Wiki

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
university:courses:electronics:electronics-lab-6m [05 Mar 2019 12:22]
amiclaus [Procedure:]
university:courses:electronics:electronics-lab-6m [12 Jul 2019 13:22] (current)
andreeapop
Line 1: Line 1:
-====== Activity ​6M. NMOS as a Current Mirror ======+====== ActivityNMOS as a Current Mirror ======
  
 ===== Objective: ===== ===== Objective: =====
Line 27: Line 27:
 ===== Hardware Setup: ===== ===== Hardware Setup: =====
  
-In the current mirror configuration,​ the opamp serves as a virtual ground at the mirror input (gate) node to convert the voltage steps from AWG 1 ( W1 output ) into current steps through the 1K? resistor. The drain voltage is swept using a ramp from AWG 2(output ​W2) set to 3V peak to peak with the offset to 1.5V. V<​sub>​DS</​sub>​ of output device M<​sub>​2</​sub>​ is measured differentially by scope inputs 1+, 1-. The mirror output current is measured by scope inputs 2+. 2- across 1K? resistor, R<​sub>​2</​sub>​.+In the current mirror configuration,​ the opamp serves as a virtual ground at the mirror input (gate) node to convert the voltage steps from AWG 1 ( W1 output ) into current steps through the 1K? resistor. The drain voltage is swept using a ramp from AWG 1(output ​W1). Load the stairstep.csv file, set amplitude ​to 1.5  (3V peak to peakwith the offset to 1.5V. 
 +V<​sub>​DS</​sub>​ of output device M<​sub>​2</​sub>​ is measured differentially by scope inputs 1+, 1-. The mirror output current is measured by scope inputs 2+. 2- across 1K? resistor, R<​sub>​2</​sub>​.
 If you don't want to use the op-amp configuration the following simplified configuration can be used as well.  If you don't want to use the op-amp configuration the following simplified configuration can be used as well. 
  
Line 41: Line 42:
 Two identical transistors with the same gate to source voltage will have the same drain current I<​sub>​D</​sub>​. The second transistor, M<​sub>​2</​sub>,​ in effect mirrors the current in the first, M<​sub>​1</​sub>​. Remembering the drain current to gate source voltage relationship for a MOS transistor: Two identical transistors with the same gate to source voltage will have the same drain current I<​sub>​D</​sub>​. The second transistor, M<​sub>​2</​sub>,​ in effect mirrors the current in the first, M<​sub>​1</​sub>​. Remembering the drain current to gate source voltage relationship for a MOS transistor:
  
-{{ :​university:​courses:​electronics:​a6m_ne1.png?​250 |}}+{{ :​university:​courses:​electronics:​a6m_ne1.png?​ 250 |}}
  
 where K =μ<​sub>​n</​sub>​C<​sub>​ox</​sub>/​2<​sub></​sub>​ and λ can be taken as process technology constants.\\ where K =μ<​sub>​n</​sub>​C<​sub>​ox</​sub>/​2<​sub></​sub>​ and λ can be taken as process technology constants.\\
university/courses/electronics/electronics-lab-6m.txt · Last modified: 12 Jul 2019 13:22 by andreeapop