AS1330 Просмотр технического описания (PDF) - austriamicrosystems AG
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AS1330 Datasheet PDF : 18 Pages
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AS1330
Datasheet - Detailed Description
8 Detailed Description
The AS1330 can operate from a single-cell input voltage (VIN) below 1V, and features fixed frequency (4MHz) and current mode PWM control for
exceptional line- and load-regulation. With low RDS(ON) and gate charge internal NMOS and PMOS switches, the device maintains high-
efficiency from light to heavy loads.
Modern portable devices frequently spend extended time in low-power or standby modes, switching to high power-drain only when certain
functions are enabled. The AS1330 is ideal for portable devices since it maintain high-power conversion efficiency over a wide output power
range, thus increasing battery life in these types of devices.
In addition to high-efficiency at moderate and heavy loads, the AS1330 includes an automatic powersave mode that improves efficiency of the
lid power converter at light loads. The powersave mode is initiated if the output load current falls below a factory programmed threshold.
Figure 19. AS1330 - Block Diagram
a L1
v 1µH
ill AA Battery
6
VIN
C1
AG t st 4.7µF
Start Up
OSC
PWM
Control
A A/B
B MUX
Sync Drive
Control
4MHz
Ramp
Generator
Slope
Compensator
Σ
s n +
e PWM –
Comp
m t –
On
4
a n Off
EN
Shutdown
Control
Shutdown
RC
CP2
CC
Powersave
o Powersave
Operation
Control
1 SW
–
VOUT
Good
+
1.65V
5
VOUT
0.25Ω 0.35Ω
Current
Sense
AS1330
3
–
gm Error
FB
Amp
+
0.8V
Ref
c 1
l SENSE
Sense & POK
Logic
4
POK
a 2 GND
1.8V
Output
C2
4.7µF
nic Low-Voltage Start-Up
h The AS1330 requires VIN of only 0.85V (typ) or higher to start up. The low-voltage start-up circuitry controls the internal NMOS switch up to a
maximum peak inductor current of 650mA (typ), with 1.5ms (approx.) off-time during start-up, allowing the devices to start up into an output load.
c With a VOUT > 1.65V, the start-up circuitry is disabled and normal fixed-frequency PWM operation is initiated. In this mode, the AS1330 operates
independent of VIN, allowing extended operating time as the battery can drop to several tenths of a volt without affecting output regulation. The
e limiting factor for the application is the ability of the battery to supply sufficient energy to the output.
TLow-Noise Fixed-Frequency Operation
Oscillator
The AS1330 switching frequency is internally fixed at 4MHz allowing the use of very small external components.
www.austriamicrosystems.com/DC-DC_Step-Up/AS1330
Revision 1.06
8 - 17
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