Voltage reference computations for memory decision feedback equalizers
View Patent ↗A device includes a combinational circuit configured to create a one or more distortion correction factors used offset inter-symbol interference from a data stream on a distorted bit. The device also includes a selection circuit coupled o the combinational circuit. The selection circuit includes a feedback pin configured to receive a control signal and an output, wherein the selection circuit is configured to select a first distortion correction factor of the one or more distortion correction factors based upon the control signal and transmit the first distortion correction factor from the output.
1. A device, comprising:
a combinational circuit configured to create a one or more distortion correction factors used offset inter-symbol interference from a data stream on a distorted bit; and
a selection circuit coupled to the combinational circuit, wherein the selection circuit comprises:
a feedback pin configured to receive a control signal; and
an output, wherein the selection circuit is configured to select a first distortion correction factor of the one or more distortion correction factors based upon the control signal and transmit the first distortion correction factor from the output.
2. The device of claim 1 , comprising a latching element having a first input configured to be coupled to the output, wherein the first input is configured to receive the first distortion correction factor.
3. The device of claim 2 , wherein the latching element is configured to generate the control signal as a binary representation of one or more previous bits of the data stream.
4. The device of claim 2 , wherein the latching element comprises a second input configured to receive the distorted bit, wherein the latching element is configured to generate a modified value of the distorted bit based upon the distortion correction factor and the distorted bit.
5. The device of claim 4 , comprising a deserializer coupled to the latching element and the selection circuit, wherein the deserializer is configured to receive the modified value of the distorted bit from the latching element and to store an indication of the modified value of the distorted bit.
6. The device of claim 5 , wherein the deserializer is configured to store the indication of the modified value of the distorted bit as the binary representation of one or more previous bits of the data stream.
7. The device of claim 5 , wherein the deserializer is configured to transmit the binary representation of the one or more previous bits of the data stream as the control signal.
8. The device of claim 1 , the selection circuit comprises a switch configured to selectively transmit the first distortion correction factor when the switch is activated via the control signal.
9. The device of claim 1 , wherein the selection circuit comprises a multiplexer.
10. The device of claim 1 , wherein the distortion correction factors are equal in number to a total number of possible binary states of the control signal.
11. The device of claim 10 , wherein total number of possible binary states of the control signal is dependent upon a number of stored values of previous bits of the data stream.
12. A device, comprising:
a first combinational circuit, comprising:
a first input configured to receive a reference signal;
a second input configured to receive an adjustment signal; and
an first output configured to transmit a first bit distortion correction value based upon the reference signal and the adjustment signal; and
a second combinational circuit, comprising:
a third input configured to receive the reference signal;
a fourth input configured to receive the adjustment signal; and
a second output configured to transmit a second bit distortion correction value based upon the reference signal and the adjustment signal, wherein the first bit distortion correction value comprises a first voltage level and the second bit distortion correction value comprises a second voltage level.
13. The device of claim 12 , wherein the first combinational circuit comprises a digital adder configured to generate a sum of the reference signal and the adjustment signal as the first bit distortion correction value.
14. The device of claim 12 , wherein the second combinational circuit comprises a digital subtractor configured to generate a difference between the reference signal and the adjustment signal as the second bit distortion correction value.
15. The device of claim 12 , comprising:
a third combinational circuit coupled to the first combinational circuit, wherein the third combinational circuit comprises:
a fifth input configured to receive the first bit distortion correction value;
a sixth input configured to receive a second adjustment signal; and
a third output configured to transmit a third bit distortion correction value based upon the first bit distortion correction value and the second adjustment signal; and
a fourth combinational circuit coupled to the first combinational circuit, wherein the fourth combinational circuit comprises:
a seventh input configured to receive the first bit distortion correction value;
an eighth input configured to receive a second adjustment signal; and
a fourth output configured to transmit a fourth bit distortion correction value based upon the first bit distortion correction value and the second adjustment signal.
16. The device of claim 12 , comprising a selection circuit configured to receive the first bit distortion correction value and the second bit distortion correction value, wherein the selection circuit is configured to selectively transmit either the first bit distortion correction value or the second bit distortion correction value based upon received indications of values of bits transmitted to a memory array for storage.
17. A method, comprising:
generating a plurality of distortion correction factors, wherein each distortion correction factor of the plurality of distortion correction factors comprises a respective voltage value determined based upon a particular bit sequence of a set number of previously received bits of a bit stream;
selecting, via selection element, a distortion correction factor of the plurality of distortion correction factors;
transmitting the distortion correction factor to a latching element;
transmitting a distorted bit to the latching element; and
generating, via the latching element, a modified value of the distorted bit based upon the distortion correction factor and the distorted bit.
18. The method of claim 17 , wherein the selecting of the distortion correction factor is based upon a control signal having a number of states equivalent to a total number of binary states of the set number of previously received bits.
19. The method of claim 18 , comprising transmitting the control signal from the latching element based upon stored indications of values of the set number of previously received bits.
20. The method of claim 17 , generating the modified value of the distorted bit as a corrected bit value having compensated for inter-symbol interference due to the set number of previously received bits.