Circuit arrangement and electrical appliance with an inductive load and a buck converter

• US 6,559,625 B2
• Filed: 08/13/2001
• Issued: 05/06/2003
• Est. Priority Date: 08/14/2000
• Status: Expired due to Term

• Current Assignee: Braum GmbH
• Original Assignee: Braun GmbH (The Procter & Gamble Company)
• Inventors: Heck, Ulrich, Schnak, Fred, Rönneberg, Gerrit, Kressmann, Frank, Freund, Dirk, Giersiepen, Martin, Harttmann, Brigitte, Hollinger, Stefan, Wunder, Dieter
• Primary Examiner(s): Vu, Bao Q.
• Application Number:
  US09/928,802
• Publication Number:
  US 20020021115A1
• Time in Patent Office: 631 Days
• Field of Search: 323/301, 323/266, 323/282, 323/299, 323/242, 323/222
• US Class Current: 323/282
• CPC Class Codes: H02M 3/155 using semiconductor devices only

Abstract

The invention is directed to a circuit arrangement with an inductive load and a buck converter, wherein the inductive load serves as coil, as well as to an electrical appliance with such a circuit arrangement.

Claims

1. A buck converter for supplying voltage to an electronic circuit, the buck converter comprising:

an inductive load provided by an electric motor;

an electronic switching device connected in series with the inductive load; and

a charge storage device in parallel with the electric motor and the electronic switching device, the charge storage device being charged via the inductive load, the electronic switching device controlling charging of the charge storage device by controlling a pulse duty cycle of current through the inductive load.

2. The buck converter of claim 1, wherein the inductive load serves as a coil to the buck converter.

3. The buck converter of claim 1 or 2, further comprising a control circuit to drive the electronic switching device.

4. The buck converter of claim 3, wherein the control circuit is adapted to be supplied with voltage from the charge storage device.

5. The buck converter of claim 3, wherein the electronic switching device is adapted to be turned on and off by the control circuit to thereby control the pulse duty cycle of current through the inductive load, wherein a ratio of turn-on duration to turn-off duration for the electronic switching device is within a range of 0.05 and 20.

6. The buck converter of claim 1, further comprising:

a charging diode, through which the inductive load charges the charge storage device.

7. The buck converter of claim 6, wherein the charging diode is a Schottky diode.

8. The buck converter of claim 6, wherein the charging diode is connected in series with the inductive load.

9. The buck converter of claim 6, further comprising:

a freewheeling diode connected to the inductive load to short-circuit induced voltage in the inductive load.

10. The buck converter of claim 9, wherein the inductive load charges the charge storage device to a voltage level that exceeds a battery voltage applied to the inductive load by no more than a difference of conducting state voltages of the charging diode and the freewheeling diode.

11. The buck converter of claim 6, further comprising:

a zener diode in parallel with the electronic switching device.

12. The buck converter of claim 1, wherein the charge storage device comprises a capacitor.

13. An electrical appliance comprising:

an electronic circuit; and

a buck converter, the buck converter comprising;

an inductive load provided by an electric motor;

an electronic switching device connected in series with the inductive load; and

a charge storage device in parallel with the electronic circuit, the charge storage device being charged via the inductive load, the electronic circuit controlling charging of the charge storage device by controlling the electronic switching device, the charge storage device supplying voltage to the electronic circuit.

14. The buck converter of claim 13, wherein the electronic switching device turns on and off to control the pulse duty cycle of current through the inductive load.

15. The buck converter of claim 13, wherein the inductive load serves as a coil to the buck converter.

16. The buck converter of claim 14, wherein the electronic switching device is adapted to be turned on and off by the electronic circuit to thereby control a pulse duty cycle of current through the inductive load, wherein a ratio of turn-on duration to turn-off duration for the electronic switching device is within a range of 0.05 and 20.

17. The buck converter of claim 13, further comprising:

a charging diode, through which the inductive load charges the charge storage device.

18. The buck converter of claim 17, wherein the charging diode is a Schottky diode.

19. The buck converter of claim 17 or 18, wherein the charging diode is connected in series with the inductive load.

20. The buck converter of claim 17, further comprising:

a freewheeling diode connected to the inductive load to short-circuit induced voltage in the inductive load.

21. The buck converter of claim 20, wherein the inductive load charges the charge storage device to a voltage level that exceeds a battery voltage applied to the inductive load by no more than a difference of conducting state voltages of the charging diode and the freewheeling diode.

22. The buck converter of claim 13, further comprising:

a zener diode in parallel with the electronic switching device.

23. The buck converter of claim 13, wherein the charge storage device comprises a capacitor.

24. The buck converter of claim 13, wherein the charge storage device does not supply voltage to the inductive load.

25. A buck converter circuit comprising:

an inductive load provided by an electric motor, the inductive load serving as a coil to the buck converter circuit; and

a charge storage device in parallel with the electric motor to provide power to an electronic circuit, the charge storage device being charged via the inductive load, wherein charging of the charge storage device is controlled by controlling a pulse duty cycle of current through the inductive load.

26. The buck converter circuit of claim 25, further comprising:

a charging diode, through which the inductive load charges the charge storage device.

27. The buck converter circuit of claim 25, further comprising:

a freewheeling diode connected to the inductive load to short-circuit induced voltage in the inductive load,

wherein the inductive load charges the charge storage device to a voltage level that exceeds a battery voltage applied to the inductive load by no more than a difference of conducting state voltages of the charging diode and the freewheeling diode.