Current mode output driver

Abstract

A current mode output driver and output current control method of controlling an output current using a gate voltage are provided. The current mode output driver, which outputs data read from a memory core to a transmission line, includes a gate voltage control circuit, a bias circuit, and a driver circuit. The gate voltage control circuit generates a predetermined gate voltage in response to a current control signal. The bias circuit outputs the gate voltage as a first enable signal in an active mode, and outputs a ground voltage as a second enable signal in a standby mode. The driver circuit drives a predetermined output current in response to the first enable signal, outputs the predetermined output voltage to the transmission line according to the data, and stops its operation in response to the second enable signal. The gate voltage control circuit changes the level of the gate voltage according to a value of the current control signal and output the changed result. Therefore, it is possible to easily increase resolution of an output current and reduce the occupied area of the current mode output driver, thereby facilitating a circuit design.

Description

technical field [0001] Embodiments of the present invention relate to a current mode output driver of a semiconductor memory device that uses a gate voltage to adjust output current and a method for adjusting output current using the current mode output driver. [0002] This application claims priority to Korean Patent Application No. 2003-32556 filed with the Korean Intellectual Property Office on May 22, 2003, the disclosure of which is incorporated herein by reference in its entirety. Background technique [0003] figure 1 A conventional data input / output interface of a semiconductor memory device such as a memory bus DRAM (hereinafter, referred to as 'RDRAM') is shown. exist figure 1 In this example, a plurality of memory devices 13 are connected to the chipset 11 through transmission lines 12 . One end of the transmission line 12 is single-ended connected to the termination resistance Rterm and the termination voltage Vterm. [0004] Each of the plurality of memory ...

AI Technical Summary

Problems solved by technology

When increasing the number of bits of the current control signal to increase the resolution of the output current Iout, the current mode output driver 30 must include additional signal lines, bias circuits and driver parts, further increasing the current mode output driver within the semiconductor chip. occupied area

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