MOSFET Vs÷n To Current Converter

Q1, Q2 and Q3 form an active voltage divider (refer to the circuit MOSFET Active Voltage Divider). In this circuit Q1, Q2 and Q3 are identical so the voltage at the gate/drain of Q3 is 1/3 of the supply voltage. The voltage at the gate/drain of Q3 is also applied to the gate of Q4 so these two MOSFETs form a current mirror. The circuit is saved with the channel width and length of Q3 equal while Q4 has an aspect ratio of 5. This results to Q4 having a drain current 5 times that of Q3.