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Reference Voltage Generator for Multi State Arrays

IP.com Disclosure Number: IPCOM000045468D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Chen, SC: AUTHOR [+3]

Abstract

In multi-state array design, there are different kinds of diodes used to provide multi-state in the array. Therefore, tracking between reference voltages and the forward voltages (VFs) of the array diodes becomes critical for sensing. The circuit shown and described herein provides this feature.

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Reference Voltage Generator for Multi State Arrays

In multi-state array design, there are different kinds of diodes used to provide multi-state in the array. Therefore, tracking between reference voltages and the forward voltages (VFs) of the array diodes becomes critical for sensing. The circuit shown and described herein provides this feature.

Notice that the two current source circuits 1 and 2 in the dotted boxes are the same. The bit select and VCC2 voltages are high enough to drive the transistors 28 and 29 into saturation.

Therefore, the currents "I" will all be equal and track with each other. Also, notice that the word lines in the array are connected to the reference voltage generator circuit. Any voltage variations in the selected word line will be reflected in the output VREF3 from the reference voltage generator. Since currents are shared between transistors 7 and 8, they will have the same VBE drop and the voltage at node N3 will be equal to that at N5. This relationship can be established as follows: VN5 - VBE + VHB + VBE - VHB=VN3.

By designing proper resistance values of R1, R2 and R5, R6, transistor 3 tries to share the same current as transistor 4 and hence the voltage at node N5 will be equal to that at N6. Now since transistors 14 and 15 pull twice the current "I", transistors 1 and 2 will have the same current "I" through them and their VBE values are equal. Therefore, the voltage at node N1 equals the voltage at node N2. Similarly the voltage at node VR equals voltage at node VREF3. It follows th...