GB2036473A - A Current Regulator Circuit, in Particular for Charging an Emergency Power Supply Unit at Constant Current - Google Patents
A Current Regulator Circuit, in Particular for Charging an Emergency Power Supply Unit at Constant Current Download PDFInfo
- Publication number
- GB2036473A GB2036473A GB7940135A GB7940135A GB2036473A GB 2036473 A GB2036473 A GB 2036473A GB 7940135 A GB7940135 A GB 7940135A GB 7940135 A GB7940135 A GB 7940135A GB 2036473 A GB2036473 A GB 2036473A
- Authority
- GB
- United Kingdom
- Prior art keywords
- transistor
- current
- light bulb
- battery
- charging
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000007600 charging Methods 0.000 title claims abstract description 37
- 238000004804 winding Methods 0.000 claims abstract description 8
- 238000010277 constant-current charging Methods 0.000 abstract description 2
- 239000004020 conductor Substances 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000017105 transposition Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from AC mains by converters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J2207/20—Charging or discharging characterised by the power electronics converter
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
A circuit for charging a storage battery (10) at constant current by means of a transformer (T) whose primary winding (12) is connected to an AC mains (11) and whose secondary winding (13) feeds a rectifier bridge (14). The storage battery is connected, at the output of the rectifier bridge, in series with a resistor (15) and a light bulb (16). A transistor (18) has its emitter-collector circuit connected in series with a resistor (19) and this series connection is connected in parallel with the light bulb (11). The transistor base is biased by a voltage divider chain (20, 21) connected between one pole of the battery and the output of the rectifier bridge. While the bulb is in order it acts both as a pilot lamp and as a regulator device to ensure substantially constant current charging of the battery. The transistor is then off. If the bulb filament breaks, the transistor is biassed to become conductor to maintain adequate charging current through the battery. <IMAGE>
Description
SPECIFICATION
A Current Regulator Circuit, in Particular for
Charging an Emergency Power Supply Unit at
Constant Current
The present invention relates to a circuit for charging a storage battery at constant current, and in particular a storage battery for an
emergency power supply unit.
Known constant current charging circuits include a transformer whose primary winding is connected to an AC electric mains supply and whose secondary winding is connected, via a rectifier bridge, to the storage battery to be charged. A resistor and a light bulb are disposed in series with the battery. The light bulb is used simultaneously as a pilot light to indicate that the charging circuit is operating, and as a device for regulating the charging current as a function of the mains voltage.
When the filament of the pilot light breaks, the charging process is interrupted. However, specifications relating to emergency power supply units stipulate that charging shall not be interrupted. An attempt has been made to remedy the drawback caused by the breakage of a filament by disposing a resistor in parallel with the light bulb so as to provide circuit continuity in the event of light bulb failure.
This solution to the problem is not entirely satisfactory. Thus if the resistance of the resistor has low resistance, the light bulb no longer performs its regulator function, while if its resistance is high, the storage battery is insufficiently charged when the light bulb has failed.
Preferred embodiments of the present invention remedy the problem of light bulb failure by providing a circuit which can be used to regulate charging when the light bulb is in order, and to maintain adequate charging when the light bulb is out of order.
The present invention provides a current regulator circuit for connection in series between a battery to be charged and a source of charging current, the current regulator circuit comprising:
a main, current-regulating path comprising an incandescent light bulb connected in series with a charging current limiting resistor;
a voltage divider chain connected in parallel with the main path; and
an auxiliary charging current path connected in parallel with the light bulb, the auxiliary charging current path comprising the emitter-collector circuit of a transistor with the emitter of the transistor being connected to the charging current limiting resistor of the main path and the base of the transistor being connected to a point on the voltage divider chain to bias the transistor in such a manner that when the light bulb is conductive the transistor is non-conductive and when the light bulb is open circuit the transistor is conductive to charge the battery with unregulated current.
