APPARATUS FOR RECHARGING AN EMERGENCY BATTERY

• US 3,735,234 A
• Filed: 04/26/1972
• Issued: 05/22/1973
• Est. Priority Date: 04/30/1971
• Status: Expired due to Term

• Current Assignee: Pierre Godard
• Original Assignee: Pierre Godard
• Inventors: Godard, Pierre
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/247,684
• Time in Patent Office: 391 Days
• Field of Search: 320/43-45,37,38,31,32,20,22 307/66
• US Class Current: 320/135
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 9/00 Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting

Abstract

Battery emergency charging device comprising a memory accumulator charged with an intensity proportional to the battery discharge intensity, characterized in that the discharge circuit of the memory accumulator comprises means for making the memory accumulator discharge intensity proportional to the battery charge intensity.

Claims

1. Device for recharging an emergency storage battery used in the event of breakdown of a normal supply circuit to said load comprising an alternating-current supply system, a charger associated with said system and having input terminals connected to the said alternating-current supply system and output terminals connected in a charging circuit to the said battery, the said charger having a high charging rate and a low charging rate, a memory accumulator, of low capacity in relation to the capacity of said storage battery and adapted to be charged from the storage battery during the periods of interruption of the alternating-current from supply circuit and to set, during the time of its discharge in a discharge circuit, the charge of the storage battery at the high rate, and further comprising means for producing a voltage proportional to current supplied by the battery to the load, an electronic direct-current amplifier for the amplifIcation of said voltage, and means for converting it into a direct charging current whose intensity is proportional to the said voltage even at the low values of the said voltage, the said direct charging current passing through the said memory accumulator for the purpose of charging it proportionally to the current supplied by the storage battery, and only when the latter feeds into the load, and comprising finally means to ensure that the discharge intensity of the memory accumulator is proportional to the charging intensity of the storage battery.

2. Device according to claim 1, in which the said last-named means comprise a device for detecting the charging intensity of the battery in its charging circuit and supplying a signal proportional to the said intensity, the said signal acting on an impedance in the discharge circuit of the memory accumulator.

3. Device according to claim 2, in which the said detecting means comprises a shunt inserted in the charging circuit of the storage battery for controlling the discharge circuit of said memory accumulator, the said signal, consisting of the voltage across the terminals of the shunt and amplifying means for said voltage.

4. Device according to claim 3, in which the said discharge circuit comprises a variable resistance consisting of a first transistor controlled as a function of the voltage across the terminals of the shunt.

5. Device according to claim 4, in which a second transistor, arranged as a diode, in thermal contact with the first transistor, is connected to the first transistor in such manner that its voltage threshold is opposed to the voltage threshold of the first transistor.

6. Device according to claim 1, in which means are provided to modify the ratio of proportionality between the discharge current of the memory accumulator and the charging current of the storage battery after a change of the charging rate.

7. Device for recharging a storage battery, intended to feed a standby load via a discharge circuit, the said apparatus comprising a first shunt inserted in the electric discharge circuit of the said battery, which effects the transformation of the continuous current flowing through it into a continuous voltage applied to at least a first transistor stage or equivalent stage, which supplies the current which charges a small accumulator which performs the function of a memory and whose discharge in a second discharge circuit serves as a timing means for controlling the change from the high charging rate to the low charging rate of the battery, the said transistor stage comprising two transistors which effect a mutual temperature compensation, the said two transistors, one of which is used as a diode, being in mutual thermal contact, having their bases electrically connected and being connected in such manner that the emitter of the transistor employed as a diode is directly connected to one end of the said first shunt, while the emitter of the other transistor is connected through a first resistor to the other end of the said first shunt, with the result that the collector current of the transistor not employed as a diode, which charges the memory accumulator, is proportional to the discharge current of the battery which flows through the said first shunt, the said discharge circuit of the memory accumulator comprising a second shunt inserted in the electric circuit of the said battery, to the terminals of which there is connected the discharge circuit of the memory accumulator which latter circuit comprises in series the said memory accumulator, and a second transistor stage comprising a third transistor connected as a diode, whose emitter is connected to a first terminal of the second shunt, and a fourth transistor whose base is connected to the collector of the third transistor and whose emitter is connected to one end of a resistor whose other end is connected to the other terminal of the second shunt, the third and fourth transistors being in mutual thermal contact and temperature-cOmpensating one another, with the result that the discharge current of the memory accumulator is proportional to the charging current of the storage battery, a fifth transistor connecting a third resistor in parallel with the second transistor which has the effect of increasing the proportionality ratio between the discharge current of the memory accumulator and the charging current of the storage battery.

8. Recharging device according to claim 7, in which said fourth resistor is connected in series with the first transistor stage in order to drain the rest current from this stage.

9. Recharging device according to claim 7, which comprises said third transistor stage disposed between the first transistor stage and a terminal of the second shunt which connects a fourth resistor in series with the first transistor stage, the rest current of the first transistor stage flowing through the latter resistor when the said last-named stage is non-conductive, and the said resistor being eliminated when the first stage is conductive.