US 4,677,325 AGranted

High voltage MOSFET switch

AssigneeSiemens Aktiengesellschaft

InventorsJosef Einzinger, Christine Fellinger, Ludwig Leipold, Jenoe Tihanyi, Roland Weber

Life of this patent

Estimating the term…

Loading patent…

Abstract

A switching circuit includes two series-connected MOSFET (1, 6) complementing one another, which are interconnected at the drain terminal of each device. The gate terminal of the MOSFET that is grounded is connected to a control input terminal (E). This gate terminal is also connected to the source terminal of a depletion FET (7). The drain terminal of the depletion FET (7) is connected to the gate terminal of the second MOSFET (6) and, in turn, is connected via a resistor (8) to a voltage source (+U). The gate terminal of the depletion FET (7) is grounded. The load (5) is then connected to the drain side of the complementary MOSFET. When the switch is in a blocking condition, the cross current is thus prevented from flowing; and the FET connected to voltage can be completely activated.

Claims4

Dependent claims

An electronic switch comprising:

(a) a first MOSFET and a second MOSFET having drain-to-source paths serially connected together;
(b) an output terminal of the switch is connected to the junction of both MOSFETs;
(c) a third MOSFET and a resistor are serially connected together;
(d) the junction between the resistor and the third MOSFET is connected to the gate terminal of the second MOSFET;
(e) the gate terminal of the first MOSFET is connected to a first of two control input terminals;
(f) the first MOSFET and the second MOSFET are enhancement FETs, and they have channel conductivity types which complement one another;
(g) the first and the second MOSFET are interconnected at the drain side of each MOSFET;
(h) the third MOSFET is a depletion FET of the same channel conductivity type as the first MOSFET;
(i) the gate terminal of the third MOSFET is connected to a source terminal of the first MOSFET and the second of the two control input terminals;
and
(j) the source terminal of the third MOSFET is connected to the first of the two control input terminals.

8 more elements

Dependencies are inferred from the claim text.