yjshih
Newbie level 1
Dear all,
In my design, I have a analog block called "IREF-gen" which supplys bais currents for all other analog blocks in my IC; inside this "IREF_gen", we use a start-up; it comes two sorts of start-up for me: one is using p-n MOS diode-connected to gen constant bias for a NMOS; initially, the NMOS' source volatge is 0V and its VGS is higher than Vth and thus can supply start-up curent for the "IREF_gen"; when its bias points constructed, the VGS value decreases and finally shut down the NMOS; the other start-up is using PMOS diode-connected to suuply start-up current for the "IREF-gen" initially; when it bias point constructed, the diode-connected PMOS switched to non-diode-connected and so the bias curent shut down from the start-up circuits! Basically I feel the second one is better choice as it can supply higher start-up current and can seperate the start-up circuits from "IREF-gen" completely when its bias points built!!! But I am not sure which one is better!!!
anyone has any commments, please??? thanks for the help!!
In my design, I have a analog block called "IREF-gen" which supplys bais currents for all other analog blocks in my IC; inside this "IREF_gen", we use a start-up; it comes two sorts of start-up for me: one is using p-n MOS diode-connected to gen constant bias for a NMOS; initially, the NMOS' source volatge is 0V and its VGS is higher than Vth and thus can supply start-up curent for the "IREF_gen"; when its bias points constructed, the VGS value decreases and finally shut down the NMOS; the other start-up is using PMOS diode-connected to suuply start-up current for the "IREF-gen" initially; when it bias point constructed, the diode-connected PMOS switched to non-diode-connected and so the bias curent shut down from the start-up circuits! Basically I feel the second one is better choice as it can supply higher start-up current and can seperate the start-up circuits from "IREF-gen" completely when its bias points built!!! But I am not sure which one is better!!!
anyone has any commments, please??? thanks for the help!!