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RP6102
Single Synchronous Buck Controller
General Description
The RP6102 PWM controller provides high efficiency, excellent transient response, and high DC output accuracy needed for stepping down high-voltage batteries to generate low-voltage CPU core, I/O, and chipset RAM supplies in notebook computers.
The constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “ instant-on” response to load transients while maintaining a relatively constant switching frequency.
The RP6102 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous rectifier MOSFETs. The buck conversion allows this device to directly step down high-voltage batteries for the highest possible efficiency. The RP6102 is intended for CPU core, chipset, DRAM, or other low-voltage supplies as low as 0.75V.
Features
Ultra-High Efficiency Resistor Programmable Current Limit by Low-Side RDS(ON) Sense (Lossless Limit) or Sense Resistor (High Accuracy) Quick Load-Step Response within 100ns 1% VOUT Accuracy over Line and Load Adjustable 0.75V to 3.3V Output Range 4.5V to 26V Battery Input Range Resistor Programmable Frequency Over/Under Voltage Protection 2 Steps Current Limit During Soft-Start Drives Large Synchronous-Rectifier FETs Power-Good Indicator RoHS Compliant and 100% Lead (Pb)-Free
Applications
Notebook Computers CPU Core Supply Chipset/RAM Supply as Low as 0.75V
Ordering Information
RP6102
Package Type S : SOP-14
Operating Temperature Range G : Green (Halogen Free with Commer-
cial Standard)
Note : Richpower Green products are :
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Pin Configurations
(TOP VIEW)
FB PGOOD
GND PGND LGATE VDDP
OC
14 VDD 2 13 VOUT 3 12 TON 4 11 EN/DEM 5 10 BOOT 6 9 UGATE 7 8 PHASE
SOP-14
Marking Information
For marking information, contact our sales representative directly or through a Richpower distributor located in your area, otherwise visit our website for detail.
RP6102-02P July 2009
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RP6102
Typical Application Circuit
VDDP 5V
C1 1uF
D1 BAT254
PGOOD CCM/DEM
R2 51k
R1 10
C2 1uF
RP6102
TON
BOOT
VDDP
UGATE
VDD
PHASE LGATE
PGOOD
OC
EN/DEM GND PGND
FB VOUT
VIN 4.5V to 26V
R3 1M
R4 2.2 R5 0
R6 10k
C3 0.1uF
C4 10uF
Q1 AO4702 L1
2.4uH
VOUT 1.2V
Q2 AO4702
R7 C7 220uF
C5 R8 C6 12k
C8 0.1uF
R9 20k
Functional Pin Description
Pin NO. 1 2 3 4 5 6 7 8 9 10
11
12 13 14
Pin Name
Pin Function
FB
VOUT Feedback Input. Connect FB to a resistor voltage divider from VOUT to GND to adjust the output from 0.75V to 3.3V.
Power Good Signal Open-Drain Output of PWM Converter. This pin will be PGOOD pulled high when the output voltage is within the target range.
GND
Ground for Analog Circuitry. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation.
PGND Power Ground.
LGATE
Low-side N-MOSFET Gate-Drive Output for PWM. This pin swings between GND and VDDP.
VDDP
VDDP is the gate driver supply for the external MOSFETs. Bypass to GND with a 1uF ceramic capacitor.
OC
PWM Current Limit Setting and sense. Connect a resistor between OC to PHASE for current limit setting.
PHASE
Inductor Connection. This pin is not only the zero-current-sense input for the PWM converter, but also the UGATE high-side gate driver return.
UGATE
High-Side N-MOSFET Floating Gate-Driver Output for the PWM converter. This pin swings between PHASE and BOOT.
BOO T
Boost Capacitor Connection for PWM Converter. Connect an external ceramic capacitor to PHASE and an external diode to VDDP.
PWM Enable and Operation Mode Selection Input. Connect to VDD for EN/DEM diode-emulation mode, connect to GND for shutdown mode and floating
the pin for CCM mode.
TO N
VIN Sense Input. Connect to VIN through a resistor. TON is an input of the PWM controller.
VOU T
VOUT Sense Input. Connect to the output of PWM converter. VOUT is an input of the PWM controller.
VDD
Analog Supply Voltage Input for the internal analog integrated circuit. Bypass to GND with a 1uF ceramic capacitor.
2 RP6102-02P July 2009
Function Block Diagram
RP6102
VOUT TON
SS(Internal)
TRIG On-time Compute 1-SHOT
-+ GM +-
Comp +
FB
VDD GND
0.75V VREF
115% VREF 70% VREF
Latch + OV S1 Q -
Latch + UV S1 Q -
90% VREF
+
SS Timer
Thermal Shutdown
EN/DEM
R SQ
Min. TOFF Q TRIG
1-SHOT
Diode Emulation
DRV DRV
20uA
+ -
BOOT UGATE PHASE
VDDP LGATE PGND
OC
PGOOD
RP6102-02P July 2009
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RP6102
Absolute Maximum Ratings (Note 1)
Input Voltage, TON to GND -------------------------------------------------------------------------------------------- −0.3V to 32V BOOT to GND ------------------------------------------------------------------------------------------------------------- −0.3V to 38V PHASE to BOOT ----------------------.