WO2014156514A1 - Charging device - Google Patents

Charging device Download PDF

Info

Publication number
WO2014156514A1
WO2014156514A1 PCT/JP2014/055530 JP2014055530W WO2014156514A1 WO 2014156514 A1 WO2014156514 A1 WO 2014156514A1 JP 2014055530 W JP2014055530 W JP 2014055530W WO 2014156514 A1 WO2014156514 A1 WO 2014156514A1
Authority
WO
WIPO (PCT)
Prior art keywords
power supply
circuit
supply circuit
power
suspension
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.)
Ceased
Application number
PCT/JP2014/055530
Other languages
French (fr)
Inventor
Yasushi Nakano
Kazuhiko Funabashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koki Holdings Co Ltd
Original Assignee
Hitachi Koki Co Ltd
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 Hitachi Koki Co Ltd filed Critical Hitachi Koki Co Ltd
Publication of WO2014156514A1 publication Critical patent/WO2014156514A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/50—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/60—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements
    • H02J7/663—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements using battery or load disconnect circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems

Definitions

  • the present invention relates to a charging device for charging a battery pack.
  • a battery pack used as a power supply for a cordless electric tool or the like incorporates a secondary battery such as nickel-cadmium battery or nickel-hydrogen battery therein.
  • a charging device for charging such a battery pack a charging device has been proposed, which is capable of reducing the power consumption during non-charging by setting the output voltage during non-charging to be lower than the output voltage during charging (see JP-A-2004-187366).
  • the present invention has been made in view of the above situations and an object thereof is to provide a charging device capable of reducing standby power.
  • a charging device comprising:
  • a power supply circuit configured to charge a battery pack
  • a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed
  • the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.
  • the power suspension circuit includes a first switching element configured to be turned on when full charge detection signal is input to a control terminal of the first switching element and a second switching element configured to be turned on when the voltage of the control terminal is changed in response to the first switching element being turned on, the first and second switching elements are provided between charging output terminals of the power supply circuit,
  • the first switching element is turned on when the second switching element is in an on state irrespective of the presence or absence of the full charge detection signal
  • the power supply circuit is suspended when the first switching element is in an on state.
  • a charging device comprising:
  • a power supply circuit configured to charge a battery pack
  • a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed
  • the power suspension circuit maintains the suspension of the power supply circuit using the power of the built-in power supply after the power supply circuit is suspended.
  • the charging device according to (4) or (5) further comprising a releasing circuit configured to release the suspension of the power supply circuit by the power suspension circuit when the battery pack is disconnected.
  • the charging device according to (5) or (6) further comprising a recharging circuit configured to resume an operation of the power supply circuit when a voltage of the built-in power supply becomes less than a predetermined value after the power supply circuit is suspended.
  • the charging device further comprising a relay switch configured to cut off current flowing through the battery pack from the power supply circuit while the operation of the power supply circuit is resumed by the recharging circuit.
  • the power suspension circuit includes a first switching element configured to be turned on when full charge detection signal is input to a control terminal and a second switching element configured to be turned on when the voltage of a control terminal is changed in response to the first switching element being turned on,
  • the first and second switching elements are provided between both terminals of the capacitor
  • the first switching element is turned on when the second switching element is in an on state irrespective of the presence or absence of the full charge detection signal, and the power supply circuit is suspended when the first switching element is in an on state.
  • the power supply circuit includes an input-side switching element configured to switch the input voltage
  • the power suspension circuit turns off the input-side switching element when the charging of the battery pack is completed.
  • the power suspension circuit includes a light emitting element insulated from a primary side of the transformer and a light receiving element provided on the primary side of the transformer,
  • the light emitting element is energized when the battery pack is fully charged, and the input-side switching element is turned off when the light receiving element receives the light from the energized light emitting element.
  • a charging device comprising:
  • a power supply circuit configured by insulating a primary side and a secondary side and configured to charge a battery pack
  • a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed
  • the power suspension circuit maintains the suspension of the power supply circuit without using power of the primary side after the power supply circuit is suspended.
  • a charging device comprising:
  • a power supply circuit configured to charge a battery pack
  • a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed
  • the power suspension circuit releases a suspension state of the power supply circuit when the battery pack is disconnected.
  • a charging device comprising:
  • a power supply circuit including a transformer having a primary side and a secondary side, and configured to charge a battery pack;
  • a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed
  • the power suspension circuit includes a transmission unit insulated from the primary side of the transformer and a reception unit provided on the primary side of the transformer,
  • the transmission unit is energized when the charging of the battery pack is completed
  • the power supply circuit is turned off when the reception unit receives the signal from the transmission unit.
  • a charging device comprising:
  • a power supply circuit configured to charge a battery pack
  • control unit configured to control charging the battery pack
  • a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed so that power supplied from the power supply circuit to the control unit is suspended
  • the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.
  • a charging device comprising:
  • a power supply circuit configured to charge a battery pack
  • control unit configured to control charging the battery pack
  • Fig. 1 is a functional block diagram of a charging device according to a first embodiment of the present invention.
  • Fig. 2 is a circuit diagram showing a specific configuration example of the charging device shown in Fig. 1.
  • Fig. 3 is an enlarged diagram of a circuit relating to a power suspension in the charging device shown in Fig. 1.
  • Fig. 4 is a functional block diagram of a charging device according to a second embodiment of the present invention.
  • Fig. 5 is an enlarged diagram of a circuit relating to a power suspension in the charging device shown in Fig. 4.
  • Fig. 6 is a time chart showing an operation relating to a capacitor recharging in the circuit shown in Fig. 5.
  • Fig. 7 is a functional block diagram of a charging device according to a third embodiment of the present invention.
  • Fig. 8 is a functional block diagram of a charging device according to a fourth embodiment of the present invention.
  • Fig. 9 is a functional block diagram of a charging device according to a fifth embodiment of the present invention.
  • Fig. 10 is a functional block diagram of a charging device according to a sixth embodiment of the present invention.
  • Fig. 1 is a functional block diagram of a charging device 3 according to a first embodiment of the present invention.
  • Fig. 2 is a circuit diagram showing a specific configuration example of the charging device 3.
  • Fig. 3 is an enlarged diagram of a circuit relating to a power suspension in the charging device 3.
  • a battery pack (secondary battery) 2 that is charged by the charging device 3 includes a single or a plurality of battery cells 2a connected in series and a thermo-sensitive element 2b such as a thermistor that is disposed in contact with or adjacent to the battery cell 2a in order to detect the temperature of the battery cell 2a.
  • the battery pack 2 includes a T terminal and an S terminal, in addition to a plus (+) terminal and a minus (-) terminal.
  • the T terminal is (directly) connected to the minus terminal on the inside of the battery pack 2.
  • the S terminal is connected to the minus terminal via the thermo-sensitive element 2b on the inside of the battery pack 2.
  • the charging device 3 is also provided with a plus terminal, a minus terminal, a T terminal and an S terminal that respectively correspond to the plus terminal, the minus terminal, the T terminal and the S terminal of the battery pack 2.
  • the plus terminal and the minus terminal of the charging device 3 are charging output terminals.
  • the power supply unit of the charging device 3 includes a first rectifier circuit 10 and a power supply circuit 20 at a primary side power supply and a third rectifier circuit 30, a fourth rectifier circuit 40 and a second constant-voltage circuit 41 at a secondary side power supply.
  • the first rectifier circuit 10 includes a diode bridge 11 and a capacitor 12 and rectifies and smoothes AC voltage supplied from a commercial AC power supply 1 to DC voltage.
  • the power supply circuit 20 includes a transformer 21, a second rectifier circuit 22, a first constant- voltage circuit 24 and a PWM control circuit 23.
  • the power supply circuit 20 adjusts the power (output power of the first rectifier circuit 10) supplied from the commercial AC power supply 1 by PWM control and outputs the power required for the charging of the battery pack 2 and the operation of each circuit on the secondary side power supply.
  • a capacitor 25 is provided between a ground on the primary side power supply and a ground on the secondary side power supply.
  • the transformer 21 includes a primary side input coil 21a, a primary side auxiliary output coil 21b, a secondary side charging output coil 21c and a secondary side auxiliary output coil 2 Id.
  • the primary side auxiliary output coil 21b is an output coil that outputs power for operating the PWM control circuit 23.
  • the secondary side charging output coil 21c is an output coil that outputs power for operating the battery pack 2.
  • the secondary side auxiliary output coil 21 d is an output coil that outputs power for operating the other circuit parts on the secondary side power supply.
  • Each of the output coils is connected to the second rectifier circuit 22, the third rectifier circuit 30 and the fourth rectifier circuit 40.
  • the second rectifier circuit 22 includes a diode 22a and a capacitor 22b and rectifies and smoothes the voltage generated in the primary side auxiliary output coil 21b.
  • the first constant-voltage circuit 24 is connected to an output side of the second rectifier circuit 22.
  • the first constant-voltage circuit 24 includes a resistor 24c and a capacitor 24f, which are connected in series between a ground and the output terminal of the first rectifier circuit 10.
  • a transistor 24a and a diode 24d are connected in parallel between a connection point of the resistor 24c and the capacitor 24f and the output terminal of the second rectifier circuit 22.
  • a resistor 24e is provided between a base and a collector of the transistor 24a.
  • a constant voltage diode 24b is provided between a ground and the base of the transistor 24a. Voltage in the connection point of the resistor 24c and the capacitor 24f is input to a PWM controller 23a of the PWM control circuit 23.
  • the PWM controller 23a applies PWM signal to a control terminal (gate) of an FET 23b as an input side switching element via the resistor 23c.
  • a resistor 23d is provided between a gate and a source of the FET 23b.
  • Phototransistors 90a, 100a for transmitting feedback signal are connected in parallel between a ground and a duty control terminal of the PWM controller 23a.
  • the PWM controller 23a controls the on-duty of the FET 23b according to various feedback signals, which will be described later.
  • the third rectifier circuit 30 includes a diode 30a and a capacitor 30b and rectifies and smoothes the voltage generated in the secondary side charging output coil 21c.
  • the fourth rectifier circuit 40 includes a diode 40a and a capacitor 40b and rectifies and smoothes the voltage generated in the secondary side auxiliary output coil 2 Id.
  • the second constant- voltage circuit 41 is connected to an output side of the fourth rectifier circuit 40.
  • the second constant- voltage circuit 41 includes a three-terminal regulator 41a and a capacitor 41b and outputs power-supply voltage Vcc of a control circuit (full charge detection circuit 160, etc., to be described later) of the charging device 3.
  • the control unit of the charging device 3 includes a first voltage feedback circuit 50, a second voltage feedback circuit 60, a charge current feedback circuit 70, a feedback signal transmission circuit 90, a power suspension circuit 100, a suspension maintaining circuit 110, a display circuit 120, a battery connection detection circuit 130, a battery temperature detection circuit 140, a battery low-temperature detection circuit 150 and a full charge detection circuit 160.
  • the first voltage feedback circuit 50 includes a constant voltage diode 50a, a resistor 50b and a diode 50c, which are connected in series.
  • the first voltage feedback circuit 50 outputs a feedback signal for controlling a switching operation of the power supply circuit 20 based on the voltage of a charging output line when the power supply circuit 20 is activated, when the battery pack 2 is charged and when the battery pack 2 is disconnected from the charging device 3 during charging.
  • the first voltage feedback circuit 50 is rendered conductive when the voltage in the charging output line exceeds the voltage specified by the constant voltage diode 50a.
  • the first voltage feedback circuit 50 supplies current to an LED 90b of the feedback signal transmission circuit 90 composed of a photo coupler, for example.
  • the phototransistor 90a receives light from the LED 90b, current corresponding to the amount of light received flows through the phototransistor.
