Bus driver for avoiding an overvoltage
AssigneeFreescale Semiconductor, Inc.
InventorsAlexis Huot-Marchand, Hamada Ahmed, Patrice Besse, Nicolas Jarrige
Life of this patent
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Abstract
An electrical circuit for manipulating at least one of a voltage and a current on a bus wire comprises a first switch having a first gate, a first source, and a first potential reduction unit. The first potential reduction unit is suitable for lowering a potential difference between the first gate and the first source of the first switch, wherein the lowering of the potential difference is caused by a shutting-off of a first control voltage.
Claims20
An electrical circuit for manipulating at least one of a voltage and a current on a bus wire, wherein the circuit comprises:
- a first switch having a first gate, a first source, and a first potential reduction unit, wherein the manipulating of the at least one of a voltage and a current on the bus wire is controllable by a change of a gate voltage at the first gate, wherein the first potential reduction unit is suitable for lowering a potential difference between the first gate and the first source of the first switch, wherein the lowering of the potential difference is causable by turning an output of a first control voltage source into an high-impedance state;
- and
- a second switch having a second gate, a second source, and a second potential reduction unit, wherein the second potential reduction unit is suitable for lowering a potential difference between the second gate and the second source of the second switch, wherein the lowering of the potential difference is caused by a shutting-off of a second control voltage.
A method for avoiding an overvoltage on a bus wire, wherein the method comprises:
- recognizing an error condition;
- breaking a first control circuit of a first gate of a first switch at an interruption moment when the first gate is supplied via the first control circuit with a first control voltage by turning an output of a first control voltage source into an high impedance state;
- lowering a voltage at the first gate with a first time constant;
- breaking a second control circuit of a second gate of a second switch, at the interruption moment when the second gate is supplied via the second control circuit with a second control voltage;
- and
- lowering a voltage at the second gate with a second time constant being higher than the first time constant.
An electrical circuit for manipulating at least one of a voltage and a current on a bus wire, wherein the electrical circuit comprises:
- a voltage supply having a first terminal coupled to the bus wire, and a second terminal coupled to a voltage reference, wherein the voltage reference is a ground;
- a protection circuit having a first terminal coupled to the bus wire, and a second terminal coupled to the voltage reference;
- a switch having a first current electrode coupled to the bus wire, a second current electrode coupled to the voltage reference, and a control electrode;
- and
- a potential reduction unit including a gate-source capacitor of the switch, and a resistor having a first terminal coupled to the control electrode of the switch and a second terminal coupled to the voltage reference, wherein the manipulating of the at least one of the voltage and the current on the bus wire is controllable by a change of a control voltage at the control electrode of the switch, wherein the potential reduction unit is suitable for lowering a potential difference between the control electrode and the second current electrode of the switch, wherein the lowering of the potential difference is causable by turning an output of a first control voltage source into an high-impedance state.
Dependencies are inferred from the claim text.