Oct 29, 2006 #1 D Davidy Junior Member level 2 Joined Sep 14, 2005 Messages 21 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,465 This is a simple amplifier in a typical bandgap circuit. Who can tell me why there is a PMOS FET "ST1" in the middle of the circuit? what is the useage of it? Thanks!
This is a simple amplifier in a typical bandgap circuit. Who can tell me why there is a PMOS FET "ST1" in the middle of the circuit? what is the useage of it? Thanks!
Oct 30, 2006 #2 Verba Member level 5 Joined Apr 11, 2003 Messages 92 Helped 7 Reputation 14 Reaction score 0 Trophy points 1,286 Activity points 491 I think it's negative FB at DC It keeps the current through P49 constant. And it helps to charge NLL, NLR capacitance
I think it's negative FB at DC It keeps the current through P49 constant. And it helps to charge NLL, NLR capacitance
Oct 31, 2006 #3 L lastdance Advanced Member level 4 Joined Feb 1, 2005 Messages 100 Helped 18 Reputation 36 Reaction score 1 Trophy points 1,298 Location Singapore Activity points 1,237 Re: What is the usage of the PMOS FET in this simple amplif when in+/- exceeds input common mode, this PFET turns on to pull VOUT low. Added after 25 seconds: when in+/- exceeds input common mode, this PFET turns on to pull VOUT low.
Re: What is the usage of the PMOS FET in this simple amplif when in+/- exceeds input common mode, this PFET turns on to pull VOUT low. Added after 25 seconds: when in+/- exceeds input common mode, this PFET turns on to pull VOUT low.