WO1995001699A1 - Electronic device for controlling application of a charging current thereto and associated method therefor - Google Patents

Electronic device for controlling application of a charging current thereto and associated method therefor Download PDF

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Publication number
WO1995001699A1
WO1995001699A1 PCT/US1994/007454 US9407454W WO9501699A1 WO 1995001699 A1 WO1995001699 A1 WO 1995001699A1 US 9407454 W US9407454 W US 9407454W WO 9501699 A1 WO9501699 A1 WO 9501699A1
Authority
WO
WIPO (PCT)
Prior art keywords
power supply
power
variable
power source
electronic device
Prior art date
Application number
PCT/US1994/007454
Other languages
French (fr)
Inventor
David M. Demuro
Original Assignee
Motorola Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Motorola Inc. filed Critical Motorola Inc.
Priority to GB9505466A priority Critical patent/GB2285717B/en
Publication of WO1995001699A1 publication Critical patent/WO1995001699A1/en

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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
    • H02J7/0068—Battery or charger load switching, e.g. concurrent charging and load supply
    • 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
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/007188—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
    • H02J7/007192—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature
    • H02J7/007194—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature of the battery
    • 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
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/061—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for DC powered loads
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/1607—Supply circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/3827—Portable transceivers
    • H04B1/3883—Arrangements for mounting batteries or battery chargers

Definitions

  • the present invention relates generally to electronic devices which may be powered by rechargeable power supplies and, more particularly, to an electronic device having a rechargeable power supply, and an associated method, connectable to an external power source capable of providing operative power to recharge the rechargeable power supply of the electronic device.
  • Many electronic devices are constructed of designs which permit powering thereof by a battery power supply comprised of one or more battery cells.
  • a battery power supply to pwoer the electronic device is necessitated when the electronic device is not, or cannot be, positioned proximate to a permanent, or other fixed, power supply.
  • a battery power supply is utilized to power the electronic device to increase the portability of the device as no power cable is required to interconnect the electronic device to the permanent, or other fixed, power supply.
  • the one or more battery cells comprising the battery power supply utilized to power the electronic device are carried directly with, or housed within, the electronic device.
  • a battery power supply is capable of storing only a finite amount of energy
  • powering of the electronic device with the battery power supply is limited by the energy storage capacity of the battery power supply.
  • Powering of the electronic device by the battery power supply causes discharge of the stored energy of the battery power supply. Once the stored energy of the battery power supply is discharged beyond a certain level, replacement of the battery power supply is necessitated to permit continued operation of the electronic device.
  • Increasing the energy storage capacity of a battery power supply such as by increasing the number of battery cells comprising such power supply, increases the size (and weight) of the power supply. Such manner of increasing the energy storage capacity of a battery power supply reduces the portability of the electronic device when the battery power supply is carried with the electronic device.
  • a portable or transportable radiotelephone is one such electronic device which is typically powered by a battery power supply.
  • the battery power supply is typically carried directly with the radiotelephone and is of a size and weight which does not unduly constrain the portability of the radiotelephone.
  • a radiotelephone includes radio transceiver circuitry including transmitter circuitry and receiver circuitry which is operative to transmit and to receive, respectively, modulated signals. In typical operation of a radiotelephone, receiver circuitry portions thereof are powered continuously while awaiting reception of signals indicative of an incoming call to the radiotelephone.
  • the transmitter circuitry portions of the radiotelephone are also powered to permit transmission of modulated signals therefrom.
  • adiotelephones operative in many cellular communication systems are constructed to transmit modulated signals therefrom and also simultaneously to receive modulated signals transmitted thereto (the modulated signals transmitted by, and to, the radiotelephone are transmitted upon separate frequency channels).
  • Radiotelephones operative in other cellular communication systems are constructed to transmit and to receive modulated signals during nonsimultaneous time periods and, during two-way communication with the radiotelephone, the receiver and transmitter circuitry portions are powered during nonsimultaneous time periods.
  • Times during which the receiver circuitry portions of the radiotelephone are powered while awaiting transmission thereto of signals indicative of an incoming call shall hereinafter be referred to as times in which the radiotelephone is in the "standby" mode.
  • a user of a radiotelephone also oftentimes provides operative power to the radiotelephone only when the user desires to initiate and thereafter effectuate a telephone call; during other times no operative power is provided to the radiotelephone, and the radiotelephone is not powered to receive signals transmitted thereto. That is to say, the user of the radiotelephone may choose not to operate the radiotelephone in the "standby" mode to receive an incoming call transmitted to the radiotelephone, but rather power the radiotelephone only during times in which the user initiates a telephone call.
  • the amounts of energy required to operate the transmitter circuitry portions of the radiotelephone are greater than the amounts of energy required to operate the receiver circuitry portions thereof. And, because practical devices are of less than ideal efficiencies, a certain portion of the energy applied to the radiotelephone is converted into heat energy which results in heat build-up of the radiotelephone. As more energy is required to operate the transmitter circuitry portions of the radiotelephone, there is a correspondingly greater amount of heat generation during operation of the transmitter circuitry portions of the radiotelephone than when only the receiver circuitry portions are operable.
  • Rechargeable battery power supplies comprised of one or more rechargeable battery cells have been developed and are commercially available. Some of such commercially- available, rechargeable battery power supplies are of constructions designed for use to power radiotelephones. The use of rechargeable battery power supplies is advantageous as the rechargeable battery cells thereof may be recharged by applying thereto a charging current generated by a power supply. Once recharged, the rechargeable battery power supply may be reused. Some constructions of rechargeable battery power supplies may be recharged, and reused, up to, and even in excess of, five hundred times.
  • a rechargeable battery power supply is typically comprised of one or more battery cells.
  • the cells are connected in a series (or other) connection, and are typically housed within a common housing.
  • the housing, together with the battery cells, comprise the battery power supply which is also oftentimes referred to as a battery pack.
  • battery For purposes of simplicity, such constructions are also generically referred to by the general term "battery”.
  • the present disclosure shall, at times, utilize such simplified terminology.
  • the battery cells of a rechargeable battery power supply are formed of various different materials of construction.
  • a rechargeable battery cell may be comprised of a lithium (Li) material, a -nickel-cadmium (Ni-Cd) material, or a nickel metal hydride (NiMH02) material. Battery cells constructed of these different materials exhibit different characteristics during charging thereof.
  • Battery charging apparatus is also commercially available to permit recharging of rechargeable battery power supplies.
  • a battery charger comprising such battery charging apparatus is typically comprised of a power source for supplying operative power to recharge the rechargeable battery power supply when suitably connected to the charging apparatus to receive the operative power.
  • the energy of the operative power applied to the rechargeable battery power supply is converted into chemical energy which is stored by the rechargeable battery cells of the battery power supply.
  • Application of the operative power to the battery cells over an elapsed period of time permits the rechargeable battery cells to become fully recharged.
  • Some battery charging apparatus are of construction- types which permit the electronic device and also the battery power supply both to receive operative power. Such battery charging apparatus provides operative power not only to recharge the rechargeable battery cells of the battery power supply but further provides operative power to permit operation of the electronic device. For instance, battery charging apparatus of construction-types permitting a radiotelephone together with a rechargeable battery pack to receive operative power to recharge the battery cells of the battery pack and also to permit operation of the circuitry of the radiotelephone is available. As mentioned previously, however, in practical devices, heat is generated as a byproduct of operation of the circuitry of the radiotelephone.
  • recharging of a battery construction is most efficiently accomplished when the voltage level of the power applied to recharge the battery "tracks" the voltage level of the rechargeable battery power supply.
  • the voltage of the power applied to the rechargeable battery power supply must be greater than the voltage levels of the rechargeable battery power supply to cause energy to be transferred to the battery power supply.
  • the voltage of the power applied to the battery power supply is significantly greater than the voltage levels of the battery power supply, a significant portion of the energy corresponding to the voltage differentials is converted into heat energy.
