Marvell International Limited

Marvell Asia Pte., Ltd.

Yunfan Zhang

Kai Wu

Xiaowei Huang

Su Win Myat

Mei Lei

A bias circuit comprises a closed loop gain stage arranged to determine a difference between a first current in a first branch circuit and a second current in a second branch circuit, where the first branch circuit and second branch circuit are coupled to respective terminals of a magnetic resistor (MR). A first set of current mirrors is arranged to provide a source current to the first terminal of the MR and the second set of current mirrors is arranged to provide a sink current to the second terminal of the MR. The first set of current mirrors and a second set of current mirrors are balanced to reduce a difference in setting time between the source current and sink current. The source current and sink current further reduce the difference between the first current and the second current to provide a constant voltage bias to the MR based on a voltage of a voltage source.

Balanced current mirrors for biasing a magnetic resistor in a hard disk drive

Aspects of the disclosure include a data storage controller that includes a main circuit, a synchronization circuit, and a detection circuit. The main circuit is configured to receive a test signal, generate a data signal based on the test signal, and generate a compensation signal based on the test signal and a phase shift selected from N predetermined phase shifts. N may be an integer greater than one. The synchronization circuit is configured to receive the data signal and the data compensation signal, and generate a delayed data signal and a latched compensation signal in response to the data signal. The detection circuit is configured to determine whether rising and falling edges of the latched compensation signal and corresponding rising and falling edges of the delayed data signal are synchronized.

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Singapore, Singapore

Yunfan Zhang