MB3778 Datasheet, PDF (13/29 Pages) Fujitsu Component Limited. – Switching Regulator Controller

MB3778
s HOW TO SET THE OUTPUT VOLTAGE
The output voltage is set using the connections shown in “Connection of error Amp. Output Voltage V0 ≥ 0” and
“Connection of Error Amp. Output Voltage V0 < 0”.
The error amplifier power is supplied by the reference voltage circuit as is that of the other internal circuits. The
common mode input voltage range is from 1.05 V to 1.45 V.
Set 1.23 V (VREF/2) as the reference input voltage that is connected to either inverting or non-inverting input
terminals.
• Connection of Error Amp. Output Voltage V0 ≥ 0
VREF
R
R1
R
R2
VO⁺
VO ⁺ =
VREF
(R1 + R2)
2 × R2
+
PIN 5 or PIN 12
−
RNF
• Connection of Error Amp. Output Voltage V0 < 0
VREF
VO^− = −
VREF
(R1 + R2) + VREF
2 × R1
R
R1
R
R2
+
−
RNF
VO^−
PIN 5
13