  • the rechargeable battery power supply When the rechargeable battery power supply is embodied as a portion of an electronic device, such as a radiotelephone, the heat energy generated during application of the charging power to the rechargeable battery power supply results in heating of the electronic device. Such heating of the electronic device may cause discomfort to a user of the electronic device and also affect the performance thereof. What is needed, therefore, is means by which charging power may be applied to a rechargeable battery embodied in an electronic device without generation of excessive amounts of heat energy.
  • the present invention accordingly, provides a device, and associated method, which overcomes the problems associated with the existing art.
  • the present invention further advantageously provides an electronic device including a rechargeable power supply wherein the electronic device is connectable to a variable-level power source which provides operative power to recharge the rechargeable power supply and also to provide operative power to operate electronic circuitry of the electronic device.
  • a variable-level power source which provides operative power to recharge the rechargeable power supply and also to provide operative power to operate electronic circuitry of the electronic device.
  • the present invention includes further advantages and features, the details of which will become more apparent upon reading the following detailed description of the preferred embodiments.
  • an electronic device which is releasably connectable to a variable- level power source is disclosed.
  • the variable-level power source has power-source control circuitry operative responsive to reception of a power-source control signal for controlling power levels of operative power generated by the variable-level power source.
  • the electronic device is operable to receive the operative power generated by the variable-level power source when the variable-level power source is connected therewith.
  • Connecting elements permit releasable connection with the variable-level power source including at least a first connecting element and a second connecting element.
  • the first connecting element permits connecting of the variable- level power source thereto, thereby to receive operative power generated by the variable-level power source thereat.
  • the second connecting element permits connection of the power- source control circuitry of the variable-level power source thereto.
  • a rechargeable power supply is coupled to receive a charging signal responsive to times in which the variable-level power source is connected to the first connecting element.
  • Voltage sensing circuitry is operative to sense voltage levels of the rechargeable power supply and to generate a signal representative of the voltage levels sensed thereby.
  • the signal representative of the voltage levels forms the power-source control signal for application to the second connecting element of the connecting elements and, in turn, to the power-source control circuitry of the variable-level power source.
  • the power levels of the power generated by the variable-level power source are thereby caused to vary responsive to the voltage levels of the rechargeable power supply.
  • FIG. 1 is a graphical representation of a typical battery charging curve wherein voltage measured across output terminals of battery cells of a rechargeable battery pack during charging thereof is plotted as a function of time;
  • FIG. 2 is a block diagram of an electrical device of a preferred embodiment of the present invention connected to a variable-level power source;
  • FIG. 3 is a block diagram, similar to that of FIG. 2, but of a radio transceiver of a preferred embodiment of the present invention connected to a variable-level power source;
  • FIG. 4 is a partial block, partial circuit schematic diagram of a charge regulator which forms a portion of the electronic device of FIG. 2 and the radio transceiver of FIG. 3;
  • FIG. 5 is a schematic representation of a cellular radiotelephone, similar to the radio transceiver shown in block form in FIG. 4, of a preferred embodiment of the present invention.
  • FIG. 6 is a flow diagram listing the method steps of the method of a preferred embodiment of the present invention.
  • a portable electronic device is oftentimes powered by a rechargeable power supply.
  • battery charging apparatus is utilized to recharge rechargeable battery cells of the rechargeable power supply.
  • Such elevation in the temperature of the radiotelephone can result in discomfort to the user of the radiotelephone as well as affecting performance of the radiotelephone.
  • the voltage levels of the operative power generated by the battery charging apparatus By causing the voltage levels of the operative power generated by the battery charging apparatus to track the voltage levels of the rechargeable battery cells of the rechargeable power supply, the amount of energy of the operative power generated by the battery charging apparatus which is converted into heat energy is minimized.
  • the voltage levels of the operative power generated by such power source need not be of a constant voltage level. Instead, the voltage levels of the operative power may be varied, thereby to reduce the amount of energy which is converted into heat energy during recharging of the battery cells of the rechargeable power supply.
  • variable-level power source comprising the battery charging apparatus with an indication of the voltage levels of the battery cells of the rechargeable power supply
  • the variable-level power source may be made operative to generate operative power of voltage levels which correspond to, but which are slightly greater than, the voltage levels of the battery cells of the rechargeable power supply, heat generation occurring during recharging of the battery cells may be reduced.
  • the voltage levels of the battery cells of the rechargeable power supply increase as the amounts of energy stored by the battery cells increases during application of operative power thereto.
  • FIG. 1 is a graphical representation of a typical battery charging curve of a nickel-cadmium rechargeable battery cell is shown.
  • the battery charging curve is formed of a plot of the voltage measured across output terminals of a nickel- cadmium rechargeable battery cell as a function of time.
  • voltage, scaled in terms of volts is plotted along ordinate axis 10 and time, scaled in terms of seconds, is represented along abscissa axis 12.
  • the resultant curve 14 generally increases over time responsive to the application of operative power thereto to recharge the battery cell. As illustrated, the general increase is, however, not linear.
  • Points 16 and 17 on curve 14 are representative of voltage levels at which the current levels of the operative power applied to the battery cells of the rechargeable battery power supply are altered. Initially, and during the period of time identified in the figure by “rapid charge phase,” the current levels of the operative power applied to the battery cell is of a relatively high value. Then, during the period of time identified in the figure by “trickle charge phase” (corresponding to curve 14 portions between points 16 and 17), the current levels of the operative power applied to the battery is of a first reduced value. Thereafter, during the period of time identified in the figure by “maintenance charge phase,” the current levels of the operative power applied to the battery cell is of a second reduced value.
  • variable-level power source 22 includes power- source control circuitry 24 as a portion thereof. Control circuitry 24 is operative to control the voltage levels of the operative power generated by variable-level power source 22.
  • Variable-level power source 22 is connected to electronic device 20 by way of lines 26 and 28 at connecting elements 34 and 40, here shown to be plug connectors represented by plug terminals enclosed by rectangles, indicated in dash.
  • Variable- level power supply 22 may, in turn, be connected to a conventional household power supply (by way of connection with plug connector 42) or other suitable power supply.
  • Variable-level power source 22 is operative to generate the operative power on line 26 of any of various voltage levels.
  • Line 46 of electronic device 20 is coupled to receive the operative power generated by power source 22 on line 26 when power source 22 is connected to electronic device 20 at connector 34.
  • Line 46 is coupled to electronic circuitry 52 of electronic device 20, thereby to provide operative power to circuitry 52 to permit operation thereof.
  • Line 46 is further coupled to charge regulator 58 which regulates the values of the operative power generated on line 46.
  • Charge regulator 58 generates a regulated signal on line 64 which is coupled to rechargeable battery power supply 70.
  • Power supply 70 is comprised of one or more rechargeable battery cells. Through such connection, the operative power generated by power source 22 on line 26 is applied to the battery cells of rechargeable battery power supply 70 to recharge the rechargeable battery cells thereof.
  • the battery cells of rechargeable battery power supply 70 convert the energy of the operative power generated by power source 22, and regulated by charge regulator 58, into chemical energy which is stored in the battery cells of the rechargeable battery power supply.
  • Battery power supply 70 is coupled to electronic circuitry 52 by way of line 72.
  • the stored energy of battery power supply 70 is utilized to power circuitry 52 to permit operation of electronic device 20 thereby.
  • Powering of circuitry 52 with the stored energy of battery power supply 70 discharges the stored energy of the battery power supply.
  • the battery cells of the battery power supply must be recharged by applying a charging current to the battery power supply to recharge the battery cells thereof.
  • Control circuitry 74 further forms a portion of electronic device 20. Control circuitry 74 is coupled to electronic circuitry 52 by way of line 76 and to charge regulator 58 by way of line 78.
  • Voltage sensing circuitry and temperature sensing circuitry additionally form portions of electronic device 20.
  • Circuitry 82 and 84 are positioned proximate to rechargeable battery power supply 70 and are operative to measure voltage levels and temperature levels, respectively, of rechargeable battery power supply 70.
