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1.X Threshold Voltage Reference

IP.com Disclosure Number: IPCOM000116586D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Andoh, H: AUTHOR

Abstract

Disclosed is an integrated circuit which can produce a voltage reference of any voltage between 1.0 and 2.0 times the threshold voltage of the chip. This circuit requires a constant current source connected to Net1 and GND, and the voltage at Net1 is the one in interest. By changing the conductances of NFET and PFET, the reference voltage can be changed.

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1.X Threshold Voltage Reference

      Disclosed is an integrated circuit which can produce a voltage
reference of any voltage between 1.0 and 2.0 times the threshold
voltage of the chip.  This circuit requires a constant current source
connected to Net1 and GND, and the voltage at Net1 is the one in
interest.  By changing the conductances of NFET and PFET, the
reference voltage can be changed.

      The circuit and the connection are described below and shown in
Fig.  1.  Tie the Source, NWELL of the PFET and Gate of NFET to Net1.
Tie the source of NFET, and the Gate of PFET to GND.  Tie the Drain
of PFET to the Drain of NFET.  A constant current is needed to bias
this circuit between Net1 and GND.

      By increasing the conductances of PFET with a fixed NFET
conductance, PFET changes its operation mode from saturation to
linear region.  The reference voltage between  Net1 and GND also
changes from two times threshold voltage to one time threshold
voltage accordingly.

      This voltage reference can be used not only as a voltage
reference but also as a biasing circuit for a transconductor as shown
in Fig. 2.