MB39A104
13
■
SETTING THE OUTPUT VOLTAGE
■
SETTING THE TRIANGULAR OSCILLATION FREQUENCY
The triangular oscillation frequency is determined by the timing capacitor (C
T
) connected to the CT terminal (pin
13), and the timing resistor (R
T
) connected to the RT terminal (pin 12).
Moreover, it shifts more greatly than the calculated values according to the constant of timing resistor (R
T
) when
the triangular wave oscillation frequency exceeds 1 MHz. Therefore, set it referring to “Triangular Wave Oscillation
Frequency vs. Timing Resistor” and “Triangular Wave Oscillation Frequency vs. Timing Capacitor” in “
■
TYPICAL
CHARACTERISTICS”.
Triangular oscillation frequency : f
OSC
−
+
+
15
10
14
(CS2)
CS1
(
−
INE2)
−
INE1
V
O
R1
R2
1.24 V
Error Amp
1.24
R2
V
O
(V)
=
(R1
+
R2)
11
•
Output Voltage Setting Circuit
f
OSC
(kHz) :=
1200000
C
T
(pF)
×
R
T
(k
Ω
)
Summary of Contents for MB39A104
Page 38: ...MB39A104 38 MEMO ...
Page 39: ...MB39A104 39 MEMO ...
