Hello good people of AAC,
Of late I have seen rectifier circuits in IC design that use MOSFET connected diodes (connecting Gate to Drain) instead of PN junction ones while claiming that the former has lower voltage drop compared to the latter. No justification was really given. I scoured the depths of the World Wide Web in a quest to find the reason behind this but, alas, my search has been in vain. I understand that by connecting the gate of the MOSFET to the drain, the MOS will only operate either in cutoff or saturation. The current in saturation is given by the oh-so famous square law that we all know by heart. However, this doesn't really explain how it compares to the EXPONENTIAL forward current of the PN junction diode in terms of voltage drop does it? Wouldn't a PN junction have a lower voltage drop than MOSFET since it has exponential forward bias current?
Of late I have seen rectifier circuits in IC design that use MOSFET connected diodes (connecting Gate to Drain) instead of PN junction ones while claiming that the former has lower voltage drop compared to the latter. No justification was really given. I scoured the depths of the World Wide Web in a quest to find the reason behind this but, alas, my search has been in vain. I understand that by connecting the gate of the MOSFET to the drain, the MOS will only operate either in cutoff or saturation. The current in saturation is given by the oh-so famous square law that we all know by heart. However, this doesn't really explain how it compares to the EXPONENTIAL forward current of the PN junction diode in terms of voltage drop does it? Wouldn't a PN junction have a lower voltage drop than MOSFET since it has exponential forward bias current?