  • the phototransistor 90a is provided between a ground and the duty control terminal of the PWM control circuit 23 (PWM controller 23a).
  • the PWM controller 23a controls the on-duty of the FET 23b in accordance with the current flowing through the phototransistor 90a (the duty is narrowed as the current becomes greater).
  • the second voltage feedback circuit 60 includes a constant voltage diode 60a, transistors 60b, 60c and other peripheral circuits.
  • the second voltage feedback circuit 60 outputs a feedback signal for controlling a switching operation of the power supply circuit 20 based on the voltage on the input side of the second constant voltage circuit 41 at standby when the battery pack 2 is disconnected from the charging device 3, at the time when the battery is in a low-temperature and at the time when full charge is detected.
  • the output terminals of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 are connected to a control terminal (base) of the transistor 60b via a resistor 60g.
  • the base-emitter of the transistor 60b are forward biased and therefore the transistor 60b is turned on when the output of the battery connection detection circuit 130 is at a high level (at standby when the battery pack 2 is disconnected from the charging device 3), when the output of the battery low-temperature detection circuit 150 is at a high level (at the time when the battery is in a low-temperature) or when the output of the full charge detection circuit 160 is at a high level (at the time when full charge is detected).
  • the transistor 60b is turned on, a path from the input terminal of the second constant voltage circuit 41 to the ground via the resistors 60e, 60f and the transistor 60b is rendered conductive and the base-emitter of the transistor 60c are forward biased whereby the transistor 60b is turned on.
  • the charge current feedback circuit 70 includes a charge current detection resistor 70a, an operational amplifier 70b and other peripheral circuits and outputs a feedback signal for controlling a switching operation of the power supply circuit 20 based on the charge current during charging.
  • the charge current detection resistor 70a is provided in the path of the charge current and converts the charge current into voltage.
  • the operational amplifier 70b, resistors 70h, 70i, 70L and a capacitor 70k constitute a differential amplifier which amplifies voltage across the charge current detection resistor 70a.
  • An output terminal of the operational amplifier 70b is connected to an anode of the LED 90b of the feedback signal transmission circuit 90 via a resistor 70j and a diode 70n.
  • the current corresponding to the output voltage of the operational amplifier 70b i.e., the current corresponding to the charge current flows through the LED 90b of the feedback signal transmission circuit 90. Further, since current corresponding to the amount of light received by the phototransistor 90a from the LED 90b flows through the phototransistor 90a, the PWM controller 23a controls the on-duty of the FET 23b.
  • resistors 70c, 70e are connected in series between a ground and the output terminal of the second constant voltage circuit 41, a resistor 70d is provided between a connection point of the resistors 70c, 70e and an inverted input terminal of the operational amplifier 70b and a resistor 70f and a transistor 70g are connected in series between a ground and a connection point of the resistors 70c, 70e.
  • a control terminal (base) of the transistor 70g is connected to the output terminals of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 via a resistor 70m.
  • the base-emitter of the transistor 70g are forward biased and therefore the transistor 70g is turned on when the output of the battery connection detection circuit 130 is at a high level (at standby when the battery pack 2 is disconnected from the charging device 3), when the output of the battery low-temperature detection circuit 150 is at a high level (at the time when the battery is in a low-temperature) or when the output of the full charge detection circuit 160 is at a high level (at the time when full charge is detected).
  • the transistor 70g is turned on, the voltage of the inverted input terminal of the operational amplifier 70b is decreased and the charge current is decreased.
  • the feedback signal transmission circuit 90 includes the phototransistor 90a and the LED 90b, which constitute a photo coupler, and transmits each feedback signal to the power supply circuit 20.
  • the display circuit 120 includes an LED 120a and other peripheral circuits and displays that the battery pack 2 is charging. Specifically, a resistor 120d, the LED 120a and a transistor 120c are connected in series between a ground and the output terminal of the second constant voltage circuit 41. Further, a resistor 120e and a transistor 120b are connected in series between a ground and the output terminal of the second constant voltage circuit 41. A resistor 120f is provided between a control terminal (base) of the transistor 120c and a collector of the transistor 120b. The control terminal (base) of the transistor 120c is connected to the output terminals of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 via a resistor 120g.
  • the output voltage of all of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 is at a low level and the transistor 120 is in an OFF state. Therefore, the base ⁇ emitter of the transistor 120c are forward biased and therefore the transistor 120c is turned on, so that the LED 120a is turned on.
  • the output voltage of at least one of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 is at a high level, the base-emitter of the transistor 120b are forward biased and therefore the transistor 120b is turned on. Then, a base voltage of the transistor 120c is decreased and the transistor 120c is turned off, so that the LED 120a is turned off.
  • the battery connection detection circuit 130 includes an operational amplifier 130a and other peripheral circuits and detects whether or not the battery pack 2 is connected to the charging device 3. Specifically, the output voltage (power supply voltage Vcc) of the second constant voltage circuit 41 is divided by resistors 130c, 130d and input to an inverted input terminal of the operational amplifier 130a. A non-inverted input terminal of the operational amplifier 130a is connected to the output terminal of the second constant voltage circuit 41 via a resistor 130e and also connected to a T terminal that is a connection terminal with the battery pack 2.
  • the T terminal Since the T terminal is connected to a ground terminal via the wiring of the battery pack 2 when the battery pack 2 is connected to the charging device 3, the voltage of the non- inverted input terminal of the operational amplifier 130a is at the same level as the ground and the output of the operational amplifier 130a is at a low level.
  • the T terminal is opened and current does not flow through the resistor 130e. At this time, the voltage of the non-inverted input terminal of the operational amplifier 130a becomes the same level as the power supply voltage Vcc and the output of the operational amplifier 130a becomes a high level.
  • the operational amplifier 130a inputs a high-level output to the second voltage feedback circuit 60, the charge current feedback circuit 70 and the display circuit 120 via a diode 130b and enables an operation of the second voltage feedback circuit 60. Further, the operational amplifier 130a sets a set value of the charge current feedback circuit 70 to a value lower than the normal value and disables the display of the display circuit 120.
  • the battery temperature detection circuit 140 includes resistors 140a, 140b that are connected in series between a ground and the output terminal of the second constant voltage circuit 41. A connection point of the voltage-dividing resistors 140a, 140b is connected to an S terminal that is a connection terminal with the battery pack 2. The thermo-sensitive element 2b is connected between the S terminal and a ground.
  • the voltage of the connection point of the voltage-dividing resistors 140a, 140b is changed in conjunction with the change in a resistance value of the thermo-sensitive element 2b according to the temperature. In a case where the temperature is increased, the resistance value of the thermo-sensitive element 2b is lowered and the voltage of the connection point of the voltage-dividing resistors 140a, 140b is decreased. In a case where the temperature is decreased, the resistance value of the thermo- sensitive element 2b is increased and the voltage of the connection point of the voltage- dividing resistors 140a, 140b is increased.
  • the voltage of the connection point of the voltage-dividing resistors 140a, 140b is output, as battery temperature information, to the battery low-temperature detection circuit 150 and the full charge detection circuit 160.
  • the battery low-temperature detection circuit 150 includes an operational amplifier 150a and other peripheral circuits and detects whether or not the temperature of the battery pack 2 is lower than a set value. Specifically, the output voltage (power supply voltage Vcc) of the second constant voltage circuit 41 is divided by resistors 150c, 150d and input to an inverted input terminal of the operational amplifier 150a. The output voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the battery temperature detection circuit 140 is input to a non-inverted input terminal of the operational amplifier 150a. A resistor 150e is provided between the output terminal and the non-inverted input terminal of the operational amplifier 150a. The resistor 150e implements a hysteresis to the output of the operational amplifier 150a.
  • the voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the non-inverted input terminal of the operational amplifier 150a is increased and the output of the operational amplifier 150a is at a high level.
  • the operational amplifier 150a inputs a high-level output to the second voltage feedback circuit 60, the charge current feedback circuit 70 and the display circuit 120 via a diode 150b and enables an operation of the second voltage feedback circuit 60. Further, the operational amplifier 150a sets a set value of the charge current feedback circuit 70 to a value lower than the normal value and disables the display of the display circuit 120. Meanwhile, the output of the operational amplifier 150a is at a high level even when the battery pack 2 is not attached to the charging device 3.
  • the full charge detection circuit 160 includes an operational amplifier 160a and other peripheral circuits and detects whether or not the battery pack 2 is fully charged, depending on whether or not the temperature of the battery pack 2 is higher than a set value. Specifically, the output voltage (power supply voltage Vcc) of the second constant voltage circuit 41 is divided by resistors 160c, 160d and input to a non-inverted input terminal of the operational amplifier 160a. The output voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the battery temperature detection circuit 140 is input to an inverted input terminal of the operational amplifier 160a. A resistor 160e is provided between the output terminal and the non-inverted input terminal of the operational amplifier 160a.
  • the resistor 160e implements a hysteresis to the output of the operational amplifier 160a.
  • the voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the inverted input terminal of the operational amplifier 160a is decreased and the output of the operational amplifier 160a is at a high level.
  • the operational amplifier 160a inputs a high-level output to the second voltage feedback circuit 60, the charge current feedback circuit 70 and the display circuit 120 via a diode 160b and enables an operation of the second voltage feedback circuit 60. Further, the operational amplifier 160a sets a set value of the charge current feedback circuit 70 to a value lower than the normal value and disables the display of the display circuit 120.
  • the high-level output of the operational amplifier 160a is input to the suspension maintaining circuit 110 as a suspension trigger signal, so that the power suspension circuit 100 and the suspension maintaining circuit 110 are operated.
  • the full charge detection may be performed in accordance with either one or both of temperature and voltage of the battery pack 2.
  • a voltage-dividing resistor may be provided between a ground and the plus terminal of the battery pack and the full charge may be determined by the operational amplifier.
  • the full charge may be detected by the signal from the protective circuit.
  • the power suspension circuit 100 includes the phototransistor 100a and an LED 100b, which constitute a photo coupler, and a resistor 100c and suspends a switching operation of the power supply circuit 20 when the battery pack 2 is fully charged.
  • the suspension maintaining circuit 110 includes transistors 110a, 110b and other peripheral circuits and is caused to continue an operation of the power suspension circuit 100 using the power of the battery pack 2 and maintains the suspension state of the power supply circuit 20 when the battery pack 2 is fully charged.
  • a combination of the power suspension circuit 100 and the suspension maintaining circuit 110 may be considered as a power suspension circuit.
  • a detailed configuration of the power suspension circuit 100 and the suspension maintaining circuit 110 will be described.
  • the resistor 100c, the LED 100b and the transistor 110a are connected in series between a high-voltage terminal and a low-voltage terminal (ground) of the third rectifier circuit 30.
  • a control terminal (base) of the transistor 110a is connected to a cathode of a diode 110c via a resistor 11 Og.
  • An anode of the diode 110c is connected to an output terminal of the operational amplifier 160a.
  • a collector of the transistor 110a is connected to a control terminal (base) of a transistor 110b (an example of a second switching element) via a resistor 11 Of.
  • a resistor 11 Oe is provided between the base- emitter of the transistor 110b.
  • a resistor 11 Od is provided between a high- voltage terminal of the third rectifier circuit 30 and the emitter of the transistor 110b.
  • the power supply circuit 20 is suspended.
  • the output of the operational amplifier 160a of the full charge detection circuit 160 is at a high level (full charge condition is satisfied) and the base-emitter of the transistor 110a are forward biased whereby the transistor 110a is turned on.
  • the base-emitter of the transistor 110b is forward biased and therefore the transistor 110b is turned on.
  • the base voltage of the transistor 110a is kept high enough to turn on the transistor 110a by the transistor 110b, as long as the battery pack 2 is connected. Accordingly, an ON state of the transistor 110a is kept, irrespective of the output of the operational amplifier 160a.
