MB39A115 Datasheet, PDF (18/42 Pages) Fujitsu Component Limited. – 5 ch DC/DC Converter IC with Synchronous Rectification

MB39A115
■ SETTING THE OUTPUT VOLTAGE
• ch.1
Vo
R3
R1
37
−INE1
R2
CS1
38
Error
Amp 1
−
+
36
+
FB1
1.00 V
1.00 V
VO =
(R1 + R2)
R2
(R1 + R3) ≥
VO
100 µA
Set R1 and R3 refer to above formula, then error amp’s response
is not slow.
• ch.2 to ch.5
Vo
R1
−INEX
R2
CSX
R3
Error
Amp X
−
+
+
FBX
1.23 V
1.23 V
VO = _R2 (R1 + R2)
(R1 + R3) ≥ ^VO
100 µA
X : Each channel number
Set R1 and R3 refer to above formula, then error amp’s response
is not slow.
■ SETTING THE TRIANGULAR WAVE OSCILLATION FREQUENCY
The triangular wave oscillation frequency can be set by connecting a timing resistor (RT ) to the RT terminal (pin
12) and a timing capacitor (CT) to the CT terminal (pin 13).
Triangular wave oscillation frequency : fOSC
620000
fOSC (kHz) =: _{CT (pF) × RT (kΩ)}
18