SYSTEMS AND METHODS FOR AUTOMATICALLY ELIMINATING IMBALANCE BETWEEN SIGNALS

• US 20070118251A1
• Filed: 11/08/2005
• Published: 05/24/2007
• Est. Priority Date: 11/08/2005
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Ho, Yu-Ping, Tseng, Jui-Hsing
• Granted Patent: US 7,362,107 B2
• Time in Patent Office: Days
• US Class Current: 700/254
• CPC Class Codes: G11C 11/401 forming cells needing refreshing or charge regeneration, i.e. dynamic cells
• CPC Class Codes: G11C 11/4076 Timing circuits for regeneration management G11C11/406
• CPC Class Codes: G11C 2207/2254 Calibration
• CPC Class Codes: G11C 29/02 Detection or location of defective auxiliary circuits, e.g. defective refresh counters
• CPC Class Codes: G11C 29/022 in I/O circuitry
• CPC Class Codes: G11C 29/023 in clock generator or timing circuitry
• CPC Class Codes: G11C 29/028 with adaption or trimming of parameters
• CPC Class Codes: G11C 29/50012 of timing
• CPC Class Codes: G11C 7/22 Read-write [R-W] timing or clocking circuits; Read-write [R-W] control signal generators or management
• CPC Class Codes: H03L 7/0812 and where no voltage or current controlled oscillator is used

Abstract

A calibrating system for automatically eliminating or reducing imbalance between a first signal and a second signal is disclosed. The calibrating system includes: a programmable delay module, receiving to the first and the second signals; a phase detecting module, coupled to the programmable delay module, for receiving the first and the second signals from the programmable delay module, and comparing a phase of a reference signal with phases of the first and the second signals, respectively; and a de-skew controlling module, coupled to the programmable delay module and the phase detecting module, for controlling the programmable delay module to eliminate imbalance between the first and the second signals by at least delaying the first signal according to a comparison result of the phase detecting module.

Claims

1. A calibrating system for automatically eliminating imbalance between a first signal and a second signal, the calibrating system comprising:

a programmable delay module, receiving the first and the second signals;

a phase detecting module, coupled to the programmable delay module, for receiving the first and the second signals output from the programmable delay module, and comparing a phase of a reference signal with phases of the first and the second signals, respectively; and

a de-skew controlling module, coupled to the programmable delay module and the phase detecting module, for controlling the programmable delay module to eliminate or reduce imbalance between the first and the second signals by at least delaying one signal according to a comparison result of the phase detecting module.

2. The calibrating system of claim 1, wherein the reference signal is the first signal.

3. The calibrating system of claim 1, wherein the de-skew controlling module sequentially shifts the phase of the reference signal, and after each shifting, the phase detecting module compares the phase of the shifted reference signal with phases of the first and the second signals to determine if a transient of the first or second signal is aligned with the shifted reference signal.

4. The calibrating system of claim 1, wherein the phase detecting module compares the phase of the reference signal with phases of the first and the second signals by periodically shifting the reference signal to detect a transient of the first signal and a transient of the second signal.

5. The calibrating system of claim 1, wherein the phase detecting module comprises:

a first phase detecting unit for detecting the transient of the first signal utilizing the reference signal;

a second phase detecting unit for detecting the transient of the second signal utilizing the reference signal; and

a first counter, starts counting a first count value serving as the comparison result when the first phase detecting unit detects the transient of the first signal, and the first counter stops counting when the second phase detecting unit detects the transient of the second signal.

6. The calibrating system of claim 1, wherein the phase detecting module comprises:

a first phase detecting unit for detecting the transient of the first signal utilizing the reference signal;

a second phase detecting unit for detecting the transient of the second signal utilizing the reference signal;

a first counter, starts counting a first count value when the first phase detecting unit detects the transient of the first signal, and stops counting when all the transient of the signals are detected; and

a second counter starts counting a second count value when the second phase detecting unit detects the transient of the second signal, and stops counting when all the transient of the signals are detected;

wherein the first and the second count values serve as the comparison result.

7. The calibrating system of claim 6, wherein one of the first and second phase detecting units detects the transient of the signal by checking if the signal is aligned with the reference signal.

8. The calibrating system of claim 6, wherein the de-skew controller programs the programmable delay module for delaying the first signal according to the first count value, and programs the programmable delay module for delaying the second signal according to the second count value.

9. The calibrating system of claim 1, wherein the first and second signals are outputted from a dynamic random access memory (DRAM).

10. The calibrating system of claim 9, wherein at least one of the first and the second signals is data signal (DQ).

11. The calibrating system of claim 9, wherein at least one of the first and the second signals is data strobe signal (DQS).

12. The calibration system of claim 9, wherein the calibration system is embedded inside a memory controller capable of sending control signals having imbalances to fetch data from the DRAM, the calibration system further comprises an output programmable delay module coupled to the de-skew controller and capable of delaying at least one of the control signals, and the de-skew controller further controls the output programmable delay module to eliminate or reduce imbalance between the control signals by at least delaying one signal according to the comparison result of the phase detecting module.

13. A calibrating method for automatically eliminating or reducing imbalance between a first signal and a second signal, the calibrating method comprising:

receiving the first and the second signals;

comparing a phase of a reference signal with phases of the first and the second signals, respectively; and

eliminating or reducing imbalance between the first and the second signals by at least delaying one of the signals according to a comparison result.

14. The calibrating method of claim 13, wherein the reference signal is the first signal.

15. The calibrating method of claim 13, wherein the step of comparing the phase of the reference signal with phases of the first and the second signals is performed by periodically shifting the reference signal to detect a transient of the first signal and a transient of the second signal.

16. The calibrating method of claim 15 further comprising:

utilizing a counter to start counting when the transient of the first signal is detected, and to stop counting when the transient of the second phase is detected in order to generate a first count value serving as the comparison result.

17. The calibrating method of claim 15 further comprising:

utilizing a first counter to start counting when the transient of the first signal is detected in order to generate a first count value; and

utilizing a second counter to start counting when the transient of the second signal is detected in order to generate a second count value;

wherein the first and the second count values serve as the comparison result.

18. The calibrating system of claim 17, further comprising:

detecting the transient of one of the first and the second signals by checking if the signal is aligned with the reference signal.

19. The calibrating system of claim 17, further comprising:

delaying the first signal according to the first count value, and delaying the second signal according to the second count value.

20. The calibrating method of claim 13, wherein the first and the second signals are outputted from a dynamic random access memory (DRAM).

21. The calibrating method of claim 20, wherein the first and the second signals are data signals (DQ).

22. The calibrating method of claim 20, wherein the first and the second signals are data strobe signals (DQS).

23. The calibration method of claim 20, further comprising:

eliminating or reducing imbalance between control signals, which are utilized to fetch data from the DRAM, by at least delaying one of the control signals according to the comparison result.