US 10,566,964 B2 · Apparatus and methods for overvoltage protection of electronic devices

Abstract

An apparatus includes a string of series-connected voltage clamp devices (e.g., metal-oxide varistors (MOVs)) coupled to at least one electronic device (e.g., a transistor or other semiconductor device). The apparatus further includes a bypass circuit configured to selectively bypass a subset of the string of series-connected voltage clamp devices to control a level at which a voltage applied to the at least one electronic device is clamped. A control circuit may be configured to cause the bypass circuit to bypass the subset of the string of series-connected voltage clamp devices responsive to a voltage applied to the at least one electronic device. For example, the control circuit may be configured to cause the bypass circuit to bypass the subset of the string of series-connected voltage clamp devices responsive to a magnitude of the voltage applied to the at least one electronic device exceeding a threshold.

Claims11

Dependent claims

An apparatus comprising:

at least two series-connected MOVs configured to clamp a voltage applied to at least one semiconductor device;
a switch configured to selectively bypass a subset of the least two series-connected MOVs;
and
a control circuit configured to cause the switch to shunt current through a first number of the at least two series-connected MOVs in a first state and to shunt current through a second number of the at least two series-connected MOVs in a second state,
wherein the first state provides a clamping voltage greater than a maximum instantaneous voltage rating of the at least one semiconductor device and wherein the second state provides a clamping voltage less than or equal to the maximum instantaneous voltage rating of the at least one semiconductor device.

2 more elements

An apparatus comprising:

a string of series-connected voltage clamp devices configured to be coupled to at least one semiconductor switch;
a bypass circuit configured to selectively bypass a subset of the string of series-connected voltage clamp devices to control a level at which a voltage across the at least one semiconductor switch is clamped;
and
a control circuit configured to cause the bypass circuit to shunt current through a first number of the series-connected voltage clamp devices in a first state and to shunt current through a second number of the series-connected voltage clamp devices in a second state responsive to the voltage across the at least one semiconductor switch,
wherein the first state provides a clamping voltage greater than a maximum instantaneous voltage rating of the at least one semiconductor switch and wherein the second state provides a clamping voltage less than or equal to the maximum instantaneous voltage rating of the at least one semiconductor switch.

2 more elements

Dependencies are inferred from the claim text.

Apparatus and methods for overvoltage protection of electronic devices

Life of this patent

Apparatus and methods for overvoltage protection of electronic devices

Life of this patent

Abstract

Claims11