DC-to-DC converter

Abstract

A DC-to-DC converter for transporting energy between two networks includes two or more converter circuits connected in parallel, wherein a first semiconductor switch that can be actuated as a function of a voltage drop across the first semiconductor switch is arranged in series to each converter circuit or a second semiconductor switch that can be actuated as a function of a voltage drop across the second semiconductor switch is arranged in series to each converter circuit.

Claims

1. A DC-to-DC converter for transporting energy between two networks, comprising: a controller; two or more converter branch circuits connected in parallel, wherein each converter branch circuit comprises: a converter circuit; a first semiconductor switch that has a resistance for generating a voltage drop in the conductive state and can be actuated as a function of this voltage drop across the first semiconductor switch arranged in series to the converter circuit; a second semiconductor switch that has a resistance for generating a voltage drop in the conductive state and can be actuated as a function of this voltage drop across the second semiconductor switch arranged in series to the converter circuit; at least one threshold switch associated with each of the first and second semiconductor switches for detecting the voltage drop across the associated semiconductor switch, and comparing the detected voltage drop with at least one switching threshold, and causing the associated semiconductor switch to open upon detecting a voltage drop above the switching threshold at the associated semiconductor switch; an RS flip-flop and the controller in communication with each of the at least one threshold switches and its associated semiconductor switch; wherein the controller and the RS flip-flop are operable to transmit a dominant signal to said associated semiconductor switch; and wherein the dominant signal is operable to (a) cause the semiconductor switch to close even if a detected voltage drop at the semiconductor switch is above the switching threshold, or (b) cause the semiconductor switch to open even if the detected voltage drop across the semiconductor switch is below the switching threshold.

2. The DC-to-DC converter according to claim 1, wherein the threshold switches have outputs and that an output signal that is dependent on the result of the comparison can be generated with the threshold switches.

3. The DC-to-DC converter according to claim 1, wherein switching thresholds of the threshold switches can be adjusted, in particular, to compensate a temperature drift of the resistor of the first or second semiconductor switch.

4. The DC-to-DC converter according to claim 3, wherein the controller can generate signals with which each semiconductor switch can be controlled and wherein connections for setting the switching thresholds of the threshold switches are connected to the controller and that the switching thresholds can be specified by the controller.

5. The DC-to-DC converter according to claim 2, wherein the output of each RS-flip-flop is connected to the control input of the associated semiconductor switch and a reset input is connected to the output of the threshold switch that detects the voltage drop of the associated semiconductor switch.

6. The DC-to-DC converter according to claim 5, wherein set inputs of the RS flip-flops are connected to the controller.

7. The DC-to-DC converter according to claim 6, wherein the set inputs are dominant with respect to the reset inputs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Reference is now made more particularly to the drawings, which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views.

(2) FIG. 1 a simplified circuit diagram of a DC-to-DC converter according to the invention.

DETAILED DESCRIPTION

(3) In the following detailed description numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, the invention is not limited in scope to the particular type of industry application depicted in the figures. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

(4) The DC-to-DC converter shown in FIG. 1 has n converter circuits, of which a first converter circuit Z1 and an n-th converter circuit Zn are shown. The converter circuits can have, in principle, any converter topology.

(5) Shown in the figure are converter circuits with buck and boost topology. Converter circuits of this topology have a first controllable switching element M11, Mn1 that is designed as a high-side switch and lies between a connection A1, An and a point SW1, SWn. The point SW1, SWn is also connected to a storage inductor L1, Ln and to a low-side switch M12, Mn2. The other connection of the storage inductor L1, Ln is connected to the connection E1, En. The other connection of the low-side switch M12, Mn2 is connected to a ground connection M1, Mn. A capacitor C1, Cn is arranged between the connection E1, En and the ground connection M1, Mn. Outside of the converter switches Z1, Zn, the ground connections M1, Mn are each connected to ground via a third controllable switching element M1m, Mnm, wherein the source connections are connected to the ground connections and the drain connections of the third controllable switching elements M1m, Mnm are connected to ground. The gate connections are connected to a controller C of the DC-to-DC converter.

(6) The third controllable switching elements M1m, Mnm are used as inverse-polarity protection for BN14 and BN48.

