|
|
PDF FAN5182 Data sheet ( Hoja de datos )
| Número de pieza | FAN5182 | |
| Descripción | Synchronous Buck Controller | |
| Fabricantes | Fairchild Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de FAN5182 (archivo pdf) en la parte inferior de esta página. Total 19 Páginas | ||
|
No Preview Available !
March 2007
FAN5182 — Adjustable Output, 1-, 2-, or 3-Phase
Synchronous Buck Controller
www.DataSheet4U.com
Features
Selectable 1-, 2-, or 3-Phase Operation at up to
1MHz per Phase
Accuracy:
- FAN5182
2%
- FAN5182_NA3E229
1%
- FAN5182_NA3E231
3%
Externally Adjustable 0.8V to 5V Output from a
12V Supply
Logic-Level PWM Outputs for Interface to External
High-Power Drivers
Active Current Balancing Between all Phases
Built-in Power-Good / Crowbar Functions
Programmable Over-Current Protection with
Adjustable Latch-Off Delay
Applications
Auxiliary Supplies
DDR Memory Supplies
Point-of-Load Supplies
Description
The FAN5182 is a highly efficient, multiphase,
synchronous buck switching regulator controller
optimized for converting a 12V main supply into a high-
current, low-voltage supply for use in point-of-load (POL)
applications. It uses a multi-loop PWM architecture to
drive the logic-level outputs at a programmable
switching frequency that can be optimized for regulator
size and efficiency. The phase relationship of the output
signals can be programmed to provide 1-, 2-, or 3-phase
operation, allowing for construction of up to three
complementary, interleaved buck switching stages.
The FAN5182 provides accurate and reliable over-
current protection and adjustable current limiting.
The FAN5182 is specified over the commercial
temperature range of 0°C to +85°C and is available in a
20-lead Quarter-Size Outline Package (QSOP).
Ordering Information
Part Number
FAN5182QSCX_NL
FAN5182QSCX_NA3E229_NL
FAN5182QSCX_NA3E231_NL
Temperature
Range
0°C to 85°C
0°C to 85°C
0°C to 85°C
Pb-
Free
Yes
Yes
Yes
Package
QSOP-20L
QSOP-20L
QSOP-20L
Packing
Method
Tape and Reel
Tape and Reel
Tape and Reel
Quantity
per Reel
2500
2500
2500
© 2005 Fairchild Semiconductor Corporation
FAN5182 Rev. 1.1.1
www.fairchildsemi.com
1 page  
Electrical Characteristics
VCC = 12V, FBRTN = GND, • indicates specifications over operating ambient temperature range.(2)
Symbol
Parameter
Conditions
Min. Typ. Max. Units
Oscillator
fOSC
TPHASE
VRT
VRAMPADJ
IRAMPADJ
Frequency Range
Frequency Variation
Output Voltage
RAMPADJ Output Voltage
RAMPADJ Input Current Range(3)
RT = 332kΩ, 3-phase
TA = 25°C, RT = 154kΩ, 3-phase
TA = 25°C, RT = 100kΩ, 3-phase
RT = 100kΩ to GND
RAMPADJ - FB - 2KΩ x IRAMPADJ
(with IRAMPADJ set to 20µA)
Voltage Error Amplifier
VOL Output Voltage Low
VOH Output Voltage High
FAN5182
2%
VFB Accuracy (Referenced to FBRTN) FAN5182_NA3E229
FAN5182_NA3E231
1%
3%
IFB
ΔVFB
IFBRTN
IO(ERR)
GBW(ERR)
Input Bias Current
Line Regulation
FBRTN Current
Output Current
DC Gain(3)
Gain Bandwidth Product(3)
Slew Rate(3)
FB = 800mV
VCC = 10V to 14V
FB forced to VOUT - 3%
COMP = FB
CCOMP = 10pF
Current-Sense Amplifier
VOS(CSA)
IBIAS(CSSUM)
GBW(CSA)
Offset Voltage
Input Bias Current
DC Gain(3)
Gain Bandwidth Product(3)
Slew Rate(3)
Input Common-Mode Range
VOL
VOH
ICSCOMP
Output Voltage Low
Output Voltage High
Output Current
CSSUM-CSREF (See Figure 3)
CCSCOMP = 10pF
CSSUM & CSREF
Current-Balance Circuit
VSW(X)CM Common-Mode Range(3)
Rsw(X) Input Resistance
ISW(X) Input Current
ΔISW(X) Input Current Matching
ΔVOS Match
Offset Voltage Matching
(Difference between phases)
SW(X) = 0V
SW(X) = 0V
SW(X) = 0V
FAN5182
FAN5182_NA3E229
FAN5182_NA3E231
• 0.25
• 155
• 155
• 155
•
• -50
0
3.1
• 784
• 792
• 786
• -4
•
• -5.5
• -50
0
VCC-2.5
-600
• 20
•4
• -7
200
400
600
2.0
800
800
800
±1
0.05
100
500
87
20
10
70
10
10
500
30
7
3.00
245
245
245
+50
100
0.3
816
808
824
+4
140
+5.5
+50
VCC-2.5
0.1
+200
40
10
+7
11
8
8
MHz
kHz
V
mV
µA
V
V
mV
mV
mV
µA
%
µA
µA
dB
MHz
V/µs
mV
nA
dB
MHz
V/µs
V
V
V
µA
mV
kΩ
µA
%
mV
mV
mV
© 2005 Fairchild Semiconductor Corporation
FAN5182 Rev. 1.1.1
5
www.fairchildsemi.com
5 Page 
The latch-off function can be reset by removing and
reapplying VCC or by pulling the EN pin low briefly. To
disable the over-current latch-off function, the external
resistor connecting the DELAY pin and ground should
be removed and a high-value resistor (>1MΩ) should be
connected from the DELAY pin to VCC. This prevents the
delay capacitor from discharging, so the 1.8V threshold
can never be reached. This pull-up resistor has some
impact to the soft-start time because the current through
this resistor adds additional current to the internal 20µA
soft-start current.
