Oscillation circuit and operation method thereof
AssigneeNEC Electronics Corporation
InventorJun Yoshida
Life of this patent
Estimating the term…
Abstract
An oscillation circuit has: a first MOS transistor having a gate connected to a first node and a source connected to the ground; a second MOS transistor having a gate connected to a second node and a source connected to the ground; a current supply circuit supplying a control current; a threshold correction circuit supplying a correction current; and a charge-discharge circuit which supplies a charge current which is a superposition of the control current and the correction current to the first node and the second node alternately in response to potentials of drains of the first and the second MOS transistors. The threshold correction circuit increases the correction current as threshold voltages of the first and the second MOS transistors become large.
Claims12
An oscillation circuit comprising:
- a first MOS transistor having a gate connected to a first node and a source connected to a first terminal with a predetermined potential;
- a second MOS transistor having a gate connected to a second node and a source connected to a second terminal with said predetermined potential;
- a current supply circuit configured to supply a control current to a third node;
- a threshold correction circuit configured to supply a correction current to said third node;
- and
- a charge-discharge circuit which charges and discharges said first node and said second node alternately by supplying a charge current which is a superposition of said control current and said correction current to said first node and said second node alternately in response to potentials of drains of said first MOS transistor and said second MOS transistor,
- wherein said threshold correction circuit comprises:
- a third MOS transistor formed on a same semiconductor substrate as said first MOS transistor and said second MOS transistor;
- and
- a correction current supplying circuit configured to supply said correction current to said third node in response to a threshold voltage of said third MOS transistor.
A method of operating an oscillation circuit,
- said oscillation circuit including:
- a first MOS transistor having a gate connected to a first node and a source connected to a first terminal with a predetermined potential;
- and
- a second MOS transistor having a gate connected to a second node and a source connected to a second terminal with said predetermined potential,
- said method comprising:
- supplying a control current;
- supplying a correction current which increases as absolute values of threshold voltages of said first MOS transistor and said second MOS transistor become larger;
- and
- charging and discharging said first node and said second node alternately by supplying a charge current which is a superposition of said control current and said correction current to said first node and said second node alternately in response to potentials of drains of said first MOS transistor and said second MOS transistor.
Dependencies are inferred from the claim text.