Charging of secondary cells (accumulators) with regulated input current

• US 8,928,285 B2
• Filed: 04/24/2012
• Issued: 01/06/2015
• Est. Priority Date: 05/05/2011
• Status: Active Grant

• Current Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Original Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Inventors: Allgaier, Volker, Isenmann, Andreas, Griessbaum, Karl
• Primary Examiner(s): Whitmore, Stacy
• Application Number:
  US13/454,633
• Publication Number:
  US 20130106358A1
• Time in Patent Office: 987 Days
• Field of Search: 320/128, 320/132, 320134-137, 320162-165, 424/426, 424/429
• US Class Current: 320/128
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence

Abstract

Stated is a charging-current regulating device for charging an energy storage device for a field device, and for regulating a charging current for the energy storage device, wherein regulating the charging current for the energy storage device takes place in such a manner that a limiting value relating to an input current of the field device is not exceeded. Regulating the charging current may take place in such a manner that energy storage takes place as quickly as possible and without overloading an input protection circuit of the field device.

Claims

1. A field device, comprising:

an input protection circuit limiting an input current load of the field device to a specifiable input current I_E;

at least one electrical consumer;

an energy storage device supplying the electrical consumer with electrical power and a current draw I_V;

a charging circuit supplying the energy storage device with energy so that the energy storage device stores the supplied energy; and

a charging-current regulating device regulating a charging current I_L fed to the charging circuit for charging the energy storage device so that a limiting value relating to the input current I_E that flows through the input protection circuit is not exceeded,

wherein a sum of the charging current I_L fed to the charging circuit and the current draw I_V of the electrical consumer corresponds to the input current I_E of the input protection circuit.

2. The field device according to claim 1, wherein the energy storage device is a unit of rechargeable batteries and wherein the unit of rechargeable batteries includes at least one rechargeable battery.

3. The field device according to claim 1, wherein the electrical consumer is a fill-level measuring device.

4. The field device according to claim 1, wherein the electrical consumer is a flow measuring device.

5. The field device according to claim 1, wherein the electrical consumer is a pressure measuring device.

6. The field device according to claim 1, wherein the current draw I_V of the electrical consumer is altered in such a manner that the charging current I_L follows a specifiable value.

7. The field device according to claim 6, wherein the specifiable value relating to the charging current I_L is kept constant.

8. The field device according to claim 1, wherein the charging-current regulating device includes a current sensing resistor R;

an operational amplifier;

a switching regulator;

wherein the input current I_E flows through the current sensing resistor R, and consequently a corresponding voltage U_R drops at the current sensing resistor R;

wherein the operational amplifier is operated with the voltage U_R as the input voltage;

wherein an output voltage of the operational amplifier is fed to the switching regulator and controls the switching regulator in such a manner that a pick-up current I_L or an output current I_A of the switching regulator can be altered; and

wherein the switching regulator is controlled by the operational amplifier in such a manner that the pick-up current I_L or the output current I_A of the switching regulator is altered in such a manner that the input current I_E flowing through the current sensing resistor R does not exceed the limiting value of the input current I_E.

9. The field device according to claim 8, wherein the operational amplifier is switched as a differential amplifier so that a voltage differential present at two inputs of the operational amplifier is output, weighted by an amplification factor, at an output of the operational amplifier.

10. The field device according to claim 8, wherein the current sensing resistor R is an ohmic resistor.