Cambridge Gan Devices Limited

Cambridge Enterprise Limited

John William Findlay

Florin Udrea

Loizos Efthymiou

Martin Arnold

Giorgia Longobardi

Sheung Wai Fung

Zahid Ansari

Tara Vishin

Wai Hon Ng

David Bruce Vail

A semiconductor switch comprising a first main terminal, a second main terminal, and a control terminal, the semiconductor switch further comprising: a III-nitride high-electron-mobility transistor (HEMT), the III-nitride HEMT comprising a first source terminal, a first drain terminal, and a first gate terminal; a first interface circuit operatively connected to the control terminal and to the first gate terminal; and a short-circuit detection circuit operatively connected to the first drain terminal and the first source terminal, the short-circuit detection circuit being configured to: sense a short-circuit across the first drain terminal and the first source terminal; and transmit a short-circuit detection signal to the first interface circuit, the first interface circuit being configured, upon receipt of the short-circuit detection signal, to cause the III-nitride HEMT to turn off, and/or to cause a voltage across the first gate terminal to be reduced.

Semiconductor switch comprising a short-circuit detection circuit

A III-nitride power semiconductor based heterojunction device comprising a substrate, a first terminal, a second terminal, a control terminal configured to receive an input switching signal during an active mode of operation and to not receive the input switching signal during a stand-by mode of operation, and an active heterojunction transistor formed on the substrate. The device further comprises a stand-by signal generation circuit configured to generate a stand-by signal when the input switching signal to the control terminal has not been detected for a set period of time, at least one Miller clamp transistor and driving circuitry associated with the at least one Miller clamp transistor, a voltage regulator circuit configured to provide at least a low power consumption output and a high power consumption output, wherein the low power consumption output is enabled at least during the stand-by mode of operation and the high power consumption output is disabled by the stand-by signal during the stand-by mode of operation, and a rail voltage terminal configured to provide an input to the voltage regulator circuit. The low power consumption output is provided to the driving circuitry of the at least one Miller clamp transistor to thereby maintain the at least one Miller clamp transistor in an on-state during the stand-by mode of operation, and the low power consumption output is provided to the stand-by signal generation circuit to thereby power up the stand-by signal generation circuit.

Stand-by circuit

A heterojunction device having at least three terminals, the at least three terminals comprising a high voltage terminal, a low voltage terminal and a control terminal. The heterojunction device further comprises at least one main power heterojunction transistor, an auxiliary gate circuit comprising at least one first low-voltage heterojunction transistor, a pull-down circuit comprising a capacitor and a charging path for the capacitor. The heterojunction device further comprises at least one monolithically integrated component, wherein the capacitor is configured to provide an internal rail voltage for the at least one monolithically integrated component.

Power semiconductor device with an auxiliary gate structure

Power semiconductor devices in GaN technology include an integrated auxiliary (double) gate terminal and a pulldown network to achieve a normally-off (E-Mode) GaN transistor with threshold voltage higher than 2V, low gate leakage current and enhanced switching performance. The high threshold voltage GaN transistor has a high-voltage active GaN device and a low-voltage auxiliary GaN device wherein the high-voltage GaN device has the gate connected to the source of the integrated auxiliary low-voltage GaN transistor and the drain being the external high-voltage drain terminal and the source being the external source terminal, while the low-voltage auxiliary GaN transistor has the gate (first auxiliary electrode) connected to the drain (second auxiliary electrode) functioning as an external gate terminal. A pull-down network for the switching-off of the high threshold voltage GaN transistor may be formed by additional auxiliary low-voltage GaN transistors and resistive elements connected with the low-voltage auxiliary GaN transistor.

An integrated circuit is provided which can sense the drain voltage of an active heterojunction transistor under different conditions and can adjust a driving signal of a gate terminal of the active heterojunction transistor in order to limit conduction losses and/or switching losses.

III-nitride power semiconductor based heterojunction device

The disclosure relates to a III-nitride power semiconductor based heterojunction device including a low voltage terminal, a high voltage terminal, a control terminal and an active heterojunction transistor formed on a substrate, and further including the following monolithically integrated components: voltage clamp circuit configured to limit a maximum potential that can be applied to the internal gate terminal, an on-state circuit configured to control the internal gate terminal of the active heterojunction transistor during an on-state operation, a turn-off circuit configured to control the internal gate terminal of the active heterojunction transistor during a turn-off operation and during an off-state.

Growing community of inventors

Cambridge, United Kingdom

John William Findlay