Write output driver with internal programmable pull-up resistors
AssigneeInfineon Technologies N.A., Inc.
InventorsSasan Cyrusian, Elmar Bach
Life of this patent
Estimating the term…
Abstract
A write output driver with internal programmable pull-up resistive devices is disclosed. The write output driver provides an integrated output driver circuit configurable to provide near end transmission line termination. The output driver is configured to provide transmission of a high-speed signal with increased frequencies over prior output drivers. The output impedance of the output driver is programmable and maintained substantially constant, despite ambient fluctuations. An internal bias signal generator is provided to control the impedance of the output driver.
Claims31
A write output driver, comprising:
- a variable tail current source operative to generate a tail current at a current node, the tail current being proportional to a first bias signal provided at a first bias input;
- a differential switch circuit coupled with the current node and being operative to selectively switch the tail current between a first output node and a second output in response to a input voltage provided at a voltage input node;
- an internal pull-up circuit being operative to generate an output voltage between the first output node and the second output node in response to the tail current, the pull-up circuit having a programmable output impedance based on a second bias signal received at a second bias input node;
- and
- a second bias signal generator operative to generate the second bias signal at the second bias input node.
A method for driving a high-speed signal, the method comprising the acts of:
- receiving a high-speed voltage signal at a differential voltage input;
- selectively switching a tail current between a first output node and a second output node in response to the high-speed voltage signal at the differential voltage input;
- programming an internal pull-up circuit to generate an output voltage with low output impedance at the first output node and at the second output node in response to tail current at the first output node and the second output node;
- calibrating an internal bias voltage source to generate a bias voltage at an output having an output impedance substantially matched with the output impedance of the internal pull-up circuit;
- and
- controlling the calibrated bias voltage source to provide a bias voltage that maintains a substantially constant output impedance for the internal pull-up circuit.
A hard-disk drive comprising a partial response, maximum likelihood based read/write channel including a write output driver with an internal programmable pull-up circuit.
Dependencies are inferred from the claim text.