  • the photo transistor 100a is provided between a ground and a duty control terminal of the PWM controller 23a. As the photo transistor 100a is turned on, the on-duty of the FET 23b is narrowed by the PWM controller 23 a and power generated in the primary side auxiliary output coil 21b of the transformer 21 is decreased.
  • the PWM control circuit 23 is suspended and power is not generated in the secondary side charging output coil 21c and the secondary side auxiliary output coil 2 Id (power supply circuit 20 is suspended).
  • the power supply circuit 20 After the power supply circuit 20 is suspended, current of the LED 100b is supplied from the battery pack 2. Further, the drive power (power for maintaining the ON state) for the transistors 110a, 110b is supplied from the battery pack 2.
  • the LED 100b is turned off, the photo transistor 100a is turned off and the suspension of the PWM control circuit 23 is released. In other w rds, the PWM controller 23a resumes switching of the FET 23b.
  • the power suspension circuit 100 and the suspension maintaining circuit 110 are operated and the switching operation of the power supply circuit 20 is suspended. Since power is not generated in each of the output coils 21b, 21c, 21d of the transformer 21 when the power supply circuit 20 is suspended, power supplied from the commercial AC power supply 1 is not consumed in most of the circuits.
  • the power suspension circuit 100 and the suspension maintaining circuit 110 are continuously operated until the battery pack 2 is disconnected from the charging device 3 and power is not applied to the charging output line. Accordingly, during that time, the consumption of the power supplied from the commercial AC power supply 1 is significantly reduced. In other words, the standby power from the full charging of the battery pack 2 to the disconnection of the battery pack 2 from the charging device 3 is significantly reduced.
  • Fig. 4 is a functional block diagram of a charging device 3 according to a second embodiment of the present invention.
  • Fig. 5 is an enlarged diagram of a circuit relating to a power suspension in the charging device 3.
  • the charging device 3 of the present embodiment is different from that of the first embodiment described by referring to Fig. 1 to Fig. 3 and has a configuration that the suspension of the power supply circuit 20 is maintained by the power of a capacitor 1 11.
  • the difference therebetween will be mainly described.
  • a diode 114 is connected between a plus terminal that is a connection terminal with the battery pack 2 and a high- voltage terminal of the third rectifier circuit 30 while arranging an anode on the high- voltage terminal side of the third rectifier circuit 30.
  • a diode 115 and the capacitor 111 are connected in series between a ground and the anode of the diode 114.
  • an anode of the diode 1 15 is connected to a high- voltage terminal of the third rectifier circuit 30 and a cathode thereof is connected to one end of the capacitor 1 1 1.
  • the other end of the capacitor 111 is connected to a ground.
  • the diode 1 14 prevents the discharge from the battery pack 2.
  • the diode 1 14 may be substituted with a relay switch.
  • the diode 1 15 prevents the power accumulated in the capacitor 111 from flowing out to other circuits.
  • the resistor 100c, the LED 100b and the transistor lOOd are connected in series between a high- voltage terminal and a low- voltage terminal of the capacitor 111.
  • a control terminal (base) of the transistor lOOd is connected to a cathode of the diode 110c via a resistor lOOe.
  • An emitter of the transistor lOOd is connected to a ground.
  • a control terminal (base) of the transistor 110a is connected to a cathode of the diode 110c via the resistor HOg.
  • An emitter of the transistor 110a is connected to a ground.
  • the resistor 11 Of is provided between a collector of the transistor 110a and a control terminal (base) of the transistor 110b.
  • the resistor HOe is provided between the base-emitter of the transistor 110b.
  • the emitter of the transistor 110b is connected to a high-voltage terminal of the capacitor 111.
  • a collector of the transistor 110b is connected to the cathode of the diode 110c via the resistor HOd.
  • resistors 112c, 112d, 112e are connected in series between a ground and a high- voltage terminal of the capacitor 111.
  • a connection point of the resistors 112d, 112e is connected to a control terminal (base) of a transistor 112a as a switching element.
  • An emitter of the transistor 112a is connected to a ground.
  • a collector of the transistor 112a is connected to the cathode of the diode 1 lOc.
  • a connection point of the resistors 112c, 112d is connected to an anode of the diode 112b.
  • a cathode of the diode 112b is connected to a T terminal that is a connection terminal with the battery pack 2.
  • a constant voltage diode 113a and resistors 113i, 113h are connected in series between the ground and the high- voltage terminal of the capacitor 111.
  • a capacitor 113d is provided between a ground and a connection point of the resistors 113i, 113h.
  • the connection point of the resistors 1131, 113h is connected to a control terminal (base) of a transistor 113b as a switching element, via a resistor 113g.
  • An emitter of the transistor 113b is connected to a ground.
  • a collector of the transistor 113b is connected to a control terminal (base) of a transistor 113c as a switching element, via a resistor 113f.
  • a resistor 113e is provided between the base-emitter of the transistor 113c.
  • the output of the operational amplifier 160a of the full charge detection circuit 160 is at a high level and the base-emitter of the transistors 110a, lOOd are forward biased whereby the transistors 110a, lOOd are turned on.
  • the base-emitter of the transistor 100 b are also forward biased and therefore the transistor 11 Od is turned on.
  • the base voltage of the transistor 110a is kept high enough to turn on the transistor 110a by the transistor 110b, as long as the battery pack 2 is connected. Accordingly, the ON state of the transistor 110a is kept, irrespective of the output of the operational amplifier 160a.
  • Fig. 6 is a time chart showing an operation relating to a capacitor recharging in the circuit shown in Fig. 5. Since the current of the LED 100b or the drive power of each switching element shown in Fig. 5 is supplied from the capacitor 111 while the power supply circuit 20 is suspended, the capacitor 111 is discharged. When the discharge is continued and therefore voltage of the capacitor 111 becomes less than the voltage specified by the constant voltage diode 1 13a, the constant voltage diode 1 13a is turned off and the base voltage of the transistor 1 13b is dropped to a ground potential and the transistor 113b is turned off. Thereby, the transistor 113c is turned off.
  • the timing when the transistors 1 13b, 1 13c are turned off is delayed by a certain period of time from the timing when the constant voltage diode 113a is turned off.
  • the delayed time is adjusted so that the transistors 113b, 113c are turned off before the voltage of the capacitor 111 is less than the minimum operating voltage of the suspension maintaining circuit 1 10.
  • the timing when the transistors 1 13b, 1 13c are turned on is delayed by a certain period of time from the timing when the constant voltage diode 113a is turned on. Owing to the delayed time, the capacitor 111 is sufficiently charged beyond the voltage specified by the constant voltage diode 113a.
  • the transistors 1 13b, 1 13c are turned on, the energization to the LED 100b is resumed and operation of the power supply circuit 20 is suspended again.
  • the present embodiment can exhibit the same effects as the first embodiment. Further, according to the present embodiment, since the energization to the LED 100b or the driving of each switching element is performed by the capacitor 111, there is no case that the power of the battery pack 2 is consumed in order to suspend the power supply circuit 20. Therefore, it is possible to prevent the remaining capacity of the battery pack 2 from being lowered even when the battery pack 2 is mounted to the charging device 3 after being fully charged. Particularly, the present embodiment is effective to a case where the battery pack 2 includes a lithium battery cell that is vulnerable to over-discharge.
  • the capacitor 111 is automatically recharged when the voltage of the capacitor 111 is dropped and therefore the present embodiment can be available even when the period from the charging completion to the disconnection of the battery pack 2 becomes longer. Further, since the on/off timing of the transistors 113b, 113c are delayed from the on/off timing of the constant voltage diode 113a by the capacitor 113d, it is possible to prevent the operation suspension and resumption of the power supply circuit 20 from being repeated frequently.
  • Fig. 7 is a functional block diagram of a charging device 3 according to a third embodiment of the present invention.
  • the charging device 3 of the present embodiment is different from that of the second embodiment described by referring to Fig. 4 and Fig. 5 in that the diode 1 14 is omitted and the connection destination of the high-voltage side of the capacitor 111, the power suspension circuit 100, the suspension maintaining circuit 1 10, the releasing circuit 112 and the capacitor recharging circuit 113 is changed from the high- voltage terminal of the third rectifier circuit 30 to the high- voltage terminal of the fourth rectifier circuit 40.
  • Remaining parts of the present embodiment other than these different parts are the same as the second embodiment.
  • the present embodiment can exhibit the same effects as the second embodiment.
  • Fourth Embodiment is a functional block diagram of a charging device 3 according to a third embodiment of the present invention.
  • the charging device 3 of the present embodiment is different from that of the second embodiment described by referring to Fig. 4 and Fig. 5 in that the diode 1 14 is
  • Fig. 8 is a functional block diagram of a charging device 3 according to a fourth embodiment of the present invention.
  • the charging device 3 of the present embodiment is different from that of the third embodiment described by referring to Fig. 7 in that a relay switch 116 is provided between a plus terminal that is a connection terminal with the battery pack 2 and the high-voltage terminal of the third rectifier circuit 30. Remaining parts of the present embodiment other than these different parts are the same as the third embodiment.
  • the power supply voltage Vcc can be used to open and close the relay switch 116. The same effect can be obtained even when the diode 114 is substituted with the relay switch, in the second embodiment described by referring to Fig. 4 and Fig. 5.
  • Fig. 9 is a functional block diagram of a charging device 3 according to a fifth embodiment of the present invention.
  • the charging device 3 of the present embodiment is different from that of the fourth embodiment described by referring to Fig. 8 and has a configuration that a microcomputer 301 is provided in the charging control circuit 300.
  • the microcomputer 301 detects whether the suspension maintaining circuit 110 is operated or not. Further, the microcomputer 301 determines whether the battery pack 2 is fully charged or not and initiates an operation of the suspension maintaining circuit 110 by a suspension trigger signal when it is determined that the battery pack 2 is fully charged (i.e., has a function of the full charge detection circuit 160). Furthermore, the microcomputer 301 controls ON/OFF of the relay switch 116.
  • the microcomputer 301 turns on the relay switch 116 during charging and turns off the relay switch 116 when it is determined that the battery pack 2 is fully charged.
  • the microcomputer 301 keeps the relay switch 116 in an OFF state (the microcomputer 301 does not start the charging of the battery pack 2), irrespective of whether the battery pack 2 is fully charged or not. Remaining parts of the present embodiment other than these different parts are the same as the fourth embodiment. The present embodiment can exhibit the same effects as the fourth embodiment.
  • Fig. 10 is a functional block diagram of a charging device 3 according to a sixth embodiment of the present invention.
  • the charging device 3 of the present embodiment is different from that of the third embodiment described by referring to Fig. 7 and has a configuration that a transformer is separately provided on a high-power side and a low-power side.
  • the power supply unit of the charging device 3 includes a low-power side transformer 200 and a high-power side transformer 210.
  • a power supply unit that handles a low power for operating a control circuit and a power supply unit that handles a high power for charging the battery pack 2 are often provided separately.
  • the low-power side transformer 200 includes an input coil 200a and output coils 200b, 200c, 200d.
  • the high-power side transformer 210 includes an input coil 210a and an output coil 210b.
  • the voltage generated in the output coil 200b is rectified and smoothed by a second rectifier circuit 201, stabilized by a first constant voltage circuit 202 and supplied to a low-power side PWM control circuit 203.
  • the output coil 200c generates power for operating a high-power side PWM control circuit 21 1.
  • the voltage generated in the output coil 200c is rectified and smoothed by a fifth rectifier circuit 204 and supplied to the PWM control circuit 211 via a start-stop circuit 205.
  • the start-stop circuit 205 turns on and off the supply of power to the PWM control circuit 21 1 by the control signal from the charging control circuit 300.
  • the voltage generated in the output coil 200d is rectified and smoothed by a fourth rectifier circuit 40 and converted into the power supply voltage Vcc for the control circuit by the second constant- voltage circuit 41.
  • the voltage generated in the charging coil 210b is rectified and smoothed by the third rectifier circuit 30 and used to charge the battery pack 2.
  • the high-power side PWM control circuit 21 1 is controlled by the charging control circuit 300 (that may include a microcomputer) so as to operate only when charging the battery pack 2.
  • the low-power side PWM control circuit 203 is a circuit that is constantly operated for supplying power to the control circuit.
  • the suspension maintaining for the PWM control circuit 203 is executed by the power suspension circuit 100 and the suspension maintaining circuit 1 10, it is possible to reduce power consumption from the commercial AC power supply 1. Remaining parts of the present embodiment other than these different parts are the same as the sixth embodiment.
  • two transformers can be used, similarly to the present embodiment.
  • a power supply such as a primary battery or secondary battery, instead of the capacitor, may be incorporated in the charging device and the suspension of the power supply circuit may be maintained by the power supply.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

