Device and Method for Supplying Direct Voltage
The invention relates to a device and method for supplying direct voltage, wherein said device comprises a first connection arrangement ( 3, 4 ) for a first direct voltage source ( 8 ) and a second connection arrangement ( 5, 6, 7 ) for a second direct voltage source ( 11 ), wherein the device ( 1 ) is provided with a protective element ( 18 ) which is connected to the first connection arrangement ( 3, 4 ) and prevents a charge equalisation between one direct voltage source ( 8, 11 ) and the other direct voltage source ( 11, 8 ). The aim of said invention is to ease the direct voltage supply ( 2 ) For this purpose the protective element ( 18 ) is also connected to the second connection arrangement ( 5, 6, 7 ) in order to prevent the defective operation of the device ( 1 ) in the case of the reversed polarity of the first direct voltage source ( 8 ).
1 . A device for supplying a direct voltage, comprising a first connection arrangement for a first direct voltage source and a second connection arrangement for a second direct voltage source, the device being provided with a protective element which is connected in series with a first connection of the first connection arrangement, wherein the protective element is additionally connected to the second connection arrangement, the protective element being a transistor, whose gate connection is connected to a second connection of the first connection arrangement, thus preventing a defective operation of the device in case of a reversed polarity of the first direct voltage source, the gate connection of the transistor also being connected to a control connection of the second connection arrangement, said control connection blocking the transistor if the second direct voltage source is connected, thus preventing a charge equalisation and a charging or discharging of one direct voltage source to the other direct voltage source.
2 . The device according to claim 1 , wherein the protective element is connected electrically in series with the first direct voltage source.
3 . The device according to claim 1 , wherein a negative connection of the protective element is connected to the first direct voltage source.
4 . The device according to claim 1 , wherein the protective element is connected to a reference potential of the device.
5 . The device according to claim 1 , wherein the second direct voltage source is electrically connected in parallel to a series connection of the first direct voltage source and the protective element.
6 . The device according to claim 1 , wherein if both the first direct voltage source and the second direct voltage source are connected, the first direct voltage source is inactive.
7 . The device according to claim 1 , wherein the first direct voltage source has a lower output voltage than the second direct voltage source.
8 . The device according to claim 1 , wherein the protective element is a field-effect-transistor with at least one drain connection, at least one source connection and at least one gate connection.
9 . The device according to claim 8 , wherein the drain connection of the field-effect-transistor is connected to a negative connection of the first connection arrangement.
10 . The device according to claim 8 , wherein the source connection of the field-effect-transistor is connected to a reference potential of the device.
11 . The device according to claim 8 , wherein the gate connection of the field-effect-transistor is connected to a control outlet of the second direct power source.
12 . The device according to claim 8 , wherein a diode is located between the gate connection of the field-effect-transistor and the reference potential of the device.
13 . The device according to claim 8 , wherein an ohmic resistor is located between the gate connection of the field-effect-transistor and a positive connection of the first connection arrangement.
14 . A method for supplying a direct voltage with a device comprising a first connection arrangement for a first direct voltage source and a second connection arrangement for a second direct voltage source, a protective element being connected to and operated in series with a first connection of the first connection arrangement, wherein the protective element being a transistor, whose gate connection is connected to a second connection of the first connection arrangement, thus preventing a defective operation of the device in the case of a reversed polarity of the first direct voltage source, the gate connection of the transistor also being connected to a control connection of the second connection arrangement, said control connection blocking the transistor if the second direct voltage source is connected, thus preventing a charge equalisation and a charging or discharging of one direct voltage source to the other direct voltage source.
15 . The method according to claim 14 , wherein the protective element prevents a charge equalisation from the second direct voltage source to the first direct voltage source.
16 . The method according to claim 14 , wherein a control outlet of the second direct voltage source, being connected to a gate connection of a field-effect-transistor serving as protective element, supplies a voltage value to the gate connection which is dependent upon a connected second direct voltage source.