High-frequency DC-DC converter control
View Patent ↗A high-frequency DC-DC converter. The high-frequency DC-DC converter comprises a resonant power stage and a controller to operate the resonant power stage. The resonant power stage is controlled by the controller with at least one of a variable frequency mode and a pulse width modulation mode to convert an input DC voltage to one of a higher output DC voltage and a lower output DC voltage.
1. A high-frequency DC-DC converter comprising:
a resonant power stage configured for variable frequency commutation control and for pulse width modulation duty cycle control; and
a controller to operate the power stage such that the commutation frequency and the duty cycle of the power stage are both varied in response to the amount of load connected to an output of the converter when the power delivered to the load is less than a predetermined threshold level, and such that the commutation frequency of the power stage is substantially fixed and the duty cycle is varied in response to the amount of load when the power delivered to the load is greater than the predetermined threshold level,
wherein the power stage is controlled by the controller to convert an input DC voltage to one of a higher output DC voltage and a lower output DC voltage.
2. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage includes a primary portion comprising four electronic switches arranged as a full-bridge switching converter.
3. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage includes a primary portion comprising four electronic switches arranged as a half-bridge switching converter.
4. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage includes a primary portion comprising four electronic switches arranged as a push-pull switching converter.
5. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage includes a secondary portion comprising four diodes arranged as a full-wave rectifier.
6. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage includes at least two electronic switches to select at least one of the variable frequency mode and the pulse width modulation mode.
7. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage is initially controlled at start-up by varying the frequency of the commutation of the resonant power stage, then controlling the commutation of the resonant power stage by pulse width modulation.
8. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage is a unidirectional resonant converter.
9. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage is a bidirectional resonant converter.
10. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage includes at least one of zero current switching and zero voltage switching.
11. The high-frequency DC-DC converter of claim 1 wherein the resonant power stage comprises an Alexander Topology.
12. A high-frequency DC-DC converter comprising:
a resonant power stage configured for variable frequency commutation control and for pulse width modulation duty cycle control, the power stage including a primary portion comprising four electronic switches arranged as a full-bridge switching converter and a secondary portion comprising four diodes arranged as a full-wave rectifier; and
a controller to operate the power stage such that the commutation frequency and the duty cycle of the power stage are both varied in response to the amount of load connected to an output of the converter when the power delivered to the load is less than a predetermined threshold level, and such that the commutation frequency of the power stage is substantially fixed and the duty cycle is varied in response to the amount of load when the power delivered to the load is greater than the predetermined threshold level,
wherein the resonant power stage is controlled by the controller to convert an input DC voltage to one of a higher output DC voltage and a lower output DC voltage.
13. A method for converting low-voltage DC to high-voltage DC comprising the steps of:
operating a power stage in resonance, the power stage being configured for variable frequency commutation control and for pulse width modulation duty cycle control; and
controlling the power stage such that the commutation frequency and the duty cycle of the power stage are both varied in response to the amount of load connected to an output of the converter when the power delivered to the load is less than a predetermined threshold level, and such that the commutation frequency of the power stage is substantially fixed and the duty cycle is varied in response to the amount of load when the power delivered to the load is greater than the predetermined threshold level, to convert an input DC voltage to one of a higher output DC voltage and a lower output DC voltage.
14. The method of claim 13 , further including the step of initially varying the frequency of the commutation of the power stage at start-up, then controlling the commutation of the power stage by pulse width modulation.
15. The method of claim 13 , further including the step of operating the resonant power stage as a unidirectional resonant converter.
16. The method of claim 13 , further including the step of operating the resonant power stage as a bidirectional resonant converter.
17. The method of claim 13 , further including the step of operating the resonant power stage with at least one of zero current switching and zero voltage switching.
18. The method of claim 13 , further including the step of operating the resonant power stage as a full-bridge switching converter.
19. The method of claim 13 , further including the step of operating the resonant power stage as a half-bridge switching converter.
20. The method of claim 13 , further including the step of operating the resonant power stage as a push-pull switching converter.