MB39A123 Datasheet, PDF (29/44 Pages) Fujitsu Component Limited. – 6 ch DC/DC Converter IC with Synchronous Rectification

MB39A123
Furthermore, the maximum duty increases when the power supply voltage and the temperature are high. It is
therefore recommended to set the duty, based on the “■ TYPICAL CHARACTERISTICS” data, so that it does
not exceed 95% under the worst conditions.
ON duty cycle vs. DTC terminal voltage
100
Ta = + 25 °C
95 _{VCC = CTL = 4 V}
FB = 2 V
90 ^{CT = 100 pF}
fosc = 200 kHz
85
fosc = 1 MHz
Calculated value
fosc = 1 MHz
80
75
fosc = 2 MHz
70
65
60
55
50
0.6
0.65
0.7
0.75
0.8
0.85
0.9
DTC terminal voltage VDTC (V)
• When dead time is set
(Setting by external resistors)
Ra
Vdt
Rb
VREF
9
R1 : 131.9 kΩ
DTCX
To PWM Comp.X
GND
10
R2 : 97.5 kΩ
X: ch.2 to ch.6
29