Patent US6448756B1 successfully refreshed from Google Patents.
US6448756B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Delay line tap setting override for delay locked loop (DLL) testability
Assignee: Micron Technology Inc
•
Filing: 2000-08-30
•
Granted: 2002-09-10
•
Expires: 2020-08-30
Abstract
Abstract An integrated circuit having a delay locked loop (DLL) connected to a test circuit. The DLL includes a plurality of taps connected to a plurality of register cells. The test circuit is capable of enabling any register cell to select a tap to test the DLL.
Inventors
- 👤 Daniel R. Loughmiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:18
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/081; H03L7/0812; H03L7/0814; H03L7/0816
Claims Analysis
Total Claims: 55
Claim 1
Independent Claim
57 words
An integrated circuit comprising: a delay locked loop (DLL) comprising a plurality of taps and a register connected to the taps for selecting the taps in response to shifting signals; and a test circuit connected to the delay locked loop, wherein the test circuit is able to select any tap,bypassing the shifting signals, to test the DLL.
Claim 2
Dependent Claim
57 words
An integrated circuit comprising: a delay locked loop (DLL) comprising a plurality of taps and a register connected to the taps for selecting the taps in response to shifting signals; and a test circuit connected to the delay locked loop, wherein the test circuit is able to select any tap,bypassing the shifting signals, to test the DLL.
Claim 3
Dependent Claim
21 words
The integrated circuit according to claim 1 , wherein the register comprises a plurality of register cells connected to the taps.
Claim 4
Dependent Claim
47 words
The integrated circuit according to claim 2 , wherein the test circuit includes a plurality of input lines to receive a plurality of input signals, wherein each unique combination of the input signals causes a unique register cell to select a known tap to test the DLL.
Claim 5
Dependent Claim
65 words
An integrated circuit comprising: a delay locked loop (DLL) comprising a plurality of taps and a register capable of selecting the taps based on shifting signals; and a test circuit connected to the delay locked loop, wherein the test circuit sends a tap position signal to the delay locked loop during a test to select a tap, bypassing the shifting signals to test the DLL.
Claim 6
Dependent Claim
65 words
An integrated circuit comprising: a delay locked loop (DLL) comprising a plurality of taps and a register capable of selecting the taps based on shifting signals; and a test circuit connected to the delay locked loop, wherein the test circuit sends a tap position signal to the delay locked loop during a test to select a tap, bypassing the shifting signals to test the DLL.
Claim 7
Dependent Claim
42 words
The integrated circuit according to claim 4 , wherein, the test circuit includes: a plurality of input lines for receiving a plurality of input signals; and a decoder for decoding a combination of the input signals to produce the tap position signal.
Claim 8
Dependent Claim
33 words
The integrated circuit according to claim 5 , wherein the number of all possible combinations of the input signals received at the input lines at least equals the total number of the taps.
Claim 9
Dependent Claim
84 words
An integrated circuit comprising: a delay locked loop (DLL) comprising a plurality of taps; and a test circuit connected to the delay locked loop, wherein the test circuit is able to select any tap to test the DLL, wherein the DLL further includes: a phase detector to provide shifting signals; and a shift register connected to the phase detector, wherein the shift register bypasses shifting signals received from the phase detector during the test and selects a tap based on the tap position signal.
Claim 10
Dependent Claim
84 words
An integrated circuit comprising: a delay locked loop (DLL) comprising a plurality of taps; and a test circuit connected to the delay locked loop, wherein the test circuit is able to select any tap to test the DLL, wherein the DLL further includes: a phase detector to provide shifting signals; and a shift register connected to the phase detector, wherein the shift register bypasses shifting signals received from the phase detector during the test and selects a tap based on the tap position signal.
Claim 11
Dependent Claim
76 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps, a shift register connected to the taps, and a phase detector connected to provide shifting signals to the shift register; and a test circuit connected to the shift register, wherein the test circuit sends control signals to the shift register during a test to enable the shift register to bypass the shifting signals to select a known tap for testing the DLL.
