Battery power supply for radiofrequency transmitter

Abstract

The invention relates to a power supply device for an RF transmitter (5), that comprises at least one battery (2) and a capacitor (3) electrically connected in parallel between the battery (2) and the RF transmitter (5), and a voltage elevator (4') for charging the capacitor (3) to a storage voltage (Vc) higher than the voltage supplied by the battery during a first charging period, wherein the voltage elevator (4') includes an inductor (L) and a diode (D) in series as well as a switch (40') capable of periodically controlling, during the charging phase, the energy build-up in the inductor (L) followed by a transfer of the accumulated energy in the capacitor (3). According to the invention, the control signal (Sc) of the switch is predetermined and has a variable period so as to control, for each period: the closing of the switch (40') for a fixed calculated period so that the current in the inductor (L) may increase from a value equal to zero up to a predetermined limit value; the opening of the switch (40') for a duration that varies as a function of the voltage (Vc) of the capacitor (3), defined so that the current in the inductor (L) may decrease from said predetermined limit value down to a value equal to zero.

Description

technical field [0001] The present invention relates to a radio frequency (RF) transmitter module powered by means of at least one battery. [0002] One field of application where the present invention is particularly applicable is (but not limited to) wireless modules for remote reading of energy meters, be they water, heat, gas or electricity meters. Background technique [0003] In this application area, the average power consumption is kept fairly low, which generally enables the use of small size, small capacity batteries, such as 3.6 Volt (V) AA batteries. However, when the module transmits an RF signal, the battery must be able to deliver a relatively large instantaneous current (on the order of several hundred milliamps (mA)) for a short period of time (eg, on the order of 1 minute). The power required at this moment may not be compatible with the use of small size, small capacity batteries, and a compromise must often be found between the power to be delivered, the...

AI Technical Summary

Problems solved by technology

In addition to the fact that the cost of the power supply equipment is increased due to the addition of additional components, current generators or current limiters add losses which reduce the efficiency of power transfer

[0022] Some known boost converters include current limiting, however these are few in number and they are more expensive

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