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Method for a wide swing, high speed current mode driver

IP.com Disclosure Number: IPCOM000009515D
Publication Date: 2002-Aug-28
Document File: 4 page(s) / 83K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a wide swing, high speed current mode driver. Benefits include improved performance, improved functionality, and improved support for high-speed serial link transmitters.

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Method for a wide swing, high speed current mode driver

Disclosed is a method for a wide swing, high speed current mode driver. Benefits include improved performance, improved functionality, and improved support for high-speed serial link transmitters.

Background

        � � � � � The predriver stage of conventional current-mode drivers is a digital buffer. Its outputs are digital signals. The predriver stage drives the current switches of the driver stage. This kind of digital predriver stage must slew faster for high-speed operation. A high slew rate consumes a lot of power. The driver stage of the conventional current-mode driver has four stage transistors in series from the power supply to the ground supply. This arrangement limits the swing range of the driver output and is not advantageous for low voltage wide-swing operation.

        � � � � � The predriver stage of the conventional current-mode driver drives out digital signals. The driver stage of the conventional current-mode driver has current switches controlled by the digital outputs of its predriver stage� (see Figure 1).

Description

        � � � � � The disclosed method is a high-speed serial link transmitter driver. It has two parts, the predriver stage and the driver stage. The predriver converts digital information into bias levels for the driver stage. The driver stage converts the bias levels into driving current to drive an external load.

        � � � � � The predriver stage for the invented current-mode driver is a bias circuit with a digital control (see Figure 2). The digital control is the data to be transmitted. The predriver can convert data to be transmitted into bias levels. These bias levels go to the driver stage and convert the data to be transmitted into driving current to drive an external load. The operation waveforms of the predriver stage are illustrated (see Figure 3).�

        � � � � � The data to be transmitted is a digital...