UCC2897A用作ACDC、输入AC180-260V，输出155V3A.是否可以使用光耦代替隔离驱动变压器，VIN输入使用90V稳压二极管，如图：是否可行？

Hi
不能的，一般光耦是低压小电流的信号处理应用，电源里的驱动一般都是CT变压器。（驱动MOS的瞬间电流很大的，而一般光耦电流很小）

Johnsin Tao你好！
这个是高速输出4A电流的光耦：Pin-compatible, drop-in upgrades for
popular high speed opto-coupled gate
drivers
 Low power diode emulator simplifies
design-in process
 0.6 and 4.0 Amp peak output drive
current
 Rail-to-rail output voltage
 Performance and reliability advantages
vs. opto-drivers
Resistant to temperature and age
10x lower FIT rate for longer service
life
14x tighter part-to-part matching
Higher common-mode transient
immunity: >50 kV/µs typical
 Robust protection features
Multiple UVLO ordering options
(5, 8, and 12 V) with hysteresis
 60 ns propagation delay, independent of
input drive current
 Wide VDD range: 6.5 to 30 V
 Up to 5000 VRMS isolation
 10 kV surge withstand capability
 AEC-Q100 qualified
 Wide operating temperature range
–40 to +125 °C
 RoHS-compliant packages
SOIC-8 (Narrow body)
DIP8 (Gull-wing)
SDIP6 (Stretched SO-6)
 Automotive-grade OPNs available
AIAG compliant PPAP documentation
support
IMDS and CAMDS listing support

Hi
如果是这样的话，虽然没有见过这样的设计，但是应该是可以的，不过最好是通过电路实际驱动MOS测试一下。
【或者说你有看到其他公司或者官方有这样的参考设计（只要是这样驱动的设计），那么应该是没有问题的】