  • Voltage sensing circuitry 82 is operative in conventional manner to measure the voltage levels of the battery cells of power supply 70 such as, for instance, by measuring voltage levels across output contacts of power supply 70.
  • Temperature sensing circuitry 84 is similarly operable in conventional manner and may, for instance, be comprised of a temperature sensor positioned to abut against the battery cells of battery power supply 70.
  • Battery power supply 70 may alternately include a temperature sensor, such as sensor 84, positioned internal to the housing of power supply 70, thereby to provide an indication of the temperature levels of the battery cells of power supply 70.
  • Voltage sensing circuitry 82 is operative to generate signals on line 86 indicative of the voltage levels of battery power supply 70.
  • temperature sensing circuitry 84 is operative to generate signals on line 88 indicative of the temperature levels of power supply 70.
  • Lines 86 and 88 are coupled to control circuitry 74 to provide to the control circuitry indications of the voltage levels and temperature levels, respectively, of battery power supply 70.
  • Line 90 extending between line 86 and connector 40 provides the signal indicative of the voltage levels of battery power supply 70 to variable-level power source 22, by way of line 28, when power source 22 is coupled to electronic device 20 at connector 40.
  • indications of the voltage levels of battery power supply 70 are provided to power-source control circuitry 24 which, in turn, controls the voltage levels of the operative power generated by power source 22.
  • the voltage levels of the operative power generated on line 26 by power source 22 and, in turn, on line 46 are dependent upon the voltage levels of battery power supply 70.
  • the regulated signal generated by charge regulator 58 on line 64 is related to the values of the operative power generated on line 46, the values of the regulated signal applied to battery power supply 70 are caused to be dependent upon the measured voltage levels of power supply 70.
  • Electronic device 20 is further shown to include input element 112 which is coupled to electronic circuitry 52 by way of line 118.
  • display element 124 comprised of, for example, light emitting diodes, is also coupled to electronic circuitry 52, here by way of line 128.
  • a user of electronic device 20 operates device 20 by appropriate actuation of input element 112 (such as, for example, actuating ofi7on actuation switches which may comprise portions of input element 112).
  • Portions of electronic circuitry 52 operative responsive to such input connect circuit elements thereof to receive operative power on either line 46 which is generated by power source 22 when connected to device 20 by way of connecting element 34 or, otherwise, to receive operative power on line 70 generated by battery power supply 70.
  • a signal indicative of such operation is supplied to control circuitry 74 by way of line 76.
  • recharging of the battery cells of battery power supply 70 is effectuated most efficiently when the voltage levels of the operative power applied to the battery cells of a rechargeable battery power supply, here power supply 70, is only slightly greater th&n the voltage levels of the battery cells of the power supply.
  • the voltage levels of the operative power generated by power source 22 significantly exceed the voltage levels of the battery power supply, a significant portion of the operative power is converted into heat energy.
  • heat energy causes heating of electronic device 20.
  • the voltage levels of the operative power generated by power source 22 is caused to be approximately one Volt greater than the voltage levels of the battery cells of the battery power supply.
  • Radiotelephone 220 corresponds to electronic device 20 of FIG. 2.
  • Variable-level power source 222 is releasably connectable to radiotelephone 220 and includes power-source control circuitry 224 as a portion thereof.
  • Variable-level power source 222 is connectable to radiotelephone 220 by way of lines 226 and 228 which are connected to connecting elements 234 and 240, here shown to be plug connectors, represented by plug terminals positioned within the rectangles shown in dash.
  • Variable-level power source 222 may, in turn, be connected to a conventional, household power supply (by way of connection with plug connector 242) or to the power supply of a motor vehicle.
  • Power source 222 is operative to generate operative power on line 226 of desired voltage levels.
  • Line 246 of radiotelephone 220 interconnects connecting elements 234 and transceiver circuitry of radiotelephone 220, here shown to be comprised of receiver circuitry portion 250 and transmitter circuitry portion 252.
  • the operative power generated by power source 222 is permitted to be applied to receiver and transmitter circuitry portions 250 and 252 to provide circuitry portions 250 and 252 with operative power to operate the respective circuitry portions.
  • Charge regulator 258 also forms a portion of radiotelephone 220 and is coupled to line 246 to receive the operative power generated by power source 222 when power source 222 is connected to connecting element 234 by way of line 226.
  • Charge regulator 258 is operative to regulate the values of the operative power generated on line 246 and to generate a regulated signal on line 264 which is applied to rechargeable battery power supply 270 to permit recharging of the battery cells thereof.
  • Rechargeable battery power supply 270 is coupled to receiver and transmitter circuitry portions 250 and 252 by way of line 272.
  • variable-level power source 222 is not connected to radiotelephone 220, energy stored within the battery cells of rechargeable battery power supply 270 is utilized to provide operative power to operate the receiver and transmitter circuitry portions.
  • Control circuitry 274 is coupled to the transmitter and receiver circuitry portions 250 and 252 by way of line 276 and to charge regulator 258 by way of line 278.
  • Voltage sensing circuitry 282 and temperature sensing circuitry 284 also form portions of radiotelephone 220. Voltage and temperature sensing circuitry 282 and 284 correspond to circuitry 82 and 84 of FIG. 2. Voltage sensing circuitry 282 is operative to generate a signal indicative of voltage levels taken across the battery cells of battery power supply 270 on line 286 and temperature sensing circuitry 284 is operative to generate a signal on line 288 indicative of the temperature levels of the battery cells of battery power supply 270. Control circuitry 274 is coupled to lines 286 and 288 to receive the signals generated upon the respective lines 286 and 288 which are generated by voltage sensing circuitry 282 and temperature sensing circuitry 284, respectively.
  • line 290 extends between line 286 and connecting element 240, thereby to provide the signal indicative of the voltage levels of the battery cells of battery power supply 270 to variable-level power source 222 when power source 222 is connected to connecting element 240 by way of line 228.
  • power-source control circuitry 224 receives the signals indicative of the voltage levels of battery power supply 270 measured by voltage sensing circuit 282.
  • Control circuitry 224 is operative to cause the voltage levels of the operative power generated by power source 222 to vary responsive to the voltage levels of the battery cells of battery power supply 270.
  • control circuitry 224 causes the voltage levels of the operative power generated by power source 222 to be of a voltage level approximately one volt greater than the measured voltage levels of the battery cells of battery power supply 270.
  • the operative power generated by power source 222 is supplied to radiotelephone 220 by way of line 226, the operative power is regulated by charge regulator 258, and a regulated signal is applied to charge the battery cells of battery power supply 270 on line 264. In such manner, the battery cells of rechargeable battery power supply 270 may be efficiently recharged.
  • Radiotelephone 220 is further shown to include input element 312 which is coupled to receiver and transmitter circuitry portions 250 and 252 by way of line 318.
  • display element 324 is also coupled to portions 250 and 252, here by way of line 328.
  • charge regulator 358 is analogous to charge regulator 258 of radiotelephone 220 of FIG. 3 and to charge regulator 58 of electronic device 20 of FIG. 2.
  • Operative power corresponding to the operative power generated by power sources 222 and 22 of the preceding figures is applied to charge regulator 358 on line 446.
  • a charge control signal is applied to charge regulator 358 on line 494 in manner analogous to the manner in which the charge control signal is generated on line 78 and 278 of charge regulators 58 and 258 of FIGS. 2 and 3, respectively.
  • a regulated signal is generated on line 464 in a manner analogous to the manners in which regulated signals are generated on lines 64 and 264 of FIGS. 2 and 3, respectively.
  • the signal generated on line 446 is applied to a source electrode of field effect transistor 504.
  • the drain electrode of transistor 504 is coupled to line 464 across resistor 510 and diode 516.
  • Comparator 524 configured to form a differential amplifier, includes a positive input coupled to the left-hand side of resistor 510 by way of resistor 530. A negative input of comparator 524 is coupled to a right-hand side of resistor 510 by way of resistor 536. Shunt resistors 542 and 548 are further coupled to the positive and negative inputs, respectively, of comparator 524.