(7) The converter circuits are connected in parallel between the networks with the potentials BN48 and BN14 that have a common ground potential.

(8) Connected in series to each converter circuit Z1, Zn, a first semiconductor switch M14, Mn4 and a second semiconductor switch M15, Mn5 are connected, wherein the first semiconductor switches M14, Mn4 connect the connections A1, An of the converter circuits Z1, Zn to the potential BN48 and the second semiconductor switches M15, Mn5 connect the connections E1, En of the converter circuits Z1, Zn to the potential BN14. The source connections are connected to the terminals or to the connections of the converter circuits.

(9) The DC-to-DC converter furthermore has threshold switches X11, X12, Xn1, Xn2, with the voltage drop across each of the first semiconductor switches M14, Mn4 or second semiconductor switches M15, Mn5 being fed to each of these threshold switches that compare these voltages with switching thresholds that are fed to the threshold switches X11, X12, Xn1, Xn2 via connections for setting the switching thresholds. The connections for adjusting the switching thresholds are connected to the controller C.

(10) The threshold switches X11, X12, Xn1, Xn2 deliver a level with a value of a logical one when the voltage drop across the first semiconductor switch M14, Mn4 or second semiconductor switch M15, Mn5 is greater than the set threshold value. Otherwise, they deliver a logical zero to their output.

(11) The outputs of the threshold switches X11, X12, Xn1, Xn2 are connected to reset inputs R of RS flip-flops RS-FF11, FS-FF12, RS-FFn1, RS-FFn2. Additional reset inputs R are also connected to the controller. The RS flip-flops RS-FF11, RS-FF12, RS-FFn1, RS-FFn2 can be reset by a logical one on the reset input, so that a logical zero is output on the outputs Q of the RS flip-flops RS-FF11, RS-FF12, RS-FFn1, RS-FFn2. The reset can be realized both by the controller C and also by the threshold switch X11, X12, Xn1, Xn2 connected to each reset input R, as long as a logical zero is applied to the dominant set inputs S of the RS flip-flops RS-FF11, RS-FF12, RS-FFn1, RS-FFn2. The set inputs S are connected to the controller C. The controller C can therefore set the RS flip-flop RS-FF11, RS-FF12, RS-FFn1, RS-FFn2 connected to a threshold switch X11, X12, Xn1, Xn2 at any time and also despite an exceeding of a switching threshold detected by this threshold switch X11, X12, Xn1, Xn2, so that a logical one is applied on the output Q of the RS flip-flop RS-FF11, RS-FF12, RS-FFn1, RS-FFn2.

(12) The outputs Q of the RS flip-flops are connected to the gate connections of the first and second semiconductor switches M14, Mn4, M15, Mn5. If a logical one is applied to the output Q of an RS flip-flop RS-FF11, RS-FF12, RS-FFn1, FS-FFn2, then the semiconductor switch M14, Mn4, M15, Mn5 connected to this RS flip-flop RS-FF11, RS-FF12, RS-FFn1, RS-FFn2 is closed. If, in contrast, a logical zero is applied, then the first or second semiconductor switch is opened.

(13) The preferred embodiments of the invention have been described above to explain the principles of the invention and its practical application to thereby enable others skilled in the art to utilize the invention in the best mode known to the inventors. However, as various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by the above-described exemplary embodiment, but should be defined only in accordance with the following claims appended hereto and their equivalents.

LIST OF REFERENCE SYMBOLS

(14) Z1 Converter circuit Zn Converter circuit E1, En Inputs of the converter circuits (in buck mode, these are outputs, in boost mode, these are inputs) A1, An Outputs of the converter circuits (in buck mode, these are inputs, in boost mode, these are outputs) M1, Mn Ground connections of the converter circuits M11, Mn1 First controllable switching elements of the converter circuits M12, Mn2 Second controllable switching elements of the converter circuits L1, L2 Coils of the converter circuits C1, Cn Capacitors of the converter circuits M1m, Mnm Third controllable switching elements M14, Mn4 First semiconductor switches M15, Mn5 Second semiconductor switches X11, Xn1 Threshold switches X12, Xn2 Threshold switches RS-FF11, RS flip-flops RS-FFn1 RS-FF12, RS flip-flops RS-FFn2 BN48 Electric system BN14 Electric system