High holding voltage, mixed-voltage domain electrostatic discharge clamp
AssigneeSofics BVBA
InventorsSven Van Wijmeersch, Benjamin Van Camp, Olivier Marichal, Johan Van der Borght
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Abstract
An electrostatic discharge (ESD) protection circuit is disclosed including at least a clamping device, a switching device, and a voltage limiter. The ESD protection circuit may include devices of different voltage domains. The switching device may be in series with the clamping device to block at least a portion of a voltage from dropping across the clamping device. The switching device may sustain higher maximum operating voltages than the clamping device.
Claims24
An electrostatic discharge (ESD) protection circuit configured to operate in a normal operation mode and an ESD operation mode, for protecting circuitry coupled between a first node and a second node, the ESD protection circuit comprising:
- at least one clamping device coupled to the first node, wherein each of the at least one clamping device is a low voltage device, wherein each of the at least one clamping device has a first maximum voltage rating during the normal operation mode, and wherein each of the at least one clamping device is configured to trigger during the ESD mode and is configured to be off during the normal operation mode;
- a switching device coupled in series with the at least one clamping device and coupled to the second node, wherein the switching device is a high voltage device, wherein the switching device has a second maximum voltage rating during the normal operation mode that is higher than the first maximum voltage rating during the normal operation mode, and wherein the switching device is configured to trigger during the ESD mode and is configured to be off during the normal operation mode;
- and
- a voltage limiter coupled to the at least one clamping device and configured to limit a voltage over the at least one clamping device during the normal operation mode.
An electrostatic discharge (ESD) protection circuit configured to operate in a normal operation mode and an ESD operation mode, for protecting circuitry coupled between a first node and a second node, the ESD protection circuit comprising:
- at least one clamping device having a maximum voltage rating below a voltage between the first node and the second node during the normal operation mode;
- a switching device;
- and
- a voltage limiter;
- wherein a combination of the voltage limiter and the switching device is configured to divide the voltage between the first node and the second node during the normal operation mode such that the voltage across the at least one clamping device is limited to a voltage below the maximum voltage rating, and wherein the switching device is configured, during the ESD mode, to drop, across the switching device, substantially all of a voltage between the first node and the second node in excess of a forward voltage drop across the at least one clamping device.
Dependencies are inferred from the claim text.