SWITCHING POWER SOURCE APPARATUS AND CONTROL METHOD THEREOF

• US 20090051333A1
• Filed: 06/05/2008
• Published: 02/26/2009
• Est. Priority Date: 08/21/2007
• Status: Active Grant

• Current Assignee: S-Printing Solution Co., Ltd. (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Jong-moon, Jung, Jee-hoon, JO, Sung-jo
• Granted Patent: US 8,030,906 B2
• Time in Patent Office: Days
• US Class Current: 323/235
• CPC Class Codes: H03K 17/0406 in composite switches
• CPC Class Codes: H03K 17/08148 in composite switches
• CPC Class Codes: H03K 17/168 in composite switches
• CPC Class Codes: H03K 17/567 Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT

Abstract

A switching power source apparatus includes a storage unit to store energy obtained from input power supplied to the storage unit, and to output at least of the stored energy as output power; a first switch; a second switch connected in series with the first switch, the series connection of the first switch and the second switch being connected to the storage unit; and a voltage clamp unit to clamp a level of a voltage applied across the series connection of the first switch and the second switch to a predetermined voltage or less. The first switch is turned on while the second switch is still turned off, and then the second switch is turned on after the first switch has been turned on to supply the input power to the storage unit from the series connection of the first switch and the second switch.

Claims

1. A switching power source apparatus, comprising:

a storage unit to store energy obtained from input power supplied to the storage unit, and to output at least some of the stored energy as output power;

a first switch;

a second switch connected in series with the first switch, the series connection of the first switch and the second switch being connected to the storage unit; and

a voltage clamp unit to clamp a level of a voltage applied across the series connection of the first switch and the second switch to a predetermined voltage or less;

wherein to supply the input power to the storage unit, the first switch is turned on while the second switch is still turned off, and then the second switch is turned on after the first switch has been turned on to supply the input power to the storage unit from the series connection of the first switch and the second switch.

2. The switching power source apparatus of claim 1, wherein the second switch has a withstanding voltage equal to or greater than a predetermined value that is high enough to withstand a maximum voltage applied across the series connection of the first switch and the second switch during operation of the switching power source apparatus.

3. The switching power source apparatus of claim 2, wherein the first switch comprises a metal-oxide-semiconductor field-effect transistor (MOSFET).

4. The switching power source apparatus of claim 3, wherein the second switch comprises a bipolar junction transistor (BJT).

5. The switching power source apparatus according to claim 4, wherein:

the MOSFET comprises a drain terminal;

the BJT comprises an emitter terminal; and

the drain terminal of the MOSFET is connected to the emitter terminal of the BJT.

6. The switching power source apparatus of claim 1, wherein the voltage clamp unit comprises a diode connected to the series connection of the first switch and the second switch to conduct a current in a direction opposite to a direction of a current that flows from the series connection of the first switch and the second switch to the storage unit when the first switch and the second switch are turned on.

7. The switching power source apparatus of claim 6, wherein the diode is connected in parallel with the series connection of the first switch and the second switch.

8. The switching power source apparatus of claim 1, wherein turning off either the first switch or the second switch turns off the switching power source apparatus.

9. The switching power source apparatus of claim 1, wherein:

the first switch comprises a first capacitor;

the second switch comprises a second capacitor; and

the first capacitor and the second capacitor form a resonant circuit with the storage unit.

10. A method of controlling a switching power source apparatus, the switching power source apparatus comprising a storage unit to store energy obtained from input power supplied to the storage unit, and to output at least some of the stored energy as output power, a first switch, a second switch connected in series with the first switch, the series connection of the first switch and the second switch being connected to the storage unit, and a voltage clamp unit to clamp a level of a voltage applied across the series connection of the first switch and the second switch to a predetermined voltage or less, the method comprising:

clamping the level of the voltage applied across the series connection of the first switch and the second switch to a predetermined voltage or less with the voltage clamp unit;

turning on the first switch on while the second switch is still turned off; and

turning on the second switch after the first switch has been turned on to supply the input power to the storage unit from the series connection of the first switch and the second switch.

11. The method of claim 10, wherein the second switch has a withstanding voltage equal to or greater than a predetermined value that is high enough to withstand a maximum voltage applied across the series connection of the first switch and the second switch during operation of the switching power source apparatus.

12. The method of claim 11, wherein the first switch comprises a metal-oxide-semiconductor field-effect transistor (MOSFET).

13. The method of claim 12, wherein the second switch comprises a bipolar junction transistor (BJT).

14. The method of claim 13, wherein:

the MOSFET comprises a drain terminal;

the BJT comprises an emitter terminal; and

the drain terminal of the MOSFET is connected to the emitter terminal of the BJT.

15. The method of claim 10, wherein the voltage clamp unit comprises a diode connected to the series connection of the first switch and the second switch to conduct a current in a direction opposite to a direction of a current that flows from the series connection of the first switch and the second switch to the storage unit when the first switch and the second switch are turned on.

16. The method of claim 10, further comprising turning off either the first switch or the second switch to turn off the switching power source apparatus.

17. The method of claim 10, wherein:

the first switch comprises a first capacitor;

the second comprises a second capacitor; and

the first capacitor and the second capacitor form a resonant circuit with the storage unit.

18. A switching power source apparatus comprising:

a storage unit to store energy, and to output at least some of the stored energy;

a first switch having a first withstanding voltage; and

a second switch having a second withstanding voltage higher than the first withstanding voltage, the second switch being connected in series with the first switch, the series connection of the first switch and the second switch being connected to the storage unit;

wherein to supply the energy to the storage unit, the first switch is turned on while the second switch is still turned off and a voltage applied across the series connection of the first switch and the second switch is substantially zero, and then the second switch is turned on after the first switch has been turned on and while the voltage applied across the series connection of the first switch and the second switch is still substantially zero to supply the energy to the storage unit from the series connection of the first switch and the second switch.

19. The switching power source apparatus of claim 18, wherein the first withstanding voltage is not high enough to withstand a maximum voltage applied across the series connection of the first switch and the second switch during operation of the switching power source apparatus.

20. The switching power source apparatus of claim 18, wherein the second withstanding voltage is high enough to withstand a maximum voltage applied across the series connection of the first switch and the second switch during operation of the switching power source apparatus.

21. The switching power source apparatus of claim 18, wherein:

the first switch comprises a metal-oxide-semiconductor field-effect transistor (MOSFET); and

the second switch comprises a bipolar junction transistor (BJT).

22. The switching power source apparatus of claim 21, wherein:

the first switch further comprises a first capacitor;

the second switch further comprises a second capacitor; and

the first capacitor and the second capacitor form a resonant circuit with the storage unit.

23. The switching power source apparatus of claim 22, wherein:

the first switch further comprises a diode connected in parallel with the MOSFET; and

the diode is turned on by a resonant operation of the resonant circuit.

24. The switching power source apparatus of claim 22, wherein:

the storage unit comprises an inductance;

the first capacitor is connected in parallel with the MOSFET;

the second capacitor is connected in parallel with the BJT and in series with the first capacitor; and

the first capacitor and the second capacitor form the resonant circuit with the inductance of the storage unit.

25. The switching power source apparatus of claim 24, wherein:

the storage unit comprises a transformer having an inductance; and

the inductance of the transformer is the inductance of the storage unit that forms the resonant circuit with the first capacitor and the second capacitor.

26. The switching power source apparatus of claim 18, further comprising a voltage clamp unit to clamp the voltage applied across the series connection of the first switch and the second switch to a substantially zero voltage.

27. The switching power source apparatus of claim 26, wherein:

the voltage clamp unit comprises a diode connected across the series connection of the first switch and the second switch to conduct a current in a direction opposite to a direction of a current that flows from the series connection of the first switch and the second switch to the storage unit when the first switch and the second switch are turned on; and

the substantially zero voltage is a forward voltage of the diode.