Claim 12
Dependent Claim
76 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps, a shift register connected to the taps, and a phase detector connected to provide shifting signals to the shift register; and a test circuit connected to the shift register, wherein the test circuit sends control signals to the shift register during a test to enable the shift register to bypass the shifting signals to select a known tap for testing the DLL.
Claim 13
Dependent Claim
64 words
The integrated circuit according to claim 8 , wherein the test circuit includes a plurality of input lines to receive a plurality of input signals, wherein the input signals are decoded by the test circuit to produce the tap position signal to select a tap, wherein a unique combination of the input signals can be pre-selected to select a position of a known tap.
Claim 14
Dependent Claim
33 words
The integrated circuit according to claim 9 , wherein the number of all possible combinations of the input signals received at the input lines at least equals the total number of the taps.
Claim 15
Dependent Claim
74 words
An integrated circuit comprising: a plurality of delay stages; a plurality of register cells connected to the delay stages through a plurality of taps for selecting the delay stages in response to shifting signals; and a test circuit connected to the register cells, wherein the test circuit sends a tap position signal to a pre-selected register cell to test a tap connected to the pre-selected register cell, bypassing the shifting signals, during a test.
Claim 16
Dependent Claim
74 words
An integrated circuit comprising: a plurality of delay stages; a plurality of register cells connected to the delay stages through a plurality of taps for selecting the delay stages in response to shifting signals; and a test circuit connected to the register cells, wherein the test circuit sends a tap position signal to a pre-selected register cell to test a tap connected to the pre-selected register cell, bypassing the shifting signals, during a test.
Claim 17
Dependent Claim
54 words
The integrated circuit according to claim 11 , wherein the test circuit includes a plurality of input lines to receive a plurality of input signals, wherein the input signals are decoded by the test circuit to produce the tap position signal, wherein the tap position signal corresponds to only one position of a tap.
Claim 18
Dependent Claim
33 words
The integrated circuit according to claim 12 , wherein the number of all possible combinations of the input signals received at the input lines at least equals the total number of the taps.
Claim 19
Dependent Claim
77 words
An integrated circuit comprising: a delay lock loop (DLL) including a plurality of taps connected to a plurality of register cells, the register cells capable of selecting the taps based on shifting signals; and a test circuit connected to the DLL, the test circuit producing a plurality of testmode address signals, wherein a unique combination of the testmode address signals enables a unique register cell to select a tap bypassing the shifting signals, to test the DLL.
Claim 20
Dependent Claim
77 words
An integrated circuit comprising: a delay lock loop (DLL) including a plurality of taps connected to a plurality of register cells, the register cells capable of selecting the taps based on shifting signals; and a test circuit connected to the DLL, the test circuit producing a plurality of testmode address signals, wherein a unique combination of the testmode address signals enables a unique register cell to select a tap bypassing the shifting signals, to test the DLL.
Claim 21
Dependent Claim
39 words
The integrated circuit according to claim 14 , wherein the test circuit includes a plurality of input lines to receive a plurality of input signals, wherein the testmode address signals are true and complement signals of the input signals.
Claim 22
Dependent Claim
102 words
An integrated circuit comprising: a delay lock loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit connected to the DLL, the test circuit producing a plurality of testmode address signals, wherein a unique combination of the testmode address signals enables a unique register cell to select a tap to test the DLL, wherein the DLL further includes a phase detector, the phase detector providing shifting signals the register cells, wherein in a test, the test circuit sends a bypass signal to the DLL to cause the register cells to bypass the shifting signals.
Claim 23
Dependent Claim
102 words
An integrated circuit comprising: a delay lock loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit connected to the DLL, the test circuit producing a plurality of testmode address signals, wherein a unique combination of the testmode address signals enables a unique register cell to select a tap to test the DLL, wherein the DLL further includes a phase detector, the phase detector providing shifting signals the register cells, wherein in a test, the test circuit sends a bypass signal to the DLL to cause the register cells to bypass the shifting signals.
