Abstract: In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

Abstract: Disclosed examples include methods, integrated circuits and switch circuits including a driver circuit and a silicon transistor or other current source circuit coupled with a gallium nitride or other high electron mobility first transistor, where the driver operatives in a first mode to deliver a control voltage signal to the first transistor, and in a second mode in response to a detected overvoltage condition associated with the first transistor to control the current source circuit to conduct a sink current from the first transistor to affect a control voltage to at least partially turn on the first transistor.

Abstract: In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

Abstract: A high-voltage transistor (HVT) structure adapts a low-voltage transistor (LUT) to high-voltage environments. The HVT structure includes a drain node, a source node, a control gate, and a field electrode. The drain node and the source node define a conductive channel, in which mobilized charges are regulated by the control gate. While being isolated from the control gate, the field electrode is configured to spread the mobilized charges in response to a field voltage. The field electrode is structured and routed to prevent charge sharing with any one of the drain node, source node, or control gate. Advantageously, the isolated field electrode minimizes the capacitance of the control gate as well as the drain and source nodes, such that the HVT can switch with less power loss and a more robust performance in a high-voltage environment.

Abstract: Disclosed examples include methods, integrated circuits and switch circuits including a driver circuit and a silicon transistor or other current source circuit coupled with a gallium nitride or other high electron mobility first transistor, where the driver operatives in a first mode to deliver a control voltage signal to the first transistor, and in a second mode in response to a detected overvoltage condition associated with the first transistor to control the current source circuit to conduct a sink current from the first transistor to affect a control voltage to at least partially turn on the first transistor.

Abstract: Disclosed examples include methods, integrated circuits and switch circuits including a driver circuit and a silicon transistor or other current source circuit coupled with a gallium nitride or other high electron mobility first transistor, where the driver operatives in a first mode to deliver a control voltage signal to the first transistor, and in a second mode in response to a detected overvoltage condition associated with the first transistor to control the current source circuit to conduct a sink current from the first transistor to affect a control voltage to at least partially turn on the first transistor.

Abstract: Disclosed examples include systems to determine an on-state impedance of a high voltage transistor, and measurement circuits to measure the drain voltage of a drain terminal of the high voltage transistor during switching, including an attenuator circuit to generate an attenuator output signal representing a voltage across the high voltage transistor when the high voltage transistor is turned on, and a differential amplifier to provide an amplified sense voltage signal according to the attenuator output signal. The attenuator circuit includes a clamp transistor coupled with the drain terminal of the high voltage transistor to provide a sense signal to a first internal node, a resistive voltage divider circuit to provide the attenuator output signal based on the sense signal, and a first clamp circuit to limit the sense signal voltage when the high voltage transistor is turned off.

Abstract: Disclosed examples include systems to determine an on-state impedance of a high voltage transistor, and measurement circuits to measure the drain voltage of a drain terminal of the high voltage transistor during switching, including an attenuator circuit to generate an attenuator output signal representing a voltage across the high voltage transistor when the high voltage transistor is turned on, and a differential amplifier to provide an amplified sense voltage signal according to the attenuator output signal. The attenuator circuit includes a clamp transistor coupled with the drain terminal of the high voltage transistor to provide a sense signal to a first internal node, a resistive voltage divider circuit to provide the attenuator output signal based on the sense signal, and a first clamp circuit to limit the sense signal voltage when the high voltage transistor is turned off.

Abstract: A high-voltage transistor (HVT) structure adapts a low-voltage transistor (LUT) to high-voltage environments. The HVT structure includes a drain node, a source node, a control gate, and a field electrode. The drain node and the source node define a conductive channel, in which mobilized charges are regulated by the control gate. While being isolated from the control gate, the field electrode is configured to spread the mobilized charges in response to a field voltage. The field electrode is structured and routed to prevent charge sharing with any one of the drain node, source node, or control gate. Advantageously, the isolated field electrode minimizes the capacitance of the control gate as well as the drain and source nodes, such that the HVT can switch with less power loss and a more robust performance in a high-voltage environment.

Abstract: A high-voltage transistor (HVT) structure adapts a low-voltage transistor (LVT) to high-voltage environments. The HVT structure includes a drain node, a source node, a control gate, and a field electrode. The drain node and the source node define a conductive channel, in which mobilized charges are regulated by the control gate. While being isolated from the control gate, the field electrode is configured to spread the mobilized charges in response to a field voltage. The field electrode is structured and routed to prevent charge sharing with any one of the drain node, source node, or control gate. Advantageously, the isolated field electrode minimizes the capacitance of the control gate as well as the drain and source nodes, such that the HVT can switch with less power loss and a more robust performance in a high-voltage environment.

