EP3977582A1

EP3977582A1 - Automatic charger switch off

Info

Publication number: EP3977582A1
Application number: EP19727708.0A
Authority: EP
Inventors: Harri Tiainen
Original assignee: Brightcharger Europe Oy Ltd
Current assignee: Brightcharger Europe Oy Ltd
Priority date: 2019-05-24
Filing date: 2019-05-24
Publication date: 2022-04-06
Also published as: WO2020240070A1

Abstract

According to an aspect, there is provided a device(100) for charging, which device(100) automatically disconnects power for charging an electrical device. The device (100) comprises a secondary circuit (20) configured to provide charging power; a primary circuit(10) configured to connect and disconnect supply power to the secondary circuit(20); and wherein the primary circuit (10) connects or disconnects the supply power based on signals received from the secondary circuit (20) indicating a charging demand.

Description

AUTOMATIC CHARGER SWITCH OFF

TECHNICAF FIEFD

[0001 ] The present application relates to the field of electronics, and more particularly to the controlling of charger power.

BACKGROUND

[0002] Battery-powered electrical devices require frequent charging. Chargers of the electrical devices may be kept plugged in to a wall constantly, even if the battery of the device is already full or disconnected from the charger. For example, a smartphone may need charging only for a few hours daily. However, the device may be charged for a considerably longer time than required to charge the battery full due to the effort required by a user to monitor the battery level. The rest of the time the charger wastes energy, reduces battery lifetime and increases the risk of fire. In general, chargers are able to switch from using the charging current to the use of standby current when the battery of a chargeable device becomes full. Although the standby current is considerably lower than charging current, on an annual level it still leads to significant electricity consumption. Furthermore, the standby current supplied by chargers to a chargeable device destroys or weakens the capacity of the battery of the chargeable device, speeding up the decrease of the capacity of the battery. The batteries may have a certain life span of an available overall charging time.

SUMMARY

[0003] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [0004] Chargers consume electricity when they are left connected to a mains current, when the charger is in the process of charging a battery, and when the charger continually keeps supplying power to a full battery. It is an object to provide a solution for controlling power of a charger by automatically disconnecting power when there is no need for charging. An embodiment may reduce the consumption when a charger is plugged in but there is no electrical device connected to the charger for charging, when the battery of the electrical device is already full, or there is no need for a charging operation.

[0005] According to a first aspect, there is provided a device for charging. The device comprises a secondary circuit configured to provide charging power; a primary circuit configured to connect and disconnect supply power to the secondary circuit; wherein the primary circuit connects or disconnects the supply power based on signals received from the secondary circuit indicating a charging demand; and wherein the primary circuit is configured to provide an auxiliary voltage from the supply power for a power switch interfacing the primary and the secondary circuits for connecting or disconnecting the supply power to the secondary circuit. Thus, unnecessary electricity consumption may be avoided. Other advantages may be to avoid harming the batteries of electrical devices and potential fire hazards.

[0006] In an embodiment, the primary circuit is configured to connect the supply power in response to a signal indicating that an electrical device is connected to the device. Thus, electricity consumption may be minimized as there is no current in the secondary circuit before it is actually needed for charging.

[0007] In an embodiment, in addition or alternatively, the primary circuit is configured to disconnect the charging power in response to a signal indicating that the connected electrical device is substantially fully charged. Thus, harming the battery with excessive charging is avoided. If the supply power was not disconnected, the charging may restart as soon as the battery level decreases even slightly. [0008] In an embodiment, in addition or alternatively, the primary circuit is configured to disconnect the supply power in response to a signal indicating that an electrical device is disconnected from the device. Thus, electricity consumption is minimized and a risk of fire avoided.

[0009] In an embodiment, in addition or alternatively, the device comprises a power switch interfacing the primary and secondary circuit configured to switch on and off power to the secondary circuit; and the primary circuit further comprises a power control unit configured to control the power switch in response to the signals. Thus, the operations of the two circuits may be linked in order to enable providing of the charging power and also to minimize energy consumption when charging is not needed.

