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AssigneeTelefonaktiebolaget L M Ericsson
InventorFolke Josef Bertil Ekelund
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A drive circuit for a controllable electronic switching element, preferably a power transistor has two part circuits. One part circuit includes a first transistor and one primary half of a current transformer the secondary winding of which is connected to the main current path of the switching element. The other part circuit consists of a second transistor and the other primary half of the current transformer. The transistor in each part circuit has its collector connected to the respective primary half and the bases of the transistors are connected together and to a voltage pulse source. The emitter of each of the transistors is connected to the control electrode of the switching element so that one of the part circuits forms a positive feedback loop for the collector current of the switching element when it is conducting and the other of the part circuits forms a negative feedback loop when the switching element is not non-conducting.
A drive circuit for a controllable electronic switch element including a main current circuit and a control current circuit whereby the flow of control current in said control current circuit controls said controllable electronic switch element to govern the flow of current in said main current circuit, said drive circuit comprising a first current circuit, a second current circuit, magnetic feedback means coupling said main current circuit to said first and second current circuits for providing feedback signals from said main current circuit to said first or second current circuits, pulse generating means for generating control pulses of first and second polarities, said first current circuit including a first controllable switching element means connected to said pulse generating means and responsive to control pulses of said first polarity for initiating the flow of a first control current to said control current circuit to render said controllable electronic switch element conducting, and said second current including a second controllable switching element means connected to said pulse generating means and responsive to control pulses of said second polarity for initiating the flow of a second control current from said control current circuit to render said controllable electronic switch element non-conducting.
Dependencies are inferred from the claim text.