  • Comparator 524 generates a differential output signal on line 554 representative of differences between the signal applied at the positive and negative inputs thereof. As the signals applied to the positive and negative inputs of comparator 524 are indicative of the voltage levels at the left- and right-hand side portions of resistor 510, the signal generated on line 554 is representative of the voltage drop across resistor 510 (and, as voltage is related to the current at the drain electrode, the signal generated on line 554 is related to the current at line 464).
  • Line 554 is coupled to a positive input of comparator 560.
  • Comparator 560 is also configured to form a differential amplifier.
  • a charge control signal generated on line 494 is applied to a negative input of comparator 560.
  • the differential output of amplifier 560 generated on line 566 is applied to a gate electrode of transistor 504 by way of resistor 572.
  • Shunt capacitor 578 is further connected between the gate electrode of transistor 504 and ground.
  • the loop formed between the drain electrode of transistor 504 and the gate electrode thereof forms a feedback loop which permits control of the current (and, hence, the power level) of the signal generated on line 464 as the value of the signal applied to the gate electrode of transistor 504 causes transistor 504 to operate in a conventional manner (analogous to operation of a valve) to control the current level of the drain electrode and line 464. And, the value of the charge control signal applied on line 494 controls the value of the signal applied to the gate electrode. Appropriate variation of the value of the signal generated on line 494 results in a signal generated on line 464 to be of any desired value.
  • Control circuitry 74 and 274 of electronic device 20 and radiotelephone 220 are operative to determine times in which the battery cells of the respective power supplies 70 and 270 are fully charged. A determination that the battery cells are fully charged may be made in several manners.
  • the time rates of change of the temperature levels of the battery cells of the battery power supplies, as measured by voltage sensing circuitry 82 and 282, respectively, is determined.
  • control circuitry 74 or 274 generates signals on lines 78 or 278, respectively, to cause charge regulators 58 and 258, respectively, to cause the regulated signals generated on lines 64 and 264, respectively, to be reduced to be of a first, reduced level.
  • control circuitry 74 and 274 is operative to generate signals on lines 78 and 278, respectively, to cause the charge regulators 58 and 258, respectively, to generate regulated signals on lines 64 and 264 to be of second, preselected values.
  • control circuitry 74 and 274 is operative in similar manners, but responsive to the temperature levels (and not the rates of change thereof) of the battery cells of battery power supplies 70 and 270.
  • control circuitry 74 and 274 When the temperature levels are measured to be greater than a first preselected value, control circuitry 74 and 274 generates signals on lines 78 and 278, respectively, to cause reduction in the values of the signals generated by charge regulators 64 and 264, respectively, which are used to recharge the battery cells of the respective power supplies.
  • control circuitry 74 and 274 is operative, again in similar manners, but responsive to voltage levels of the battery cells of power supplies 70 and 270 measured by voltage sensing circuitry 82 and 282, respectively.
  • control circuitry 74 and 274 is operative to cause the signal generated by charge regulator 58 or 258 to be of a first, reduced level.
  • Radiotelephone 620 corresponds to radiotelephone 220 shown in the block diagram of FIG. 3. Elements of radiotelephone 220 shown in block form in FIG. 3 are disposed within the housing of radiotelephone 620 of FIG. 5 but for rechargeable battery power supply 270 which here is shown to comprise battery pack 624.
  • Radiotelephone 620 is connected to variable-level power source 622 by way of lines 626 and 628 which connect power source 622 to connecting elements of radiotelephone 620 through plug connector 630.
  • Plug connector 642 is also shown in the figure permitting connection of power source 626 to a conventional household power supply.
  • plug connector 642 comprises a plug connector permitting connection to a conventional household power supply, other plug connectors permitting connection to other types of power supplies are, of course, similar possible.
  • radiotelephone 620 may be conveniently operated by a user in spite of the connection between radiotelephone 620 and power source 622. Because the voltage levels of the operative power generated by power source 622 tracks the voltage levels of the battery pack, recharging of the battery cells of the battery pack is efficiently accomplished without conversion of excessive amounts of energy into heat energy.
  • FIG. 6 is a logical flow diagram listing the method steps of the method, referred to generally by reference numeral 800, of a preferred embodiment of the present invention.
  • the method is operable to receive operative power generated by a variable-level power source having power-source control circuitry operative responsive to reception of a power-source control signal when the variable-level power source is connected to the radiotelephone.
  • variable-level power source is releasably connected to the radiotelephone.
  • a rechargeable power supply is coupled to receive a charging signal responsive to times in which the variable-level power source is coupled to provide operative power to the radiotelephone.
  • the transceiver circuitry is provided with either the operative power generated by the variable-level power source or power generated by the energy stored by the rechargeable power supply.
  • a signal representative of the voltage levels of the rechargeable power supply is generated.
  • the signal representative of the voltage levels forms the power-source control signal for application to the variable-level power source and, in turn, to the power- source control circuitry of the variable-level power source, thereby to cause the power levels of the power generated by the variable-level power source to vary responsive to the voltage levels of the rechargeable power supply.

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Abstract

An electronic device (20), such as a radiotelephone, is connectable to a variable-level power source (22). The electronic device (20) includes a rechargeable power source (70) as a portion thereof. Power source control signals (28) are generated for application to the variable-level power source (22) indicative of voltage levels of the rechargeable power supply (70). The voltage levels of the operative power generated by the variable-level power source (22) is caused to be of levels responsive to measured levels of the voltage of the rechargeable power supply (70). The voltage levels of the operative power of the variable-level power source (22) thereby track the voltage levels of the rechargeable power supply (70).

Description

ELECTRONIC DEVICE FOR CONTROLLING
APPLICATION OF A CHARGING CURRENT
THERETO AND ASSOCIATED METHOD THEREFOR
The present invention is a continuation in part of patent application serial number 083,751, filed on June 30, 1993, entitled "Electronic Device Having Internal Charge Regulator for Controlling Application of a Charging Current Thereto and Associated Method Therefor" by David M. DeMuro.
Background of the Invention:
The present invention relates generally to electronic devices which may be powered by rechargeable power supplies and, more particularly, to an electronic device having a rechargeable power supply, and an associated method, connectable to an external power source capable of providing operative power to recharge the rechargeable power supply of the electronic device.
Many electronic devices are constructed of designs which permit powering thereof by a battery power supply comprised of one or more battery cells. In some instances, use of a battery power supply to pwoer the electronic device is necessitated when the electronic device is not, or cannot be, positioned proximate to a permanent, or other fixed, power supply. In other instances, a battery power supply is utilized to power the electronic device to increase the portability of the device as no power cable is required to interconnect the electronic device to the permanent, or other fixed, power supply. Typically, the one or more battery cells comprising the battery power supply utilized to power the electronic device are carried directly with, or housed within, the electronic device. However, because a battery power supply is capable of storing only a finite amount of energy, powering of the electronic device with the battery power supply is limited by the energy storage capacity of the battery power supply. Powering of the electronic device by the battery power supply causes discharge of the stored energy of the battery power supply. Once the stored energy of the battery power supply is discharged beyond a certain level, replacement of the battery power supply is necessitated to permit continued operation of the electronic device. Increasing the energy storage capacity of a battery power supply, such as by increasing the number of battery cells comprising such power supply, increases the size (and weight) of the power supply. Such manner of increasing the energy storage capacity of a battery power supply reduces the portability of the electronic device when the battery power supply is carried with the electronic device. Accordingly, when designing a battery power supply, a compromise is made between increased energy storage capacity and reduced portability of the electronic device which carries such a battery power supply. A portable or transportable radiotelephone is one such electronic device which is typically powered by a battery power supply. The battery power supply is typically carried directly with the radiotelephone and is of a size and weight which does not unduly constrain the portability of the radiotelephone. A radiotelephone includes radio transceiver circuitry including transmitter circuitry and receiver circuitry which is operative to transmit and to receive, respectively, modulated signals. In typical operation of a radiotelephone, receiver circuitry portions thereof are powered continuously while awaiting reception of signals indicative of an incoming call to the radiotelephone. Thereafter, the transmitter circuitry portions of the radiotelephone are also powered to permit transmission of modulated signals therefrom. adiotelephones operative in many cellular communication systems are constructed to transmit modulated signals therefrom and also simultaneously to receive modulated signals transmitted thereto (the modulated signals transmitted by, and to, the radiotelephone are transmitted upon separate frequency channels). Radiotelephones operative in other cellular communication systems are constructed to transmit and to receive modulated signals during nonsimultaneous time periods and, during two-way communication with the radiotelephone, the receiver and transmitter circuitry portions are powered during nonsimultaneous time periods.
