[AP4460]

014012310-E-01

2015/04

- 9 -

F1, F2 and F3 switches compose the Power Path function. The F1 switch is placed between the PPIN pin and the

VS1 pin, F2 switch is placed between the VS1 pin and the VS2 pin and F3 switch is placed between the VS1 pin

and the VOUT pin. The F1 switch is synchronized with DC-DC convertor statement that is controlled by the VD

VD charge is transferred to VS1 to charge the external capacitor until VD voltage becomes less than

output is available for system loads. The F3 switch is turned OFF when the VS1 voltage becomes less than

the F2 and F3 switches change to OFF state.

Figure 4. State Transition of the Power Path Switches

10.2 Determine the control threshold of the DC-DC converter and power path

Four resistors are needed to connect in series between the VREF pin and GND to determine the output target of

super capacitor. The voltages between each resistor should be input to the VDSET pin, the VSSET pin and the

VLSET pin. The control threshold of the DC-DC convertor input voltage can be determined by connecting three

resistors in series between the VREF pin and GND, and the voltages between each resistor should be input to the

MPPH pin and the MPPL pin. The connection of resistors is shown in Figure 5.

Figure 5. Resistor connection circuit