CA1308166C - Charging control apparatus - Google Patents
Charging control apparatusInfo
- Publication number
- CA1308166C CA1308166C CA000559877A CA559877A CA1308166C CA 1308166 C CA1308166 C CA 1308166C CA 000559877 A CA000559877 A CA 000559877A CA 559877 A CA559877 A CA 559877A CA 1308166 C CA1308166 C CA 1308166C
- Authority
- CA
- Canada
- Prior art keywords
- voltage
- charging
- ramp
- output
- reference voltage
- 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.)
- Expired - Lifetime
Links
Landscapes
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A charging control apparatus comprising a switching circuit for controlling a charging current from a charging power source to a storage battery. A reference voltage is provided which increases with a ramp corresponding to a value equal to, or more than, the maximum ramp value of the charging characteristic of the battery and a reference voltage is also provided which increases with time with a ramp corresponding to a value equal to, or less than, the minimum ramp value of the charging characteristic. The terminal voltage of the battery is sensed by a voltage sensor. A first comparator compares the reference voltage and a first sensed voltage from the voltage sensor. The ramp of the reference voltage is switched in accordance with the output of the first comparator. A second comparator compares the reference voltage and a second sensed voltage from the voltage sensor. The switching circuit is controlled by the output of the second comparator.
A charging control apparatus comprising a switching circuit for controlling a charging current from a charging power source to a storage battery. A reference voltage is provided which increases with a ramp corresponding to a value equal to, or more than, the maximum ramp value of the charging characteristic of the battery and a reference voltage is also provided which increases with time with a ramp corresponding to a value equal to, or less than, the minimum ramp value of the charging characteristic. The terminal voltage of the battery is sensed by a voltage sensor. A first comparator compares the reference voltage and a first sensed voltage from the voltage sensor. The ramp of the reference voltage is switched in accordance with the output of the first comparator. A second comparator compares the reference voltage and a second sensed voltage from the voltage sensor. The switching circuit is controlled by the output of the second comparator.
Description
``` ~308~66 CHARGING CONTROL APPARATUS
This invention relates to a charging control apparatus and more particularly to such apparatus which appropriately controls the charging of various storage batteries, inclusive of rapid charging of enclosed nickel-cadmium batteries.
The prior art will be discussed hereinbelow.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention there is provided a battery charging control apparatus comprising:
a charging power supply source; a switching circuit for controlling the charging current from said charging power source to a storage battery; ramp generating means for providing a first ramp re~erence voltage increasi.ng with time corresponding to a value equal to, or more than, the maximum ramp value o~ the charging characteristic of the storage battery and a ~econd ramp re~erence voltage increasing with timo and corresponding to a value eqyal to, or less than, the ' minimum ramp value o~ the charging characteristic o~ the storage battery; a voltage sensor for sensing respective first and ~econd voltages relating to the terminal voltage of said storage battery; ~irst comparing means ~or providing a ~irst output when said ~ir~t voltage coincides with said ~irst ramp re~erence voltage and a second output when said first voltage coincide~ with said second ramp re~erence voltage; said ramp generating means providing said ~irst ramp reference voltage ,. ...
. 1 '' , , ,, .~
. ' . ~ .
-~ ~36)816S
with said second output and said first ramp reference voltage with said first output; and second comparing means for controlling said switching circuit to terminate charging when said second voltage coincides with said second ramp reference voltage.
BRIEF DESCRIPTION OF THE DR~WINGS
Fig. 1 illustrates the principles of a charging .Z
~ ,' ,, Z~
.~, ..
~ ~ L
`::
I la ,, .1 ~'.Z
. :
. .
' ~ .
:,:
~ , -` 1 3Q8~66 control apparatus according to this invention;
Fig. 2 is a circuit diagram of the apparatus;
Figs. 3 and 4 show an example of the charging characteristic; and Fig. 5 is a circuit diagram in which the charging control apparatus according to this invention is used.
There are various known apparatus of such type. For example, a device which stores the highest value of the terminal voltage of a storage battery and controls the charging when the terminal voltage is lowered by more than a predetermined value from the highest value. According to this application, a fully charged state of an enclosed nickel-cadmium battery is achieved by controlling the charging when the terminal voltage is lowered by a predetermined value from its highest value at the end o~ the charging. Such predetermined value is about 20 mV at lC charging and a very ~ine value. In addition, in this charging device, the highest tQrminal voltage stored in the capacitor decreases with time ,~
due to leakage o~ electric current, so that control Or the ¢harging becomes impossible.
