AS1301 austriamicrosystems AG, AS1301 Datasheet - Page 10

• Manufacturer Part Number: AS1301
• Description: 5V/50mA Low Noise Inductorless Boost Converter
• Manufacturer: austriamicrosystems AG

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AS1301
Data Sheet
Switch Configuration
The AS1301 has nine built-in power switches in the shape of two coupled H-bridge topologies. The system features
1:2 and 2:3 operation mode as well as an 1:1 operation where the input is directly connected to the output. This
feedthrough mode is suitable for input voltages higher than the output voltage.
In 2:3 operation mode two flying capacitors are placed in series and each capacitor is charged to a half of the input
voltage. In pumping phase the flying capacitors are place in parallel. The bottom-plate of the parallel flying capacitors
C
boosted to a voltage equal to V
voltage in 2:3 mode can be up to one and a half of V
adapts the power transistor’s on-resistance to drop some voltage. The 2:3 operation mode runs in single-phase
operation only.
In 1:2 operation mode just one of both flying capacitors is placed in series to the input voltage, and therefore charged
to the input voltage. During pumping phase the input voltage is connected to the bottom of the charged flying capacitor
C
capacitor to the output, the output can be charged to double of V
regulation loop limits the charge transfer to the output. In collaboration with the second flying capacitor this mode
features dual-phase operation.
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Figure 27. 2:3 Single Phase Operating Mode
Figure 28. 1:2 Dual Phase Operating Mode
FLY1 and
FLY
V
V
BATT
BATT
. The voltage at the top-plate of the capacitor is now boosted to 2V
C
Charging Flying Capacitors
Charging C
FLY2
- D e t a i l e d D e s c r i p t i o n
is then connected to the input voltage so that the voltage at the top-plate of the flying capacitors is
FLY1
, C
SW2
FLY2
SW2
C
C
FLY1
FLY1
BATT
used for output voltage
+ V
SW4
SW4
SW1
SW1
BATT
SW3
SW3
C
C
/2. By connecting the top-plate of the capacitors to the output, the output
FLY2
FLY2
V
V
OUT
OUT
BATT
Revision 1.00
. If the top-plate voltage is higher than 5V, the regulation loop
V
V
BATT
BATT
BATT
. If the top-plate voltage is higher than 5V the
Generating Output Voltage
Charging C
BATT
. By connecting the top-plate of the
FLY2
, C
SW2
SW2
C
FLY1
C
FLY1
FLY1
used for output voltage
SW4
SW4
SW1
SW1
SW3
SW3
C
C
FLY2
FLY2
V
V
OUT
OUT
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