| US 7,466,200 B2 | ||
| Composite output stage for hard disk drive preamplifier | ||
| Jonathan H. Fischer, Longmont, Colo. (US) | ||
| Assigned to Agere Systems Inc., Allentown, Pa. (US) | ||
| Filed on Aug. 31, 2005, as Appl. No. 11/216,993. | ||
| Claims priority of provisional application 60/616790, filed on Oct. 06, 2004. | ||
| Prior Publication US 2006/0072232 A1, Apr. 06, 2006 | ||
| Int. Cl. H03F 3/45 (2006.01); G11B 5/02 (2006.01) | ||
| U.S. Cl. 330—257 [360/67] | 39 Claims |
| 1. An apparatus for supplying a load current to a load in response to a differential input signal comprising a first and a
second input signal, the apparatus comprising:
an output buffer for producing a first current at a first load terminal and a second current at a second load terminal, wherein
the first and the second currents are functionally related to the first input signal and the second input signal, and wherein
the load is connected between the first and the second load terminals;
a first current source connected to the first load terminal for supplying a variable third current as a function of the differential
input signal; and
a second current source connected to the second load terminal for supplying a variable fourth current as a function of the
differential input signal, wherein the first, second third and fourth currents cooperate to determine the load current.
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