Claim 24
Dependent Claim
105 words
An integrated circuit comprising: a delay lock loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit connected to the DLL, the test circuit producing a plurality of testmode address signals, wherein a unique combination of the testmode address signals enables a unique register cell to select a tap to test the DLL, wherein the test circuit further includes a reset signal, wherein at the beginning of a test, the reset signal resets the register cells to the same state, and wherein during the test, one of the register cells changes from one state to another state.
Claim 25
Dependent Claim
105 words
An integrated circuit comprising: a delay lock loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit connected to the DLL, the test circuit producing a plurality of testmode address signals, wherein a unique combination of the testmode address signals enables a unique register cell to select a tap to test the DLL, wherein the test circuit further includes a reset signal, wherein at the beginning of a test, the reset signal resets the register cells to the same state, and wherein during the test, one of the register cells changes from one state to another state.
Claim 26
Dependent Claim
82 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps, and a register to select the taps based on shifting signals; and a test circuit comprising: a bypass circuit connect to the DLL; a testmode control signals generator connected to the DLL; and a testmode address generator connected to the DLL for generating an address, wherein the test circuit is able to select any tap based on the address and bypassing the shifting signals to test the DLL.
Claim 27
Dependent Claim
82 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps, and a register to select the taps based on shifting signals; and a test circuit comprising: a bypass circuit connect to the DLL; a testmode control signals generator connected to the DLL; and a testmode address generator connected to the DLL for generating an address, wherein the test circuit is able to select any tap based on the address and bypassing the shifting signals to test the DLL.
Claim 28
Dependent Claim
34 words
The integrated circuit according to claim 18 , wherein the register includes a plurality of register cells connected to the tap, and a phase detector connected to provide shifting signals to the register cells.
Claim 29
Dependent Claim
43 words
The integrated circuit according to claim 19 , wherein the testmode address generator receives a plurality of input signals to generate a plurality of testmode address signals, wherein each unique combination of the testmode address signals is encoded to a unique register cell.
Claim 30
Dependent Claim
88 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit comprising: a bypass circuit connect to the DLL; a testmode control signals generator connected to the DLL; and a testmode address generator connected to the DLL, wherein the test circuit is able to select any tap to test the DLL, wherein the bypass circuit causes the register cells to bypass the shifting signals from the phase detector during a test of the DLL.
Claim 31
Dependent Claim
88 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit comprising: a bypass circuit connect to the DLL; a testmode control signals generator connected to the DLL; and a testmode address generator connected to the DLL, wherein the test circuit is able to select any tap to test the DLL, wherein the bypass circuit causes the register cells to bypass the shifting signals from the phase detector during a test of the DLL.
Claim 32
Dependent Claim
90 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit comprising: a bypass circuit connect to the DLL; a testmode control signals generator connected to the DLL; and a testmode address generator connected to the DLL, wherein the test circuit is able to select any tap to test the DLL, wherein the testmode control signals generator generates a reset signal to reset the register cells to the same state at the beginning of a test.
Claim 33
Dependent Claim
90 words
An integrated circuit comprising: a delay locked loop (DLL) including a plurality of taps connected to a plurality of register cells; and a test circuit comprising: a bypass circuit connect to the DLL; a testmode control signals generator connected to the DLL; and a testmode address generator connected to the DLL, wherein the test circuit is able to select any tap to test the DLL, wherein the testmode control signals generator generates a reset signal to reset the register cells to the same state at the beginning of a test.
Claim 34
Dependent Claim
77 words
A memory comprising: address lines for receiving input signals; a delay lock loop (DLL) including a plurality of taps capable of being selected in response to shifting signals; and a test circuit connected to the address lines and the DLL, wherein the test circuit decodes a combination of the input signals received at the address lines to produce a tap position signal to select a tap, bypassing the shifting signals, to test the DLL during a test.
