High-Efficiency Notebook Computer
Power Supply Controller
a
ADP3020
GENERAL DESCRIPTION
FEATURES
The ADP3020 is a highly efficient dual synchronous buck switch-
ing regulator controller optimized for converting the battery or
Wide Input Voltage Range: 4.5 V to 25 V
High Conversion Efficiency > 96%
adapter input into the system supply voltages required in note-
book computers. The ADP3020 uses a dual-mode PWM/Power
Saving Mode architecture to maintain efficiency over a wide
load range. The oscillator frequency can be programmed for
200 kHz, 300 kHz, or 400 kHz operation, or it can be synchro-
nized to an external clock signal of up to 600 kHz.
Integrated Current Sense—No External Resistor Required
Low Shutdown Current: 7 A (Typical)
Dual Synchronous Buck Controllers with Selectable
PWM/Power-Saving Mode Operation
Built-In Gate Drive Boost Circuit for Driving External
N-Channel MOSFETs
Two Independently Programmable Output Voltages
Fixed 3.3 V or Adjustable (1.25 V to VIN–0.5 V)
Fixed 5 V or Adjustable (1.25 V to VIN–0.5 V)
Programmable PWM Frequency
Integrated Linear Regulator Controller
Extensive Circuit Protection Functions
38-Lead TSSOP Package
The ADP3020 provides accurate and reliable short circuit pro-
tection using an internal current sense circuit, which reduces
cost and increases overall efficiency. Other protection features
include programmable soft-start, UVLO, and integrated output
undervoltage/overvoltage protection. The ADP3020 contains a
linear regulator controller that is designed to drive an external
P-channel MOSFET or PNP transistor. The linear regulator
output is adjustable, and can be used to generate the auxiliary
voltages required in many laptop designs.
APPLICATIONS
Notebook Computers and PDAs
Portable Instruments
General Purpose DC-DC Converters
FUNCTIONAL BLOCK DIAGRAM
V
IN
5.5V TO 25V
PFO
ADP3020
1.20V
5V LINEAR
REF
Q1
Q2
Q3
L2
L1
5V
3.3V
5V
SMPS
3.3V
SMPS
Q4
SS3
SS5
Q5
LINEAR
CONTROLLER
PWRGD
2.5V
POWER-ON
RESET
REV. 0
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reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements 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 Analog Devices.
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© Analog Devices, Inc., 2000