A charging device includes: a power supply circuit configured to charge a battery pack; and a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed. The power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.

Description

DESCRIPTION
TITLE OF INVENTION CHARGING DEVICE
TECHNICAL FIELD
The present invention relates to a charging device for charging a battery pack.
BACKGROUND ART
A battery pack used as a power supply for a cordless electric tool or the like incorporates a secondary battery such as nickel-cadmium battery or nickel-hydrogen battery therein. As a charging device for charging such a battery pack, a charging device has been proposed, which is capable of reducing the power consumption during non-charging by setting the output voltage during non-charging to be lower than the output voltage during charging (see JP-A-2004-187366).
SUMMARY OF INVENTION
In a configuration where a power supply circuit is operated even after the battery pack is fully charged, the effect of reducing standby power is not sufficient even when the output voltage is set to a low value.
The present invention has been made in view of the above situations and an object thereof is to provide a charging device capable of reducing standby power.
Aspects of the present invention provide the following arrangements:
(1) A charging device comprising:
a power supply circuit configured to charge a battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.
(2) The charging device according to (1), wherein the power suspension circuit releases the suspension of the power supply circuit when the battery pack is disconnected.
(3) The charging device according to (1) or (2), wherein
the power suspension circuit includes a first switching element configured to be turned on when full charge detection signal is input to a control terminal of the first switching element and a second switching element configured to be turned on when the voltage of the control terminal is changed in response to the first switching element being turned on, the first and second switching elements are provided between charging output terminals of the power supply circuit,
the first switching element is turned on when the second switching element is in an on state irrespective of the presence or absence of the full charge detection signal, and
the power supply circuit is suspended when the first switching element is in an on state.
(4) A charging device comprising:
a power supply circuit configured to charge a battery pack;
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed; and
a built-in power supply,
wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the built-in power supply after the power supply circuit is suspended.
(5) The charging device according to (4), wherein the built-in power supply includes a capacitor configured to be charged by an output voltage of the power supply circuit.
(6) The charging device according to (4) or (5) further comprising a releasing circuit configured to release the suspension of the power supply circuit by the power suspension circuit when the battery pack is disconnected.
(7) The charging device according to (5) or (6) further comprising a recharging circuit configured to resume an operation of the power supply circuit when a voltage of the built-in power supply becomes less than a predetermined value after the power supply circuit is suspended.
(8) The charging device according to (7) further comprising a relay switch configured to cut off current flowing through the battery pack from the power supply circuit while the operation of the power supply circuit is resumed by the recharging circuit.
(9) The charging device according to any one of (4) to (8), wherein
the power suspension circuit includes a first switching element configured to be turned on when full charge detection signal is input to a control terminal and a second switching element configured to be turned on when the voltage of a control terminal is changed in response to the first switching element being turned on,
the first and second switching elements are provided between both terminals of the capacitor,
the first switching element is turned on when the second switching element is in an on state irrespective of the presence or absence of the full charge detection signal, and the power supply circuit is suspended when the first switching element is in an on state.
(10) The charging device according to any one of (1 ) to (9), wherein
the power supply circuit includes an input-side switching element configured to switch the input voltage, and
the power suspension circuit turns off the input-side switching element when the charging of the battery pack is completed.
(11) The charging device according to (10), wherein the power supply circuit is of an insulation type including a transformer.
(12) The charging device according to (11), wherein
the power suspension circuit includes a light emitting element insulated from a primary side of the transformer and a light receiving element provided on the primary side of the transformer,
the light emitting element is energized when the battery pack is fully charged, and the input-side switching element is turned off when the light receiving element receives the light from the energized light emitting element.
(13) A charging device comprising:
a power supply circuit configured by insulating a primary side and a secondary side and configured to charge a battery pack; and,
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit maintains the suspension of the power supply circuit without using power of the primary side after the power supply circuit is suspended.
(14) A charging device comprising:
a power supply circuit configured to charge a battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit releases a suspension state of the power supply circuit when the battery pack is disconnected.
(15) The charging device according to (14), wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit. (16) The charging device according to (14) further comprising a built-in power supply, wherein the power suspension circuit maintains the suspension of the power supply circuit using the built-in power supply after the power supply circuit is suspended.
(17) The charging device according to (16), wherein the built-in power supply is configured by a capacitor configured to be charged by an output voltage of the power supply circuit.
(18) A charging device comprising:
a power supply circuit including a transformer having a primary side and a secondary side, and configured to charge a battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit includes a transmission unit insulated from the primary side of the transformer and a reception unit provided on the primary side of the transformer,
wherein the transmission unit is energized when the charging of the battery pack is completed, and
wherein the power supply circuit is turned off when the reception unit receives the signal from the transmission unit.
(19) A charging device comprising:
a power supply circuit configured to charge a battery pack;
a control unit configured to control charging the battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed so that power supplied from the power supply circuit to the control unit is suspended,
wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.
(20) A charging device comprising:
a power supply circuit configured to charge a battery pack; and
a control unit configured to control charging the battery pack,
wherein power supplied from the power supply circuit to the control unit is cut off after charging of the battery pack is completed, and
wherein power is supplied from the power supply circuit to the control unit when the battery pack is detached from the power supply circuit. Any combinations of the above-described components and modifications in a method or system of the present invention are also effective as an aspect of the present invention.
According to the present invention, it is possible to provide a charging device capable of reducing standby power, as compared to a prior art.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a functional block diagram of a charging device according to a first embodiment of the present invention.
Fig. 2 is a circuit diagram showing a specific configuration example of the charging device shown in Fig. 1.
Fig. 3 is an enlarged diagram of a circuit relating to a power suspension in the charging device shown in Fig. 1.
Fig. 4 is a functional block diagram of a charging device according to a second embodiment of the present invention.
Fig. 5 is an enlarged diagram of a circuit relating to a power suspension in the charging device shown in Fig. 4.
Fig. 6 is a time chart showing an operation relating to a capacitor recharging in the circuit shown in Fig. 5.
Fig. 7 is a functional block diagram of a charging device according to a third embodiment of the present invention.
Fig. 8 is a functional block diagram of a charging device according to a fourth embodiment of the present invention.
Fig. 9 is a functional block diagram of a charging device according to a fifth embodiment of the present invention.
Fig. 10 is a functional block diagram of a charging device according to a sixth embodiment of the present invention.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The same or similar reference numerals are applied to the same or similar parts and elements throughout the drawings, and the duplicated description thereof will be omitted. Further, the embodiment is illustrative and not intended to limit the present invention. It should be noted that all the features and their combinations described in the embodiment are not necessarily considered as an essential part of the present invention.
First Embodiment
Fig. 1 is a functional block diagram of a charging device 3 according to a first embodiment of the present invention. Fig. 2 is a circuit diagram showing a specific configuration example of the charging device 3. Fig. 3 is an enlarged diagram of a circuit relating to a power suspension in the charging device 3.
As shown in Fig. 2, a battery pack (secondary battery) 2 that is charged by the charging device 3 includes a single or a plurality of battery cells 2a connected in series and a thermo-sensitive element 2b such as a thermistor that is disposed in contact with or adjacent to the battery cell 2a in order to detect the temperature of the battery cell 2a. The battery pack 2 includes a T terminal and an S terminal, in addition to a plus (+) terminal and a minus (-) terminal. The T terminal is (directly) connected to the minus terminal on the inside of the battery pack 2. The S terminal is connected to the minus terminal via the thermo-sensitive element 2b on the inside of the battery pack 2. The charging device 3 is also provided with a plus terminal, a minus terminal, a T terminal and an S terminal that respectively correspond to the plus terminal, the minus terminal, the T terminal and the S terminal of the battery pack 2. Here, the plus terminal and the minus terminal of the charging device 3 are charging output terminals.
Next, a configuration of a power supply unit of the charging device 3 will be described. The power supply unit of the charging device 3 includes a first rectifier circuit 10 and a power supply circuit 20 at a primary side power supply and a third rectifier circuit 30, a fourth rectifier circuit 40 and a second constant-voltage circuit 41 at a secondary side power supply. The first rectifier circuit 10 includes a diode bridge 11 and a capacitor 12 and rectifies and smoothes AC voltage supplied from a commercial AC power supply 1 to DC voltage. The power supply circuit 20 includes a transformer 21, a second rectifier circuit 22, a first constant- voltage circuit 24 and a PWM control circuit 23. The power supply circuit 20 adjusts the power (output power of the first rectifier circuit 10) supplied from the commercial AC power supply 1 by PWM control and outputs the power required for the charging of the battery pack 2 and the operation of each circuit on the secondary side power supply. A capacitor 25 is provided between a ground on the primary side power supply and a ground on the secondary side power supply.
The transformer 21 includes a primary side input coil 21a, a primary side auxiliary output coil 21b, a secondary side charging output coil 21c and a secondary side auxiliary output coil 2 Id. The primary side auxiliary output coil 21b is an output coil that outputs power for operating the PWM control circuit 23. The secondary side charging output coil 21c is an output coil that outputs power for operating the battery pack 2. The secondary side auxiliary output coil 21 d is an output coil that outputs power for operating the other circuit parts on the secondary side power supply. Each of the output coils is connected to the second rectifier circuit 22, the third rectifier circuit 30 and the fourth rectifier circuit 40. The second rectifier circuit 22 includes a diode 22a and a capacitor 22b and rectifies and smoothes the voltage generated in the primary side auxiliary output coil 21b. The first constant-voltage circuit 24 is connected to an output side of the second rectifier circuit 22. The first constant-voltage circuit 24 includes a resistor 24c and a capacitor 24f, which are connected in series between a ground and the output terminal of the first rectifier circuit 10. A transistor 24a and a diode 24d are connected in parallel between a connection point of the resistor 24c and the capacitor 24f and the output terminal of the second rectifier circuit 22. A resistor 24e is provided between a base and a collector of the transistor 24a. A constant voltage diode 24b is provided between a ground and the base of the transistor 24a. Voltage in the connection point of the resistor 24c and the capacitor 24f is input to a PWM controller 23a of the PWM control circuit 23. The PWM controller 23a applies PWM signal to a control terminal (gate) of an FET 23b as an input side switching element via the resistor 23c. A resistor 23d is provided between a gate and a source of the FET 23b. Phototransistors 90a, 100a for transmitting feedback signal are connected in parallel between a ground and a duty control terminal of the PWM controller 23a. The PWM controller 23a controls the on-duty of the FET 23b according to various feedback signals, which will be described later.
