Datasheet

P
−
+
P
P
V
CC
V
FB
Current
Sense
Gate Drive
GND
Controller
P
P
P P
TLVH431
V
O
3.3 V
V
I
120 V
∼
∼
TLVH431, TLVH431A, TLVH431B
TLVH432, TLVH432A, TLVH432B
SLVS555I –NOVEMBER 2004–REVISED SEPTEMBER 2009....................................................................................................................................... www.ti.com
APPLICATION INFORMATION
Figure 21. Flyback With Isolation Using TLVH431 and TLVH432 as Voltage Reference and Error Amplifier
Figure 21 shows the TLVH431 used in a 3.3-V isolated flyback supply. Output voltage V
O
can be as low as
reference voltage V
REF
(1.24 V). The output of the regulator plus the forward voltage drop of the optocoupler LED
(1.24 + 1.4 = 2.64 V) determine the minimum voltage that can be regulated in an isolated supply configuration.
Regulated voltage as low as 2.7 Vdc is possible in the topology shown in Figure 21.
22 Submit Documentation Feedback Copyright © 2004–2009, Texas Instruments Incorporated
Product Folder Link(s): TLVH431 TLVH431A TLVH431B TLVH432 TLVH432A TLVH432B