US 4,727,269 A · Temperature compensated sense amplifier

Abstract

A temperature compensated sense amplifier is connected to the sense node of a memory array which is OR tied to the bit lines of the array. A PNP current mirror supplies voltage independent controlled current to the sense node. A level shifting stage is connected to the sense node to establish a threshold sensing level, and to switch on to steer the current into the amplifier stage. A compensation stage is connected to the level shifting stage and the amplifier stage to compensate for the .beta. factors of the transistors and the resistive changes with temperature. A temperature compensated current sink is connected to the PNP current mirror to track over temperature in opposition therewith and maintain a constant current into the sense node. The level shifting stage and the amplifier stage also include temperature compensating features to provide a sensing threshold which tracks constantly over the operating temperature range.

Claims20

Dependent claims

A sense amplifier for detecting and amplifying a varying voltage signal indicative of high and low logic level shifts at a sense node, comprising:

level shifting means, connected to the sense node, for establishing an input voltage threshold level coresponding to the high logic level and a high impedance at voltages below said voltage threshold level;
a transistor amplifier connected to said level shifting means, the level shifting means switching to form a current path from said sense node to the transistor amplifier for any signal portion above the voltage threshold level;
and
temperature compensation means, connected to the transistor amplifier along a first path in order to compensate for the positive B gain temperature characteristic of said transistor amplifier and the level shifting means along a second path for maintaining a substantially constant voltage difference between the voltage threshold level and the low logic level.

1 more element

In a sense amplifier having a driver transistor with an output electrode coupled to an output node and a second electrode coupled to a first voltage reference and an input transistor with a first electrode coupled to a voltage supply and a control electrode coupled to a sense node, the improvement comprising:

a switching transistor having a first electrode coupled to said control electrode of said input transistor, a second electrode coupled to a control electrode of said driver transistor and a control electrode coupled to a second electrode of said input transistor;
and
a temperature compensation circuit having a first transistor with a first electrode coupled to said control electrode of said switching transistor with a first electrode and a second transistor coupled to said control electrode of said driver transistor, said first and second transistors having second electrodes coupled to a second voltage reference and control electrodes coupled to a third voltage source such that said first and second transistors being connected to conduct more current with increasing temperature.

Dependencies are inferred from the claim text.

Temperature compensated sense amplifier

Life of this patent

Temperature compensated sense amplifier

Life of this patent

Abstract

Claims20