Claim 35
Dependent Claim
77 words
A memory comprising: address lines for receiving input signals; a delay lock loop (DLL) including a plurality of taps capable of being selected in response to shifting signals; and a test circuit connected to the address lines and the DLL, wherein the test circuit decodes a combination of the input signals received at the address lines to produce a tap position signal to select a tap, bypassing the shifting signals, to test the DLL during a test.
Claim 36
Dependent Claim
54 words
The memory according to claim 23 , wherein the DLL further includes: a phase detector to provide the shifting signals; and a shift register connected to the phase detector, wherein the shift register bypasses shifting signals received from the phase detector during the test and selects a tap based on the tap position signal.
Claim 37
Dependent Claim
25 words
The memory according to claim 23 , wherein the test circuit includes a decoder to decode the input signals to produce the tap position signal.
Claim 38
Dependent Claim
32 words
The memory according to claim 23 , wherein the number of all possible combinations of the input signals received at the address lines at least equals the total number of the taps.
Claim 39
Independent Claim
102 words
A system comprising: a processor; a memory connected to the processor, the memory comprising: address lines for receiving input signals; a delay lock loop having a plurality of taps, and a register for selecting the taps based on shifting signals; and a test circuit connected to the address lines and the delay lock loop, wherein the test circuit decodes a combination of the input signals received at the address lines to produce a tap position signal, wherein the tap position signal enables the delay locked loop to select a known tap, bypassing the shifting signals, to test the DLL during a test.
Claim 40
Independent Claim
102 words
A system comprising: a processor; a memory connected to the processor, the memory comprising: address lines for receiving input signals; a delay lock loop having a plurality of taps, and a register for selecting the taps based on shifting signals; and a test circuit connected to the address lines and the delay lock loop, wherein the test circuit decodes a combination of the input signals received at the address lines to produce a tap position signal, wherein the tap position signal enables the delay locked loop to select a known tap, bypassing the shifting signals, to test the DLL during a test.
Claim 41
Dependent Claim
25 words
The system according to claim 27 , wherein the test circuit includes a decoder to decode the input signals to produce the tap position signal.
Claim 42
Dependent Claim
32 words
The system according to claim 27 , wherein the number of all possible combinations of the input signals received at the address lines at least equals the total number of the taps.
Claim 43
Independent Claim
72 words
A method of testing a delay locked loop, the method comprising: initiating a testmode signal; decoding a combination of input signals to produce a tap position signal, the tap position signal corresponding to a known position of a tap; sending the tap position signal to a register cell connected to the tap; bypassing shifting signals sent to the register; and enabling the register cell to select the tap to test the DLL.
Claim 44
Independent Claim
72 words
A method of testing a delay locked loop, the method comprising: initiating a testmode signal; decoding a combination of input signals to produce a tap position signal, the tap position signal corresponding to a known position of a tap; sending the tap position signal to a register cell connected to the tap; bypassing shifting signals sent to the register; and enabling the register cell to select the tap to test the DLL.
Claim 45
Independent Claim
71 words
A method of testing a delay locked loop (DLL), the method comprising: assigning position numbers to a plurality of taps; receiving input signals at address lines; decoding the input signals to produce a tap position signal; sending the tap position signal to a shift register; bypassing shifting signals sent to the shift register; and selecting a tap corresponding to the tap position signal, bypassing the shifting signals, to test the DLL.
Claim 46
Independent Claim
71 words
A method of testing a delay locked loop (DLL), the method comprising: assigning position numbers to a plurality of taps; receiving input signals at address lines; decoding the input signals to produce a tap position signal; sending the tap position signal to a shift register; bypassing shifting signals sent to the shift register; and selecting a tap corresponding to the tap position signal, bypassing the shifting signals, to test the DLL.