Times during which the receiver circuitry portions of the radiotelephone are powered while awaiting transmission thereto of signals indicative of an incoming call shall hereinafter be referred to as times in which the radiotelephone is in the "standby" mode. (It should, of course, be noted that a user of a radiotelephone also oftentimes provides operative power to the radiotelephone only when the user desires to initiate and thereafter effectuate a telephone call; during other times no operative power is provided to the radiotelephone, and the radiotelephone is not powered to receive signals transmitted thereto. That is to say, the user of the radiotelephone may choose not to operate the radiotelephone in the "standby" mode to receive an incoming call transmitted to the radiotelephone, but rather power the radiotelephone only during times in which the user initiates a telephone call.)
Generally, the amounts of energy required to operate the transmitter circuitry portions of the radiotelephone are greater than the amounts of energy required to operate the receiver circuitry portions thereof. And, because practical devices are of less than ideal efficiencies, a certain portion of the energy applied to the radiotelephone is converted into heat energy which results in heat build-up of the radiotelephone. As more energy is required to operate the transmitter circuitry portions of the radiotelephone, there is a correspondingly greater amount of heat generation during operation of the transmitter circuitry portions of the radiotelephone than when only the receiver circuitry portions are operable.
Rechargeable battery power supplies comprised of one or more rechargeable battery cells have been developed and are commercially available. Some of such commercially- available, rechargeable battery power supplies are of constructions designed for use to power radiotelephones. The use of rechargeable battery power supplies is advantageous as the rechargeable battery cells thereof may be recharged by applying thereto a charging current generated by a power supply. Once recharged, the rechargeable battery power supply may be reused. Some constructions of rechargeable battery power supplies may be recharged, and reused, up to, and even in excess of, five hundred times.
As mentioned previously, a rechargeable battery power supply is typically comprised of one or more battery cells. The cells are connected in a series (or other) connection, and are typically housed within a common housing. The housing, together with the battery cells, comprise the battery power supply which is also oftentimes referred to as a battery pack. For purposes of simplicity, such constructions are also generically referred to by the general term "battery". The present disclosure shall, at times, utilize such simplified terminology.
The battery cells of a rechargeable battery power supply are formed of various different materials of construction. For instance, a rechargeable battery cell may be comprised of a lithium (Li) material, a -nickel-cadmium (Ni-Cd) material, or a nickel metal hydride (NiMH02) material. Battery cells constructed of these different materials exhibit different characteristics during charging thereof.
Battery charging apparatus is also commercially available to permit recharging of rechargeable battery power supplies. A battery charger comprising such battery charging apparatus is typically comprised of a power source for supplying operative power to recharge the rechargeable battery power supply when suitably connected to the charging apparatus to receive the operative power. The energy of the operative power applied to the rechargeable battery power supply is converted into chemical energy which is stored by the rechargeable battery cells of the battery power supply. Application of the operative power to the battery cells over an elapsed period of time permits the rechargeable battery cells to become fully recharged.
However, because practical devices are of less than ideal efficiencies, a certain portion of the energy applied to the battery cells are converted into heat energy which causes heat build-up of the battery cells. Some battery charging apparatus are of construction- types which permit the electronic device and also the battery power supply both to receive operative power. Such battery charging apparatus provides operative power not only to recharge the rechargeable battery cells of the battery power supply but further provides operative power to permit operation of the electronic device. For instance, battery charging apparatus of construction-types permitting a radiotelephone together with a rechargeable battery pack to receive operative power to recharge the battery cells of the battery pack and also to permit operation of the circuitry of the radiotelephone is available. As mentioned previously, however, in practical devices, heat is generated as a byproduct of operation of the circuitry of the radiotelephone. And, heat is also generated as a byproduct of the process of recharging the battery cells of the battery power supply. Various of the rechargeable battery constructions comprising the battery cells of a rechargeable battery power supply exhibit charging curves (which are plots of voltage scaled as a function of time). Over time, during recharging of such constructions of battery cells, as the amount of energy stored therein increases, the voltage levels of the battery cells of the power supply increases. Recharging of the rechargeable power supply is most efficiently accomplished when the voltage level of the power applied to the battery constructions is slightly greater (for example, approximately one Volt greater) than the voltage levels of the battery constructions. That is to say, recharging of a battery construction is most efficiently accomplished when the voltage level of the power applied to recharge the battery "tracks" the voltage level of the rechargeable battery power supply. The voltage of the power applied to the rechargeable battery power supply must be greater than the voltage levels of the rechargeable battery power supply to cause energy to be transferred to the battery power supply. However, when the voltage of the power applied to the battery power supply is significantly greater than the voltage levels of the battery power supply, a significant portion of the energy corresponding to the voltage differentials is converted into heat energy.
When the rechargeable battery power supply is embodied as a portion of an electronic device, such as a radiotelephone, the heat energy generated during application of the charging power to the rechargeable battery power supply results in heating of the electronic device. Such heating of the electronic device may cause discomfort to a user of the electronic device and also affect the performance thereof. What is needed, therefore, is means by which charging power may be applied to a rechargeable battery embodied in an electronic device without generation of excessive amounts of heat energy.
Summary of the Invention:
The present invention, accordingly, provides a device, and associated method, which overcomes the problems associated with the existing art.
The present invention further advantageously provides an electronic device including a rechargeable power supply wherein the electronic device is connectable to a variable-level power source which provides operative power to recharge the rechargeable power supply and also to provide operative power to operate electronic circuitry of the electronic device. The present invention includes further advantages and features, the details of which will become more apparent upon reading the following detailed description of the preferred embodiments. In accordance with the present invention, therefore, an electronic device which is releasably connectable to a variable- level power source is disclosed. The variable-level power source has power-source control circuitry operative responsive to reception of a power-source control signal for controlling power levels of operative power generated by the variable-level power source. The electronic device is operable to receive the operative power generated by the variable-level power source when the variable-level power source is connected therewith. Connecting elements permit releasable connection with the variable-level power source including at least a first connecting element and a second connecting element. The first connecting element permits connecting of the variable- level power source thereto, thereby to receive operative power generated by the variable-level power source thereat. The second connecting element permits connection of the power- source control circuitry of the variable-level power source thereto. A rechargeable power supply is coupled to receive a charging signal responsive to times in which the variable-level power source is connected to the first connecting element. Voltage sensing circuitry is operative to sense voltage levels of the rechargeable power supply and to generate a signal representative of the voltage levels sensed thereby. The signal representative of the voltage levels forms the power-source control signal for application to the second connecting element of the connecting elements and, in turn, to the power-source control circuitry of the variable-level power source. The power levels of the power generated by the variable-level power source are thereby caused to vary responsive to the voltage levels of the rechargeable power supply.
Brief Description of the Drawings:
The present invention will be better understood when read in light of the accompanying drawings in which:
FIG. 1 is a graphical representation of a typical battery charging curve wherein voltage measured across output terminals of battery cells of a rechargeable battery pack during charging thereof is plotted as a function of time;
FIG. 2 is a block diagram of an electrical device of a preferred embodiment of the present invention connected to a variable-level power source;
FIG. 3 is a block diagram, similar to that of FIG. 2, but of a radio transceiver of a preferred embodiment of the present invention connected to a variable-level power source;
FIG. 4 is a partial block, partial circuit schematic diagram of a charge regulator which forms a portion of the electronic device of FIG. 2 and the radio transceiver of FIG. 3;
FIG. 5 is a schematic representation of a cellular radiotelephone, similar to the radio transceiver shown in block form in FIG. 4, of a preferred embodiment of the present invention; and
FIG. 6 is a flow diagram listing the method steps of the method of a preferred embodiment of the present invention.
