Electronic circuit with a current ripple filter

• US 9,971,315 B2
• Filed: 04/10/2012
• Issued: 05/15/2018
• Est. Priority Date: 04/10/2012
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Olsson, Jrgen, Appelberg, Mikael, Svensson, Martin
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Dhillon, Jagdeep
• Application Number:
  US14/385,330
• Publication Number:
  US 20150061411A1
• Time in Patent Office: 2,226 Days
• Field of Search: 307131, 307 52, 307 49, 307 66, 307 64, 307 86, 307 82, 327552, 327559, 327134, 330127, 315201, 315291, 323282, 323299
• CPC Class Codes: G05B 9/02 electric
• CPC Class Codes: H02J 1/02 Arrangements for reducing harmonics or ripples
• CPC Class Codes: H02J 3/01 Arrangements for reducing harmonics or ripples
• CPC Class Codes: H02M 1/15 using active elements
• CPC Class Codes: H03G 1/00 Details of arrangements for controlling amplification
• CPC Class Codes: H03H 7/0107 Non-linear filters
• CPC Class Codes: Y02E 40/40 Arrangements for reducing harmonics

Abstract

An electronic circuit comprising an ACRF comprising an active component, an energy storage unit, an input port and an output port. The electronic circuit comprises a control unit to control the ACRF. A detector detects a short circuit at the input port or the absence of an energy supply at the input port. The control unit controls the ACRF to function as an ACRF if the detector detects a power supply connected to the input port or that there is no short circuit at the input port, and controls the ACRF to stop functioning as an ACRF and to discharge energy from its energy storage unit to its output port if the detector detects a short circuit at the input port or no power supply connected to the input port.

Claims

1. An electronic circuit comprising:

an active current ripple filter (ACRF), the ACRF comprising one or more active components and an energy storage unit, and an input port and an output port,

a control unit connected to and arranged for the control of the ACRF,

a first detector connected to the control unit and arranged to detect a short circuit at the ACRF'"'"'s input port or the absence of an energy supply at the ACRF'"'"'s input port,

the control unit being arranged to control the ACRF to function as an ACRF if the first detector detects that there is a power supply connected to the ACRF'"'"'s input port or that there is no short circuit at the ACRF'"'"'s input port, wherein functioning as an ACRF means regulating an output current level at the input port,

the control unit being arranged to control the ACRF to stop functioning as an ACRF and to discharge energy from its energy storage unit to its output port if the first detector detects that there is a short circuit at the ACRF'"'"'s input port or that there is no power supply connected to the ACRF'"'"'s input port,

wherein the energy storage unit includes a capacitor,

the ACRF further comprising a first transistor and a second transistor connected in parallel with the capacitor.

2. The electronic circuit of claim 1, further comprising a second detector for measuring an amplitude of a current at the ACRF'"'"'s input port, said second detector being connected to the control unit, the control unit being arranged to control the level of a current at the ACRF'"'"'s output port based on the measurements from the second detector when the ACRF is controlled to function as an ACRF.

3. An electronic circuit comprising:

an input port comprising two connections between which a voltage may be applied;

an output port comprising two connections between which a voltage may appear;

an active current ripple filter (ACRF), the ACRF including;

a first FET transistor and a second FET transistor, wherein a drain of the first FET transistor is connected to a source of the second FET transistor;

an energy store capacitor, wherein the first and second FET transistors are connected in parallel to the energy store capacitor; and

an inductor having first and second ends, wherein the first tend of the inductor is connected between the drain of the first FET transistor and the source of the second FET transistor and the second end of the inductor is connected to one of the two connections of the output port;

a first detector for detecting voltage, the first detector located between the input port and the ACRF;

a second detector for detecting current, the second detector located between the first detector and the ACRF;

a ripple filter capacitor located between the first detector and the second detector and for filtering frequencies above a threshold frequency; and

a digital switch-mode controller (DSMC) connected to the ACRF, wherein the DSMC is configured to;

1) control the ACRF to inject current if a current at the input port is detected to increase at more than a first rate;

2) control the ACRF to sink current if the current at the input port is detected to decrease at more than a second rate; and

3) control the ACRF to act as an Automatic Hold Up (AHU) instead of as an ACRF if the first detector detects that there is a short circuit at the ACRF'"'"'s input port or that there is no power supply connected to the ACRF'"'"'s input port is detected.

4. The electronic circuit of claim 3, wherein the control unit is configured to inject current by increasing a duty cycle of the second FET transistor and decreasing a duty cycle of the first FET transistor, thereby causing current from the ACRF, through the inductor, to increase.

5. The electronic circuit of claim 3, wherein the control unit is configured to sink current by decreasing a duty cycle of the second transistor and increasing a duty cycle of the first transistor, thereby causing current into the ACRF, through the inductor, to increase.