Electric power conversion systems – Current conversion – With means to selectively provide d.c. of either polarity
Patent
1998-12-14
1999-12-07
Wong, Peter S.
Electric power conversion systems
Current conversion
With means to selectively provide d.c. of either polarity
363 56, 323222, H02M 702, H02M 7122
Patent
active
059994266
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, generally, to a circuit arrangement for producing an output voltage of opposite polarity to the operating voltage, and a circuit arrangement which operates at a particularly low current level.
It also relates, in particular, to a circuit arrangement which, in an electronic device supplied with a battery voltage (for example), in a mobile radio set (mobile telephone) or a portable computer (laptop), produces a negative voltage from a positive voltage.
2. Description of the Prior Art
Circuit arrangements of this type are generally known. They are used, for example, in mobile radio sets which are supplied with a battery voltage and have one or more MMIC (Monolithic Microwave Integrated Circuit) Chips (for example, an MMIC power amplifier) based on MESFET technology, to produce a negative gate bias voltage for the MESFET(s). In the case of a first circuit variant, using which a negative voltage can be produced in a battery-powered electronic device, an AC voltage is produced by means of an oscillator or multivibrator, and is subsequently rectified. In the case of mobile telephones, it is likewise possible to produce a negative voltage by rectifying a received radio-frequency signal which is applied to the input of an MMIC power amplifier.
However, both of these methods have disadvantages. For example, in the case of the option mentioned first, an additional AC signal is produced by the oscillator in the electronic device which can adversely affect the operating characteristics of the device. For example, adjacent components in the electronic device, such as microprocessors, can be influenced, and this can lead to malfunctions.
In the case of the second method mentioned, it is particularly disadvantageous that the MMIC power amplifier is not switched on until after the radio-frequency signal has been applied, and can be operated only at relatively high signal levels.
SUMMARY OF THE INVENTION
The present invention is thus direct to developing a low-noise circuit arrangement of the type mentioned initially by means of which any adverse effect on the operating characteristics of an electronic device is reduced, and which can at the same time be produced cost-effectively and in a space-saving manner. Further, this circuit arrangement is intended to be suitable, in particular, for use in a mobile radio set, and to operate at particularly low current levels, while avoiding the disadvantages mentioned above.
This object is achieved by a circuit arrangement which includes a coil coupled between a first connection of a load path of a transistor, in particular a source-drain path of a field effect transistor, and a first circuit input connection, as well as between a second connection of the load path of the transistor and a fixed reference-earth potential. An operating voltage with a second polarity (for example, positive) with respect to the reference-earth potential can be applied to the first circuit input connection. Furthermore, a control connection of the transistor is coupled via a control line to a second circuit input connection, to which an AC voltage can be applied. A first capacitor is coupled between the first connection of the load path of the transistor and a cathode of a first diode, and the cathode of the first diode is coupled to an anode of a second diode. A cathode of the second diode is coupled to the fixed reference-earth potential, while a second capacitor is coupled between the fixed reference-earth potential and an anode of the first diode. The anode of the first diode is connected to a circuit output connection, at which an output voltage can be picked off with a first polarity (for example, negative) with respect to the fixed reference-earth potential.
The circuit arrangement according to the present invention operates on the basic principle that the first capacitor is charged, to a voltage which is positive with respect to the fixed reference-earth potential, by means of a voltage rise on the coil after t
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patent: 3863138 (1975-01-01), Lace
patent: 4045719 (1977-08-01), Salzer
patent: 4281377 (1981-07-01), Evans
patent: 4320447 (1982-03-01), Krauss
patent: 4922401 (1990-05-01), Lipman
patent: 5396165 (1995-03-01), Hwang et al.
Halbleiter Schaltungstechnik, U Tietz, Springer-Verlag Berlin, New York 1974 pp. 34-36.
Electronics Letters--Jun. 8, 1995, vol. 31, No. 12, pp. 933-935ds, Turner, pp. 931-935.
Meier Thomas
Schopf Klaus Jurgen
Patel Rajnikant B.
Siemens Aktiengesellschaft
Wong Peter S.
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