
PERIPHERALS
TQFP32
MEMORY
P
L5994A
L5994A
L5994
1/26

Related parts for L5994A

L5994A Summary of contents

Page 1

... 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 CONSUMPTION 4.75V TO 25V OPERATING SUPPLY VOLTAGE EXCELLENT LOAD TRANSIENT RESPONSE "PULSE SKIPPING" FUNCTION OUTPUT UNDER VOLTAGE SHUTDOWN ...

Page 2

... 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 for 12V bus and is also possible to use it for the regulation of 2.5V from 5V bus. ...

Page 3

... H1GATE = H2GATE = OPEN RUN1= RUN2 = SREG5 (DRIVERS OFF) RUNQ=RUN2=GND NOSKIP=GND Vin=12V Vin=20V 20V in NOSKIP = REG5 40mA i1sns v1sns VSOFT1 = 3.1V V > 6. < 5.8V in L5994 - L5994A + ERROR SUMMING SLOPE - + - + - OVER CURRENT COMPARATOR VREF + - ZERO CROSSING Hside COMPARATOR LOGIC AND + SHOOT- - PREG5 THROUGH ...

Page 4

... 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 mode threshold 19 20 voltage V Over voltage threshold ON 20 V2SNS Under voltage threshold ON ...

Page 5

... V Input voltage range DRLIN I Bias Current FBLIN V Input voltage clamp CP “One Shot” activation threshold (L5994A only) “One Shot” Pulse (L5994A only) INTERNAL REGULATOR DRIVER SECTION V VREG5 output voltage 29 I Totale current capability 29 V Swith-over threshold voltage 5SW V Reference voltage ...

Page 6

... 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 supply. It must be connected to PREG5 pin through a R-C low-pass filter. ...

Page 7

... Each PWM regulator includes control circuitry as well as gate-drive circuits for a step-down DC-DC converter in buck topology using synchronous rectification and current mode control. The two regulators are independent and almost identical. As one can see in the Block Diagram, they share only L5994 - L5994A Function 7/26 ...

Page 8

... 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 level (below 0 applied and enable its operation with a high logic level (above 2 ...

Page 9

... Schottky diode is not turned on, except for the small time in which neither MOSFET is conducting. The effect is a considerable reduction of power loss dur- ing the recirculation period ESR -------------------------- -------------------------------------------------------------------------------------- - ens HSTRAP Vin Q L REG5 NQ SLOPE + - COMPENSATION + - VREF + - L5994 - L5994A Rsense Co Ro ESR Rf Cf 9/26 ...

Page 10

... 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 turn- ing on during the above mentioned dead-time. Both conduction and reverse recovery losses are cut down and efficiency can improve of 1-2% in some cases ...

Page 11

... VDRLIN is influenced by the voltage spikes at switching transients. An internal clamp limits the voltage on the VDRLIN pin at a maximum value of 16V, but, in case of intervention, the chip power dissipation will rise.The linear driver is always active as long as PREG5 and VREF are present on the chip (see the relevant section); it Vcc VDRLIN VFBLIN L5994 L5994 - L5994A Vout 11/26 ...

Page 12

... The additional winding may be implemented with L5994 if the relative section is loaded enough. To overcome this problem, in L5994A, when the VDRLIN voltage falls below a certain threshold (13.7V ±5%) because of too light a load on the section 2, the relevant synchronous rectifier is turned on for 1.5 s max. during the interval in which the inductor current is zero (" ...

Page 13

... CRST PWROK2 RUN1 VOUT1 H1GATE R1GATE PWROK1 c) SHUTDOWN TIMING SEQUENCE (2) RUN2 t VOUT2 t H2GATE t R2GATE t CRST PWROK2 t RUN1 t VOUT1 t H1GATE R1GATE t PWROK1 t b) SHUTDOWN TIMING SEQUENCE (1) t VOUT2 t H2GATE t R2GATE t CRST t PWROK t VOUT1 t H1GATE t R1GATE t d) OVP TIMING SEQUENCE L5994 - L5994A 13/26 ...

Page 14

... 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 shutdown for a safe and reliable behaviour under all conditions. ...

Page 15

... OUT12 RF ----------------------------------------------- - I V 5.1 – whichever gives the higher value for L INMAX 5.1 V – 5.1 INMA --------------------------------------------------------- - INM AX L5994 - L5994A 3.3 RF – 3.3 V INM AX OUT12 is above 13V. To reduce the DRLIN 5.1 5.1 – OUT12 . With a primary in- 5PMIN + I OUT12 15/26 ...

Page 16

... 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 V with a certain margin, so the selection will address 20V or 30V devices. ...

Page 17

... In pulse-skipping operation, the capacitive component of the output ripple is comparable to the resistive one OUT Pc ESR I ------------------------------------------------------ - = IN OUT ------------------------------- - OUT OUT » ---------------------------------------------- - IN ESR · L3PK OUT3 ----------------------- + -- - OUT 12 V 5.1 4 – RPKX ESR ----------------- - L5994 - L5994A V V – IN OUT frequencies up to IN(DC) is related to the IN ) 5.1 V 5.1 – IN ---------------------------------------- - 17/26 ...

Page 18

... 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 arise from specifications regarding the maximum - undershoot overshoot, V OUT C ---------------------------------------------------------------------------------------- - OUT - V OUT whichever is greater, and where Dmax is the maximum duty cycle and the quantities are relevant either to the +3 ...

Page 19

... 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 withstand a pulsed current whose peak value is approximately: ...

Page 20

... 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 assembled and tested demonstration board that implements a standard ap- plication circuit, configured according to the following specifications: Input Voltage Range 25V ...

Page 21

... This means that the minimum ON-time of the high-side MOSFET is too long for the thruput energy level at the operating frequency. Thus the control sys- tem begins skipping conduction cycles to avoid the output voltage drifting upwards. L5994 - L5994A 21/26 ...

Page 22

... 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 C3,C7,C8,C20 C9,C15 C10,C11,C13,C14 C16,C17,C23 C18,C19 ...

Page 23

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

Page 24

... 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 Vin=15V 0.001 0.005 0.01 0.05 0.1 Figure 11. Demo Board Efficiency vs Output Current EFF. (%) Vin=6V 90 Vin=20V ...

Page 25

... L 0.45 0.60 0.75 0.018 L1 1.00 K (min.), 7 (max inch TYP. MAX. 0.063 0.006 0.055 0.057 0.015 0.018 0.008 0.354 0.276 0.220 0.031 0.354 0.276 0.220 0.024 0.030 0.039 TQFP32 L5994 - L5994A OUTLINE AND MECHANICAL DATA TQFP32 A1 0.10mm .004 Seating Plane 25/26 ...

Page 26

... 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 from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice ...

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