The third rectifier circuit 30 includes a diode 30a and a capacitor 30b and rectifies and smoothes the voltage generated in the secondary side charging output coil 21c. The fourth rectifier circuit 40 includes a diode 40a and a capacitor 40b and rectifies and smoothes the voltage generated in the secondary side auxiliary output coil 2 Id. The second constant- voltage circuit 41 is connected to an output side of the fourth rectifier circuit 40. The second constant- voltage circuit 41 includes a three-terminal regulator 41a and a capacitor 41b and outputs power-supply voltage Vcc of a control circuit (full charge detection circuit 160, etc., to be described later) of the charging device 3.
Next, a configuration of a control unit of the charging device 3 will be described. The control unit of the charging device 3 includes a first voltage feedback circuit 50, a second voltage feedback circuit 60, a charge current feedback circuit 70, a feedback signal transmission circuit 90, a power suspension circuit 100, a suspension maintaining circuit 110, a display circuit 120, a battery connection detection circuit 130, a battery temperature detection circuit 140, a battery low-temperature detection circuit 150 and a full charge detection circuit 160. A charging control circuit 300 shown in Fig. 1 is configured by incorporating, as one block, the first voltage feedback circuit 50, the second voltage feedback circuit 60, the charge current feedback circuit 70, the feedback signal transmission circuit 90, the display circuit 120, the battery connection detection circuit 130, the battery temperature detection circuit 140, the battery low-temperature detection circuit 150 and the full charge detection circuit 160, which are shown in Fig. 2. The first voltage feedback circuit 50 includes a constant voltage diode 50a, a resistor 50b and a diode 50c, which are connected in series. The first voltage feedback circuit 50 outputs a feedback signal for controlling a switching operation of the power supply circuit 20 based on the voltage of a charging output line when the power supply circuit 20 is activated, when the battery pack 2 is charged and when the battery pack 2 is disconnected from the charging device 3 during charging. Specifically, the first voltage feedback circuit 50 is rendered conductive when the voltage in the charging output line exceeds the voltage specified by the constant voltage diode 50a. At this time, the first voltage feedback circuit 50 supplies current to an LED 90b of the feedback signal transmission circuit 90 composed of a photo coupler, for example. When the phototransistor 90a receives light from the LED 90b, current corresponding to the amount of light received flows through the phototransistor. The phototransistor 90a is provided between a ground and the duty control terminal of the PWM control circuit 23 (PWM controller 23a). The PWM controller 23a controls the on-duty of the FET 23b in accordance with the current flowing through the phototransistor 90a (the duty is narrowed as the current becomes greater).
The second voltage feedback circuit 60 includes a constant voltage diode 60a, transistors 60b, 60c and other peripheral circuits. The second voltage feedback circuit 60 outputs a feedback signal for controlling a switching operation of the power supply circuit 20 based on the voltage on the input side of the second constant voltage circuit 41 at standby when the battery pack 2 is disconnected from the charging device 3, at the time when the battery is in a low-temperature and at the time when full charge is detected. Specifically, the output terminals of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 are connected to a control terminal (base) of the transistor 60b via a resistor 60g. The base-emitter of the transistor 60b are forward biased and therefore the transistor 60b is turned on when the output of the battery connection detection circuit 130 is at a high level (at standby when the battery pack 2 is disconnected from the charging device 3), when the output of the battery low-temperature detection circuit 150 is at a high level (at the time when the battery is in a low-temperature) or when the output of the full charge detection circuit 160 is at a high level (at the time when full charge is detected). When the transistor 60b is turned on, a path from the input terminal of the second constant voltage circuit 41 to the ground via the resistors 60e, 60f and the transistor 60b is rendered conductive and the base-emitter of the transistor 60c are forward biased whereby the transistor 60b is turned on. Then, current flows from the input terminal of the second constant voltage circuit 41 to the LED 90b of the feedback signal transmission circuit 90 via the transistor 60c, the resistor 60d, the constant voltage diode 60a and a diode 60h when the voltage of the input terminal of the second constant voltage circuit 41 exceeds the voltage specified by the constant voltage diode 60a. Since current corresponding to the amount of light received flows through the photo transistor 90a that receives light from the LED 90b, the P WM controller 23a controls the on-duty of the FET 23b.
The charge current feedback circuit 70 includes a charge current detection resistor 70a, an operational amplifier 70b and other peripheral circuits and outputs a feedback signal for controlling a switching operation of the power supply circuit 20 based on the charge current during charging. Specifically, the charge current detection resistor 70a is provided in the path of the charge current and converts the charge current into voltage. The operational amplifier 70b, resistors 70h, 70i, 70L and a capacitor 70k constitute a differential amplifier which amplifies voltage across the charge current detection resistor 70a. An output terminal of the operational amplifier 70b is connected to an anode of the LED 90b of the feedback signal transmission circuit 90 via a resistor 70j and a diode 70n. Therefore, the current corresponding to the output voltage of the operational amplifier 70b, i.e., the current corresponding to the charge current flows through the LED 90b of the feedback signal transmission circuit 90. Further, since current corresponding to the amount of light received by the phototransistor 90a from the LED 90b flows through the phototransistor 90a, the PWM controller 23a controls the on-duty of the FET 23b.
Further, in the charge current feedback circuit 70, resistors 70c, 70e are connected in series between a ground and the output terminal of the second constant voltage circuit 41, a resistor 70d is provided between a connection point of the resistors 70c, 70e and an inverted input terminal of the operational amplifier 70b and a resistor 70f and a transistor 70g are connected in series between a ground and a connection point of the resistors 70c, 70e. A control terminal (base) of the transistor 70g is connected to the output terminals of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 via a resistor 70m. The base-emitter of the transistor 70g are forward biased and therefore the transistor 70g is turned on when the output of the battery connection detection circuit 130 is at a high level (at standby when the battery pack 2 is disconnected from the charging device 3), when the output of the battery low-temperature detection circuit 150 is at a high level (at the time when the battery is in a low-temperature) or when the output of the full charge detection circuit 160 is at a high level (at the time when full charge is detected). When the transistor 70g is turned on, the voltage of the inverted input terminal of the operational amplifier 70b is decreased and the charge current is decreased.
The feedback signal transmission circuit 90 includes the phototransistor 90a and the LED 90b, which constitute a photo coupler, and transmits each feedback signal to the power supply circuit 20.
The display circuit 120 includes an LED 120a and other peripheral circuits and displays that the battery pack 2 is charging. Specifically, a resistor 120d, the LED 120a and a transistor 120c are connected in series between a ground and the output terminal of the second constant voltage circuit 41. Further, a resistor 120e and a transistor 120b are connected in series between a ground and the output terminal of the second constant voltage circuit 41. A resistor 120f is provided between a control terminal (base) of the transistor 120c and a collector of the transistor 120b. The control terminal (base) of the transistor 120c is connected to the output terminals of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 via a resistor 120g. While the battery pack 2 is charged, the output voltage of all of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 is at a low level and the transistor 120 is in an OFF state. Therefore, the base · emitter of the transistor 120c are forward biased and therefore the transistor 120c is turned on, so that the LED 120a is turned on. On the other hand, when the battery pack 2 is not charged, the output voltage of at least one of the battery connection detection circuit 130, the battery low-temperature detection circuit 150 and the full charge detection circuit 160 is at a high level, the base-emitter of the transistor 120b are forward biased and therefore the transistor 120b is turned on. Then, a base voltage of the transistor 120c is decreased and the transistor 120c is turned off, so that the LED 120a is turned off.
The battery connection detection circuit 130 includes an operational amplifier 130a and other peripheral circuits and detects whether or not the battery pack 2 is connected to the charging device 3. Specifically, the output voltage (power supply voltage Vcc) of the second constant voltage circuit 41 is divided by resistors 130c, 130d and input to an inverted input terminal of the operational amplifier 130a. A non-inverted input terminal of the operational amplifier 130a is connected to the output terminal of the second constant voltage circuit 41 via a resistor 130e and also connected to a T terminal that is a connection terminal with the battery pack 2. Since the T terminal is connected to a ground terminal via the wiring of the battery pack 2 when the battery pack 2 is connected to the charging device 3, the voltage of the non- inverted input terminal of the operational amplifier 130a is at the same level as the ground and the output of the operational amplifier 130a is at a low level. On the other hand, when the battery pack 2 is disconnected from the charging device 3, the T terminal is opened and current does not flow through the resistor 130e. At this time, the voltage of the non-inverted input terminal of the operational amplifier 130a becomes the same level as the power supply voltage Vcc and the output of the operational amplifier 130a becomes a high level. The operational amplifier 130a inputs a high-level output to the second voltage feedback circuit 60, the charge current feedback circuit 70 and the display circuit 120 via a diode 130b and enables an operation of the second voltage feedback circuit 60. Further, the operational amplifier 130a sets a set value of the charge current feedback circuit 70 to a value lower than the normal value and disables the display of the display circuit 120. The battery temperature detection circuit 140 includes resistors 140a, 140b that are connected in series between a ground and the output terminal of the second constant voltage circuit 41. A connection point of the voltage-dividing resistors 140a, 140b is connected to an S terminal that is a connection terminal with the battery pack 2. The thermo-sensitive element 2b is connected between the S terminal and a ground. The voltage of the connection point of the voltage-dividing resistors 140a, 140b is changed in conjunction with the change in a resistance value of the thermo-sensitive element 2b according to the temperature. In a case where the temperature is increased, the resistance value of the thermo-sensitive element 2b is lowered and the voltage of the connection point of the voltage-dividing resistors 140a, 140b is decreased. In a case where the temperature is decreased, the resistance value of the thermo- sensitive element 2b is increased and the voltage of the connection point of the voltage- dividing resistors 140a, 140b is increased. The voltage of the connection point of the voltage-dividing resistors 140a, 140b is output, as battery temperature information, to the battery low-temperature detection circuit 150 and the full charge detection circuit 160.
