Abstract An MOS-FET switching circuit for high voltage, bipolar, common mode analog input signals. The source-drain terminals of a switching transistor are connected in series in the signal path, and a transformer secondary winding supplying a floating drive signal is connected across the transistor gate-body terminals. The drain-source terminals of a control transistor are connected between the source terminal of the switching transistor and one end of the transformer winding to isolate the input signal from the gate terminal of the switching transistor. When a drive signal is applied, the control transistor turns on which places the drive signal across the source-gate terminals of the switching transistor to turn the latter on in a positive manner.
In a floating drive switching circuit for a bipolar, analog input signal including a switching MOS-FET having its source and drain terminals connected between an input terminal and an output terminal, the improvement comprising: a. a control MOS-FET, b. means having first and second terminals for applying a drive signal to the circuit, the first terminal being connected to the gate terminals of both the switching and control MOS-FET''s, c. means connecting the input terminal to the drain terminal of the control MOS-FET, and d. means connecting the second terminal of the drive signal applying means to the source and body terminals of the control MOS-FET and to the body terminal of the switching MOS-FET.
Claim 2
Dependent Claim
115 words
In a floating drive switching circuit for a bipolar, analog input signal including a switching MOS-FET having its source and drain terminals connected between an input terminal and an output terminal, the improvement comprising: a. a control MOS-FET, b. means having first and second terminals for applying a drive signal to the circuit, the first terminal being connected to the gate terminals of both the switching and control MOS-FET''s, c. means connecting the input terminal to the drain terminal of the control MOS-FET, and d. means connecting the second terminal of the drive signal applying means to the source and body terminals of the control MOS-FET and to the body terminal of the switching MOS-FET.
Claim 3
Dependent Claim
21 words
A switching circuit as defined in claim 1 wherein the drive signal applying means is the secondary winding of a transformer.