The auxiliary charging current path preferable includes an auxiliary resistor connected in series with the collector of the transistor, the resistance value of the auxiliary resistor being chosen so that, when the transistor is conductive, the current flowing through the transistor is limited by the auxiliary resistor rather than by the baseemitter potential of the transistor.
The invention also provides a battery charger circuit incorporating the above-defined current regulator circuit.
An embodiment of the invention is described with reference to the accompanying drawing in which the single figure illustrates the circuit diagram of an emergency power supply unit implementing the invention.
In the figure, reference 10 designates a storage battery charged at constant current from AC mains 11 via a transformer T whose primary winding 12 is connected to the mains and whose secondary winding 1 3 feeds a rectifier bridge. A negative output of the bridge is connected directly to the negative terminal of the storage battery; a positive output of the bridge is connected to the positive terminal of the storage battery via a current regulator circuit having a main path which comprises a charging current limiting resistor 1 5 and an incandescent light bulb 16 which regulates the charging current of the battery against voltage variations in the mains 11 and in the battery voltage.
The emitter of an NPN transistor 18 is connected to the point common to the resistor 1 5 and to the light bulb 1 6 and the collector of the transistor is connected via a resistor 1 9 to the positive output of the bridge. This connection constitutes an auxiliary charging current path. The base of the transistor is biased by a voltage tapped from a voltage divider chain comprising two resistors 20 and 21 connected in parallel with the main path formed by the light bulb 16 and the resistor 1 5.
The charging circuit operates as follows:
When mains 11 voltage is present and when the light bulb 1 6 is in good condition, the charging current of the battery passes through the light bulb 1 6 and the resistor 1 5. The transistor 1 8 is then non-conductive, since the voltage applied to its emitter (resistor 15) is higher than the voltage applied to its base (resistor 21), due to a suitable choice of resistance values for the various resistors.
The charging current is regulated by the light bulb, whose resistance varies with variations in mains voltage.
If the filament of the light bulb breaks, charging is maintained by means of the transistor 1 8 which becomes conductive, since the potential of the emitter decreases suddenly to a value lower than that of the base; the charging current then passes through the resistor 19, the transistor 1 8 and the resistor 1 5. Clearly the charging current provided by the auxiliary charging current path must be less than that provided by the main path in order to ensure that the emitter voltage stays far enough below the base voltage for the transistor to remain switched on.
The resistance of the resistor 19 is chosen so as to ensure that substantially all of the voltage drop due to the slightly lower charging current appears across the resistor rather than across the transistor, thereby reducing the power dissipating requirements for the transistor. Furthermore, since the circuit no longer includes a regulator device, protection must be provided against possible increases in the mains voltage. Thus it is essential for the unregulated charging current to be kept below the normal regulated charging current. However, a charging current which is sufficient to comply with the specifications can still be maintained.
The invention is in no way limited to the embodiment described by way of example. In particular, the NPN transistor can be replaced by a
PNP transistor by making the necessary transpositions in the connections.
Claims (4)
1. A current regulator circuit for connection in series between a battery to be charged and a source of charging current, the current regulator circuit comprising:
a main current-regulating path comprising an incandescent light bulb connected in series with a charging current limiting resistor;
a voltage divider chain connected in parallel with the main path; and
an auxiliary charging current path connected in parallel with the light bulb, the auxiliary charging current path comprising the emitter-collector circuit of a transistor with the emitter of the transistor being connected to the charging current limiting resistor of the main path and the base of the transistor being connected to a point on the voltage divider chain to bias the transistor in such a manner that when the light bulb is conductive the transistor is non-conductive and when the light bulb is open circuit the transistor is conductive to charge the battery with unregulated current.
2. A current regulator circuit according to
Claim 1, wherein the auxiliary charging current path includes an auxiliary resistor connected in series with the collector of the transistor, the resistance of the auxiliary resistor being chosen so that, when the transistor is conductive, the current flowing through the transistor is limited by the auxiliary resistor rather than by the baseemitter potential of the transistor.
