Multi-function power control circuit using enhancement mode gallium nitride (GaN) high electron mobility transistors (HEMTs)
Embodiments of the present disclosure relate to a multi-function circuit. The circuit comprises a low side circuit that is comprised with a first set of enhancement mode transistors. The half bridge circuit also includes a high side circuit that is comprised of a second set of transistors. Each of the enhancement mode transistors of the first set and second set of enhancement mode transistors are Gallium Nitride (GaN) transistors. In some embodiments, the GaN transistors are High Electron Mobility Transistors (HEMTs). In additional embodiments, the GaN transistors are configured and operated as saturated switches. In further embodiments, the half bridge circuit is designed as a discrete circuit. Additionally, each of the first set and second set of transistors, diodes, resistors, and all passive elements are discrete components arranged to form a half bridge circuit. In fact, the entire half bridge circuit is built from discrete components.
1. A multi-function circuit comprising:
a low side circuit comprising a first set of enhancement mode transistors; and
a high side discrete circuit comprising a second set of enhancement mode transistors;
wherein each enhancement mode transistor of both the first and the second sets of enhancement mode transistors is a GaN high electron mobility transistor (HEMT) configured to be an active switching element;
wherein the high side discrete circuit comprises a high side switch control gate forming a high side subordinate half bridge circuit configured to directly drive a GaN high side power switch, the high side subordinate half bridge circuit comprises:
a high side subordinate half bridge high side switch and a high side subordinate half bridge low side switch;
a state controller comprising a first transistor and a second transistor in electrical communication with the high side subordinate half bridge high side switch and the high side subordinate half bridge low side switch, wherein the state controller is configured to at least determine ON/OFF logic state information of the high side subordinate half bridge circuit; and
a first bootstrap circuit in electrical communication with at least the high side subordinate half bridge high side switch, wherein the first bootstrap circuit is configured to act as a charge pump to control, in combination with the first transistor of the state controller, an on/off state of the high side subordinate half bridge high side switch.
2. The multi-function circuit of claim 1 , wherein the low side circuit includes a GaN low side power switch having a low side switch control gate, the low side switch control gate forming a low side subordinate half bridge circuit configured to directly drive the GaN low side power switch.
3. The multi-function circuit of claim 2 , further comprising a first rectifier diode and a second rectifier diode, the first and second rectifier diodes having an anti-parallel configuration with respect to both the GaN low side power switch and the GaN high side power switch.
4. The multi-function circuit of claim 3 , wherein the low side subordinate half bridge circuit includes a low side subordinate half bridge high side switch.
5. The multi-function circuit of claim 4 , further comprising a second bootstrap circuit in electrical communication with the low side subordinate half bridge high side switch, the second bootstrap circuit configured to act as a charge pump to control an on/off state of the low side subordinate half bridge high side switch.
6. The multi-function circuit of claim 5 further comprising a bias path from a voltage bias input terminal through the second bootstrap circuit to a low side subordinate half bridge low side switch, the bias path configured to charge a capacitor of the second bootstrap circuit for controlling the on/off state of the low side subordinate half bridge high side switch.
7. The multi-function circuit of claim 6 further comprising a delay circuit connecting the second bootstrap circuit to the low side subordinate half bridge high side switch, the delay circuit configured to control a timing of a change in the on/off state of the low side subordinate half bridge high side switch in response to a change in the on/off state of the low side subordinate half bridge low side switch.
8. The multi-function circuit of claim 7 further comprising a capacitor bypass circuit in electrical communication with a drain of the low side subordinate half bridge high side switch and a source of the low side subordinate half bridge low side switch, the capacitor bypass circuit configured to provide high frequency charge storage for a current required by the GaN HEMT low side power switch.
9. The multi-function circuit of claim 8 wherein the capacitor bypass circuit is in electrical communication with a bias power supply and is configured to utilize a voltage blocking diode to provide a charging path to ground potential for the capacitor of the bootstrap circuit; and wherein the voltage blocking diode is configured to conduct capacitor charging current when a high side power switch is off, the voltage blocking diode further configured to block bypass capacitor discharge current when the high side power switch is on.
10. The multi-function circuit of claim 1 , wherein the high side subordinate half bridge circuit includes a bias controller in electrical communication with the high side subordinate half bridge high side switch, the bias controller configured to electrically communicate ground potential-based state control and timing signal delays to the high side subordinate half bridge via a state controller circuit.
11. The multi-function circuit of claim 1 further comprising a voltage level-shifter/inverter configured to provide OFF/ON state information from a ground potential-based logic control input in electrical communication with the high side power switch driver, the voltage level-shifter/inverter configured to control an OFF/ON state of the GaN high side power switch.
12. The multi-function circuit of claim 1 wherein an entirety of the multi-function circuit is comprised of discrete enhancement-mode GaN circuitry.
13. The multi-function circuit of claim 1 wherein the low side circuit is a discrete circuit.
14. A multi-function circuit comprising:
a low side circuit including a GaN-based low side subordinate half bridge circuit; and
a high side discrete circuit including a GaN-based high side subordinate half bridge circuit;
wherein each enhancement mode transistor of both the low side circuit and the high side discrete circuit is configured to be an active switching element;
wherein the GaN-based high side subordinate half bridge circuit is configured to directly drive a GaN high side power switch, the GaN-based high side subordinate half bridge circuit comprises:
a high side subordinate half bridge high side switch and a high side subordinate half bridge low side switch;
a state controller comprising a first transistor and a second transistor in electrical communication with the high side subordinate half bridge high side switch and the high side subordinate half bridge low side switch, wherein the state controller is configured to at least determine ON/OFF logic state information of the high side subordinate half bridge circuit; and
a first bootstrap circuit in electrical communication with at least the high side subordinate half bridge high side switch, wherein the first bootstrap circuit is configured to act as a charge pump to control, in combination with the first transistor of the state controller, an on/off state of the high side subordinate half bridge high side switch.
15. A multi-function circuit comprising:
a GaN-based low side circuit including:
a GaN-based low side switch having a low side switch control gate, the low side switch control gate forming a low side subordinate half bridge circuit, and
a GaN-based low side switch driver having an output connected to the low side switch control gate; and
a GaN-based high side discrete circuit including:
a GaN-based high side switch having a high side switch control gate, the high side switch control gate forming a high side subordinate half bridge circuit, and
a GaN-based high side switch driver having an output connected to the high side switch control gate, wherein the GaN-based high side switch driver comprises:
a high side subordinate half bridge high side switch and a high side subordinate half bridge low side switch;
a state controller comprising a first transistor and a second transistor in electrical communication with the high side subordinate half bridge high side switch and the high side subordinate half bridge low side switch, wherein the state controller is configured to at least determine ON/OFF logic state information of the high side subordinate half bridge circuit; and
a first bootstrap circuit in electrical communication with at least the high side subordinate half bridge high side switch, wherein the first bootstrap circuit is configured to act as a charge pump to control, in combination with the first transistor of the state controller, an on/off state of the high side subordinate half bridge high side switch;
wherein each enhancement mode transistor of both the GaN-based low side circuit and the GaN-based high side discrete circuit is a GaN high electron mobility transistor (HEMT) configured to be an active switching element.