Methods and apparatus for over-voltage protection of device inputs
AssigneeTexas Instruments Incorporated
InventorsChristopher Michael Graves, John Edward Esquivel, James Craig Spurlin
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Abstract
Methods and apparatus for over-voltage protection of device inputs are disclosed. An example apparatus to protect a device from an over-voltage condition disclosed herein comprises a switch coupled between a device input and at least one component of the device, and a voltage compensator to pull a control input of the switch to a voltage associated with the device input to open the switch to protect the device component from the over-voltage condition.
Claims24
An apparatus to protect a device from an over-voltage condition, the apparatus comprising:
- a switch coupled between a device input and at least one component of the device;
- and
- a voltage compensator to pull a control input of the switch to a voltage associated with the device input to open the switch to protect the device component from the over-voltage condition, wherein the voltage compensator opens the switch for both a positive over-voltage condition and a negative over-voltage condition, the voltage compensator operable to open the switch both when the apparatus is in a powered condition or an unpowered condition using power from an input signal received by the device input.
A method to protect a device from an over-voltage condition, the method comprising:
- closing a switch coupled between a device input and a component of the device when the over-voltage condition does not occur;
- and
- opening the switch for both a positive over-voltage condition and a negative over-voltage condition, wherein opening the switch comprises pulling a control input of the switch to a voltage associated with the device input, wherein opening the switch occurs both when the apparatus is in a powered condition or an unpowered condition using power from an input signal received by the device input.
A device with over-voltage protection, the device comprising:
- a device input to couple an input signal to a component of the device;
- and
- an over-voltage protection circuit coupled between the device input and the device component to protect the device component from an over-voltage condition comprising one of a positive over-voltage condition and a negative over-voltage condition associated with the device input, wherein the over-voltage protection circuit is configured to isolate the device component from the device input using a voltage associated with the device input instead of directing the voltage associated with the device input to ground when the over-voltage condition occurs, wherein opening a switch occurs both when the device is in a powered condition or an unpowered condition.
An over-voltage protection circuit for inclusion in a device, the over-voltage protection circuit comprising:
- a switch coupled between a device input and at least one component of the device, wherein the switch comprises a first pair of field effect transistors coupled together at a switch control node, wherein the switch control node is configured to turn the first pair of field effect transistors at least one of ON to close the switch or OFF to open the switch;
- a comparator to detect an over-voltage condition associated with the device input by comparing an input voltage at the device input to a threshold;
- and
- a voltage compensator to pull the switch control node to the input voltage at the device input to turn OFF the first pair of field effect transistors to open the switch when the detected over-voltage condition corresponds to a negative over-voltage condition but not when the detected over-voltage condition corresponds to a positive over-voltage condition, wherein the voltage compensator comprises a second pair of field effect transistors configured to turn ON to pull the switch control node to the input voltage at the device input when a negative over-voltage condition occurs, and wherein the second pair of field effect transistors are configured to turn OFF to have no substantial effect on the switch control node otherwise.
Dependencies are inferred from the claim text.