Write amplifier with improved switching performance, output common-mode voltage, and head current control
US6064261A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1999 |
| Grant date | May 16, 2000 |
| Priority date | — |
| Expiry date | Apr 23, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45479
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A write amplifier is provided with one or more improved switching performance, low output common-mode voltage, and precise write head current control. A low output common-mode voltage is achieved using a combination of circuit components which limit the undesirable delivery of current from a differential pair of transistors used for switching, or steering, the current delivered to the write head. Additionally, a voltage source within the amplifier precisely controls the write current delivered to the differential pair. Toward that end, the introduction of operational amplifiers, resistors, and a transistor to provide a circuit wherein the current delivered to the write head by the voltage source is predominantly a function of a write current and a corresponding resistive network, comprised of the write head and resistors connected to the collectors of the differential pair, and wherein the write head current is substantially independent of the current used to perform switching through the differential pair itself. Furthermore, the switching of the differential pair is improved by tying the bases of the differential pair together and capacitively bypassing them to ground and connect…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.