The battery low-temperature detection circuit 150 includes an operational amplifier 150a and other peripheral circuits and detects whether or not the temperature of the battery pack 2 is lower than a set value. Specifically, the output voltage (power supply voltage Vcc) of the second constant voltage circuit 41 is divided by resistors 150c, 150d and input to an inverted input terminal of the operational amplifier 150a. The output voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the battery temperature detection circuit 140 is input to a non-inverted input terminal of the operational amplifier 150a. A resistor 150e is provided between the output terminal and the non-inverted input terminal of the operational amplifier 150a. The resistor 150e implements a hysteresis to the output of the operational amplifier 150a. When the temperature of the battery pack 2 is lower than a set value, the voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the non-inverted input terminal of the operational amplifier 150a is increased and the output of the operational amplifier 150a is at a high level. The operational amplifier 150a inputs a high-level output to the second voltage feedback circuit 60, the charge current feedback circuit 70 and the display circuit 120 via a diode 150b and enables an operation of the second voltage feedback circuit 60. Further, the operational amplifier 150a sets a set value of the charge current feedback circuit 70 to a value lower than the normal value and disables the display of the display circuit 120. Meanwhile, the output of the operational amplifier 150a is at a high level even when the battery pack 2 is not attached to the charging device 3.
The full charge detection circuit 160 includes an operational amplifier 160a and other peripheral circuits and detects whether or not the battery pack 2 is fully charged, depending on whether or not the temperature of the battery pack 2 is higher than a set value. Specifically, the output voltage (power supply voltage Vcc) of the second constant voltage circuit 41 is divided by resistors 160c, 160d and input to a non-inverted input terminal of the operational amplifier 160a. The output voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the battery temperature detection circuit 140 is input to an inverted input terminal of the operational amplifier 160a. A resistor 160e is provided between the output terminal and the non-inverted input terminal of the operational amplifier 160a. The resistor 160e implements a hysteresis to the output of the operational amplifier 160a. When the temperature of the battery pack 2 is higher than a set value, the voltage (voltage of the connection point of the voltage-dividing resistors 140a, 140b) of the inverted input terminal of the operational amplifier 160a is decreased and the output of the operational amplifier 160a is at a high level. The operational amplifier 160a inputs a high-level output to the second voltage feedback circuit 60, the charge current feedback circuit 70 and the display circuit 120 via a diode 160b and enables an operation of the second voltage feedback circuit 60. Further, the operational amplifier 160a sets a set value of the charge current feedback circuit 70 to a value lower than the normal value and disables the display of the display circuit 120. Further, the high-level output of the operational amplifier 160a is input to the suspension maintaining circuit 110 as a suspension trigger signal, so that the power suspension circuit 100 and the suspension maintaining circuit 110 are operated. Here, the full charge detection may be performed in accordance with either one or both of temperature and voltage of the battery pack 2. In a case where the voltage of the battery pack 2 is detected, a voltage-dividing resistor may be provided between a ground and the plus terminal of the battery pack and the full charge may be determined by the operational amplifier. Alternatively, in a case where a protective circuit is provided in the battery pack 2, the full charge may be detected by the signal from the protective circuit.
Hereinafter, a configuration related to the power suspension when the charging of the battery pack 2 is completed will be described.
The power suspension circuit 100 includes the phototransistor 100a and an LED 100b, which constitute a photo coupler, and a resistor 100c and suspends a switching operation of the power supply circuit 20 when the battery pack 2 is fully charged. The suspension maintaining circuit 110 includes transistors 110a, 110b and other peripheral circuits and is caused to continue an operation of the power suspension circuit 100 using the power of the battery pack 2 and maintains the suspension state of the power supply circuit 20 when the battery pack 2 is fully charged. Here, a combination of the power suspension circuit 100 and the suspension maintaining circuit 110 may be considered as a power suspension circuit. Hereinafter, a detailed configuration of the power suspension circuit 100 and the suspension maintaining circuit 110 will be described. The resistor 100c, the LED 100b and the transistor 110a (an example of a first switching element) are connected in series between a high-voltage terminal and a low-voltage terminal (ground) of the third rectifier circuit 30. A control terminal (base) of the transistor 110a is connected to a cathode of a diode 110c via a resistor 11 Og. An anode of the diode 110c is connected to an output terminal of the operational amplifier 160a. A collector of the transistor 110a is connected to a control terminal (base) of a transistor 110b (an example of a second switching element) via a resistor 11 Of. A resistor 11 Oe is provided between the base- emitter of the transistor 110b. A resistor 11 Od is provided between a high- voltage terminal of the third rectifier circuit 30 and the emitter of the transistor 110b.
As soon as the battery pack 2 is fully charged, the power supply circuit 20 is suspended. In other words, the output of the operational amplifier 160a of the full charge detection circuit 160 is at a high level (full charge condition is satisfied) and the base-emitter of the transistor 110a are forward biased whereby the transistor 110a is turned on. Then, the base-emitter of the transistor 110b is forward biased and therefore the transistor 110b is turned on. Thereafter, the base voltage of the transistor 110a is kept high enough to turn on the transistor 110a by the transistor 110b, as long as the battery pack 2 is connected. Accordingly, an ON state of the transistor 110a is kept, irrespective of the output of the operational amplifier 160a. While the transistor 110a is in the ON state, current flows through the LED 100b (an example of a transmission unit) that is a light emitting side of the photo coupler, so that the LED 100b emits light and the photo transistor 100a (an example of a reception unit) that is a light receiving side of the photo coupler is turned on. The photo transistor 100a is provided between a ground and a duty control terminal of the PWM controller 23a. As the photo transistor 100a is turned on, the on-duty of the FET 23b is narrowed by the PWM controller 23 a and power generated in the primary side auxiliary output coil 21b of the transformer 21 is decreased. Accordingly, the PWM control circuit 23 is suspended and power is not generated in the secondary side charging output coil 21c and the secondary side auxiliary output coil 2 Id (power supply circuit 20 is suspended). After the power supply circuit 20 is suspended, current of the LED 100b is supplied from the battery pack 2. Further, the drive power (power for maintaining the ON state) for the transistors 110a, 110b is supplied from the battery pack 2. On the other hand, when the battery pack 2 is disconnected from the charging device 3, the LED 100b is turned off, the photo transistor 100a is turned off and the suspension of the PWM control circuit 23 is released. In other w rds, the PWM controller 23a resumes switching of the FET 23b.
According to the present embodiment, the following effects can be obtained.
(1) When the full charge is detected by the full charge detection circuit 160, the power suspension circuit 100 and the suspension maintaining circuit 110 are operated and the switching operation of the power supply circuit 20 is suspended. Since power is not generated in each of the output coils 21b, 21c, 21d of the transformer 21 when the power supply circuit 20 is suspended, power supplied from the commercial AC power supply 1 is not consumed in most of the circuits. When starting to operate once, the power suspension circuit 100 and the suspension maintaining circuit 110 are continuously operated until the battery pack 2 is disconnected from the charging device 3 and power is not applied to the charging output line. Accordingly, during that time, the consumption of the power supplied from the commercial AC power supply 1 is significantly reduced. In other words, the standby power from the full charging of the battery pack 2 to the disconnection of the battery pack 2 from the charging device 3 is significantly reduced.
(2) Since the suspension of the power supply circuit 20 is automatically released when the battery pack 2 is disconnected from the charging device 3, it is not necessary for a user to perform an operation (operation of inserting or removing a power plug, etc.) for releasing the suspension of the power supply circuit 20 when charging next battery pack 2.
(3) Since the signal transmission from the power suspension circuit 100 provided on the secondary side of the transformer 21 is performed by the photo coupler, it is possible to secure the insulation between the primary side and the secondary side of the transformer 21.
Second Embodiment
Fig. 4 is a functional block diagram of a charging device 3 according to a second embodiment of the present invention. Fig. 5 is an enlarged diagram of a circuit relating to a power suspension in the charging device 3. The charging device 3 of the present embodiment is different from that of the first embodiment described by referring to Fig. 1 to Fig. 3 and has a configuration that the suspension of the power supply circuit 20 is maintained by the power of a capacitor 1 11. Hereinafter, the difference therebetween will be mainly described.
A diode 114 is connected between a plus terminal that is a connection terminal with the battery pack 2 and a high- voltage terminal of the third rectifier circuit 30 while arranging an anode on the high- voltage terminal side of the third rectifier circuit 30. A diode 115 and the capacitor 111 are connected in series between a ground and the anode of the diode 114. In other words, an anode of the diode 1 15 is connected to a high- voltage terminal of the third rectifier circuit 30 and a cathode thereof is connected to one end of the capacitor 1 1 1. The other end of the capacitor 111 is connected to a ground. The diode 1 14 prevents the discharge from the battery pack 2. The diode 1 14 may be substituted with a relay switch. The diode 1 15 prevents the power accumulated in the capacitor 111 from flowing out to other circuits.
As shown in Fig. 5, in the power suspension circuit 100, the resistor 100c, the LED 100b and the transistor lOOd (an example of a first switching element) are connected in series between a high- voltage terminal and a low- voltage terminal of the capacitor 111. A control terminal (base) of the transistor lOOd is connected to a cathode of the diode 110c via a resistor lOOe. An emitter of the transistor lOOd is connected to a ground.
In the suspension maintaining circuit 110, a control terminal (base) of the transistor 110a is connected to a cathode of the diode 110c via the resistor HOg. An emitter of the transistor 110a is connected to a ground. The resistor 11 Of is provided between a collector of the transistor 110a and a control terminal (base) of the transistor 110b. The resistor HOe is provided between the base-emitter of the transistor 110b. The emitter of the transistor 110b is connected to a high-voltage terminal of the capacitor 111. A collector of the transistor 110b is connected to the cathode of the diode 110c via the resistor HOd.
In a releasing circuit 112, resistors 112c, 112d, 112e are connected in series between a ground and a high- voltage terminal of the capacitor 111. A connection point of the resistors 112d, 112e is connected to a control terminal (base) of a transistor 112a as a switching element. An emitter of the transistor 112a is connected to a ground. A collector of the transistor 112a is connected to the cathode of the diode 1 lOc. A connection point of the resistors 112c, 112d is connected to an anode of the diode 112b. A cathode of the diode 112b is connected to a T terminal that is a connection terminal with the battery pack 2.
