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AS1301

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

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

regulation loop limits the charge transfer to the output. In collaboration with the second flying capacitor this mode

features dual-phase operation.

Figure 27. 2:3 Single Phase Operating Mode

SW1

SW3

SW2

SW4

Charging Flying Capacitors

SW1

SW3

SW2

SW4

Generating Output Voltage

Figure 28. 1:2 Dual Phase Operating Mode

SW1

SW3

SW2

SW4

SW1

SW3

SW2

SW4