Description of the Preferred Embodiments: As mentioned hereinabove, a portable electronic device is oftentimes powered by a rechargeable power supply. When the rechargeable power supply is depleted of stored energy, battery charging apparatus is utilized to recharge rechargeable battery cells of the rechargeable power supply.
Several constructions of battery charging apparatus are available which permit the portable electronic device to be positioned together with the rechargeable power supply carried therewith such that operative power is provided both to the rechargeable battery cells of the rechargeable power supply and also to the circuitry of the electronic device.
However, because power transfer between the battery charging apparatus and the electronic device is not wholly efficient, a certain portion of the energy of the operative power generated by the battery charging apparatus is converted into heat energy which elevates the temperature of the electronic device. And, when the voltage levels of the operative power generated by the battery charging apparatus is significantly higher than the voltage levels of the battery cells of the rechargeable power supply, large portions of the operative power generated by the battery charging apparatus is converted into heat energy. As a result, the temperature of the electronic device powered by such rechargeable power supply exhibits a significant rise in temperature. In the particular instance in which the electronic device comprises a radiotelephone operative in a cellular communication system, conversion of operative power generated by the battery charging apparatus into heat energy causes an elevation of the temperature of the radiotelephone. Such elevation in the temperature of the radiotelephone can result in discomfort to the user of the radiotelephone as well as affecting performance of the radiotelephone. By causing the voltage levels of the operative power generated by the battery charging apparatus to track the voltage levels of the rechargeable battery cells of the rechargeable power supply, the amount of energy of the operative power generated by the battery charging apparatus which is converted into heat energy is minimized.
When the battery charging apparatus comprises a variable-level power source, the voltage levels of the operative power generated by such power source need not be of a constant voltage level. Instead, the voltage levels of the operative power may be varied, thereby to reduce the amount of energy which is converted into heat energy during recharging of the battery cells of the rechargeable power supply.
By providing the variable-level power source comprising the battery charging apparatus with an indication of the voltage levels of the battery cells of the rechargeable power supply, the variable-level power source may be made operative to generate operative power of voltage levels which correspond to, but which are slightly greater than, the voltage levels of the battery cells of the rechargeable power supply, heat generation occurring during recharging of the battery cells may be reduced.
As also mentioned previously, the voltage levels of the battery cells of the rechargeable power supply increase as the amounts of energy stored by the battery cells increases during application of operative power thereto.
FIG. 1 is a graphical representation of a typical battery charging curve of a nickel-cadmium rechargeable battery cell is shown. The battery charging curve is formed of a plot of the voltage measured across output terminals of a nickel- cadmium rechargeable battery cell as a function of time. In FIG. 1, voltage, scaled in terms of volts, is plotted along ordinate axis 10 and time, scaled in terms of seconds, is represented along abscissa axis 12. The resultant curve 14 generally increases over time responsive to the application of operative power thereto to recharge the battery cell. As illustrated, the general increase is, however, not linear. Points 16 and 17 on curve 14 are representative of voltage levels at which the current levels of the operative power applied to the battery cells of the rechargeable battery power supply are altered. Initially, and during the period of time identified in the figure by "rapid charge phase," the current levels of the operative power applied to the battery cell is of a relatively high value. Then, during the period of time identified in the figure by "trickle charge phase" (corresponding to curve 14 portions between points 16 and 17), the current levels of the operative power applied to the battery is of a first reduced value. Thereafter, during the period of time identified in the figure by "maintenance charge phase," the current levels of the operative power applied to the battery cell is of a second reduced value.
Characteristic charging curves of other types of battery constructions may be similarly shown. While such other types of battery constructions have charging curves of other characteristic shapes, the general increase in voltage as increasing amounts of energy are stored by such batteries generally holds true. In any event, by causing the variable- level power source comprising the battery charging apparatus to track the voltage of the battery cells to which operative power is applied, generation of heat energy is reduced. Turning next to the block diagram of FIG. 2, an electronic device, referred to generally by reference numeral 20, of a preferred embodiment of the present invention is positioned in releasable connection with variable-level power source 22. Variable-level power source 22 includes power- source control circuitry 24 as a portion thereof. Control circuitry 24 is operative to control the voltage levels of the operative power generated by variable-level power source 22.
Variable-level power source 22 is connected to electronic device 20 by way of lines 26 and 28 at connecting elements 34 and 40, here shown to be plug connectors represented by plug terminals enclosed by rectangles, indicated in dash. Variable- level power supply 22 may, in turn, be connected to a conventional household power supply (by way of connection with plug connector 42) or other suitable power supply.
Variable-level power source 22 is operative to generate the operative power on line 26 of any of various voltage levels. Line 46 of electronic device 20 is coupled to receive the operative power generated by power source 22 on line 26 when power source 22 is connected to electronic device 20 at connector 34. Line 46, in turn, is coupled to electronic circuitry 52 of electronic device 20, thereby to provide operative power to circuitry 52 to permit operation thereof.
Line 46 is further coupled to charge regulator 58 which regulates the values of the operative power generated on line 46. Charge regulator 58 generates a regulated signal on line 64 which is coupled to rechargeable battery power supply 70. Power supply 70 is comprised of one or more rechargeable battery cells. Through such connection, the operative power generated by power source 22 on line 26 is applied to the battery cells of rechargeable battery power supply 70 to recharge the rechargeable battery cells thereof. The battery cells of rechargeable battery power supply 70 convert the energy of the operative power generated by power source 22, and regulated by charge regulator 58, into chemical energy which is stored in the battery cells of the rechargeable battery power supply.
Battery power supply 70 is coupled to electronic circuitry 52 by way of line 72. When power source 22 is not connected to electronic device 20 to provide operative power thereto, the stored energy of battery power supply 70 is utilized to power circuitry 52 to permit operation of electronic device 20 thereby. Powering of circuitry 52 with the stored energy of battery power supply 70, however, discharges the stored energy of the battery power supply. Once the stored energy of battery power supply 70 is depleted beneath a certain level, the battery cells of the battery power supply must be recharged by applying a charging current to the battery power supply to recharge the battery cells thereof. Control circuitry 74 further forms a portion of electronic device 20. Control circuitry 74 is coupled to electronic circuitry 52 by way of line 76 and to charge regulator 58 by way of line 78.
Voltage sensing circuitry and temperature sensing circuitry additionally form portions of electronic device 20. Circuitry 82 and 84 are positioned proximate to rechargeable battery power supply 70 and are operative to measure voltage levels and temperature levels, respectively, of rechargeable battery power supply 70.
Voltage sensing circuitry 82 is operative in conventional manner to measure the voltage levels of the battery cells of power supply 70 such as, for instance, by measuring voltage levels across output contacts of power supply 70.
Temperature sensing circuitry 84 is similarly operable in conventional manner and may, for instance, be comprised of a temperature sensor positioned to abut against the battery cells of battery power supply 70. Battery power supply 70 may alternately include a temperature sensor, such as sensor 84, positioned internal to the housing of power supply 70, thereby to provide an indication of the temperature levels of the battery cells of power supply 70.
Voltage sensing circuitry 82 is operative to generate signals on line 86 indicative of the voltage levels of battery power supply 70. Similarly, temperature sensing circuitry 84 is operative to generate signals on line 88 indicative of the temperature levels of power supply 70. Lines 86 and 88 are coupled to control circuitry 74 to provide to the control circuitry indications of the voltage levels and temperature levels, respectively, of battery power supply 70.