In a capacitor recharging circuit 113, a constant voltage diode 113a and resistors 113i, 113h are connected in series between the ground and the high- voltage terminal of the capacitor 111. A capacitor 113d is provided between a ground and a connection point of the resistors 113i, 113h. The connection point of the resistors 1131, 113h is connected to a control terminal (base) of a transistor 113b as a switching element, via a resistor 113g. An emitter of the transistor 113b is connected to a ground. A collector of the transistor 113b is connected to a control terminal (base) of a transistor 113c as a switching element, via a resistor 113f. A resistor 113e is provided between the base-emitter of the transistor 113c.
When the battery pack 2 is fully charged, the output of the operational amplifier 160a of the full charge detection circuit 160 is at a high level and the base-emitter of the transistors 110a, lOOd are forward biased whereby the transistors 110a, lOOd are turned on. In conjunction with the ON of the transistor 110a, the base-emitter of the transistor 100 b are also forward biased and therefore the transistor 11 Od is turned on. Thereafter, the base voltage of the transistor 110a is kept high enough to turn on the transistor 110a by the transistor 110b, as long as the battery pack 2 is connected. Accordingly, the ON state of the transistor 110a is kept, irrespective of the output of the operational amplifier 160a.
While the transistor 1 OOd is in the ON state, current flows through the LED 100b that is a light emitting side of a photo coupler, so that the LED 100b emits light and, similar to the first embodiment, the photo transistor that is a light receiving side of the photo coupler is turned on whereby the power supply circuit 20 is suspended. After the power supply circuit 20 is suspended, current of the LED 100b is supplied from the capacitor 111. Further, the drive power (power for maintaining the ON state) for each of the switching elements shown in Fig. 5 is also supplied from the capacitor 111.
Since a connection point of the resistors 112c, 112d is connected to a ground by the diode 112b while the battery pack 2 is connected to the charging device 3, voltage between the base-emitter of the transistor 112a is smaller than the voltage required for the ON state and the transistor 112a is turned off. On the other hand, when the battery pack 2 is disconnected from the charging device 3, a cathode of the diode 112b is opened and the base-emitter of the transistor 112a are forward biased whereby the transistor 112a is turned on. Then, the base voltage of the transistors lOOd, 110a is dropped to the same degree as the ground and the transistors lOOd, 110a are turned off. Thereby, the LED 100b is turned off and, similar to the first embodiment, the suspension of the PWM control circuit 23 is released (the power supply circuit 20 resumes operation).
Fig. 6 is a time chart showing an operation relating to a capacitor recharging in the circuit shown in Fig. 5. Since the current of the LED 100b or the drive power of each switching element shown in Fig. 5 is supplied from the capacitor 111 while the power supply circuit 20 is suspended, the capacitor 111 is discharged. When the discharge is continued and therefore voltage of the capacitor 111 becomes less than the voltage specified by the constant voltage diode 1 13a, the constant voltage diode 1 13a is turned off and the base voltage of the transistor 1 13b is dropped to a ground potential and the transistor 113b is turned off. Thereby, the transistor 113c is turned off. However, by the delaying effect of the capacitor 113d, the timing when the transistors 1 13b, 1 13c are turned off is delayed by a certain period of time from the timing when the constant voltage diode 113a is turned off. Preferably, the delayed time is adjusted so that the transistors 113b, 113c are turned off before the voltage of the capacitor 111 is less than the minimum operating voltage of the suspension maintaining circuit 1 10.
When the transistor 113c is turned off, energization from the capacitor 111 to the LED 100b is shut off. As a result, the suspension of the power supply circuit 20 is released and the power supply circuit 20 resumes operation. In other words, switching by the PWM control circuit 23 is resumed and the capacitor 111 is charged by the output voltage of the third rectifier circuit 30. When the voltage of the capacitor 111 exceeds the voltage specified by the constant voltage diode 113a by the charging, the constant voltage diode 113a is turned on and the transistors 113b, 113c are also turned on. However, by the delaying effect of the capacitor 113d, the timing when the transistors 1 13b, 1 13c are turned on is delayed by a certain period of time from the timing when the constant voltage diode 113a is turned on. Owing to the delayed time, the capacitor 111 is sufficiently charged beyond the voltage specified by the constant voltage diode 113a. When the transistors 1 13b, 1 13c are turned on, the energization to the LED 100b is resumed and operation of the power supply circuit 20 is suspended again.
Remaining parts of the present embodiment other than the above-described part are the same as the first embodiment. The present embodiment can exhibit the same effects as the first embodiment. Further, according to the present embodiment, since the energization to the LED 100b or the driving of each switching element is performed by the capacitor 111, there is no case that the power of the battery pack 2 is consumed in order to suspend the power supply circuit 20. Therefore, it is possible to prevent the remaining capacity of the battery pack 2 from being lowered even when the battery pack 2 is mounted to the charging device 3 after being fully charged. Particularly, the present embodiment is effective to a case where the battery pack 2 includes a lithium battery cell that is vulnerable to over-discharge. Further, the capacitor 111 is automatically recharged when the voltage of the capacitor 111 is dropped and therefore the present embodiment can be available even when the period from the charging completion to the disconnection of the battery pack 2 becomes longer. Further, since the on/off timing of the transistors 113b, 113c are delayed from the on/off timing of the constant voltage diode 113a by the capacitor 113d, it is possible to prevent the operation suspension and resumption of the power supply circuit 20 from being repeated frequently.
Third Embodiment
Fig. 7 is a functional block diagram of a charging device 3 according to a third embodiment of the present invention. The charging device 3 of the present embodiment is different from that of the second embodiment described by referring to Fig. 4 and Fig. 5 in that the diode 1 14 is omitted and the connection destination of the high-voltage side of the capacitor 111, the power suspension circuit 100, the suspension maintaining circuit 1 10, the releasing circuit 112 and the capacitor recharging circuit 113 is changed from the high- voltage terminal of the third rectifier circuit 30 to the high- voltage terminal of the fourth rectifier circuit 40. Remaining parts of the present embodiment other than these different parts are the same as the second embodiment. The present embodiment can exhibit the same effects as the second embodiment. Fourth Embodiment
Fig. 8 is a functional block diagram of a charging device 3 according to a fourth embodiment of the present invention. The charging device 3 of the present embodiment is different from that of the third embodiment described by referring to Fig. 7 in that a relay switch 116 is provided between a plus terminal that is a connection terminal with the battery pack 2 and the high-voltage terminal of the third rectifier circuit 30. Remaining parts of the present embodiment other than these different parts are the same as the third embodiment. According to the present embodiment, it is possible to prevent the battery pack 2 from being charged during the recharging of the capacitor 111 by opening (cutting off) the relay switch 116 during the recharging of the capacitor 111. The power supply voltage Vcc can be used to open and close the relay switch 116. The same effect can be obtained even when the diode 114 is substituted with the relay switch, in the second embodiment described by referring to Fig. 4 and Fig. 5.
Fifth Embodiment
Fig. 9 is a functional block diagram of a charging device 3 according to a fifth embodiment of the present invention. The charging device 3 of the present embodiment is different from that of the fourth embodiment described by referring to Fig. 8 and has a configuration that a microcomputer 301 is provided in the charging control circuit 300. The microcomputer 301 detects whether the suspension maintaining circuit 110 is operated or not. Further, the microcomputer 301 determines whether the battery pack 2 is fully charged or not and initiates an operation of the suspension maintaining circuit 110 by a suspension trigger signal when it is determined that the battery pack 2 is fully charged (i.e., has a function of the full charge detection circuit 160). Furthermore, the microcomputer 301 controls ON/OFF of the relay switch 116. In other words, the microcomputer 301 turns on the relay switch 116 during charging and turns off the relay switch 116 when it is determined that the battery pack 2 is fully charged. In addition, when the suspension maintaining circuit 110 is operated during the recharging of the capacitor 111 (during the returning of the power supply voltage Vcc), the microcomputer 301 keeps the relay switch 116 in an OFF state (the microcomputer 301 does not start the charging of the battery pack 2), irrespective of whether the battery pack 2 is fully charged or not. Remaining parts of the present embodiment other than these different parts are the same as the fourth embodiment. The present embodiment can exhibit the same effects as the fourth embodiment.
Sixth Embodiment
Fig. 10 is a functional block diagram of a charging device 3 according to a sixth embodiment of the present invention. The charging device 3 of the present embodiment is different from that of the third embodiment described by referring to Fig. 7 and has a configuration that a transformer is separately provided on a high-power side and a low-power side. Hereinafter, the difference therebetween will be mainly described. The power supply unit of the charging device 3 includes a low-power side transformer 200 and a high-power side transformer 210. In a charging device having charge power in excess of 100 W, a power supply unit that handles a low power for operating a control circuit and a power supply unit that handles a high power for charging the battery pack 2 are often provided separately.
The low-power side transformer 200 includes an input coil 200a and output coils 200b, 200c, 200d. The high-power side transformer 210 includes an input coil 210a and an output coil 210b. The voltage generated in the output coil 200b is rectified and smoothed by a second rectifier circuit 201, stabilized by a first constant voltage circuit 202 and supplied to a low-power side PWM control circuit 203. The output coil 200c generates power for operating a high-power side PWM control circuit 21 1. The voltage generated in the output coil 200c is rectified and smoothed by a fifth rectifier circuit 204 and supplied to the PWM control circuit 211 via a start-stop circuit 205. The start-stop circuit 205 turns on and off the supply of power to the PWM control circuit 21 1 by the control signal from the charging control circuit 300. The voltage generated in the output coil 200d is rectified and smoothed by a fourth rectifier circuit 40 and converted into the power supply voltage Vcc for the control circuit by the second constant- voltage circuit 41. The voltage generated in the charging coil 210b is rectified and smoothed by the third rectifier circuit 30 and used to charge the battery pack 2.
The high-power side PWM control circuit 21 1 is controlled by the charging control circuit 300 (that may include a microcomputer) so as to operate only when charging the battery pack 2. On the other hand, normally, the low-power side PWM control circuit 203 is a circuit that is constantly operated for supplying power to the control circuit. In the present embodiment, since the suspension maintaining for the PWM control circuit 203 is executed by the power suspension circuit 100 and the suspension maintaining circuit 1 10, it is possible to reduce power consumption from the commercial AC power supply 1. Remaining parts of the present embodiment other than these different parts are the same as the sixth embodiment. Also in a configuration that the power suspension circuit 100 and the suspension maintaining circuit 1 10 are driven by the power of the battery pack 2 as in the first embodiment, two transformers can be used, similarly to the present embodiment.
Although the present invention has been described by referring to the illustrative embodiments as described above, it will be obvious to those skilled in the art that various changes and modifications may be made to each part or each process in the illustrative embodiments within the scope of the invention as described in claims. For example, a power supply such as a primary battery or secondary battery, instead of the capacitor, may be incorporated in the charging device and the suspension of the power supply circuit may be maintained by the power supply.
This application claims priority from Japanese Patent Application No. 2013-070665 March 28, 2013, the entire contents of which are incorporated herein by reference.

