Power supply unit, parallel operation control circuit applied thereto, and parallel operation control method

• US 6,014,322 A
• Filed: 06/26/1998
• Issued: 01/11/2000
• Est. Priority Date: 08/14/1997
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ikarashi, Yukio, Higashi, Shinya
• Primary Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US09/105,169
• Time in Patent Office: 564 Days
• Field of Search: 363/65, 363/67, 363/69, 363/70, 363/71, 363/74, 363/79, 363/80
• US Class Current: 363/65
• CPC Class Codes: H02J 1/001 Hot plugging or unplugging of load or power modules to or from power distribution networks
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence

Abstract

An anode voltage of a diode for reverse current prevention provided in each power supply module is output to a current balance control terminal via a resistor. The current balance control terminals of the respective power supply modules are mutually connected, and an average level of the anode voltages in the reverse current prevention diodes of the respective power supply modules is applied to the current balance control terminals as a reference voltage level. By executing the switching control for the power MOSFET in each power supply module so as to make the anode voltage of the reverse current prevention diode in each power supply module equal to the reference voltage, the output current values of the respective power supply modules are set to be equal.

Claims

1. A power supply unit having a plurality of parallel connected power supply modules, for driving a load by parallel outputs of the power supply modules, each of said plurality of power supply modules comprising:

a power supply output terminal connected commonly to said plurality of power supply modules;

a reverse current prevention element connected to said power supply output terminal; and

a voltage control circuit for controlling an input terminal voltage level of the reverse current prevention element of a same power supply module such that input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules are equal.

2. A unit according to claim 1, wherein said voltage control circuit compares an average level of the input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules with the input terminal voltage level of the reverse current prevention element of the same power supply module, and controls the input terminal voltage level of the reverse current prevention element in its own power supply module so as to reduce an error of said voltage levels.

3. A unit according to claim 2, wherein said reverse current prevention element comprises a diode having an input terminal connected to a voltage converter and an output terminal connected to said power supply output terminal.

4. A unit according to claim 2, wherein said reverse current prevention element comprises a transistor, a current path of said transistor is connected between a voltage converter and said power supply output terminal, and a switch control signal is supplied to a control terminal of said transistor to turn on/off said transistor.

5. A unit according to claim 4, wherein said transistor is a power MOSFET.

6. A unit according to claim 2, wherein each of said power supply modules is constituted to be freely detached from a main body of said power supply unit.

7. A power supply unit having a plurality of parallel connected power supply modules, for driving a load by parallel outputs from the power supply modules, each of said plurality of power supply modules comprising:

a power supply output terminal connected commonly to said plurality of power supply modules;

a voltage converter including a switching element;

a reverse current prevention element connected between said voltage converter and said power supply output terminal;

a voltage deriving terminal for commonly connecting an input terminal of the reverse current prevention element of a same power supply module with input terminals of reverse current prevention elements in the other power supply modules; and

a voltage control circuit for controlling an input terminal voltage level of the reverse current prevention element of the same power supply module such that input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules are equal,

said voltage control circuit including a comparator circuit for inputting a voltage level of said voltage deriving terminal as a reference voltage, comparing the reference voltage with the input terminal voltage level of the reverse current prevention element of the same power supply module and outputting an error between said voltage levels, and

said voltage control circuit controlling said switching element in accordance with the error.

8. A unit according to claim 7, wherein said reverse current prevention element comprises a diode having an input terminal connected to a voltage converter and an output terminal connected to said power supply output terminal.

9. A unit according to claim 7, wherein said reverse current prevention element comprises a transistor, a current path of said transistor is connected between said voltage converter and said power supply output terminal, and a switch control signal is supplied to a control terminal of said transistor to turn on/off said transistor.

10. A unit according to claim 9, wherein said transistor is a power MOSFET.

11. A unit according to claim 7, wherein each of said power supply modules is constituted to be freely detached from a main body of said power supply unit.

17. A unit according to claim 7, wherein said voltage control circuit compares an average level of the input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules with the input terminal voltage level of the reverse current prevention element of the same power supply module, and controls the input terminal voltage level of the reverse current prevention element of the same power supply module so as to reduce an error of said voltage levels.

12. A parallel operation control circuit, used in a power supply unit having a plurality of parallel connected power supply modules and driving a load by parallel outputs from said power supply modules, for controlling the parallel operation of said plurality of power supply modules, said circuit comprising:

a plurality of reverse current prevention elements provided respectively at power supply output terminals of said plurality of power supply modules; and

a voltage control circuit for controlling an input terminal voltage level of the reverse current prevention element of a same power supply module such that input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules are equal,

said voltage control circuit comparing an average level of the input terminal voltage levels in the reverse current prevention elements in said plurality of power supply modules with the input terminal voltage level of the reverse current prevention element in each of said power supply modules, and controlling the input terminal voltage level of the reverse current prevention element in each of said power supply modules in accordance with an error of said voltage levels.

13. A parallel operation control method for use in a power supply unit including a plurality of power supply modules connected in parallel via power supply output terminals and driving a load by parallel outputs of said power supply modules, said method comprising the steps of:

connecting reverse current prevention elements to said plurality of power supply output terminals, respectively; and

controlling an input terminal voltage level of the reverse current prevention element of a same power supply module such that the input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules are equal, in each of said plurality of power supply modules.