Line 90, extending between line 86 and connector 40 provides the signal indicative of the voltage levels of battery power supply 70 to variable-level power source 22, by way of line 28, when power source 22 is coupled to electronic device 20 at connector 40. In such manner, indications of the voltage levels of battery power supply 70 are provided to power-source control circuitry 24 which, in turn, controls the voltage levels of the operative power generated by power source 22. Thereby, the voltage levels of the operative power generated on line 26 by power source 22 and, in turn, on line 46 are dependent upon the voltage levels of battery power supply 70. As the regulated signal generated by charge regulator 58 on line 64 is related to the values of the operative power generated on line 46, the values of the regulated signal applied to battery power supply 70 are caused to be dependent upon the measured voltage levels of power supply 70.
Electronic device 20 is further shown to include input element 112 which is coupled to electronic circuitry 52 by way of line 118. Similarly, display element 124, comprised of, for example, light emitting diodes, is also coupled to electronic circuitry 52, here by way of line 128. A user of electronic device 20 operates device 20 by appropriate actuation of input element 112 (such as, for example, actuating ofi7on actuation switches which may comprise portions of input element 112). Portions of electronic circuitry 52 operative responsive to such input connect circuit elements thereof to receive operative power on either line 46 which is generated by power source 22 when connected to device 20 by way of connecting element 34 or, otherwise, to receive operative power on line 70 generated by battery power supply 70. When electronic circuitry 52 is operative, a signal indicative of such operation is supplied to control circuitry 74 by way of line 76.
As mentioned previously, recharging of the battery cells of battery power supply 70 is effectuated most efficiently when the voltage levels of the operative power applied to the battery cells of a rechargeable battery power supply, here power supply 70, is only slightly greater th&n the voltage levels of the battery cells of the power supply. When the voltage levels of the operative power generated by power source 22 significantly exceed the voltage levels of the battery power supply, a significant portion of the operative power is converted into heat energy. Such heat energy causes heating of electronic device 20. However, by causing the voltage levels of the operative power generated by power source 22 to track the voltage levels of the battery cells of the battery power supply, conversion of the operative power into heat energy is reduced. (In a preferred embodiment of the present invention, the voltage levels of the operative power generated by the power source 22 is caused to be approximately one Volt greater than the voltage levels of the battery cells of the battery power supply.)
Turning next to the block diagram of FIG. 3, a radio transceiver, here a radiotelephone, referred to generally by reference numeral 220, of a preferred embodiment of the present invention is shown. Radiotelephone 220 corresponds to electronic device 20 of FIG. 2. Variable-level power source 222 is releasably connectable to radiotelephone 220 and includes power-source control circuitry 224 as a portion thereof.
Variable-level power source 222 is connectable to radiotelephone 220 by way of lines 226 and 228 which are connected to connecting elements 234 and 240, here shown to be plug connectors, represented by plug terminals positioned within the rectangles shown in dash. Variable-level power source 222 may, in turn, be connected to a conventional, household power supply (by way of connection with plug connector 242) or to the power supply of a motor vehicle. Power source 222 is operative to generate operative power on line 226 of desired voltage levels.
Line 246 of radiotelephone 220 interconnects connecting elements 234 and transceiver circuitry of radiotelephone 220, here shown to be comprised of receiver circuitry portion 250 and transmitter circuitry portion 252. When power source 222 is connected to connecting element 234 of radiotelephone 220, the operative power generated by power source 222 is permitted to be applied to receiver and transmitter circuitry portions 250 and 252 to provide circuitry portions 250 and 252 with operative power to operate the respective circuitry portions. Charge regulator 258 also forms a portion of radiotelephone 220 and is coupled to line 246 to receive the operative power generated by power source 222 when power source 222 is connected to connecting element 234 by way of line 226. Charge regulator 258 is operative to regulate the values of the operative power generated on line 246 and to generate a regulated signal on line 264 which is applied to rechargeable battery power supply 270 to permit recharging of the battery cells thereof.
Rechargeable battery power supply 270 is coupled to receiver and transmitter circuitry portions 250 and 252 by way of line 272. When variable-level power source 222 is not connected to radiotelephone 220, energy stored within the battery cells of rechargeable battery power supply 270 is utilized to provide operative power to operate the receiver and transmitter circuitry portions. Control circuitry 274 is coupled to the transmitter and receiver circuitry portions 250 and 252 by way of line 276 and to charge regulator 258 by way of line 278.
Voltage sensing circuitry 282 and temperature sensing circuitry 284 also form portions of radiotelephone 220. Voltage and temperature sensing circuitry 282 and 284 correspond to circuitry 82 and 84 of FIG. 2. Voltage sensing circuitry 282 is operative to generate a signal indicative of voltage levels taken across the battery cells of battery power supply 270 on line 286 and temperature sensing circuitry 284 is operative to generate a signal on line 288 indicative of the temperature levels of the battery cells of battery power supply 270. Control circuitry 274 is coupled to lines 286 and 288 to receive the signals generated upon the respective lines 286 and 288 which are generated by voltage sensing circuitry 282 and temperature sensing circuitry 284, respectively. line 290 extends between line 286 and connecting element 240, thereby to provide the signal indicative of the voltage levels of the battery cells of battery power supply 270 to variable-level power source 222 when power source 222 is connected to connecting element 240 by way of line 228. In particular, power-source control circuitry 224 receives the signals indicative of the voltage levels of battery power supply 270 measured by voltage sensing circuit 282.
Control circuitry 224 is operative to cause the voltage levels of the operative power generated by power source 222 to vary responsive to the voltage levels of the battery cells of battery power supply 270. In a preferred embodiment, control circuitry 224 causes the voltage levels of the operative power generated by power source 222 to be of a voltage level approximately one volt greater than the measured voltage levels of the battery cells of battery power supply 270. The operative power generated by power source 222 is supplied to radiotelephone 220 by way of line 226, the operative power is regulated by charge regulator 258, and a regulated signal is applied to charge the battery cells of battery power supply 270 on line 264. In such manner, the battery cells of rechargeable battery power supply 270 may be efficiently recharged.
Radiotelephone 220 is further shown to include input element 312 which is coupled to receiver and transmitter circuitry portions 250 and 252 by way of line 318. Similarly, display element 324 is also coupled to portions 250 and 252, here by way of line 328.
Turning next to the partial block, partial schematic diagram of FIG. 4, a charge regulator, here designated by reference numeral 358, is shown. Charge regulator 358 is analogous to charge regulator 258 of radiotelephone 220 of FIG. 3 and to charge regulator 58 of electronic device 20 of FIG. 2. Operative power corresponding to the operative power generated by power sources 222 and 22 of the preceding figures is applied to charge regulator 358 on line 446. A charge control signal is applied to charge regulator 358 on line 494 in manner analogous to the manner in which the charge control signal is generated on line 78 and 278 of charge regulators 58 and 258 of FIGS. 2 and 3, respectively. And, a regulated signal is generated on line 464 in a manner analogous to the manners in which regulated signals are generated on lines 64 and 264 of FIGS. 2 and 3, respectively. The signal generated on line 446 is applied to a source electrode of field effect transistor 504. The drain electrode of transistor 504 is coupled to line 464 across resistor 510 and diode 516.
Comparator 524, configured to form a differential amplifier, includes a positive input coupled to the left-hand side of resistor 510 by way of resistor 530. A negative input of comparator 524 is coupled to a right-hand side of resistor 510 by way of resistor 536. Shunt resistors 542 and 548 are further coupled to the positive and negative inputs, respectively, of comparator 524.
Comparator 524 generates a differential output signal on line 554 representative of differences between the signal applied at the positive and negative inputs thereof. As the signals applied to the positive and negative inputs of comparator 524 are indicative of the voltage levels at the left- and right-hand side portions of resistor 510, the signal generated on line 554 is representative of the voltage drop across resistor 510 (and, as voltage is related to the current at the drain electrode, the signal generated on line 554 is related to the current at line 464).
