Half bridge driver circuits
GaN-based half bridge power conversion circuits employ control, support and logic functions that are monolithically integrated on the same devices as the power transistors. In some embodiments, a low side GaN device communicates through one or more level shift circuits with a high side GaN device. Both the high side and the low side devices may have one or more integrated control, support and logic functions.
1. A half bridge GaN circuit, comprising:
a low side circuit, comprising:
a low side switch comprising a low side switch control gate, a first source, and a first drain, and
a low side switch driver, configured to control a conductivity state of the low side switch according to a first input signal;
a high side circuit, comprising:
a high side switch comprising a high side switch control gate, a second source, and a second drain, wherein the second source is connected to the first drain, and
a high side switch driver referenced to a voltage at the second source, wherein the high side switch driver is configured to control a conductivity state of the high side switch according to a second input signal,
wherein the high side switch driver is configured to prevent a change of conductivity state of the high side switch in response to voltage transients of the voltage of the second source,
wherein the low side circuit further comprises a level shift circuit configured to receive the second input signal and to generate a level shift signal configured to control an output state of the high side switch driver.
2. The half bridge GaN circuit of claim 1 , wherein the high side circuit further comprises a receiver circuit configured to receive the level shift signal and to generate a receiver output signal configured to control the output state of the high side switch driver.
3. The half bridge GaN circuit of claim 2 , wherein the low side switch driver comprises a pulse generator configured to generate a pulse in response to signal a causing the low side switch to become non-conductive, and to transmit the pulse to the level shift circuit, and the level shift signal is configured to, in response to receiving the pulse, generate a blanking signal.
4. The half bridge GaN circuit of claim 3 , wherein the receiver circuit is configured to, in response to receiving the blanking signal, generate a signal causing the high side switch to be nonconductive.
5. The half bridge GaN circuit of claim 1 , wherein the level shift signal comprises a pulse generated in response to the second input signal transitioning from a high logic state to a low logic state.
6. The half bridge GaN circuit of claim 1 , wherein the high side switch driver is configured to control the conductivity state of the high side switch according to a plurality of pulses, and wherein durations of on and off times of the high side switch are based on durations of the pulses.
7. The half bridge GaN circuit of claim 1 , wherein the high side circuit further comprises a trigger circuit configured to, in response to a voltage of a first power supply referenced to the voltage of the second source being less than a threshold greater than the voltage of the second source, cause the high side switch to turn-off.
8. A half bridge GaN circuit, comprising:
a low side circuit, comprising:
a low side switch comprising a low side switch control gate, a first source, and a first drain, and
a low side switch driver, configured to control a conductivity state of the low side switch according to a first input signal;
a high side circuit, comprising:
a high side switch comprising a high side switch control gate, a second source, and a second drain, wherein the second source is connected to the first drain, and
a high side switch driver referenced to a voltage at the second source, wherein the high side switch driver is configured to control a conductivity state of the high side switch according to a plurality of pulses, and wherein durations of on and off times of the high side switch are based on durations of the pulses,
wherein the low side circuit further comprises a level shift circuit configured to generate the pulses in response to a second input signal.
9. The half bridge GaN circuit of claim 8 , wherein the high side circuit further comprises a receiver circuit configured to receive the pulses and to generate a receiver output signal configured to control an output state of the high side switch driver based on the pulses.
10. The half bridge GaN circuit of claim 9 , wherein the low side switch driver comprises a pulse generator configured to generate a low side pulse in response to a signal causing the low side switch to become non-conductive, and to transmit the low side pulse to the level shift circuit, and wherein the level shift circuit is configured to, in response to receiving the low side pulse, generate a blanking signal.
11. The half bridge GaN circuit of claim 10 , wherein the receiver circuit is configured to, in response to receiving the blanking signal, generate a signal causing the high side switch to be nonconductive.
12. The half bridge GaN circuit of claim 8 , wherein each of the pulses are generated in response to the second input transitioning from a high logic state to a low logic state.
13. A half bridge GaN circuit, comprising:
a low side circuit, comprising:
a low side switch comprising a low side switch control gate, a first source, and a first drain, and
a low side switch driver, configured to control a conductivity state of the low side switch according to a first input signal;
a high side circuit, comprising:
a high side switch comprising a high side switch control gate, a second source, and a second drain, wherein the second source is connected to the first drain, and
a high side switch driver referenced to a voltage at the second source, wherein the high side switch driver is configured to control a conductivity state of the high side switch according to a second input signal, and
a trigger circuit configured to, in response to a voltage of a first power supply referenced to the voltage of the second source being less than a threshold greater than the voltage of the second source, cause the high side switch to turn-off,
wherein the low side circuit further comprises a level shift circuit configured to receive the second input signal and to generate a level shift signal configured to control an output state of the high side switch driver.
14. The half bridge GaN circuit of claim 13 , wherein the high side circuit further comprises a receiver circuit configured to receive the level shift signal and to generate a receiver output signal configured to control the output state of the high side switch driver.
15. The half bridge GaN circuit of claim 14 , wherein the low side switch driver comprises a pulse generator configured to generate a pulse in response to signal a causing the low side switch to become non-conductive, and to transmit the pulse to the level shift circuit, and the level shift signal is configured to, in response to receiving the pulse, generate a blanking signal.
16. The half bridge GaN circuit of claim 15 , wherein the receiver circuit is configured to, in response to receiving the blanking signal, generate a signal causing the high side switch to be nonconductive.
17. The half bridge GaN circuit of claim 13 , wherein the level shift signal comprises a pulse generated in response to the second input transitioning from a high logic state to a low logic state.