Electricity: power supply or regulation systems – In shunt with source or load – Using choke and switch across source
Reexamination Certificate
2000-11-07
2001-09-04
Berhane, Adolf Deneke (Department: 2838)
Electricity: power supply or regulation systems
In shunt with source or load
Using choke and switch across source
C323S282000
Reexamination Certificate
active
06285171
ABSTRACT:
The invention relates to a DC-DC converter comprising
input terminals for connecting it to a supply-voltage source,
a first branch, coupled to one of the input terminals, which includes a series arrangement of an inductive element and a unidirectional element,
switching means comprising at least two switching elements, each switching element forming part of a switching branch which includes a series arrangement of the switching element and an impedance, said switching branch being connected with a first end to a point between the inductive element and the unidirectional element, and with a second end to one of the input terminals,
a control circuit coupled to control electrodes of the switching elements for rendering the switching means alternately conducting and non-conducting,
a current sensor provided with an output coupled to the control circuit for generating a signal which, during operation, is present at the output and which is a measure of a current through the switching means.
Such a DC-DC converter is disclosed in U.S. Pat. No. 4,291,259. In the known DC-DC converter, the impedances in the switching branches are formed by ohmic resistances. The impedance value of these ohmic resistances in the switching branches is such that, when the switching elements are in the conducting state, the current in each switching branch is determined by the impedance value of the ohmic resistance in the switching branch. As a result, there is a simple relation between the currents in the different switching branches. This makes it possible to control the total current through the switching means by controlling the current in a switching branch. The current sensor is formed by one of the resistances in the switching branches, the voltage across the resistance forming the signal which is a measure of the current through the switching means. As a result, the control circuit controls the conduction state of all switching elements in dependence upon the voltage across the ohmic resistance connected in series with one of the switching elements. An advantage of the known DC-DC converters is that the current sensor is constructed in a very simple manner. A drawback of the known DC-DC converter is, however, that the ohmic resistances in the switching branches have a comparatively high impedance value, causing a comparatively high power dissipation in these ohmic resistances during operation.
It is an object of the invention to provide a DC-DC converter wherein the current through the switching means is controlled, and wherein, during operation, the power dissipation occurring in the switching branches is comparatively small.
To achieve this, a DC-DC converter as described in the opening paragraph is characterized in accordance with the invention in that each of the impedances in the switching branches is connected via a signal branch to the output of the current sensor, and the current sensor comprises the impedances in the switching branches and the signal branches.
As each of the impedances in the switching branches is connected, via a signal branch, to the output of the current sensor, the signal at the output of the current sensor is a measure of the total current through the switching means, and not only of the current in a switching branch. As the total current through the switching means is measured, a simple relation between the currents in the different switching branches is not necessary. For this reason, the impedance values of the impedances in the switching branches can be chosen to be comparatively low, and, during operation, only a comparatively small power dissipation occurs in these impedances. This power dissipation decreases as the impedance value of the impedances in the switching branches decreases, and as the impedance of the signal branches increases.
In a comparatively simple and hence inexpensive embodiment of a DC-DC converter in accordance with the invention, the impedances in the switching branches are formed by ohmic resistances.
It has been found to be advantageous to provide each of the signal branches with an ohmic resistance. As a result, the power dissipation in the DC-DC converter is further reduced.
REFERENCES:
patent: 4291259 (1981-09-01), Marumoto et al.
patent: 4392103 (1983-07-01), O'Sullivan et al.
patent: 4529927 (1985-07-01), O'Sullivan et al.
patent: 4999566 (1991-03-01), Kuehn
patent: 5027051 (1991-06-01), Lafferty
patent: 5233287 (1993-08-01), Lenk
patent: 5350997 (1994-09-01), Ghotbi et al.
patent: 5461302 (1995-10-01), Garcia et al.
patent: 5909108 (1999-06-01), He et al.
patent: 5949222 (1999-09-01), Buono
patent: 6008630 (1999-12-01), Prasad
patent: 55149854A (1980-11-01), None
patent: 0514064A2 (1992-11-01), None
patent: 0514064A3 (1992-11-01), None
Langeslag Wilhelmus Hunderikus Maria
Wessels Johannes Hendrik
Berhane Adolf Deneke
U.S. Philips Corporation
LandOfFree
DC-DC converter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with DC-DC converter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DC-DC converter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2513741