BATTERY POWER SUPPLY FOR RADIOFREQUENCY TRANSMITTER

• US 20100301829A1
• Filed: 01/08/2009
• Published: 12/02/2010
• Est. Priority Date: 01/25/2008
• Status: Abandoned Application

• Current Assignee: Itron France S.A.S. (Itron, Inc.)
• Original Assignee: Actaris SAS (Itron, Inc.)
• Inventors: Bulteau, Serge
• Application Number:
  US12/863,635
• Publication Number:
  US 20100301829A1
• Time in Patent Office: Days
• US Class Current: 323/304
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

The invention relates to a power supply device for an RF transmitter (5), the device comprising at least one battery (2) and at least one capacitor (3) electrically connected in parallel between the battery (2) and the RF transmitter (5), and voltage-raising means (4′) for charging the capacitor (3) to a storage voltage (V_C) higher than the voltage delivered by the battery during an initial charging stage, the voltage-raising means (4′) comprising an inductor (L) and a diode (D) in series, and associated with a switch (40′) suitable, during the storage stage, for periodically causing energy to be accumulated in the inductor (L) followed by transferring the accumulated energy into the capacitor (3). According to the invention, a switch-control signal (S_C) is predetermined and of variable period so as to act, during each period, to cause: the switch (40′) to close over a fixed duration that is calculated so as to enable the current flowing in the inductor (L) to increase from a value of zero up to a predefined limit value; and the switch (40′) to open over a duration that is variable and a function of the voltage (V_C) across the capacitor (3), the duration being defined in such a manner as to enable the current flowing in the inductor (L) to decrease from said predefined limit value to a value of zero.

Claims

1-4. -4. (canceled)

5. A power supply device for an RF transmitter module, the device comprising at least one battery and at least one capacitor forming an energy storage circuit electrically connected in parallel between the battery and the RF transmitter module, the power supply device also including voltage-raising means for charging the capacitor to a storage voltage that is higher than the voltage delivered by the battery during an initial charging stage, the voltage-raising means comprising an inductor (L) and a diode connected in series between the battery and the capacitor, and switch means suitable for acting during the initial charging stage to cause energy to be accumulated periodically in the inductor, and then to cause the accumulated energy to be transferred into the capacitor, the device also including a control module suitable for generating a control signal (S_C) for the switch means, firstly to disconnect the capacitor from the RF transmitter module during the initial capacitor-charging stage, and secondly to disconnect the voltage-raising means from the battery during a subsequent capacitor discharge stage, the device being characterized in that said control signal (S_C) is predetermined and of variable period, and is suitable, during each period, to cause:

said switch means to close over a fixed duration (T_ON) calculated so as to enable the current (I_L) flowing through the inductor to increase from a value of zero up to a predefined limit value (I_Lpeak); and

said switch means to open over a duration (T_OFF) that is variable and a function of the voltage (V_C) across the terminals of the capacitor, and that is defined in such a manner as to enable the current (I_L) flowing through the inductor to decrease from said predefined limit value (I_Lpeak) to a value of zero.

6. A power supply device according to claim 5, further including a controlled voltage regulator suitable for being connected in series between the capacitor and the RF transmitter module, said regulator reducing the stored voltage to a predetermined voltage value for powering the module during the discharge stage.

7. A power supply device according to claim 5, wherein said control module is adapted to trigger said charging stage immediately prior to delivering the current peak, at an instant that is soon enough before the current peak delivery instant to enable the capacitor to be charged completely.

8. A remote-reading module for an energy meter, including a power supply device according to claim 5.