MOS TRANSISTOR CONTROL

• US 20090230906A1
• Filed: 03/22/2006
• Published: 09/17/2009
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Valeo Equipements Electriques Moteur (Valeo SE)
• Original Assignee: Valeo Equipements Electriques Moteur (Valeo SE)
• Inventors: Sardat, Pierre
• Granted Patent: US 7,737,650 B2
• Time in Patent Office: Days
• US Class Current: 318/400.260
• CPC Class Codes: H03K 17/063 in field-effect transistor switches

Abstract

The invention concerns a method for controlling a switching assembly comprising a plurality of transistors connected in parallel, having a linear operating mode, a closed-switch operating mode and an off operating mode including a first operating phase during which a current flows from a source terminal to a drain terminal and a second operating phase during which no current flows. The method includes the following successive steps; (a) controlling the switching assembly in closed-switch mode during part of the first phase; (b) controlling the switching assembly in linear mode; (c) controlling the assembly in off mode during part of the second phase.

Claims

1. A method of controlling a switching assembly comprising:

a plurality of transistors connected in parallel;

a linear operating mode in which an internal resistance of said plurality of transistors can be controlled in a given range of values;

a closed-switch operating mode, in which said internal resistance is equal to a minimum value; and

an off operating mode, in which said internal resistance is equal to a maximum value;

wherein said method further comprises;

a first operating phase during which a current flows from a source terminal to a drain terminal of said plurality of transistors;

a second operating phase in which no current flows;

wherein said method which comprises said steps according to which, successively;

(a) wherein said plurality of transistors of the switching assembly are controlled in a common fashion in closed-switch mode during at least part of said first phase;

(b) wherein said plurality of transistors are controlled in a common fashion in linear mode at the end of said first phase during at least a first given period; and

(c) wherein said plurality of transistors are controlled in a common fashion in off mode during at least part of said second phase.

2. The method according to claim 1, also comprising a step, prior to step, during which said switching assembly is controlled in linear mode during at least part of said first phase.

3. The method according to claim 1, implemented in an electrical conversion bridge functioning periodically, according to which said first period is greater than or equal to 5% of said first phase.

4. The method according to claim 1, according to which a drain/source voltage Uds increases during said second phase, and reaches a slope of maximum rise, and according to which said plurality of transistors in the switching assembly have a short stray capacitance discharge time so that a gate/source voltage Ugs is substantially less than a given threshold value when the drain/source voltage Uds reaches the said slope of maximum rise.

5. The method according to claim 1, according to which implemented in an electrical conversion bridge.

6. The method according to claim 5, according to which the electrical conversion bridge is connected to a rotary electrical machine able to function alternately as an alternator or as a motor.

7. The method according to claim 1, implemented in order to control a switch.

8. A device for controlling a switching assembly comprising a plurality of transistors connected in parallel, comprising means for implementing said method according to claim 1.

9. The device according to claim 8, also comprising a comparator and adjustment means comprising:

a capacitor and a resistor connected in series between an output of said comparator and an input of said comparator, a resistor connected between the said output of the comparator and the gate terminal of the switching assembly, and a resistor connected between the said input of said comparator and the drain terminal of said switching assembly.

10. A method of controlling a switching assembly comprising a plurality of transistors adapted to comprise the following operating modes:

a linear operating mode in which an internal resistance of said plurality of transistors can be controlled in a given range of values;

an off operating mode in which said internal resistance is equal to a maximum value;

said method comprising the steps of;

causing a first operating phase during which a current flows from a source terminal to a drain terminal of said plurality of transistors;

causing a second operating phase in which no current flows;

controlling said plurality of transistors in a closed-switch operating mode during at least part of said first operating phase;

wherever said internal resistance is equal to a minimum value during said closed switch operating mode;

controlling said plurality of transistors in said linear operating mode at the end of said first operating phase during at least a first given period; and

controlling said plurality of transistors in said off operating mode during at least part of said second operating phase.

11. The method according to claim 10, also comprising a step during which the switching assembly is controlled in said linear operating mode during at least part of the first operating phase.

12. The method according to claim 10, implemented in an electrical conversion bridge functioning periodically, according to which the said first period is greater than or equal to 5% of the first operating phase.

13. The method according to claim 10, according to which a drain/source voltage Uds of said plurality of transistors increases during the second operating phase, and reaches a slope of maximum rise, and according to which said plurality of transistors in the switching assembly have a short stray capacitance discharge time so that a gate/source voltage Ugs is substantially less than a given threshold value when the drain/source voltage Uds reaches the said slope of maximum rise.

14. The method according to claim 10, according to which said method is implemented in an electrical conversion bridge.

15. The method according to claim 14, according to which the electrical conversion bridge is connected to a rotary electrical machine able to function alternately as an alternator or as a motor.

16. A method according to claim 10, wherein said switching assembly, further comprises a comparator and adjustment means comprising;

a capacitor and a resistor connected in series between an output of the comparator and an input of the comparator, a resistor connected between the said output of the comparator and the gate terminal of the switching assembly, and a resistor connected between the said input of the comparator and said drain terminal of the switching assembly.