During start-up, when the output voltage is below
200mV, a secondary current limit is activated. This is
necessary because the voltage swing of CSCOMP
cannot go below ground. This secondary current limit
clamps the COMP voltage to 2V.
An inherent, per-phase current limit protects individual
phases if one or more phases cease to function
because of a faulty component. This limit is based on
the maximum normal mode COMP voltage.
Power-Good Monitoring
The power-good comparator monitors the output voltage
via the FB pin. The PWRGD pin is an open-drain output
whose high level (when connected to a pull-up resistor)
indicates that the output voltage is within the nominal
limits specified in the Electrical Characteristic table.
PWRGD goes low if the output voltage is outside the
specified range or whenever the EN pin is pulled low.
Figure 10 shows the PWRGD response when the input
power supply is switched off.
Enable and UVLO
To begin switching, the input supply (VCC) to the
controller must be higher than the UVLO threshold, and
the EN pin must be higher than its logic threshold. If
UVLO is less than the threshold or the EN pin is logic
low, the FAN5182 is disabled. This holds the PWM
outputs at ground, shorts the delay capacitor to ground,
and holds the ILIMIT pin at ground.
In the application circuit, the ILIMIT pin should be
connected to the OD pins of the FAN5109 drivers.
Grounding the ILIMIT pin disables the drivers such that
both HDRV and LDRV hold low. This feature is
important in preventing fast discharge of the output
capacitors when the controller shuts off. If the driver
outputs are not disabled, a negative output voltage can
be generated due to high current discharged from the
output capacitors through the inductors.
FAN5182 in Single-Phase Applications
NOTE: When the FAN5182 is configured for single-
phase applications, it is actually operating internally as a
two-phase controller. It therefore should be configured
as a two-phase controller with only one phase populated
externally.
To accomplish this, PWM3 needs be grounded (to
configure the FAN5182 as a two-phase controller) and
the clock frequency set to two times the required phase
switching frequency. PWM1 should be used to drive the
external phase electronics (driver and MOSFETs). The
SW2 and SW3 pins should be connected to ground to
minimize any potential spurious noise paths.
WARNING: Do not connect PWM2 to ground.
As noted above, when using the FAN5182 in single-
phase applications, it is actually operating internally as a
two-phase controller and PWM2 may be switching.
FAN5182 as a Voltage-Mode Controller
The SW pins are used to measure the current flowing
through the bottom FET. This current information is
used to balance the phase currents in a multiphase
application and create an inner current-feedback loop in
the control loop, making the FAN5182 a current-mode
controller.
Figure 10. Shutdown Waveforms
As part of the protection for the load and output
components of the supply, the PWM outputs are driven
low (turning on the low-side MOSFETs) when the output
voltage exceeds the crowbar trip point. This crowbar
action stops once the output voltage falls below the
reset threshold of approximately 650mV.
Turning on the low-side MOSFETs pulls down the output
as the reverse current builds up in the inductors. If the
output over-voltage is due to a short in the high-side
MOSFET, this crowbar action can trip the input supply
over-current protection or blow the input fuse, protecting
the load from damage.
In single-phase applications where phase current
balance is not required, the current loop can be
defeated by disconnecting the SW pins from the output
FETs and shorting the SW pin to ground. This changes
the control loop from current-mode control to voltage-
mode control.
WARNING: The compensation requirements for a
voltage-mode control design differ for current-mode
control design. The Application Information section of
this datasheet is for a current-mode control design. The
compensation section “Closed-Loop Compensation
Design” does not apply to voltage-mode designs.
© 2005 Fairchild Semiconductor Corporation
FAN5182 Rev. 1.1.1
11
www.fairchildsemi.com
11 Page | ||
| Páginas | Total 19 Páginas | |
| PDF Descargar | [ Datasheet FAN5182.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| FAN5182 | Synchronous Buck Controller | Fairchild Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |