MB3759 Datasheet, PDF (17/27 Pages) Fujitsu Component Limited. – Switching Regulator Controller (Switchable between push-pull and single-end functions)

MB3759
R1
+
VIO
−
R2
RS ^IO
VO
GND
VO
VO
VIO > 0
VIO < 0
IO
0
IL1
(2) Example that does not use a diode
VREF
R3
VIO
+
−
IO
RS
VO
R1
R4
R2
GND
VO
VO
R1
R1+R2
>
R4
R3+R4
R1
R1+R2
<
R4
R3+R4
0
IO
0
IL1
The output current IO after current limiting is:
IO =
1
RS
[( ^R1 –
R1 + R2
R3R+4R4)
VO
+
R4 _VREF
R3 + R4
–
VIO
]
(R2
>>
R1)
In this case, a current flows into the reference voltage source via R3 and R4 if VO > VREF. To maintain the stability
of the reference voltage, design the circuit such that this does not exceed 200 µA.
17