upc1909 Renesas Electronics Corporation., upc1909 Datasheet - Page 18

• Manufacturer Part Number: upc1909
• Description: Switching Regulator Control Ic
• Manufacturer: Renesas Electronics Corporation.

18
4. SETTINGS
4.1 Controller Settings
Figure 4-1 below. The feedback gain is primarily determined by the R
triangle wave based on the FB pin voltage.
Caution When using a shunt regulator such as the
4.2 Startup Circuit, Low Voltage Malfunction Prevention Circuit Settings
The feedback circuit for when the converter output voltage is detected on the secondary side is configured as shown in
The voltage of the FB pin is input to PWM comparators 1 and 2.
During steady operation (DTC
The startup circuit is configured as shown in Figure 4-2 below.
set bearing in mind the variation of the C
photocoupler grounded at the emitter ground.
From comparator output
2
< FB < DTC
Primary coil
Figure 4-1. Feedback Circuit Configuration
Shunt regulator
Data Sheet G14309EJ2V0DS00
N
V
CC IN
P
I
K
Figure 4-2. Startup Circuit
1
), the duty of OUT
D
N
1
Z
R
1
GND
R
V
Photo-
coupler
C
2
REF
FB
1
14
12
3
TR
PC1093 for the secondary-side detector, I
C
C
3
in the photocoupler. Also, be sure to use the
2
1
1
PWM comparator 1
PWM comparator 2
and OUT
resistor.
R
R
3
4
2
14
13
9
3
is determined by the slice level of the
V
V
DTC
GND
To output circuit of OUT
To output circuit of OUT
CC
REF
1
1
2
PC1909
k
must be