ELECTRONIC DEVICE AND METHOD FOR TRACKING ENERGY CONSUMPTION

• US 20140253096A1
• Filed: 03/07/2013
• Published: 09/11/2014
• Est. Priority Date: 03/07/2013
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Diewald, Horst, Zipperer, Johann, Weber, Peter, Brauchle, Anton
• Granted Patent: US 9,146,263 B2
• Time in Patent Office: Days
• US Class Current: 324/103.R
• CPC Class Codes: G01R 21/00 Arrangements for measuring electric power or power factor G01R7/12 takes precedence
• CPC Class Codes: G01R 21/007 Adapted for special tariff measuring G01R21/01, G01R21/02, G01R21/08, G01R21/10, G01R21/1278 and G01R21/1333 take precedence
• CPC Class Codes: G01R 22/10 using digital techniques
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision

Abstract

The invention relates to an apparatus and method for tracking energy consumption. An energy tracking system comprises at least one switching element, at least one inductor and a control block to keep the output voltage at a pre-selected level. The switching elements are configured to apply the source of energy to the inductors. The control block compares the output voltage of the energy tracking system to a reference value and controls the switching of the switched elements in order to transfer energy for the primary voltage into a secondary voltage at the output of the energy tracking system. The electronic device further comprises an ON-time and OFF-time generator and an accumulator wherein the control block is coupled to receive a signal from the ON-time and OFF-time generator and generates switching signals for the at least one switching element in the form of ON-time pulses with a constant ON-time.

Claims

1. An electronic device comprising an energy tracking system, the energy tracking system comprising at least one switching element, at least one inductor, an voltage compare block, the at least one switching element being configured to switch a current through the at least one inductor and an energy tracking control block being configured to control the switching of the at least one switching element in order to transfer energy from a primary voltage applied at the input of the energy tracking system into a secondary voltage at the output of the energy tracking system, wherein the electronic device further comprises an ON-time and OFF-time generator, at least one control logic block and an accumulator wherein the at least one control logic block is coupled to receive a signal from the ON-time and OFF-time generator and to generate switching signals for the at least one switching element in the form of ON-time pulses with a constant ON-time, and wherein the accumulator is configured to collect the number of ON-time pulses for determining the consumed energy based on the number of ON-time pulses per time.

2. The energy tracking system of claim 1 further comprising a first capacitor coupled to the input of the energy transfer system;

wherein the ON-time of the at least one switching element, the value of the at least one inductance and the value of the first capacitor are configured so as to limit the energy taken from the energy source during each ON-time.

3. The energy tracking system of claim 1 further comprising a second capacitor coupled to the output of the energy transfer system wherein the energy in the at least one inductor and the value of the second capacitor are configured so as to keep the output voltage level of the energy transfer system during each OFF-time within the limits of the system requirements.

4. The energy tracking system of claim 1 wherein the ON-time is long enough to store at least enough energy in the at least one inductor to operate the maximum load applied at the output of the energy tracking system.

5. The energy tracking system of claim 1 wherein the OFF-time is long enough that substantially all energy stored in the energy transfer system during each ON-time pulse is transferred to the second capacitor.

6. The energy tracking system of claim 3 wherein when the output voltage of the energy tracking system falls below a predefined voltage level the drop in voltage is identified.

7. The energy tracking system of claim 3 wherein when the output voltage of the energy tracking system raises above a predefined voltage level the raise in voltage is identified.

8. The energy tracking system of claim 3 wherein the energy tracking system further comprises a reference resistor that is configured to be coupled to the output of energy tracking system for normalizing the energy determined based on the count of the pulses per time.

9. An electronic device comprising an energy tracking system, the energy tracking system comprising at least one energy transfer block and a control circuit wherein the control circuit is configured to control switching of energy in the at least one energy transfer block in order to transfer energy from a primary voltage applied at an input of the energy tracking system into a secondary voltage at the output of the energy tracking system;

wherein the control circuit comprises an ON-time and OFF-time generator, at least one control logic block and an accumulator wherein the at least one control logic block is coupled to receive a signal from the ON-time and OFF-time generator and to generate switching signals for the at least one energy transfer block in the form of ON-time pulses with a constant ON-time, and wherein the accumulator is configured to collect the number of ON-time pulses for determining the consumed energy based on the number of ON-time pulses per time.

10. The electronic device of claim 9 wherein the at least one energy transfer block comprises:

an inductor having a first terminal and a second terminal wherein the second terminal is connected to an output of the at least one energy transfer block;

a first switching element, the first switching element being connected to the control circuit, an input of the at least one energy transfer block and to the first terminal of the inductor.

11. The electronic device of claim 10 wherein the at least one transfer block further comprises:

a diode having a cathode and an anode wherein the cathode is connected to the first terminal of the inductor and the anode is connected to ground;

a second switching element, the second switching element being connected to the control circuit, the first terminal of the inductor and to ground.

12. A method of measuring power consumption of an electronic device, the electronic device comprising an energy tracking system, the energy tracking system comprising at least one switched transistor and at least one inductor wherein the at least one switched transistor is configured to switch a current through the at least one inductor and an error amplifier is configured to control the switching of the at least one switched transistor in order to convert a primary voltage applied at the input of the energy tracking system into a secondary voltage at the output of the energy tracking system, the method comprising the steps of:

switching the at least one switched transistor with pulses having a constant ON-time;

controlling the frequency of ON-time pulses in response to a change of the output voltage determined by the error amplifier;

determining the frequency of ON-time pulses; and

determining the power consumption based on the frequency of the ON-time pulses.

13. The method according to claim 12 wherein the current variation is derived from the variation of OFF-time frequency.

14. The method according to claim 12 wherein the charge transferred through the at least one switched transistor during an ON-time pulse is at least a factor of fifty smaller than a charge stored on a first capacitor coupled to the input of the energy tracking system and a charge stored on a second capacitor coupled to the output of the energy tracking system.

15. The method according to claim 12 further comprising the step of calibrating the energy consumption by coupling at least one reference impedance to the output of the energy tracking system.