THV3056_Rev.2.00_E
● Output Voltage Setting
Figure 13 shows ch-1 output voltage setting model. The voltage on INV1 pin is equal to the voltage on VREF pin due to
the effect of feed-back. The voltage on INV_1 pin is the divided voltage of Vout by R1 and R2.
So,
R2
R1 + R2
Vout1
R1
------------------
Vout1
= VREF
FB1
C2
Therefore,
C1
R1
Error AMP1
R3
Vout1 = VREF 1 + -----
-
R2
PWM Comparator
INV1
+
VREF
R2
=1.2V
Since VREF =1.2V, then
R1
R2
Vout1 = 1.2 1 + -----
Vout2
FB2
C4
Similarly the output voltage of ch-2 and ch-3 is
described as follows.
R4
R6
C3
R4
R5
Error AMP2
Vout2 = 0.85 1 + -----
-
PWM Comparator
INV2
+
VREF
=0.85V
R5
R7
R8
Vout3 = 1.2 1 + -----
Vout3
R7
FB3
C6
C5
ErrorAMP3
R9
-
PWM Comparator
INV3
+
VREF
=1.2V
R8
Figure 13. Output Voltage Setting
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THine Electronics, Inc.
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