 Longitudinal magnetic recording media and magnetic memory units |
| As discussed above, it may be said that there have been strong demands for highly reliable magnetic ... |
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| Thin-film recording medium with thin metal sublayer |
| The present invention includes, in one aspect, an improvement in a magnetic film recording medium ... |
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| Process of making a magnetic recording medium |
| We claim: 1. A process for the manufacture of a magnetic recording medium by vacuum-depositing a ... |
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| Magnetic recording disk and sputtering process and apparatus for producing same |
| The present invention provides a continuous production from a direct current planar magnetron ... |
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| Method of forming thin-film recording medium |
| It is one general object of the invention to provide a thin film medium having high coercivity, ... |
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| Longitudinal magnetic recording media with fine grain crystal magnetic layer |
| OF THE EMBODIMENTS The surface of a disk substrate of an aluminum alloy containing 4% by weight of ... |
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| Oxidation resistant low expansion superalloys |
| The embodiments of the invention in which an exclusive property or privilege is claimed are defined ... |
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| Electric contact material and a manufacturing method therefor |
| OF THE INVENTION As shown in the sectional view of the FIGURE, an electric contact material ... |
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| Nickel alloy |
| OF PREFERRED EMBODIMENT The alloy of the present invention comprises 8 to 34 atom% of Al, 2 to 70 ... |
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Current-limiting circuit
| Details |
Inventors: Fujihira, Tatsuhiko;
Assignee: Fuji Electric Co., Ltd. (Kawasaki, JP)
Primary Examiner: Callahan; Timothy P.
Assistant Examiner: Ton; My-Trang Nu
Attorney, Agent or Firm: Brumbaugh, Graves, Donohue & Raymond
A current-limiting circuit provides prevention of an oscillation phenomenon resulting from a feedback of the current-limiting signal, which is generated by the output of an operational amplifier, to an input of the operational amplifier via a current-mirror element. Gain adjusting elements are connected between a first input terminal of the operational amplifier and the common control terminal, and between the first input terminal and the current-mirror terminal, respectively. The gain adjusting elements' impedance ratio is used to adjust the feedback gain and thereby prevent the oscillation phenomenon. Furthermore, inputting a selected analog voltage into a second input terminal of the operational amplifier maintains the currents constant at two or more desired levels. In addition, a constant voltage source that can be used even with a low power source voltage, and which is suitable for a current-limiting circuit, is provided by connecting a depletion-type MOSFET and an enhancement-type MOSFET in series. |
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DETAILED DESCRIPTION In order to achieve the above objectives, the present invention provides a current-limiting circuit in which first and second main terminals of a main semiconductor element are used as the terminals of the circuit, while the output current from the main semiconductor element is suppressed below a certain value by controlling the input to the control terminal of the main semiconductor element.
The input of the main semiconductor element is controlled by the output of an operational amplifier, which output is in turn generated by comparing a reference voltage with the voltage between the two terminals of a current-detection element.
The current-detection element is connected between a second main terminal of a current-mirror element and the second main terminal of the main semiconductor element.
A current that is proportional to the output current flowing across the first main terminal and the second main terminal of the main semiconductor element flows through the current-mirror element.
The reference voltage is applied to a first input terminal of the operational amplifier, and a first gain-adjusting element is connected between the second input terminal and the second main terminal of the current-mirror element.
A second gain-adjusting element, which has an impedance of a predetermined ratio relative to impedance of the first gain adjusting element, is connected between the control terminals of the main semiconductor element.
In the present invention, it is preferable that the output terminal of the operational amplifier be connected to a drive circuit in which the main terminal is connected to the control terminals of the main semiconductor element.
The op-amp's output terminal is also connected to the control terminal of a switching element connected to the second main terminal of the main semiconductor element, or alternatively, connected to the control terminal of the main semiconductor element.
In these arrangements, it is preferable that the connection to the control terminal of the main semiconductor element is made via a resistor that limits the operating speed of the main semiconductor element
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Metal Working 
