S1F76540 Series

◊Setup conditions of Figure 2.12

• Internal clock

: ON (Low Output mode)

 

 

 

 

 

 

 

 

• Booster circuit : ON

 

 

 

 

 

 

 

 

• Regulator

: ON (if CT = –0.04%/°C)

 

 

 

 

 

 

 

 

 

VDD

 

 

 

 

 

 

 

 

 

 

 

 

VI

 

 

 

 

 

 

 

 

 

VI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6VI – (2∗VF)

 

 

4VI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6VI

 

 

 

 

 

 

VO'

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2∗VF

 

 

 

 

 

 

 

 

 

 

Figure 2.13 Potential relationship during 6-time boosting using diodes

◊Power-off procedure

•Set the POFF1 pin to low (VI) to turn off all circuits.

◊Output voltages

•When diodes are used for voltage boosting, the characteristics of diodes directly affect on the voltage boosting characteristics. The forward voltage drop (VF) of diodes can reduce the booster output voltage. As the example of Figure 2.12 uses two diodes, the drop of “V F” voltage multiplied by two occurs as shown in Figure 2.13. The booster output voltage is expressed by equation (5).

To increase the VO' value, use the diodes having a smaller VF.

VO' = 6× VI – 2× VF

• • • • Equation (5)

◊Notes

1 Input and output current conditions

To satisfy the input and output current ratings, limit the total current does not exceed the rated input current. The total current means the total boost time multiplied by the output load current. The example of Figure 2.12 has the maximum load current of 13.3 mA ( = 80 mA divided by 6).

2Input and output voltage conditions

To satisfy the input and output voltage ratings, take care not to violate the electric potential relationship of higher time boosting using diodes. The example of Figure 2.12 must have the “V I” that can satisfy the input voltage conditions during 6-time boosting (see Table 2.3).

◊Application in other setup conditions

1 When used in the High Output mode Connect the FC pin to the VI pin.

2When changing the temperature coefficient (CT)

Change the TC1 and TC2 pin setup by following the definition of Table 2.7.

2–34

EPSON

S1F70000 Series Technical Manual