|
|
PDF RT9246A Data sheet ( Hoja de datos )
| Número de pieza | RT9246A | |
| Descripción | Multi-Phase PWM Controller | |
| Fabricantes | Richtek Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de RT9246A (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
www.DataSheet4U.com
RT9246A
Multi-Phase PWM Controller for CPU Core Power Supply
General Description
The RT9246A is a multi-phase buck DC/DC controller
integrated with all control functions for GHz CPU VRM.
The RT9246A controls 2 or 3 buck switching stages
operating in interleaved phase set automatically. The multi-
phase architecture provides high output current while
maintaining low power dissipation on power devices and
low stress on input and output capacitors. The high
equivalent operating frequency also reduces the
component dimension and the output voltage ripple in load
transient.
RT9246A controls both voltage and current loops to achieve
good regulation, response & power stage thermal balance.
Precise current loop using Inductor DCR as sense
component builds precise load line for strict VRM DC &
transient specification and also ensures thermal balance
of different power stages. The settings of current sense,
droop tuning, VCORE initial offset and over current protection
are independent to compensation circuit of voltage loop.
The feature greatly facilitates the flexibility of CPU power
supply design and tuning.
The DAC output of RT9246A supports K8 CPU by 5-bit
VID input, precise initial value & smooth VCORE transient
at VID jump. The IC monitors the VCORE voltage for PGOOD
and over-voltage protection. Soft-start, over-current
protection and programmable under-voltage lockout are
also provided to assure the safety of microprocessor and
power system.
Ordering Information
RT9246A
Package Type
C : TSSOP-28
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Note :
RichTek Pb-free and Green products are :
`RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
`100% matte tin (Sn) plating.
DS9246A-04 March 2007
Features
z Multi-Phase Power Conversion with Automatic
Phase Selection
z K8 DAC Output with Active Droop Compensation
for Fast Load Transient
z Smooth VCORE Transition at VID Jump
z Power Stage Thermal Balance by Inductor DCR
Current Sense
z Hiccup Mode Over-Current Protection
z Programmable Switching Frequency (50kHz to
400kHz per Phase), Under-Voltage Lockout and
Soft-Start
z High Ripple Frequency Times Channel Number
z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z AMD® AthlonTM 64 and OpteronTM Processors Voltage
Regulator
z Low Output Voltage, High Current DC-DC Converters
z Voltage Regulator Modules
Pin Configurations
(TOP VIEW)
VID4
VID3
VID2
VID1
VID0
NC
FBRTN
FB
COMP
PGOOD
DVD
SS
RT
VOSS
28
2 27
3 26
4 25
5 24
6 23
7 22
8 21
9 20
10 19
11 18
12 17
13 16
14 15
TSSOP-28
VCC
PWM1
PWM2
PWM3
NC
ISP1
ISP2
ISP3
NC
GND
ADJ
IOUT
ICOMMON
IMAX
www.richtek.com
1
1 page  
RT9246A
Table 1. Output Voltage Program
VID4
VID3
VID2
VID1
VID0
Nominal Output Voltage DACOUT
00000
1.550
00001
1.525
00010
1.500
00011
1.475
00100
1.450
00101
1.425
00110
1.400
00111
1.375
01000
1.350
01001
1.325
01010
1.200
01011
1.275
01100
1.250
01101
1.225
01110
1.200
01111
1.175
10000
1.150
10001
1.125
10010
1.100
10011
1.075
10100
1.050
10101
1.025
10110
1.000
10111
0.975
11000
0.950
11001
0.925
11010
0.900
11011
0.875
11100
0.850
11101
0.825
11110
0.800
11111
Shutdown
Note: (1) 0 : Connected to GND
(2) 1 : Open
DS9246A-04 March 2007
www.richtek.com
5
5 Page 
RT9246A
Over Current Protection
PWM
ICORE
VSS
VCORE
(5V/Div)
(10A/Div)
(2V/Div)
(500mV/Div)
Time (5ms/Div)
Figure 4. The Over Current Protection in the soft start
interval
where N is the phase number of operation.
The averaged current IX is also injected into the resistor
RIOUT connected to IOUT pin for monitoring load current.
Voltage at IOUT pin VIOUT is proportional to load current
and is calculated as:
VIOUT
=
8
IX
x
RIOUT
=
8
x
ICORE
Nx
x RADJ x
RCOMM
RLX
VCORE
RFB1
IVOSS 4
DAC
Error
- Amp.
+
VADJ
8IX
RADJ
Over Current Protection
Figure 6. Load Line and Offset Function
(5A/Div)
ICORE
(1V/Div)
VSS
Time (2.5ms/Div)
Figure 5. Over Current Protection at steady state
Droop and Load Line Setting
RT9246A injects averaged phase current IX into the
resistor RADJ connected to ADJ pin to generate a load-
current-dependent voltage VADJ for droop setting:
VADJ = 8IX RADJ
VADJ is then subtracted form VID_DAC output as the real
reference voltage at non-inverting input of the error amplifier
as shown if Figure 6. Consequently, load line slope is
calculated as:
Load Line
=
ΔVCORE
ΔICORE
=
8
x RADJ x RLX
N x RCOMM
Output Voltage Offset Function
RT9246A provides programmable initial offset function.
External resistor RVOSS and voltage source at VOSS pin
generate offset current IVOSS =
VVOSS
RVOSS
, where VVOSS is 1V typical. One quarter of IVOSS flows
through RFB1 as shown in Figure 6. Error amplifier would
hold the inverting pin equal to VDAC − VADJ. A constant
offset voltage is consequently added to VDAC − VADJ as :
VCORE
=
VDAC
−
VADJ
+
4
RFB1
x RVOSS
Current Ratio Setting
Current ratio adjustment is possible as described below.
It is important for achieving thermal balance in practical
application where thermal conditions between phases are
not identical. Figure 7 shows the application circuit of GM
for current ratio requirement. According to Basic Circuit
Theory, if
LX
RLX
= (RSX // RPX) x CX
then
VX =
RPX
RSX+RPX
x ILX x RLX
DS9246A-04 March 2007
www.richtek.com
11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet RT9246A.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| RT9246 | Multi-Phase PWM Controller | Richtek Technology |
| RT9246A | Multi-Phase PWM Controller | Richtek Technology |
| 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 |