Line 554 is coupled to a positive input of comparator 560. Comparator 560 is also configured to form a differential amplifier. A charge control signal generated on line 494 is applied to a negative input of comparator 560. The differential output of amplifier 560 generated on line 566 is applied to a gate electrode of transistor 504 by way of resistor 572. Shunt capacitor 578 is further connected between the gate electrode of transistor 504 and ground. The loop formed between the drain electrode of transistor 504 and the gate electrode thereof forms a feedback loop which permits control of the current (and, hence, the power level) of the signal generated on line 464 as the value of the signal applied to the gate electrode of transistor 504 causes transistor 504 to operate in a conventional manner (analogous to operation of a valve) to control the current level of the drain electrode and line 464. And, the value of the charge control signal applied on line 494 controls the value of the signal applied to the gate electrode. Appropriate variation of the value of the signal generated on line 494 results in a signal generated on line 464 to be of any desired value.
Control circuitry 74 and 274 of electronic device 20 and radiotelephone 220 are operative to determine times in which the battery cells of the respective power supplies 70 and 270 are fully charged. A determination that the battery cells are fully charged may be made in several manners.
In first embodiments of the present invention, the time rates of change of the temperature levels of the battery cells of the battery power supplies, as measured by voltage sensing circuitry 82 and 282, respectively, is determined. When the time rate of change exceeds a first preselected value, control circuitry 74 or 274 generates signals on lines 78 or 278, respectively, to cause charge regulators 58 and 258, respectively, to cause the regulated signals generated on lines 64 and 264, respectively, to be reduced to be of a first, reduced level. When the time rate of change of the temperature levels of the battery cells exceeds second predetermined levels, control circuitry 74 and 274 is operative to generate signals on lines 78 and 278, respectively, to cause the charge regulators 58 and 258, respectively, to generate regulated signals on lines 64 and 264 to be of second, preselected values.
In second preferred embodiments of the present invention, control circuitry 74 and 274 is operative in similar manners, but responsive to the temperature levels (and not the rates of change thereof) of the battery cells of battery power supplies 70 and 270. When the temperature levels are measured to be greater than a first preselected value, control circuitry 74 and 274 generates signals on lines 78 and 278, respectively, to cause reduction in the values of the signals generated by charge regulators 64 and 264, respectively, which are used to recharge the battery cells of the respective power supplies.
And, in third embodiments of the present invention, control circuitry 74 and 274 is operative, again in similar manners, but responsive to voltage levels of the battery cells of power supplies 70 and 270 measured by voltage sensing circuitry 82 and 282, respectively. With reference to the graphical representation of FIG. 1, when the measured voltage levels of the battery cells of battery power supply 70 or 270 is beyond a level corresponding to point 16 on curve 14, control circuitry 74 and 274 is operative to cause the signal generated by charge regulator 58 or 258 to be of a first, reduced level. And, when the voltage levels of the battery cells of the power supplies 70 and 270 peak and then reach a second, preselected value, control circuitry 74 and 274 generate signals on line 78 and 278 to cause charge regulators 58 and 258 to generate signals on lines 64 and 264 of second, reduced levels. Turning next to the schematic view of FIG. 5, a radiotelephone, referred to generally by reference numeral 620, is shown. Radiotelephone 620 corresponds to radiotelephone 220 shown in the block diagram of FIG. 3. Elements of radiotelephone 220 shown in block form in FIG. 3 are disposed within the housing of radiotelephone 620 of FIG. 5 but for rechargeable battery power supply 270 which here is shown to comprise battery pack 624. Radiotelephone 620 is connected to variable-level power source 622 by way of lines 626 and 628 which connect power source 622 to connecting elements of radiotelephone 620 through plug connector 630. (Connecting elements of radiotelephone 620 are hidden from view in the figure, but correspond to connecting elements 234 and 240 of FIG. 3.) Plug connector 642 is also shown in the figure permitting connection of power source 626 to a conventional household power supply. (While plug connector 642 comprises a plug connector permitting connection to a conventional household power supply, other plug connectors permitting connection to other types of power supplies are, of course, similar possible.)
Because power source 622 is positioned remote from radiotelephone 620, but connected thereto by way of lines 626 and 628, radiotelephone 620 may be conveniently operated by a user in spite of the connection between radiotelephone 620 and power source 622. Because the voltage levels of the operative power generated by power source 622 tracks the voltage levels of the battery pack, recharging of the battery cells of the battery pack is efficiently accomplished without conversion of excessive amounts of energy into heat energy.
FIG. 6 is a logical flow diagram listing the method steps of the method, referred to generally by reference numeral 800, of a preferred embodiment of the present invention. The method is operable to receive operative power generated by a variable-level power source having power-source control circuitry operative responsive to reception of a power-source control signal when the variable-level power source is connected to the radiotelephone.
First, and as indicated by block 806, the variable-level power source is releasably connected to the radiotelephone. Next, and as indicated by block 812, a rechargeable power supply is coupled to receive a charging signal responsive to times in which the variable-level power source is coupled to provide operative power to the radiotelephone. Next, and as indicated by block 818, the transceiver circuitry is provided with either the operative power generated by the variable-level power source or power generated by the energy stored by the rechargeable power supply.
Next, and as indicated by block 824, a signal representative of the voltage levels of the rechargeable power supply is generated. The signal representative of the voltage levels forms the power-source control signal for application to the variable-level power source and, in turn, to the power- source control circuitry of the variable-level power source, thereby to cause the power levels of the power generated by the variable-level power source to vary responsive to the voltage levels of the rechargeable power supply.
While the present invention has been described in connection with the preferred embodiments shown in the various figures, it is to be understood that other similar embodiments may be used and modifications and additions may be made to the described embodiments for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.

Claims

ClaimsWhat is claimed is:
1. An electronic device releasably connectable to a variable-level power source to receive power generated by the variable level power source when connected therewith, said electronic device comprising:
a connector capable of connection with the variable-level power source, said connector including a first connecting element to receive power generated by the variable-level power source and a second connecting element to provide a power- source control signal to the variable-level power source;
a rechargeable power supply operatively coupled to the first connecting element to receive the power from the variable-level power source and operatively coupled to the second connecting element to provide the power-source control signal indicative of voltage levels of the rechargeable power supply.
2. An electronic device according to claim 1, wherein the rechargeable power supply comprises a battery power supply comprised of at least one battery cell.
3. An electronic device according to claim 1, further comprising electronic circuitry operatively coupled to alternately receive either one of the power generated by the variable-level power source at the first connecting element and power generated by energy stored by said rechargeable power supply.
4. An electronic device according to claim 3, wherein the electronic circuitry comprises at least portions of a radio transceiver.
5. An electronic device according to claim 4, wherein the radio transceiver comprises a radiotelephone.
6. An electronic device according to claim 1, further comprising a charge regulator operatively coupled between the first connecting element of said connector and said rechargeable power supply to receive the power from the variable-level power source and to regulate a current of the power from the variable-level power source by producing a regulated charging signal for recharging said rechargeable power supply.
7. An electronic device according to claim 6, wherein said charge regulator comprises a feedback control circuit operatively coupled to receive a charge regulation signal and to compare a signal indicative of current in the regulated charging signal with the charge regulation signal to regulate the current of the power.
8. A method of recharging a rechargeable power supply using power generated by a variable level power source connected therewith, said method comprising the steps of:
(a) receiving power generated by the variable-level power source and applying such power to the rechargeable power supply to recharge the rechargeable power supply; and
(b) providing a power-source control signal to the variable-level power source indicative of voltage levels of the rechargeable power supply.
9. A method according to claim 8, wherein said step (b) comprises the substep of (bl) providing the power source control signal based on the voltage levels of the rechargeable power supply.
10. A method according to claim 8, further comprising the step of (c) charge regulating a current of the power from the variable-level power source and producing a regulated charging signal for recharging of the rechargeable power supply.
PCT/US1994/007454 1993-06-30 1994-06-30 Electronic device for controlling application of a charging current thereto and associated method therefor WO1995001699A1 (en)

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GB2285717B (en) 1998-04-01
GB9505466D0 (en) 1995-05-03
GB2285717A (en) 1995-07-19
CN1113404A (en) 1995-12-13

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