3. A current regulator circuit substantially as herein described with reference to the accompanying drawing.
4. A battery charger circuit comprising a transformer having a primary winding for connection to AC mains and a secondary winding connected to a rectifier bridge, the current regulator circuit of any preceding claim being connected in series with the DC output from the rectifier bridge and terminals for connection to a storage battery.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7832610A FR2441940A1 (en) | 1978-11-20 | 1978-11-20 | CONSTANT CURRENT CHARGING DEVICE, ESPECIALLY FOR A SAFETY BLOCK |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2036473A true GB2036473A (en) | 1980-06-25 |
| GB2036473B GB2036473B (en) | 1983-01-12 |
Family
ID=9215054
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7940135A Expired GB2036473B (en) | 1978-11-20 | 1979-11-20 | Current regulator circuit in particular for charging an emergency power supply unit at constant current |
Country Status (3)
| Country | Link |
|---|---|
| ES (1) | ES486114A1 (en) |
| FR (1) | FR2441940A1 (en) |
| GB (1) | GB2036473B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0047183A1 (en) * | 1980-09-03 | 1982-03-10 | Reactomatic Limited | A dry cell battery re-activator |
| GB2178608A (en) * | 1985-06-14 | 1987-02-11 | Yu Zhiwei | Recharging dry cell batteries |
| CN104578339A (en) * | 2014-12-24 | 2015-04-29 | 国家电网公司 | Inductive power-obtaining device of high-voltage line robot and working method of inductive power-obtaining device |
| CN104836316A (en) * | 2015-04-29 | 2015-08-12 | 苏州锟恩电子科技有限公司 | Current-adjustable constant current charging circuit |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB947491A (en) * | 1959-04-06 | 1964-01-22 | Astaron Electronics Ltd | Improvements in or relating to electric circuits |
| FR1314842A (en) * | 1962-02-13 | 1963-01-11 | Yardney International Corp | Charging control device for accumulator batteries |
| FR1384845A (en) * | 1963-11-29 | 1965-01-08 | Pellam S A Soc | Improvements to static switching devices |
| US3413537A (en) * | 1965-01-21 | 1968-11-26 | Robert L. Sharp | Constant current battery charger |
| FR1444910A (en) * | 1965-05-28 | 1966-07-08 | Accumulateur Chargeur Dary | Power supply group |
-
1978
- 1978-11-20 FR FR7832610A patent/FR2441940A1/en active Granted
-
1979
- 1979-11-19 ES ES486114A patent/ES486114A1/en not_active Expired
- 1979-11-20 GB GB7940135A patent/GB2036473B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0047183A1 (en) * | 1980-09-03 | 1982-03-10 | Reactomatic Limited | A dry cell battery re-activator |
| GB2178608A (en) * | 1985-06-14 | 1987-02-11 | Yu Zhiwei | Recharging dry cell batteries |
| CN104578339A (en) * | 2014-12-24 | 2015-04-29 | 国家电网公司 | Inductive power-obtaining device of high-voltage line robot and working method of inductive power-obtaining device |
| CN104578339B (en) * | 2014-12-24 | 2017-03-22 | 国家电网公司 | Inductive power-obtaining device of high-voltage line robot and working method of inductive power-obtaining device |
| CN104836316A (en) * | 2015-04-29 | 2015-08-12 | 苏州锟恩电子科技有限公司 | Current-adjustable constant current charging circuit |
| CN104836316B (en) * | 2015-04-29 | 2017-11-28 | 苏州锟恩电子科技有限公司 | A kind of constant-current charging circuit of adjustable current |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2036473B (en) | 1983-01-12 |
| FR2441940A1 (en) | 1980-06-13 |
| FR2441940B1 (en) | 1982-06-04 |
| ES486114A1 (en) | 1980-05-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |