HA16116FP/FPJ, HA16121FP/FPJ
2. DC/DC Converter Output Voltage Setting and Error Amp Usage
2.1 Positive Voltage Booster (V
O
> V
IN
) or Step-Down (V
IN
> V
O
> Vref)
Use
V
O
=
R
1
+ R
2
⋅
Vref (V)
R
2
Booster output is possible only at channel 2 of HA16121.
HA16116 or channel 1 of HA16121 are used.
V
O
R
1
R
2
V
O
R
1
IN(−)2
−
R
2
+
For step-down output, both channels of
Error amp.
IN(−)1
−
IN(+)1 +
CH1
CH2
Vref pin
Vref
2.5 V
(internal connection)
Figure 2.1
2.2 Negative Voltage (V
O
< Vref) for Inverting Output
Use
V
O
=
−Vref ⋅
R
3
+ R
4
R
1
⋅
−
1
R
3
R
1
+ R
2
(V)
Channel 1 is used for inverting output on both ICs.
Vref pin
R
1
R
3
IN(+)2
R
4
V
O
Vref 2.5 V
IN(−)1
R
2
−
+
Error amp
CH1
Figure 2.2 Inverting Output
Rev.2.0, Sep.18.2003, page 9 of 33