When the battery is overcharged, overdischarged or le~t unused ~or a long time, a peak value o~ the terminal voltage such as generated at the charging end may be generated at the beginning of the charging, a~ shown in Fig. 3. When tbe environmental temperature is above 40-C, the terminal voltage may virtually not decrease even at the end o~ the charging, as shown in Fig. 4, to thereby generate insufflcient charging or overcharging.
~,, J ~
~" ?h :' : . .
" ~
-~ ~3~)8166 In order to solve sUch problems, there is a known ; device which has either an initial lock timer which stops the charging control for a predetermined time at the beginning of the charging or an overcharging protective timer which stops the charging a predetermined time after the charging has started. Provision of such timer would render the circuit complicated. In addition, if a partially discharged battery which, for example, has a remaining capacity of about 50% is lC charged under a condition where the environmental temperature is above 40-C, a peak value will be generated in about 30 minutes. However, since the terminal voltage hardly lowers~ a terminal voltage Which is lowered by the predetermined value ~rom the highest value cannot be sensed, so that the charging continues until a time set by the overcharging protective timer to thereby create overcharging.
ThiS invention eliminates the above drawbacks. It ~
iB an ob~ect of this invention to provide a charging control apparatus Which ha8 a circuit structure capable o~
appropriately ¢harging any kind o~ storage battery ln any di~charged ~tate to thereby to prevent overcharging and insu~icient charging o~ various kinds o~ 8torage batteries inoluding an enC106ed battery used in electronic devices, e8pecially partially discharged batterie8.
An embodiment of thiS invention Will now be 6 de~cribed. In Fig. 2, a storage battery 10 i6 charged via a ' i:
~witching circuit 11 Which controls the charging current ~rom a charging power source 12. In order to sense a voltage corre8ponding to the terminal v ltage, the terminal voltage o~
. .
~ 3~ 6~
the battery is applied across the terminal 1-1 and 1-2 of a voltage sensor 1. A constant-voltage diode 1-3 and a resistor 1-4 are connected in series across the terminals 1-1 and 1-2, and a series connection of resistors 1-5 and 1-6 is connected in parallel with the diode 1-3. Resistor 1-4 is connected in parallel with a capacitor 1-7. A first voltage sensed by the voltage sensor 1 is obtained from the junction between the diode 1-3 and resistor 1-4, output from a terminal 1-8 J
, ., '' ' ,, ~3 5:)816~;
and input to a non-inverting input terminal of a first comparator 2. A second sensed voltage is obtained from the junctioa between resistor 1-5 and 1-6, output from a terminal 1-9 and input to an inverting input terminal of a second comparator 8. The output from first comparator 2 is input to one terminal of an AND gate 4-1 of a frequency divider 4 and a 1:16 divider output 4-3 which is the fourth stage output of a counter 4-2 is input to another input terminal of AND gate 4-1 in order to obtain a ramp-like refere~ce voltage corresponding to the maximum ramp value of the charging characteristic. On the other hand, clock pulses having a predetermined frequency output from a clock pulse generator 3 are input to a clock input terminal 4-4 of counter 4-2 within the frequency divider 4. In order to obtain a ramp-like reference voltage ¢orresponding to a minimum ramp value of the charging characteristic, a ls2048 divider output 4-5 which is the 11th stage output of counter 4-2 is input to one of input termlnals of an OR gate 4-6, the other input terminal of which receives the output of AND gate 4-1. The output of OR gate 4-6 i~ input to a clock input terminal of counter 5, the re~pective frequency division outputs from counter 5 are output at 7-1 via a resistor ladder 6 having an additive fu~ctio~ aad an amplifier 7 having an impedance conversion function as a ramp-like reference voltage corresponding to the maximum or minimum ramp value of the ~3~18166 charging characteristic. Namely, counter 5, resistor ladder 6 and amplifier 7 perform a D to A conversion. The reference voltage is input to a~ inverting terminal of first comparator 2 and a no~ verti~g input terminal of second comparator 8, the output of which controls the operation of switching circuit 11.
The switching circuit 11 includes a charging power source 12 which in turn comprises a rectifier which rectifies a commercially available power source and a ringing choke type converter, and a constant-voltage, constant-current control chopper circuit which receives an input from the power source 12. The switching circuit 11 and charging power source 12 will now be described in more ; detail with reference to Fig. 5. The charging power source 12 includes a réctifier circuit 12-3 which has a ~witch 12-2 which switches between a voltage doubler rectification used when the voltage of the commercial available power source 12-1 is at a 100 V ~ystem and a full-wave rectification u~ed when the voltage ls at a 200 V sy~tem, and a ringing choke type converter 12-4 with the ~witching circuit 11 being isolated from the commercially available power source 12-1. The switching circuit 11 has a tran~i~tor 11-1 which i~ ~ubjected to constant-voltage and con~tant-current control by a charging control device including the first and second comparators 2 and 8.
