MB3881 Datasheet, PDF (24/40 Pages) Fujitsu Component Limited. – 8-ch DC/DC Converter IC with Synchronous Rectifier for Voltage Step-up and Step-down

MB3881
s SAMPLE POWER SUPPLY USING CHANNEL 8 AS SELF-POWER SUPPLY
Using channel 8 as the self-power supply, the MB3881 can support a wide range of supply voltages and operate
at low input voltage (Vin ≥ 1.8 V).
The following example shows sample power supply using a transformer.
VSS (O)
Vin
H _FB8
4
5
−IN8
+IN8
6
Error
− ^Amp.8
+
OUT8
64
2
RB8
H
VO8-1
(15 V)
<CCD>
VO8-2
(7 V)
<LCD>
VO8-3
(−7 V)
<CCD>
VO8-4
(−15 V)
<LCD>
VCC
VCC (O)
The following settings are used in “APPLICATION EXAMPLE”.
• VSS(O) is set to the number of turnings that produces Vin - 1.8 V.
• VCC and VCC(O) are set to the number of turnings that produces Vin + 2.2 V.
Note that, because channels 1 to 4 operate at VCC ≥ 4 V, they must be set to the number of turnings that
produces Vin + 2.2 V or more so that they operate at Vin ≥ 1.8 V.
24