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July 2000
ML4880*
Portable PC/PCMCIA Power Controller
GENERAL DESCRIPTION
The ML4880 Portable PC and PCMCIA Power Controller
is a complete solution for DC/DC power conversion for
portable computing systems with single or multiple
PCMCIA slots.
The device provides two synchronous buck controllers to
implement mixed voltage systems and a flyback controller
for 12V V
PP
generation for PCMCIA slots. The flyback
architecture enables generation of high currents (150mA
or more per slot) on the 12V bus for multiple slot PCMCIA
applications.
Each regulator can be independently switched off to fully
isolate the load from the power supply. The PFM
architecture will automatically adjust switching frequency
at light loads in order to maintain power conversion
efficiencies in excess of 90% over a wide output power
range.
FEATURES
s
s
Regulation to
±3%
maximum: provides 2% PCMCIA
switch matrix margin
Two synchronous buck controllers for 3.3/3V, 5V
generation, and a flyback for high current, 12V
generation from 5.5V to 18V input
Regulator power conversion efficiencies > 90%
Pulse frequency modulation for high efficiency
operation
Independent regulator shutdown for full load isolation
Adjustable current limit
Wide input voltage range (5.5V to 18V)
s
s
s
s
s
(* Indicates Part is End Of Life as of July 1, 2000)
BLOCK DIAGRAM
VIN
15
24
V
REG
CLAMP
GATE
CLAMP
CLAMP A
P DRV A
2
16
VIN
BUCK REGULATOR A
BIAS
CIRCUITS
13
+
N DRV A
ISENSE A
PWR GND A
23
14
4
VIN
5.5 – 18V
6
GND
VOUT A
2.5 – 3.5V
7
GND
SHDN A
SHDN B
SHDN C
SHUTDOWN
LOGIC
–
VFB A
9
TO SYSTEM
POWER
MANAGEMENT
11
18
10
VIN
CLAMP
GATE
CLAMP
CLAMP B
1
P DRV B
19
FLYBACK REGULATOR C
+
17
N DRV C
ISENSE C
BUCK REGULATOR B
+
N DRV B
ISENSE B
PWR GND B
22
20
5
3
VOUT C
6V – 15V
12
VOUT B
4.5 – 5.0V
VFB C
PWR GND C
–
VFB B
8
–
21
1
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