When a storage battery 10 is connected to the :: ;
:` - . .
.~ ,. . .
~ ............ . .
~ 3~:)8~6~
chargi~g control apparatus according to this invention, as shown in Fig~ 1, clock pulse generator 3 generates pulses at a constant frequency, the terminal voltage of the battery is applied across the terminal 1-1 and 1-2 of voltage sensor 1, and counter 5 is reset by a differenti-ating circuit 9 including a capacitor 9-1 and resistor 9-2. Therefore, the output 7-1 of amplifier 7 becomes 0 V, the output of the first comparator 2 becomes high and the output of second comparator 8 becomes low. When the output of second comparator 8 is low, the switching circuit 11 is arranged to be turned on, and charging to battery 10 starts via switching circuit 11 from power source 12. Pulses having the same frequency as the fourth stage output 4-3 of counter 4-2 appear at the output of AND gate 4-1 which receives the output of first comparator 2 and the fourth stage output 4-3 of counter 4-2. Pulses ., having the same frequency as the fourth stage output 4-3 of counter 4-2 appear at the output of OR gate 4-6 which receives the first mentioned pulses and the 11th stage output of counter 4-2. Thus a ramp corresponding to the freguency of the fourth stage output 4-3 of couater 4-2, i.e., a ramp-like refere~ce voltage correspo~ding to the maximum value of ramp of the charging characteristic, is obtained at the output 7-1 via counter 5, resistor ladder 6 and amplifier 7. This operation will be described with reference to Fig. 1. The ramp-like reference voltage ll '' " ;, ,.
' - ~3C)~3~6~
corresponding to the maximum ramp value of the charging characteristic i~creases with that ramp when the charging starts and coincides with the charging characteristic curve at a time ~01 when the environmental temperature is at 20C and at a time tO2 when the environmental temperature is at 40C. Therefore, the output of second comparator 8 remains low until the times tOl and tO2 are reached, so that the switching circuit 11 will not be turned off even if a peak is generated at the beginning of the chargi~g as shown by broken lines in Fig. 1. When the ramp-like reference voltage ~1 coincides with the charging characteristic curve, the output of the first comparator 2 becomes low and the output of AND gate 4-1 also becomes low. Therefore, pulses having the same frequency as the 11th output 4-5 of counter 4-2 appear at the output of OR
gate 4-6 while a ramp-like reference voltage corresponding to a ramp corresponding to the freque~cy of the 11th output 4-5 of cou~ter 4-2, namely, the minimum ramp value of the charging characteristic, via cou~ter 5, resistor ladder 6 and amplifier 7 are obtained at the output 7-1.
As chargi~g proceeds and the terminal voltage of the battery increases in this way, the ramp-like reference voltage increases with a ramp corresponding to the mi~imum ramp of the charging characteristic. When gases start to be produced at the e~d of the charging, the termi~al voltage rapidly increases and an increase in the reference ~ "'-' ', :
~, ' ' ,:.' )816S
voltage does not follow, so that the output of the first comparator 2 becomes high again. Therefore, the reference voltage increases with a ramp corresponding to the maximum ramp value of the charging characteristic. When the battery reaches its fully charged state and a peak value or a flat portion appears at its terminal voltage, the reference voltage again start to increase with a ramp corresponding to the minimum ramp value of the charging characteristic. Thereafter, even if the terminal voltage starts to lower or remains flat, the reference voltage continues to increase, so that the difference between the terminal voltage and the reference voltage becomes ~V at a time tl when the environmental temperature is at 20C and at time t2 when the environmental temperature is at 40C.
If the value of resistors 1-5 and 1-6 are determined such that the 4V value coincides with the difference voltage between the first seAsed voltage output from the terminal 8 of voltage sensor 1 and the second sensed voltage output from the terminal 1-9, the output of second comparator 8 becomes high at times tl and t2, 80 that the switching circuit ll is turned off to thereby stop charging.
The lC charging of a single enclosed nickel-cadmium battery will now be described using the charging control apparatus according to this invention. In that case, the terml~al voltage changes between 1.3 V and 1.6 V
: - g _ - -- - -- , ,,, , ", ; . .
.. ,........ :'' , , ' ~:
. . :
-13~)~316~
and increases at a rate of about 1 mV/minute, so that the output voltage of termi~al 1-8 cha~ges betwee~ 0.3 V a~d 0.6 V assuming that constant-voltage diode 1-3 provides 1.0 V. Assumes that the oscillating frequency of clock pulse generator 3 is 107 Hz. The fourth stage output of counter 4-2 which provides a ramp-like reference voltage correspondi~g to the maximum ramp value of the chargi~g characteristic is a 16-divided freque~cy which provides 6.7 Hz while the 11th stage output of counter 4-2 which provides a ramp-like refere~ce voltage corresponding to the minimum ramp value of the charging characteristic is a 2048-divided frequency which provides 0.052 Hz.