14. A method according to claim 13, wherein said controlling step includes a step of comparing an average level of input terminal voltage levels of reverse current prevention elements in said plurality of power supply modules with an input terminal voltage level of a reverse current prevention element of the same power supply module, in each of said plurality of power supply modules, and controlling the input terminal voltage level of the reverse current prevention element in its own power supply module so as to correct an error of the voltage levels.

15. A parallel operation control method for use in a power supply unit including a plurality of power supply modules connected in parallel via power supply output terminals and driving a load by parallel outputs of said power supply modules, said method comprising the steps of:

providing a voltage converter having a switching element in each of said plurality of power supply modules;

connecting a reverse current prevention element between said voltage converter and said power supply output terminal, in each of said plurality of power supply modules;

connecting commonly the input terminal of the reverse current prevention element of a same power supply module to the input terminals of the reverse current prevention elements in the power supply modules other than its own power supply module via voltage deriving terminals, in each of said plurality of power supply modules; and

providing in each of said plurality of power supply modules a comparator circuit for inputting a voltage level of said voltage deriving terminal as a reference voltage, comparing the reference voltage with a voltage level of the input terminal of the reverse current prevention element in its own power supply module and outputting an error of the voltage levels, so as to control said switching element in accordance with the error.

16. A power supply unit having a plurality of parallel connected power supply modules, for driving a load by parallel outputs of the power supply modules, each of said plurality of power supply modules comprising:

a power supply output terminal connected commonly to said plurality of power supply modules;

a reverse current prevention element connected to said power supply output terminal;

a voltage deriving terminal, connected commonly to said plurality of power supply modules, for deriving input terminal voltage levels of the reverse current prevention elements of other ones of said plurality of power modules; and

a voltage control circuit, which includes a resistor connected between an input terminal of the reverse current prevention element of a same power supply power module and said voltage deriving terminal, for controlling an input terminal voltage level of the reverse current prevention element of the same power supply power module to be equal to the derived voltage level of said voltage deriving terminal, in accordance with a voltage difference produced by said resistor.

18. A power supply unit having a plurality of parallel connected power supply modules, for driving a load by parallel outputs of the power supply modules, each of said plurality of power supply modules comprising:

a power supply output terminal connected commonly to said plurality of power supply modules;

a reverse current prevention element connected to said power supply output terminal; and

an analog voltage circuit for controlling an input terminal voltage level of the reverse current prevention element of a same power supply module such that input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules are equal.

19. A unit according to claim 18, wherein said analog voltage control circuit compares an average level of the input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules with the input terminal voltage level of the reverse current prevention element of the same power supply module, and controls the input terminal voltage level of the reverse current prevention element of the same power supply module so as to reduce an error of said voltage levels.

20. A unit according to claim 19, wherein said reverse current prevention element comprises a diode having an input terminal connected to a voltage converter and an output terminal connected to said power supply output terminal.

21. A unit according to claim 19, wherein said reverse current prevention element comprises a transistor, a current path of said transistor is connected between a voltage converter and said power supply output terminal, and a switch control signal is supplied to a control terminal of said transistor to turn on/off said transistor.

22. A unit according to claim 21, wherein said transistor is a power MOSFET.

23. A unit according to claim 19, wherein each of said power supply modules is constituted to be freely detached from a main body of said power supply unit.

24. A parallel operation control circuit, used in a power supply unit having a plurality of parallel connected power supply modules and driving a load by parallel outputs from said power supply modules, for controlling the parallel operation of said plurality of power supply modules, said circuit comprising:

a plurality of reverse current prevention elements provided respectively at power supply output terminals of said plurality of power supply modules; and

an analog voltage control circuit for controlling an input terminal voltage level of the reverse current prevention element of a same power supply module such that input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules are equal,

said analog control circuit comparing an average level of the input terminal voltage levels in the reverse current prevention elements in said plurality of power supply modules with the input terminal voltage level of the reverse current prevention element in each of said power supply modules, and controlling the input terminal voltage level of the reverse current prevention element in each of said power supply modules in accordance with an error of said voltage levels.

25. A parallel operation control method for use in a power supply unit including a plurality of power supply modules connected in parallel via power supply output terminals and driving a load by parallel outputs of said power supply modules, said method comprising the steps of:

connecting reverse current prevention elements to said plurality of power supply output terminals, respectively; and

controlling an input terminal voltage level of the reverse current prevention element of a same power supply module with an analog control circuit, such that the input terminal voltage levels of the reverse current prevention elements in said plurality of power supply modules are equal, in each of said plurality of power supply modules.

26. A method according to claim 25, wherein said controlling step includes a step of comparing an average level of input terminal voltage levels of reverse current prevention elements in said plurality of power supply modules with an input terminal voltage level of a reverse current prevention element of a same power supply module, in each of said plurality of power supply modules, and controlling the input terminal voltage level of the reverse current prevention element of the same power supply module so as to correct an error of the voltage levels.