求助大神，两个放大器并联的原因是什么，有什么好处

两个放大器，分别是以PMOS和NMOS为输入管的全差分放大器，放大器的输入分别是VINN1，VINP1和VINN2，VINP2，输出分别是VOUTN1，VOUTP1和VOUTN2，VOUTP2，这两个放大器的输入与输出端相连，即VINN1与VINN2，VINP1和VINP2，VOUTN1和VOUTN2，VOUTP1和VOUTP2相连，请问大神，这样的好处是什么?

想做成共模输入轨到轨吧?

I think this circuit the input common range can from 0V to AVDD(Power supply)
but these type circuit has Non Constant gm characteristic from 0V to AVDD,
and make Amplifier unstabile in some input common range
some paper has method to make gm is constant.