Therefore, when charging starts, the reference voltage increases with a ramp correspondi~g to a 6.7 Hz pulse, so that if resistor ladder 6 and the gai~ of amplifier 7 are determined such that the output 7-1 of amplifier 7 increases 0.2 mV at a time when one pulse is counted, 6.7 pulses are counted for one second. Therefore, the reference voltage incxeases with a rate of 80 mV/minute and becomes 0.4 V five minutes after charging starts to thereby exceed the output of terminal 1-8. When the output of first comparator 2 becomes low, the reference voltage increases with a ramp corresponding to a 0.052 Hz pulse, 50 that 0.052 pulses are counted for one second and the reference voltage increases with a rate 0.63 mV/minu~es. If the values of resistors 1-5 and 1-6 are )816S
determined such that ~V is 20 mV in order to sense the fully charged state properly, it is possible to stop the charging 32 minutes after the peak value is arrived at even if the charging characteristic becomes flat to thereby prevent overcharging. When the terminal voltage is lowered, the charging is stopped earlier for an increase in the reference voltage, but the ramp with which ~, ~
the reference voltage increases~is very small, so that Lnsufficient charging does not occur.
In the particular embodiment, it is assumed that the oscillating freque~cy of clock pulse generator 3 is 107 Hz. In addition, the fourth stage output of counter 4-2 i8 used to obtain a ramp-like reference voltage corresponding to the maximum ramp value of the ,, charging characteristic and the 11th stage output of counter 4-2 is u~ed to obtain a ramp-like reference ~, voltage corre~ponding to the minimum ramp of the charging characteristic. This is 90 becau~e the charged battery i9 ~,;
~ a ~ole enclosed ~ickel-cadmium ~torage battery, so that ,,,;
the refereace voltage may optionally be changed so as to , ,~ .
corre~pond to a value above the maximum ramp value, or a value below the minimum ramp value, of the charging characteristic of the charged battery or so as to depend ", on the number of batteries used. The difference voltage -; ~ av between the first and second seased voltages of the voltage sensor may be changed optionally, Of course, the , ;,, ; ': ' ~
- ,~. .
' ,',: :' ' :.
."
-:,.",, , ~ :, ~
~3~ 316~;
switching circuit 11 may be modified so as to iaclude a series circuit of resistor 11-2 and diode 11-3 to perform limiting control mstead of on/off control.
As described in detail in the particular embodiment, according to the inventive charging control apparatus, the use of a ramp-like reference voltage corresponding to a value above the maximum ramp value of the the charging characteristic~prevents charging from stopping even Lf a peak appears on~the terminal voltage at ~the beginning of charging. The ramp-like reference voltage correspondlng to a value below the minimum ramp value of charging characteristic prevents the battery from being overcharged or insufflciently charged even if a peak appears on the charging voItage in the vicinity of the fully charged state and the terminal voltage starts then to lower or remain~ unchaged. Thus it is possible to partially charge variou~ batteries, especially partially dl~charged batteries, inclusive of enclosed nickel-cadmium b~tteries.
, ~ ~
,:: .. - ~, , :
, ,.,, ~, : -~:
,,:
, ,, :
" :
,~
,, .
. ' ~, , .: .
:.:, . -- - . .
, .
This invention relates to a charging control apparatus and more particularly to such apparatus which appropriately controls the charging of various storage batteries, inclusive of rapid charging of enclosed nickel-cadmium batteries.
The prior art will be discussed hereinbelow.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention there is provided a battery charging control apparatus comprising:
a charging power supply source; a switching circuit for controlling the charging current from said charging power source to a storage battery; ramp generating means for providing a first ramp re~erence voltage increasi.ng with time corresponding to a value equal to, or more than, the maximum ramp value o~ the charging characteristic of the storage battery and a ~econd ramp re~erence voltage increasing with timo and corresponding to a value eqyal to, or less than, the ' minimum ramp value o~ the charging characteristic o~ the storage battery; a voltage sensor for sensing respective first and ~econd voltages relating to the terminal voltage of said storage battery; ~irst comparing means ~or providing a ~irst output when said ~ir~t voltage coincides with said ~irst ramp re~erence voltage and a second output when said first voltage coincide~ with said second ramp re~erence voltage; said ramp generating means providing said ~irst ramp reference voltage ,. ...