Claims

1. A charging device comprising:
a power supply circuit configured to charge a battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.
2. The charging device according to claim 1, wherein the power suspension circuit releases the suspension of the power supply circuit when the battery pack is disconnected.
3. The charging device according to claim 1 or 2, wherein
the power suspension circuit includes a first switching element configured to be turned on when full charge detection signal is input to a control terminal of the first switching element and a second switching element configured to be turned on when the voltage of the control terminal is changed in response to the first switching element being turned on,
the first and second switching elements are provided between charging output terminals of the power supply circuit,
the first switching element is turned on when the second switching element is in an on state irrespective of the presence or absence of the full charge detection signal, and
the power supply circuit is suspended when the first switching element is in an on state.
4. A charging device comprising:
a power supply circuit configured to charge a battery pack;
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed; and
a built-in power supply,
wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the built-in power supply after the power supply circuit is suspended.
5. The charging device according to claim 4, wherein the built-in power supply includes a capacitor configured to be charged by an output voltage of the power supply circuit.
6. The charging device according to claim 4 or 5 further comprising a releasing circuit configured to release the suspension of the power supply circuit by the power suspension circuit when the battery pack is disconnected.
7. The charging device according to claim 5 or 6 further comprising a recharging circuit configured to resume an operation of the power supply circuit when a voltage of the built-in power supply becomes less than a predetermined value after the power supply circuit is suspended.
8. The charging device according to claim 7 further comprising a relay switch configured to cut off current flowing through the battery pack from the power supply circuit while the operation of the power supply circuit is resumed by the recharging circuit.
9. The charging device according to any one of claims 4 to 8, wherein
the power suspension circuit includes a first switching element configured to be turned on when full charge detection signal is input to a control terminal and a second switching element configured to be turned on when the voltage of a control terminal is changed in response to the first switching element being turned on,
the first and second switching elements are provided between both terminals of the capacitor,
the first switching element is turned on when the second switching element is in an on state irrespective of the presence or absence of the full charge detection signal, and
the power supply circuit is suspended when the first switching element is in an on state.
10. The charging device according to any one of claims 1 to 9, wherein
the power supply circuit includes an input-side switching element configured to switch the input voltage, and
the power suspension circuit turns off the input-side switching element when the charging of the battery pack is completed.
11. The charging device according to claim 10, wherein the power supply circuit is of an insulation type including a transformer.
12. The charging device according to claim 11, wherein
the transformer has a primary side and a secondary side,
the power suspension circuit includes a light emitting element insulated from the primary side of the transformer and a light receiving element provided on the primary side of the transformer,
the light emitting element is energized when the battery pack is fully charged, and the input-side switching element is turned off when the light receiving element receives the light from the energized light emitting element.
13. A charging device comprising:
a power supply circuit having a primary side and a secondary side insulated from the primary side and configured to charge a battery pack; and,
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit maintains the suspension of the power supply circuit without using power of the primary side after the power supply circuit is suspended.
14. A charging device comprising:
a power supply circuit configured to charge a battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit releases a suspension state of the power supply circuit when the battery pack is disconnected.
15. The charging device according to claim 14, wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.
16. The charging device according to claim 14 further comprising a built-in power supply, wherein the power suspension circuit maintains the suspension of the power supply circuit using the built-in power supply after the power supply circuit is suspended.
17. The charging device according to claim 16, wherein the built-in power supply is configured by a capacitor configured to be charged by an output voltage of the power supply circuit.
18. A charging device comprising:
a power supply circuit including a transformer having a primary side and a secondary side, and configured to charge a battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed,
wherein the power suspension circuit includes a transmission unit insulated from the primary side of the transformer and a reception unit provided on the primary side of the transformer,
wherein the transmission unit is energized when the charging of the battery pack is completed, and
wherein the power supply circuit is turned off when the reception unit receives the signal from the transmission unit.
19. A charging device comprising:
a power supply circuit configured to charge a battery pack;
a control unit configured to control charging the battery pack; and
a power suspension circuit configured to suspend the power supply circuit after charging of the battery pack is completed so that power supplied from the power supply circuit to the control unit is suspended,
wherein the power suspension circuit maintains the suspension of the power supply circuit using the power of the battery pack after the suspension of the power supply circuit.
20. A charging device comprising:
a power supply circuit configured to charge a battery pack; and
a control unit configured to control charging the battery pack,
wherein power supplied from the power supply circuit to the control unit is cut off after charging of the battery pack is completed, and
wherein power is supplied from the power supply circuit to the control unit when the battery pack is detached rom the power supply circuit.
PCT/JP2014/055530 2013-03-28 2014-02-26 Charging device Ceased WO2014156514A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2013070665A JP2014195362A (en) 2013-03-28 2013-03-28 Charging device
JP2013-070665 2013-03-28

Publications (1)

Publication Number Publication Date
WO2014156514A1 true WO2014156514A1 (en) 2014-10-02

Family

ID=50346065

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2014/055530 Ceased WO2014156514A1 (en) 2013-03-28 2014-02-26 Charging device

Country Status (2)

Country Link
JP (1) JP2014195362A (en)
WO (1) WO2014156514A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017084528A1 (en) * 2015-11-20 2017-05-26 深圳市祝你快乐科技有限公司 Energy-saving charger capable of automatically powering off

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7002919B2 (en) * 2016-12-16 2022-01-20 ローム株式会社 Insulation synchronous rectification type DC / DC converter, power adapter and electronic equipment, DC / DC converter control method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004187366A (en) 2002-11-29 2004-07-02 Hitachi Koki Co Ltd General-purpose charging device
US20090206792A1 (en) * 2008-02-15 2009-08-20 Hyatt Edward C Automatic disconnect of an ac source from a converter
US20110095728A1 (en) * 2009-10-28 2011-04-28 Superior Communications, Inc. Method and apparatus for recharging batteries in a more efficient manner

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004187366A (en) 2002-11-29 2004-07-02 Hitachi Koki Co Ltd General-purpose charging device
US20090206792A1 (en) * 2008-02-15 2009-08-20 Hyatt Edward C Automatic disconnect of an ac source from a converter
US20110095728A1 (en) * 2009-10-28 2011-04-28 Superior Communications, Inc. Method and apparatus for recharging batteries in a more efficient manner

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017084528A1 (en) * 2015-11-20 2017-05-26 深圳市祝你快乐科技有限公司 Energy-saving charger capable of automatically powering off
US10749364B2 (en) 2015-11-20 2020-08-18 Shenzhen Znkl Technology Co., Ltd Energy-saving charger capable of automatically powering off

Also Published As

Publication number Publication date
JP2014195362A (en) 2014-10-09

Similar Documents

Publication Publication Date Title
US8659263B2 (en) Power supply circuit having low idle power dissipation
US7948212B2 (en) Battery pack and charging method
US9966772B2 (en) Battery-charge control device, battery charger and battery pack
CN101416367B (en) Battery charger
EP3018814B1 (en) Power converter with automatic mode switching
US8841880B2 (en) Battery charger with charge abnormality checking function
US20130093381A1 (en) Energy saving cable assembly
US20100096928A1 (en) Automatic start-up circuit and uninterruptible power supply apparatus having such automatic start-up circuit
CN1835331B (en) battery charger
US20150084581A1 (en) Charging device configured to reduce power consumption during non-charging period
WO2012132376A2 (en) Charger and power supply system
US20130257359A1 (en) Charger
JP2014042372A (en) Charging device
US20110169341A1 (en) Power saving circuit
US7652450B2 (en) Secondary battery charging device
WO2014156514A1 (en) Charging device
JP2000324690A (en) Standby power supply system
JP4163640B2 (en) Charger
CN101331660B (en) Circuits for small electrical equipment
KR20010051942A (en) Electronic apparatus including remote control receiving system and ac adapter system
US8891252B2 (en) Offline power supply and apparatus for charging a plug-in vehicle
WO2010074351A2 (en) Charging device
JP2010115047A (en) Charger
JPH11252822A (en) Power supply device
JP2013070453A (en) Charger

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14712052

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14712052

Country of ref document: EP

Kind code of ref document: A1