Abstract: In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

Abstract: Disclosed examples include methods, integrated circuits and switch circuits including a driver circuit and a silicon transistor or other current source circuit coupled with a gallium nitride or other high electron mobility first transistor, where the driver operatives in a first mode to deliver a control voltage signal to the first transistor, and in a second mode in response to a detected overvoltage condition associated with the first transistor to control the current source circuit to conduct a sink current from the first transistor to affect a control voltage to at least partially turn on the first transistor.

Abstract: In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

Abstract: Disclosed examples include systems to determine an on-state impedance of a high voltage transistor, and measurement circuits to measure the drain voltage of a drain terminal of the high voltage transistor during switching, including an attenuator circuit to generate an attenuator output signal representing a voltage across the high voltage transistor when the high voltage transistor is turned on, and a differential amplifier to provide an amplified sense voltage signal according to the attenuator output signal. The attenuator circuit includes a clamp transistor coupled with the drain terminal of the high voltage transistor to provide a sense signal to a first internal node, a resistive voltage divider circuit to provide the attenuator output signal based on the sense signal, and a first clamp circuit to limit the sense signal voltage when the high voltage transistor is turned off.

Abstract: A high-voltage transistor (HVT) structure adapts a low-voltage transistor (LVT) to high-voltage environments. The HVT structure includes a drain node, a source node, a control gate, and a field electrode. The drain node and the source node define a conductive channel, in which mobilized charges are regulated by the control gate. While being isolated from the control gate, the field electrode is configured to spread the mobilized charges in response to a field voltage. The field electrode is structured and routed to prevent charge sharing with any one of the drain node, source node, or control gate. Advantageously, the isolated field electrode minimizes the capacitance of the control gate as well as the drain and source nodes, such that the HVT can switch with less power loss and a more robust performance in a high-voltage environment.

Abstract: A method includes forming a first epitaxial layer over a semiconductor substrate and etching the first epitaxial layer to form multiple separated first epitaxial regions. The method also includes forming a second epitaxial layer over the etched first epitaxial layer. Each epitaxial layer includes at least one Group III-nitride, and the epitaxial layers collectively form a buffer. The method further includes forming a device layer over the buffer and fabricating a semiconductor device using the device layer. The second epitaxial layer could include second epitaxial regions substantially only on the first epitaxial regions. The second epitaxial layer could also cover the first epitaxial regions and the substrate, and the second epitaxial layer may or may not be etched. The device layer could be formed during the same operation used to form the second epitaxial layer.

Abstract: A method includes forming a first epitaxial layer over a semiconductor substrate and etching the first epitaxial layer to form multiple separated first epitaxial regions. The method also includes forming a second epitaxial layer over the etched first epitaxial layer. Each epitaxial layer includes at least one Group III-nitride, and the epitaxial layers collectively form a buffer. The method further includes forming a device layer over the buffer and fabricating a semiconductor device using the device layer. The second epitaxial layer could include second epitaxial regions substantially only on the first epitaxial regions. The second epitaxial layer could also cover the first epitaxial regions and the substrate, and the second epitaxial layer may or may not be etched. The device layer could be formed during the same operation used to form the second epitaxial layer.

Abstract: In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

Abstract: A semiconductor device includes a first layer and a second layer over the first layer. The first and second layers are configured to form an electron gas layer at an interface of the first and second layers. The semiconductor device also includes an Ohmic contact and multiple conductive vias through the second layer. The conductive vias are configured to electrically couple the Ohmic contact to the electron gas layer. The conductive vias could have substantially vertical sidewalls or substantially sloped sidewalls, or the conductive vias could form a nano-textured surface on the Ohmic contact. The first layer could include Group III-nitride nucleation, buffer, and channel layers, and the second layer could include a Group III-nitride barrier layer.

Abstract: A semiconductor device includes a bidirectional GaN FET formed on a non-insulating substrate. The semiconductor device further includes a first electrical clamp connected between the substrate and a first source/drain node of the bidirectional GaN FET, and a second electrical clamp connected between the substrate and a second source/drain node of the bidirectional GaN FET. The first clamp and the second clamp are configured to bias the substrate at a lower voltage level of an applied bias to the first source/drain node and an applied bias to the second source/drain node, within an offset voltage of the relevant clamp.