. 1 '' , , ,, .~
. ' . ~ .
-~ ~36)816S
with said second output and said first ramp reference voltage with said first output; and second comparing means for controlling said switching circuit to terminate charging when said second voltage coincides with said second ramp reference voltage.
BRIEF DESCRIPTION OF THE DR~WINGS
Fig. 1 illustrates the principles of a charging .Z
~ ,' ,, Z~
.~, ..
~ ~ L
`::
I la ,, .1 ~'.Z
. :
. .
' ~ .
:,:
~ , -` 1 3Q8~66 control apparatus according to this invention;
Fig. 2 is a circuit diagram of the apparatus;
Figs. 3 and 4 show an example of the charging characteristic; and Fig. 5 is a circuit diagram in which the charging control apparatus according to this invention is used.
There are various known apparatus of such type. For example, a device which stores the highest value of the terminal voltage of a storage battery and controls the charging when the terminal voltage is lowered by more than a predetermined value from the highest value. According to this application, a fully charged state of an enclosed nickel-cadmium battery is achieved by controlling the charging when the terminal voltage is lowered by a predetermined value from its highest value at the end o~ the charging. Such predetermined value is about 20 mV at lC charging and a very ~ine value. In addition, in this charging device, the highest tQrminal voltage stored in the capacitor decreases with time ,~
due to leakage o~ electric current, so that control Or the ¢harging becomes impossible.
When the battery is overcharged, overdischarged or le~t unused ~or a long time, a peak value o~ the terminal voltage such as generated at the charging end may be generated at the beginning of the charging, a~ shown in Fig. 3. When tbe environmental temperature is above 40-C, the terminal voltage may virtually not decrease even at the end o~ the charging, as shown in Fig. 4, to thereby generate insufflcient charging or overcharging.
~,, J ~
~" ?h :' : . .
" ~
-~ ~3~)8166 In order to solve sUch problems, there is a known ; device which has either an initial lock timer which stops the charging control for a predetermined time at the beginning of the charging or an overcharging protective timer which stops the charging a predetermined time after the charging has started. Provision of such timer would render the circuit complicated. In addition, if a partially discharged battery which, for example, has a remaining capacity of about 50% is lC charged under a condition where the environmental temperature is above 40-C, a peak value will be generated in about 30 minutes. However, since the terminal voltage hardly lowers~ a terminal voltage Which is lowered by the predetermined value ~rom the highest value cannot be sensed, so that the charging continues until a time set by the overcharging protective timer to thereby create overcharging.
ThiS invention eliminates the above drawbacks. It ~
iB an ob~ect of this invention to provide a charging control apparatus Which ha8 a circuit structure capable o~
appropriately ¢harging any kind o~ storage battery ln any di~charged ~tate to thereby to prevent overcharging and insu~icient charging o~ various kinds o~ 8torage batteries inoluding an enC106ed battery used in electronic devices, e8pecially partially discharged batterie8.
An embodiment of thiS invention Will now be 6 de~cribed. In Fig. 2, a storage battery 10 i6 charged via a ' i:
~witching circuit 11 Which controls the charging current ~rom a charging power source 12. In order to sense a voltage corre8ponding to the terminal v ltage, the terminal voltage o~
. .
~ 3~ 6~
the battery is applied across the terminal 1-1 and 1-2 of a voltage sensor 1. A constant-voltage diode 1-3 and a resistor 1-4 are connected in series across the terminals 1-1 and 1-2, and a series connection of resistors 1-5 and 1-6 is connected in parallel with the diode 1-3. Resistor 1-4 is connected in parallel with a capacitor 1-7. A first voltage sensed by the voltage sensor 1 is obtained from the junction between the diode 1-3 and resistor 1-4, output from a terminal 1-8 J
, ., '' ' ,, ~3 5:)816~;
and input to a non-inverting input terminal of a first comparator 2. A second sensed voltage is obtained from the junctioa between resistor 1-5 and 1-6, output from a terminal 1-9 and input to an inverting input terminal of a second comparator 8. The output from first comparator 2 is input to one terminal of an AND gate 4-1 of a frequency divider 4 and a 1:16 divider output 4-3 which is the fourth stage output of a counter 4-2 is input to another input terminal of AND gate 4-1 in order to obtain a ramp-like refere~ce voltage corresponding to the maximum ramp value of the charging characteristic. On the other hand, clock pulses having a predetermined frequency output from a clock pulse generator 3 are input to a clock input terminal 4-4 of counter 4-2 within the frequency divider 4. In order to obtain a ramp-like reference voltage ¢orresponding to a minimum ramp value of the charging characteristic, a ls2048 divider output 4-5 which is the 11th stage output of counter 4-2 is input to one of input termlnals of an OR gate 4-6, the other input terminal of which receives the output of AND gate 4-1. The output of OR gate 4-6 i~ input to a clock input terminal of counter 5, the re~pective frequency division outputs from counter 5 are output at 7-1 via a resistor ladder 6 having an additive fu~ctio~ aad an amplifier 7 having an impedance conversion function as a ramp-like reference voltage corresponding to the maximum or minimum ramp value of the ~3~18166 charging characteristic. Namely, counter 5, resistor ladder 6 and amplifier 7 perform a D to A conversion. The reference voltage is input to a~ inverting terminal of first comparator 2 and a no~ verti~g input terminal of second comparator 8, the output of which controls the operation of switching circuit 11.
