Constant current limiting protection for series coupled power supplies
View Patent ↗A control circuit for controlling multiple power supplies having their outputs coupled in series is configured to in response to an output current reaching a defined current threshold of a power supply of the power supplies, control the power supply to operate in its constant current mode so that the output current is regulated at the defined current threshold as the remaining power supplies operate in their constant voltage mode, and in response to the output voltage of the power supply reaching a defined voltage threshold, control the power supply to operate in its constant voltage mode so that the power supply provides a first regulated output voltage to its output as the remaining power supplies provide a second regulated output voltage different than the first regulated output voltage to their output. Various other systems, power supplies, control circuit and methods are also disclosed.
1. A power supply system comprising:
a plurality of power supplies configured to provide an output current to a load, each power supply of the plurality of power supplies configured to operate in a constant current mode and a constant voltage mode, said each power supply including a defined current threshold, a defined voltage threshold, and an output for providing an output voltage, the outputs of the plurality of power supplies coupled in series; and
a control circuit coupled to said each power supply, the control circuit configured to:
control the plurality of power supplies to operate in their constant voltage mode allowing the output current of the plurality of power supplies to vary;
in response to the output current of the plurality of power supplies reaching the defined current threshold of one power supply of the plurality of power supplies, control said one power supply to operate in its constant current mode, while the other one or more power supplies of the plurality of power supplies remain operating in their constant voltage mode, so that the output current of the plurality of power supplies is regulated at the defined current threshold of said one power supply; and
in response to the output voltage of said one power supply reaching its defined voltage threshold, control said one power supply to operate again in its constant voltage mode so that said one power supply provides a first regulated output voltage to its output as the remaining one or more power supplies of the plurality of power supplies provide a second regulated output voltage different than the first regulated output voltage to their output(s).
2. The power supply system of claim 1 wherein the control circuit is configured to initially control said each power supply to operate in its constant voltage mode so that said each power supply provides the second regulated output voltage to its output.
3. The power supply system of claim 1 wherein the control circuit is configured to control another power supply of the plurality of power supplies to operate in its constant current mode so that the output current is regulated at the defined current threshold of said another power supply in response to the output current reaching the defined current threshold of said another power supply of the plurality of power supplies.
4. The power supply system of claim 3 wherein the defined current threshold of said another power supply is different than the defined current threshold of said one power supply.
5. The power supply system of claim 3 wherein the control circuit is configured to control said another power supply to operate again in its constant voltage mode in response to the output voltage of said another power supply reaching its defined voltage threshold.
6. The power supply system of claim 1 wherein the control circuit includes a plurality of current control loops and a plurality of voltage control loops corresponding to the plurality of power supplies and wherein each voltage control loop includes a voltage reference for regulating the output voltage of its corresponding power supply.
7. The power supply system of claim 6 wherein the current control loop and the voltage control loop corresponding to said one power supply are configured to operate at the same time.
8. The power supply system of claim 6 wherein the voltage reference of said each voltage control loop is fixed when its corresponding power supply is operated in its constant voltage mode.
9. The power supply system of claim 6 wherein the voltage reference of said each voltage control loop is fixed when its corresponding power supply is operated in its constant voltage mode and wherein the voltage reference of said each voltage control loop is adjustable when its corresponding power supply is operated in its constant current mode.
10. The power supply system of claim 9 wherein the voltage reference of said each voltage control loop is adjustable based on an output of its corresponding current control loop.
11. The power supply system of claim 9 wherein the voltage reference of said each voltage control loop is adjusted lower when its corresponding power supply is operated in its constant current mode.
12. The power supply system of claim 1 wherein the second regulated output voltage of said one power supply is greater than the first regulated output voltage.
13. The power supply system of claim 1 wherein the control circuit includes a digital controller.
14. The power supply system of claim 1 wherein said one power supply includes at least one power switch and wherein the control circuit is configured to control the at least one power switch.
15. The power supply system of claim 14 wherein the control circuit is configured to control the at least one power switch of said one power supply based on a sawtooth signal.
16. The power supply system of claim 15 wherein the sawtooth signal represents a ramp signal when said one power supply is operated in its constant voltage mode.
17. The power supply system of claim 16 wherein the sawtooth signal represents a switching current of said one power supply when said one power supply is operated in its constant current mode.
18. A control circuit for controlling a plurality of power supplies configured to provide an output current to a load, each power supply of the plurality of power supplies configured to operate in a constant current mode and a constant voltage mode, said each power supply including a defined current threshold, a defined voltage threshold, and an output for providing an output voltage, the outputs of the plurality of power supplies coupled in series, the control circuit configured to:
control the plurality of power supplies to operate in their constant voltage mode allowing the output current of the plurality of power supplies to vary;
in response to the output current of the plurality of power supplies reaching a defined current threshold of one power supply of the plurality of power supplies, control said one power supply to operate in its constant current mode, while the other one or more power supplies of the plurality of power supplies remain operating in their constant voltage mode, so that the output current of the plurality of power supplies is regulated at the defined current threshold of said one power supply; and
in response to the output voltage of said one power supply reaching its defined voltage threshold, control said one power supply to operate again in its constant voltage mode so that said one power supply provides a first regulated output voltage to its output as the remaining one or more power supplies of the plurality of power supplies provide a second regulated output voltage different than the first regulated output voltage to their output(s).
19. The control circuit of claim 18 wherein the control circuit is configured to control another power supply of the plurality of power supplies to operate in its constant current mode so that the output current is regulated at the defined current threshold of said another power supply in response to the output current reaching the defined current threshold of said another power supply of the plurality of power supplies.
20. The control circuit of claim 19 wherein the control circuit is configured to control said another power supply to operate again in its constant voltage mode in response to the output voltage of said another power supply reaching its defined voltage threshold.
21. A power supply system comprising:
a plurality of power supplies configured to provide an output current to a load, each power supply of the plurality of power supplies configured to operate in a constant current mode and a constant voltage mode, said each power supply including a defined current threshold and an output for providing an output voltage, the outputs of the plurality of power supplies coupled in series; and
a control circuit coupled to said each power supply, the control circuit configured to in response to the output current of the plurality of power supplies reaching a defined current threshold of one power supply of the plurality of power supplies, control said one power supply to operate in its constant current mode, while the other one or more power supplies of the plurality of power supplies operate in their constant voltage mode, so that the output current of the plurality of power supplies is regulated at the defined current threshold of said one power supply.
22. The power supply system of claim 21 wherein the control circuit is configured to initially control said each power supply to operate in its constant voltage mode so that said each power supply provides the second regulated output voltage to its output.
23. The power supply system of claim 21 wherein the control circuit is configured to control another power supply of the plurality of power supplies to operate in its constant current mode so that the output current is regulated at the defined current threshold of said another power supply in response to the output current reaching the defined current threshold of said another power supply of the plurality of power supplies.
24. The power supply system of claim 21 wherein the control circuit includes a plurality of current control loops and a plurality of voltage control loops corresponding to the plurality of power supplies and wherein each voltage control loop includes a voltage reference for regulating the output voltage of its corresponding power supply.
25. The power supply system of claim 24 wherein the current control loop and the voltage control loop corresponding to said one power supply are configured to operate at the same time.
26. The power supply system of claim 25 wherein the voltage reference of said each voltage control loop is fixed when its corresponding power supply is operated in its constant voltage mode, and wherein the voltage reference of said each voltage control loop is adjustable when its corresponding power supply is operated in its constant current mode.
27. The power supply system of claim 21 wherein said one power supply includes at least one power switch, and wherein the control circuit is configured to control the at least one power switch based on a sawtooth signal.