Reference current generator, and method of programming, adjusting and/or operating same
View Patent ↗There are many inventions described and illustrated herein. In a first aspect, the present invention is a technique and circuitry for reading data that is stored in memory cells. In one embodiment of this aspect, the present invention is a technique and circuitry for generating a reference current that is used, in conjunction with a sense amplifier, to read data that is stored in memory cells of a DRAM device. The technique and circuitry for generating a reference current may be implemented using an analog configuration, a digital configuration, and/or combinations of analog and digital configurations.
1. A semiconductor dynamic random access memory device comprising:
a plurality of bit lines, including a first bit line;
a plurality of memory cells, including a first memory cell coupled to the first bit line, each memory cell includes:
at least one transistor including a source region, a drain region, a body region disposed between the source and drain regions, and a gate spaced apart from and capacitively coupled to the body region, wherein the body region is electrically floating; and
a first data state and a second data state, wherein the memory cell is in (1) the first data state when the transistor includes a first charge in the body region, and (2) the second data state when the transistor includes a second charge in the body region;
a sense amplifier, having first and second inputs, wherein the first input is coupled to the first bit line; and
a digitally controlled reference current generator, coupled to the second input of the sense amplifier, to generate a reference current in response to a reference current control word, wherein the sense amplifier uses the reference current to sense the data state of the first memory cell.
2. The semiconductor dynamic random access memory device of claim 1 wherein the digitally controlled reference current generator is selectively coupled to the second input when the sense amplifier is sensing the data state of the first memory cell.
3. The semiconductor dynamic random access memory device of claim 1 wherein the digitally controlled reference current generator includes a digital-to-analog converter.
4. The semiconductor dynamic random access memory device of claim 1 further including a control unit, coupled to the digitally controlled reference current generator, to generate the reference current control word.
5. The semiconductor dynamic random access memory device of claim 4 wherein the control unit uses a successive approximation technique to determine the reference current control word.
6. The semiconductor dynamic random access memory device of claim 5 wherein the control unit is selectively coupled to the sense amplifier to execute the successive approximation technique that determines the reference current control word.
7. The semiconductor dynamic random access memory device of claim 1 further including a control unit to generate the reference current control word during an initialization sequence of the memory device.
8. The semiconductor dynamic random access memory device of claim 1 further including a control unit to generate the reference current control word during normal operation of the memory device.
9. The semiconductor dynamic random access memory device of claim 1 further including a control word memory to store the reference current control word.
10. The semiconductor dynamic random access memory device of claim 9 wherein the reference current control word is permanently, semi-permanently or temporarily stored in the control word memory.
11. The semiconductor dynamic random access memory device of claim 10 wherein the control word memory is a register.
12. A semiconductor dynamic random access memory device comprising:
a plurality of bit lines, including a first bit line and a second bit line;
a plurality of memory cells, including a first memory cell coupled to the first bit line and a second memory cell coupled to the second bit line, wherein each memory cell includes:
a transistor including a source region, a drain region, a body region disposed between the source and drain regions, and a gate spaced apart from the body region, wherein the body region is electrically floating; and
a first data state and a second data state, wherein the memory cell is in (1) the first data state when the transistor includes a first charge in the body region, and (2) the second data state when the transistor includes a second charge in the body region;
a sense amplifier, having first and second inputs, wherein the first input is coupled to the first bit line; and
a digitally controlled reference current generator, coupled to the second input of the sense amplifier, to generate a reference current in response to a reference current control word, wherein the sense amplifier uses the reference current to sense the data state of the first memory cell.
13. The semiconductor dynamic random access memory device of claim 12 further including a control unit, coupled to the digitally controlled reference current generator, to generate the reference current control word.
14. The semiconductor dynamic random access memory device of claim 13 wherein the control unit uses a successive approximation technique to determine the reference current control word.
15. The semiconductor dynamic random access memory device of claim 14 wherein the control unit is selectively coupled to the sense amplifier to execute the successive approximation technique that determines the reference current control word.
16. The semiconductor dynamic random access memory device of claim 12 wherein:
the second input of the sense amplifier is selectively coupled to the second bit line; and
the sense amplifier uses a second reference current to sense the data state of the second memory cell.
17. The semiconductor dynamic random access memory device of claim 12 wherein a memory control unit provides the reference current control word to the memory device during an initialization sequence of the memory device.
18. The semiconductor dynamic random access memory device of claim 12 further including a control unit to generate the reference current control word during normal operation or a re-initialization sequence of the memory device.
19. The semiconductor dynamic random access memory device of claim 12 further including a control word memory to store the reference current control word.
20. The semiconductor dynamic random access memory device of claim 19 wherein the reference current control word is permanently, semi-permanently or temporarily stored in the control word memory.
21. The semiconductor dynamic random access memory device of claim 20 wherein the control word memory is a register.
22. The semiconductor dynamic random access memory device of claim 21 wherein a memory control unit provides the reference current control word to the memory device during an initialization sequence, normal operation or a re-initialization sequence of the memory device and wherein the memory device stores the reference current control word in the register.
23. The semiconductor dynamic random access memory device of claim 21 further including a control unit to generate the reference current control word and store the control word in the register.