The switching circuit 11 includes a charging power source 12 which in turn comprises a rectifier which rectifies a commercially available power source and a ringing choke type converter, and a constant-voltage, constant-current control chopper circuit which receives an input from the power source 12. The switching circuit 11 and charging power source 12 will now be described in more ; detail with reference to Fig. 5. The charging power source 12 includes a réctifier circuit 12-3 which has a ~witch 12-2 which switches between a voltage doubler rectification used when the voltage of the commercial available power source 12-1 is at a 100 V ~ystem and a full-wave rectification u~ed when the voltage ls at a 200 V sy~tem, and a ringing choke type converter 12-4 with the ~witching circuit 11 being isolated from the commercially available power source 12-1. The switching circuit 11 has a tran~i~tor 11-1 which i~ ~ubjected to constant-voltage and con~tant-current control by a charging control device including the first and second comparators 2 and 8.
When a storage battery 10 is connected to the :: ;
:` - . .
.~ ,. . .
~ ............ . .
~ 3~:)8~6~
chargi~g control apparatus according to this invention, as shown in Fig~ 1, clock pulse generator 3 generates pulses at a constant frequency, the terminal voltage of the battery is applied across the terminal 1-1 and 1-2 of voltage sensor 1, and counter 5 is reset by a differenti-ating circuit 9 including a capacitor 9-1 and resistor 9-2. Therefore, the output 7-1 of amplifier 7 becomes 0 V, the output of the first comparator 2 becomes high and the output of second comparator 8 becomes low. When the output of second comparator 8 is low, the switching circuit 11 is arranged to be turned on, and charging to battery 10 starts via switching circuit 11 from power source 12. Pulses having the same frequency as the fourth stage output 4-3 of counter 4-2 appear at the output of AND gate 4-1 which receives the output of first comparator 2 and the fourth stage output 4-3 of counter 4-2. Pulses ., having the same frequency as the fourth stage output 4-3 of counter 4-2 appear at the output of OR gate 4-6 which receives the first mentioned pulses and the 11th stage output of counter 4-2. Thus a ramp corresponding to the freguency of the fourth stage output 4-3 of couater 4-2, i.e., a ramp-like refere~ce voltage correspo~ding to the maximum value of ramp of the charging characteristic, is obtained at the output 7-1 via counter 5, resistor ladder 6 and amplifier 7. This operation will be described with reference to Fig. 1. The ramp-like reference voltage ll '' " ;, ,.
' - ~3C)~3~6~
corresponding to the maximum ramp value of the charging characteristic i~creases with that ramp when the charging starts and coincides with the charging characteristic curve at a time ~01 when the environmental temperature is at 20C and at a time tO2 when the environmental temperature is at 40C. Therefore, the output of second comparator 8 remains low until the times tOl and tO2 are reached, so that the switching circuit 11 will not be turned off even if a peak is generated at the beginning of the chargi~g as shown by broken lines in Fig. 1. When the ramp-like reference voltage ~1 coincides with the charging characteristic curve, the output of the first comparator 2 becomes low and the output of AND gate 4-1 also becomes low. Therefore, pulses having the same frequency as the 11th output 4-5 of counter 4-2 appear at the output of OR
gate 4-6 while a ramp-like reference voltage corresponding to a ramp corresponding to the freque~cy of the 11th output 4-5 of cou~ter 4-2, namely, the minimum ramp value of the charging characteristic, via cou~ter 5, resistor ladder 6 and amplifier 7 are obtained at the output 7-1.
