MB3827 Datasheet, PDF (28/41 Pages) Fujitsu Component Limited. – 6-ch DC/DC Converter IC With Synchronous Rectification for voltage step-up and step-down

MB3827
s SAMPLE POWER SUPPLY USING SELF-POWER SUPPLY (Channel 7)
The MB3827 has a built-in self-supply channel (channel 7), capable of supplying the IC with power through
transformer winding, with low input voltage (Vin ≥ 1.8V) drive capability. Following figure shows a sample of a
power supply using the transformer.
Vin
VG (O)
VSS (O)
H
FB7
5
I
6
−IN7−1
Error
− ^Amp.7
H
8
+IN7
−IN7−2
I
7
10 kΩ
+
Voffset
1.6 V
OUT7
1
2
RB7
VCC
VCC (O)
Note: The following settings are shown in “APPLICATION EXAMPLE”.
• VSS(0) is Vin −1.6V, from the voltage offset between −IN7-1 and −IN7-2.
• VCC and VCC(0) are set at the winding that produces Vin +1.6V.
• VG(0) is set at the winding that produces 8V.
Note that because channels 1-6 operate at Vcc ≥ 4V, Vcc and Vcc(0) must be set at the winding that produces
VIN + 2.2V in order to operate at VIN ≥ 1.8V.
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