Claim 47
Independent Claim
63 words
A method of testing a delay locked loop, the method comprising: activating a testmode signal; activating a bypass signal to cause a shift register to bypass shifting signals from a phase detector; decoding a plurality of input signals to produce a tap position signal; and enabling the shift register to select a tap based on the tap position signal to test the DLL.
Claim 48
Independent Claim
63 words
A method of testing a delay locked loop, the method comprising: activating a testmode signal; activating a bypass signal to cause a shift register to bypass shifting signals from a phase detector; decoding a plurality of input signals to produce a tap position signal; and enabling the shift register to select a tap based on the tap position signal to test the DLL.
Claim 49
Dependent Claim
20 words
The method according to claim 32 further comprises decoding a combination of input signals to produce the tap position signal.
Claim 50
Independent Claim
79 words
A method of testing a delay locked loop, the method comprising: activating a testmode signal; bypassing shifting signals sent to a plurality of register cells; resetting the register cells to the same state; and producing a unique combination of tap position signals to change a known register cell corresponding to the unique combination of tap position signals to the to a different state, wherein the different state enables the known register cell to select a known tap for testing.
Claim 51
Independent Claim
79 words
A method of testing a delay locked loop, the method comprising: activating a testmode signal; bypassing shifting signals sent to a plurality of register cells; resetting the register cells to the same state; and producing a unique combination of tap position signals to change a known register cell corresponding to the unique combination of tap position signals to the to a different state, wherein the different state enables the known register cell to select a known tap for testing.
Claim 52
Independent Claim
130 words
A method of testing a delay locked loop, the method comprising: activating a testmode signal; resetting a plurality of register cells to the same state; producing a combination of tap position signals to change a known register cell corresponding to the unique combination of tap position signals to the to a different state, wherein the different state enables the known register cell to select a known tap for testing, wherein producing a combination of tap position signals including: selecting a combination of input signals corresponding to a predetermined encoding scheme; producing a plurality of testmode address signals, the testmode address signals representing true and complement signals of the input signals; and selecting a unique combination of signals from the testmode address signals to produce the combination of tap position signals.
Claim 53
Independent Claim
130 words
A method of testing a delay locked loop, the method comprising: activating a testmode signal; resetting a plurality of register cells to the same state; producing a combination of tap position signals to change a known register cell corresponding to the unique combination of tap position signals to the to a different state, wherein the different state enables the known register cell to select a known tap for testing, wherein producing a combination of tap position signals including: selecting a combination of input signals corresponding to a predetermined encoding scheme; producing a plurality of testmode address signals, the testmode address signals representing true and complement signals of the input signals; and selecting a unique combination of signals from the testmode address signals to produce the combination of tap position signals.
Claim 54
Independent Claim
80 words
A method of testing a delay locked loop, the method comprising: encoding a plurality of register cells with a predetermined encoding scheme; receiving a plurality of input signals; producing a plurality of testmode address signals from the input signals; selecting a unique combination of the testmode address signals; selecting a register cell based on the combination of the testmode address signals; bypassing shifting signals sent to the register cell; and selecting a tap connected to the register cell for testing.
Claim 55
Independent Claim
80 words
A method of testing a delay locked loop, the method comprising: encoding a plurality of register cells with a predetermined encoding scheme; receiving a plurality of input signals; producing a plurality of testmode address signals from the input signals; selecting a unique combination of the testmode address signals; selecting a register cell based on the combination of the testmode address signals; bypassing shifting signals sent to the register cell; and selecting a tap connected to the register cell for testing.
References Cited (Backward Citations)
US4805195A
Cited
US5796673A
Cited
US5781055A
Cited
US5940608A
Cited
US6069507A
Cited
US6297680B1
Cited
US6255880B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-09-09 | 2006-03-11 | 2006-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-09-09 | 2010-03-11 | 2010-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-09-09 | 2014-03-11 | 2014-09-10 | $7700.00 | Window Closed / Lapsed |