As chargi~g proceeds and the terminal voltage of the battery increases in this way, the ramp-like reference voltage increases with a ramp corresponding to the mi~imum ramp of the charging characteristic. When gases start to be produced at the e~d of the charging, the termi~al voltage rapidly increases and an increase in the reference ~ "'-' ', :
~, ' ' ,:.' )816S
voltage does not follow, so that the output of the first comparator 2 becomes high again. Therefore, the reference voltage increases with a ramp corresponding to the maximum ramp value of the charging characteristic. When the battery reaches its fully charged state and a peak value or a flat portion appears at its terminal voltage, the reference voltage again start to increase with a ramp corresponding to the minimum ramp value of the charging characteristic. Thereafter, even if the terminal voltage starts to lower or remains flat, the reference voltage continues to increase, so that the difference between the terminal voltage and the reference voltage becomes ~V at a time tl when the environmental temperature is at 20C and at time t2 when the environmental temperature is at 40C.
If the value of resistors 1-5 and 1-6 are determined such that the 4V value coincides with the difference voltage between the first seAsed voltage output from the terminal 8 of voltage sensor 1 and the second sensed voltage output from the terminal 1-9, the output of second comparator 8 becomes high at times tl and t2, 80 that the switching circuit ll is turned off to thereby stop charging.
The lC charging of a single enclosed nickel-cadmium battery will now be described using the charging control apparatus according to this invention. In that case, the terml~al voltage changes between 1.3 V and 1.6 V
: - g _ - -- - -- , ,,, , ", ; . .
.. ,........ :'' , , ' ~:
. . :
-13~)~316~
and increases at a rate of about 1 mV/minute, so that the output voltage of termi~al 1-8 cha~ges betwee~ 0.3 V a~d 0.6 V assuming that constant-voltage diode 1-3 provides 1.0 V. Assumes that the oscillating frequency of clock pulse generator 3 is 107 Hz. The fourth stage output of counter 4-2 which provides a ramp-like reference voltage correspondi~g to the maximum ramp value of the chargi~g characteristic is a 16-divided freque~cy which provides 6.7 Hz while the 11th stage output of counter 4-2 which provides a ramp-like refere~ce voltage corresponding to the minimum ramp value of the charging characteristic is a 2048-divided frequency which provides 0.052 Hz.
Therefore, when charging starts, the reference voltage increases with a ramp correspondi~g to a 6.7 Hz pulse, so that if resistor ladder 6 and the gai~ of amplifier 7 are determined such that the output 7-1 of amplifier 7 increases 0.2 mV at a time when one pulse is counted, 6.7 pulses are counted for one second. Therefore, the reference voltage incxeases with a rate of 80 mV/minute and becomes 0.4 V five minutes after charging starts to thereby exceed the output of terminal 1-8. When the output of first comparator 2 becomes low, the reference voltage increases with a ramp corresponding to a 0.052 Hz pulse, 50 that 0.052 pulses are counted for one second and the reference voltage increases with a rate 0.63 mV/minu~es. If the values of resistors 1-5 and 1-6 are )816S
determined such that ~V is 20 mV in order to sense the fully charged state properly, it is possible to stop the charging 32 minutes after the peak value is arrived at even if the charging characteristic becomes flat to thereby prevent overcharging. When the terminal voltage is lowered, the charging is stopped earlier for an increase in the reference voltage, but the ramp with which ~, ~
the reference voltage increases~is very small, so that Lnsufficient charging does not occur.
In the particular embodiment, it is assumed that the oscillating freque~cy of clock pulse generator 3 is 107 Hz. In addition, the fourth stage output of counter 4-2 i8 used to obtain a ramp-like reference voltage corresponding to the maximum ramp value of the ,, charging characteristic and the 11th stage output of counter 4-2 is u~ed to obtain a ramp-like reference ~, voltage corre~ponding to the minimum ramp of the charging characteristic. This is 90 becau~e the charged battery i9 ~,;
~ a ~ole enclosed ~ickel-cadmium ~torage battery, so that ,,,;
the refereace voltage may optionally be changed so as to , ,~ .
corre~pond to a value above the maximum ramp value, or a value below the minimum ramp value, of the charging characteristic of the charged battery or so as to depend ", on the number of batteries used. The difference voltage -; ~ av between the first and second seased voltages of the voltage sensor may be changed optionally, Of course, the , ;,, ; ': ' ~
- ,~. .
' ,',: :' ' :.
."
-:,.",, , ~ :, ~
~3~ 316~;
switching circuit 11 may be modified so as to iaclude a series circuit of resistor 11-2 and diode 11-3 to perform limiting control mstead of on/off control.
As described in detail in the particular embodiment, according to the inventive charging control apparatus, the use of a ramp-like reference voltage corresponding to a value above the maximum ramp value of the the charging characteristic~prevents charging from stopping even Lf a peak appears on~the terminal voltage at ~the beginning of charging. The ramp-like reference voltage correspondlng to a value below the minimum ramp value of charging characteristic prevents the battery from being overcharged or insufflciently charged even if a peak appears on the charging voItage in the vicinity of the fully charged state and the terminal voltage starts then to lower or remain~ unchaged. Thus it is possible to partially charge variou~ batteries, especially partially dl~charged batteries, inclusive of enclosed nickel-cadmium b~tteries.
