Voltage-switching device

• US 4,751,408 A
• Filed: 08/26/1986
• Issued: 06/14/1988
• Est. Priority Date: 09/06/1985
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF
• Original Assignee: Thomson-CSF
• Inventors: Rambert, Bernard
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Phan, Trong Q.
• Application Number:
  US06/900,484
• Time in Patent Office: 658 Days
• Field of Search: 307/570, 307/571, 307/574, 307/575, 307/577, 307/583, 307/584, 307/254, 361/58, 361/126, 361/127
• US Class Current: 327/436
• CPC Class Codes: H03K 17/102 in field-effect transistor switches
• CPC Class Codes: H03K 17/691 using transformer coupling

Abstract

In a voltage-switching device for such applications as the control of electron tube grids in the field of radar or telecommunications, the total voltages to be switched are distributed at the terminals of a series-connected array of MOS field-effect transistors, thereby ensuring that each individual transistor is not liable to carry voltages in excess of such values which could result in transistor damage or destruction.

Claims

1. A voltage-switching element, wherein said voltage-switching element has a first input and a first output connected in parallel through a forward-biased diode, a resistor, a capacitor and a resistor connected in series, and a second input connected to the source of an insulated-gate field-effect (MOSFET) power transistor, a second output connected to the drain of said insulated-gate field-effect (MOSFET) power transistor, said first input being connected to the gate of said insulated-gate field-effect (MOSFET) power transistor.

3. A voltage-switching element according to claim 1, wherein said voltage-switching element further comprises a diode connected between a lead extending from the capacitor to the series-connected resistor and the first output, said diode being reverse-biased.

4. A voltage-switching element according to claim 1 wherein said voltage switching element further comprises a low-value resistor placed between said gate of said insulated-gate field-effect (MOSFET) power transistor and said first input.

5. A voltage-switching element according to claim 1, wherein two oppositely-biased transils, a resistor and a further resistor placed in series with a capacitor are mounted in parallel between the gate and the source of the insulated-gate field-effect (MOSFET) power transistor.

2. A voltage-switching element, wherein said voltage-switching element has a first input and a first output connected in parallel through a forward-biased diode, a resistor and a capacitor, a second input connected to the source of an insulated-gate field-effect (MOSFET) power transistor, a second output connected to the drain of said insulated-gate field-effect (MOSFET) power transistor, said first input being connected to the gate of said insulated-gate field-effect (MOSFET) power transistor.

6. A voltage-switching element according to claim 2, wherein the source and the drain of the insulated-gate field-effect (MOSFET) power transistor are connected through a forwrd-biased diode.

7. A device according to claim 6, wherein the capacitance of the capacitors follows an arithmetical progression having a common difference equal to the value of the parasitic gate-source capacitances of the insulated-gate field-effect (MOSFET) power transistors.

8. A voltage-switching element according to claim 6, wherein said voltage-switching element further includes voltage storage means including a diode and a capacitor which can be charged through said diode, said diode being mounted in top-to-tail relation with a Zener diode to form a diode assembly.

9. A voltage-switching element according to claim 8, wherein a further capacitor is connected to the terminals of the Zener diode.

10. A voltage switching element according to claim 8, wherein said voltage storage means comprises two diode assemblies of opposite polarity, a Zener diode being employed for storing the negative voltages and the positive voltages.