A semiconductor memory device including an array of memory cells. The memory device includes a first output driver coupled to a first output terminal, and a second output driver coupled to a second output terminal. The memory device further includes a voltage divider coupled between the first and second output terminals, to generate a control voltage based on a voltage level present on the first output terminal and a voltage level present on the second output terminal. The memory device further includes a comparator, coupled to the voltage divider, to compare the control voltage with a reference voltage, wherein an amount of voltage swing of the first output driver is adjusted based on the comparison between the control voltage and the reference voltage.
This is a continuation of application Ser. No. 09/559,115, filed Apr. 26, 2000, U.S. Pat. No. 6,294,934, which is a continuation of application Ser. No. 09/141,675, filed Aug. 27, 1998, U.S. Pat. No. 6,094,075, which claims priority to the provisional patent application entitled "Current Control Circuit", Ser. No. 60/073,353, filed Feb. 2, 1998, and the provisional patent application entitled "Current Control Technique", Ser. No. 60/057,400, filed Aug. 29, 1997.
A method of addressing a memory device on a memory module includes determining whether a command has been issued to the memory module. An evaluation state is entered if the command has been issued. While in the evaluation state, it is determined whether an identification signal has been issued for the memory device to initiate action. Action is initiated if the identification signal indicates that the memory device is to respond to the command issued.
An input voltage is applied to an inverting input terminal of a comparator having no hysteresis. A first constant voltage is divided by resistors to create a reference voltage. The reference voltage is applied to a non-inverting input terminal of the comparator through a resistor. Only while an output voltage of the comparator is a low level, a predetermined constant current is supplied to a supply point of the reference voltage and a constant current of the same magnitude is absorbed from the non-inverting input terminal of the comparator.
A comparator circuit with comparing means for comparing first and second voltages, has current source circuitry for providing current to said comparing means, said current source circuitry having an input for receiving a clock signal having first and second states, whereby the comparing means starts to compare the first and second voltages when the clock signal makes a transition from the first state to the second state; and means for determining when said comparing means has completed a comparison of said first and second voltages and for switching off said current source circuitry and hence said comparing means when said comparison has been completed.
A method for calibration of memory circuits is provided that adjusts memory circuit output parameters based on data eye measurements. Data eye patterns from the memory circuit outputs are measured by the memory controller for different settings of the memory circuit output parameters. Memory circuit output parameters can be adjusted to settings that correspond to widest average data eye widths, highest average data eye heights, or other suitable criteria.
The invention is directed to a device for calibrating signals, whereby at least two signal circuits are provided for generating signals. In order to calibrate the signals, elements are provided that evaluate the signals generated by the signal circuits and, dependent thereon, drive at least one of the at least two signal circuits such that the time reference of the signals generated by the signal circuits relative to one another is set corresponding to at least one prescribed value.
