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PWM comparator, are you refer to the comparator that produce the PWM signal in the DC/DC converter IC?
Basically, comparator are operational amplifier without compensation. They are operating in large signal model. They need high gain, fast slew rate => Speed, and also low offset and the last two stages or more are always inverters. You have only the first to second stages design to play with. You can design an OTA. or simple two stages in the opamp design. You can also design multiple stages using a few differential pairs with resistor load before a large gain stage.
Thank you for your reply. Yes, I will use this comparator in my boost converter. To be specific, this comparator will be used in front of the logic block, which is a pure digital block. Do I need to use latch structure in this comparator? If so, what's the structure of this comparator? Thanks.
Normally, there is a SR FF after the comparator output to set ot reset the output of the Boost or Buck converter. So I guess you do not need to design a latch comparator at all.. Depending on the operating switching frequency, the only concern is the delay time and the gain of the comparator. You may need to increase the bias current to reduce the delay time.