Circuit arrangement and method for detecting a charge

• US 8,547,067 B2
• Filed: 09/24/2010
• Issued: 10/01/2013
• Est. Priority Date: 03/19/2009
• Status: Active Grant

• Current Assignee: Braun GmbH (The Procter & Gamble Company)
• Original Assignee: Braun GmbH (The Procter & Gamble Company)
• Inventors: Faranda, Leo, Skopp, Frank Stefan, Klemm, Torsten
• Primary Examiner(s): Fantu, Yalkew
• Application Number:
  US12/889,729
• Publication Number:
  US 20110012567A1
• Time in Patent Office: 1,103 Days
• Field of Search: 320/132
• US Class Current: 320/132
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters

Abstract

A circuit arrangement that has an energy source that can provide a charging voltage for charging an electrical energy storage unit in a charging circuit when it is connected to an energy supply, wherein it is possible to represent the charging voltage using an alternating quantity, and that has a capacitor circuit having a first capacitor element, a first valve element, and the energy source, wherein the first capacitor element is charged by the energy source via the first valve element if the charging voltage is negative, so that, if the charging voltage is positive, the voltage over the first capacitor element has the same orientation in the capacitor circuit, in terms of sign, as the charging voltage, and the voltage over the capacitor element.

Claims

1. A circuit arrangement having:

an AC energy source that can provide an alternating charging voltage for charging an electrical energy storage unit in a charging circuit when the electrical energy storage unit is connected to an energy supply, wherein the alternating charging voltage is represented by an alternating quantity;

and having a capacitor circuit having a first capacitor element, a first valve element, and the energy source, wherein the first capacitor element is charged by the energy source via the first valve element if the charging voltage is negative, so that if the charging voltage is positive, the voltage over the first capacitor element has the same orientation in the capacitor circuit, in terms of sign, as the charging voltage, and the voltage over the capacitor element and the energy source can be detected using a control apparatus.

2. The circuit arrangement according to claim 1, further including a second valve element arranged between a direct voltage and the first valve element that limits the voltage over the energy source and the capacitor element to the sum of the direct voltage and the forward voltage of the second valve element.

3. The circuit arrangement according to claim 1, wherein when the charging voltage is negative and the voltage over the first valve element is limited to the forward voltage of the first valve element.

4. The circuit arrangement according to claim 2, further having a control apparatus for detecting the voltage over the capacitor element and the energy source.

5. The circuit arrangement according to claim 1, wherein the energy source comprises a coil element that can be used to connect energy.

6. The circuit arrangement according to claim 1, further including a third valve element arranged in the charging circuit for rectifying the charging voltage, wherein the capacitor circuit is arranged upstream of the third valve element in the direction of the charging current.

7. The circuit arrangement according to claim 1, wherein a first resistor element is arranged in the capacitor circuit for limiting the charging flux in the capacitor circuit.

8. The circuit arrangement according to claim 1, further including a second valve element, wherein at least one of the first valve element and the second valve element is arranged within the control apparatus.

9. The circuit arrangement according to claim 1, wherein the first valve element includes a Zener diode.

10. The circuit arrangement according to claim 1, further including a pull down element arranged parallel to the first valve element over which the first capacitor element may be discharged if the circuit arrangement is not connected to the energy supply.

11. The circuit arrangement according to claim 1, further including a voltage converter for supplying the control apparatus.

12. The circuit arrangement according to claim 1, wherein the capacitor circuit includes a fourth valve element in series with the first capacitor element, and a second capacitor element parallel to the first valve element.

13. The circuit arrangement according to claim 1, wherein the circuit arrangement is arranged in a small electrical device and the energy storage unit is a battery.

14. The circuit arrangement according to claim 1, further including a controllable circuit element for switching the charging current disposed in the charging circuit.

15. A method for charge detection in a circuit arrangement having an AC energy source that provides an alternating charging voltage (V_L) for charging an electrical energy storage unit in a charging circuit when it is connected to an energy supply, wherein the alternating charging voltage (V_L) is represented by an alternating quantity, wherein a first capacitor element is charged by the energy source via a first valve element when the charging voltage (V_L) is negative, so that when the charging voltage (V_L) is positive, the voltage (U_BA) over the first capacitor element has the same orientation in the capacitor circuit, in terms of sign, as the charging voltage (V_L), and the voltage (U_CD) over the capacitor element and the energy source can be detected using a control apparatus.

16. The method according to claim 15, wherein a second valve element is disposed between a direct current and the first valve element and limits the voltage over the energy source and the capacitor element to the sum of the voltage for the direct voltage and the forward voltage of the second valve element.

17. The method according to claim 15, wherein the voltage over the capacitor element and the energy source is detected by a control apparatus.

18. The method according to claim 15, wherein the charging voltage is rectified by a third valve element.

19. The method according to claim 15, wherein the first capacitor element is discharged when the circuit arrangement is not connected to the energy supply via a pull down element that is arranged parallel to the first valve element.

20. The method according to claim 15 used in a small electrical device.