, ~ ~
,:: .. - ~, , :
, ,.,, ~, : -~:
,,:
, ,, :
" :
,~
,, .
. ' ~, , .: .
:.:, . -- - . .
, .
Claims (3)
1. A battery charging control apparatus comprising: a charging power supply source;
a switching circuit for controlling the charging current from said charging power source to a storage battery;
ramp generating means for providing a first ramp reference voltage increasing with time corresponding to a value equal to, or more than, the maximum ramp value of the charging characteristic of the storage battery and a second ramp reference voltage increasing with time and corresponding to a value equal to, or less than, the minimum ramp value of the charging characteristic of the storage battery;
a voltage sensor for sensing respective first and second voltages relating to the terminal voltage of said storage battery;
first comparing means for providing a first output when said first voltage coincides with said first ramp reference voltage and a second output when said first voltage coincides with said second ramp reference voltage;
said ramp generating means providing said first ramp reference voltage with said second output and said first ramp reference voltage with said first output; and second comparing means for controlling said switching circuit to terminate charging when said second voltage coincides with said second ramp reference voltage.
a switching circuit for controlling the charging current from said charging power source to a storage battery;
ramp generating means for providing a first ramp reference voltage increasing with time corresponding to a value equal to, or more than, the maximum ramp value of the charging characteristic of the storage battery and a second ramp reference voltage increasing with time and corresponding to a value equal to, or less than, the minimum ramp value of the charging characteristic of the storage battery;
a voltage sensor for sensing respective first and second voltages relating to the terminal voltage of said storage battery;
first comparing means for providing a first output when said first voltage coincides with said first ramp reference voltage and a second output when said first voltage coincides with said second ramp reference voltage;
said ramp generating means providing said first ramp reference voltage with said second output and said first ramp reference voltage with said first output; and second comparing means for controlling said switching circuit to terminate charging when said second voltage coincides with said second ramp reference voltage.
2. A battery charging control apparatus according to claim 1, wherein the charging power supply source includes a rectifier for rectifying a commercially available power source and a ringing choke type converter and wherein the switching circuit includes a chopper circuit for receiving the output of the converter to control charging of the battery.
3. A charging control apparatus according to claim 1, wherein the first sensed voltage from the voltage sensor is lower by a predetermined value than the second sensed voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000559877A CA1308166C (en) | 1988-02-25 | 1988-02-25 | Charging control apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000559877A CA1308166C (en) | 1988-02-25 | 1988-02-25 | Charging control apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1308166C true CA1308166C (en) | 1992-09-29 |
Family
ID=4137514
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000559877A Expired - Lifetime CA1308166C (en) | 1988-02-25 | 1988-02-25 | Charging control apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1308166C (en) |
-
1988
- 1988-02-25 CA CA000559877A patent/CA1308166C/en not_active Expired - Lifetime
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5523667A (en) | Alkaline battery charger and method of operating same | |
| EP0406858B1 (en) | A battery charger and method for a portable wireless telephone set having means for tricklingly charging the battery with an increased current during a stand-by period of the telephone set | |
| US5185565A (en) | Charge control apparatus for use with electronic equipment | |
| US5998966A (en) | Microcontrolled battery charger | |
| US4607208A (en) | Battery charger | |
| US4855663A (en) | Charging control apparatus | |
| US5321347A (en) | Battery charger device and method | |
| US5619116A (en) | Universal battery charger chargeable with relevant current dependent on cell number | |
| EP0226253B1 (en) | Power supply circuit | |
| US5541491A (en) | Battery charging apparatus | |
| JPH1032938A (en) | Battery charger | |
| FI109567B (en) | Quick charging device | |
| US5274321A (en) | Battery charger | |
| US5537024A (en) | Circuit arrangement to detect a voltage | |
| CA1308166C (en) | Charging control apparatus | |
| GB2262004A (en) | Charging batteries in portable equipment | |
| US5568040A (en) | Charging arrangement for the time-controlled charging of at least one rechargeable cell | |
| JP3267708B2 (en) | Charging device | |
| JP2995142B2 (en) | Series battery charger | |
| JPH04281334A (en) | Quick charger | |
| JP3175839B2 (en) | Charging device and charging method | |
| JP3033591B2 (en) | Charge controller | |
| SU1677698A1 (en) | Rectified voltage switching stabilizer | |
| JPH058764Y2 (en) | ||
| JPH07147734A (en) | Charger of series batteries |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |