MB3759 Datasheet, PDF (19/27 Pages) Fujitsu Component Limited. – Switching Regulator Controller (Switchable between push-pull and single-end functions)

MB3759
5. Example Power Supply Voltage Supply Circuit
(1) Supplied via a Zener diode
VIN
R
C
VZ
VCC = VZ
VCC
MB3759
(2) Supplied via a three-terminal regulator
AC
VIN
VZ
VCC
MB3759
VCC = VIN − VZ
Three-terminal
regulator
VCC
MB3759
6. Example Protection Circuit for Output Transistor
Due to its monolithic IC characteristics, applying a negative voltage greater than the diode voltage ( =: 0.5 V) to
the substrate (pin 7) of the MB3759 causes a parasitic effect in the IC which can result in misoperation.
Accordingly, the following measures are required if driving a transformer or similar directly from the output
transistor of the IC.
(1) Protect the output transistor from the parasitic effect by using a Schottky barrier diode.
8
9
11
SBD
10
19