[0010] In an embodiment, in addition or alternatively, the secondary circuit comprises a connector configured to provide connection means for the electrical device to connect to the device, and to provide signals to the primary circuit indicating when the electrical device is connected. The embodiment enables indicating of the charging demand. The primary circuit may then control the power of the secondary circuit in a suitable manner to answer the demand.

[001 1 ] In an embodiment, in addition or alternatively, the primary circuit comprises a controller. The controller is configured to receive current value signals from the secondary circuit; detect when the electrical device is substantially fully charged based on the current values; and control the operation of the primary circuit to disconnect the supply power. Thus, the supply power may be disconnected timely when there is no more need for charging.

[001 2] In an embodiment, in addition or alternatively, the primary circuit comprises a primary rectifier configured to provide a constant voltage when the device is connected to a power supply. Thus, an auxiliary voltage is provided to enable connecting and disconnecting the supply power to the secondary circuit. The device consumes only a minimal amount of energy, while it is still simultaneously ready to start a charging operation.

[001 3] In an embodiment, in addition or alternatively, the secondary circuit comprises a secondary rectifier configured to provide an operating current for a connector and the controller. Because the current is provided for the operations of the second circuit as well as the controller through the same rectifier, when the supply power to the secondary circuit is disconnected, the device consumes hardly any energy at times when there is no demand for charging.

[001 4] In an embodiment, in addition or alternatively, the secondary circuit comprises a detector configured to determine the charging current and provide charging current values to the controller. The embodiment enables providing signals indicating the charge level of the battery to the controller for actuating switch off operations at the right time.

[001 5] In an embodiment, in addition or alternatively, the controller is configured to actuate a hold unit configured to cause the power control unit to switch off the power switch in response to detecting that the electrical device is substantially fully charged. Thus, the power control unit may be caused to switch off power when the battery is full even though the chargeable device is still plugged in.

[001 6] In an embodiment, the auxiliary voltage comprises constant

DC voltage, which is substantially lower that a voltage of the supply power. Only a low voltage need to be maintained for powering up the charger device.

[001 7] In an embodiment, the power switch comprises a led and an opto-isolator, wherein based on the auxiliary voltage and the led controls the opto-isolator for connector or disconnecting the supply power. Since there is no noteworthy load when primary circuit operates, the consumption of the charger device is negligible or very low.

[001 8] In an embodiment, a connection to a chargeable device is configured operate as a voltage divider and provide a connection to a ground for a transistor in the power control unit so as to provide current to the led of the power switch. A sufficient voltage may be provided to active the transistor in the power control unit, and current may flow through the power switch led for switching on the starting the secondary circuit operating.

[001 9] Many of the attendant features will be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

[0020] The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein:

[0021 ] FIG. 1 illustrates a schematic representation of a block diagram of a charger according to an embodiment.

[0022] FIG. 2A illustrates a schematic representation of a block diagram of operation of a charger when an electrical device is connected to the charger.

[0023] FIG. 2B illustrates a schematic representation of a block diagram of operation of the charger when the connected electrical device is substantially fully charged.

[0024] FIG. 2C illustrates a schematic representation of a block diagram of the charger when the electrical device is disconnected from the charger.

DETAIFED DESCRIPTION

[0025] The detailed description provided below in connection with the appended drawings is intended as a description of the embodiments and is not intended to represent the only forms in which the embodiment may be constructed or utilized. However, the same or equivalent functions and structures may be accomplished by different embodiments.

[0026] According to an embodiment, a charger may comprise a primary and a secondary circuit. The secondary circuit may be configured to operate similarly to a conventional charger for providing the charging current. The primary circuit may be configured to control supply power needed to operate the secondary circuit. In other words, the primary circuit makes it possible that the voltage does not need to be maintained outside of the time of the charger’s intended use for the charging circuit. When there is no demand for charging, for example no electrical device is connected to the charger or the battery of the connected device is full, the charger may be arranged to operate in a“zero state”. The zero state refers to a state in which the charger hardly consumes any energy, meaning nearly zero watts. Conventional chargers may operate in a stand-by mode when the battery of the electrical device is full and start charging again when the battery level drops. Contrary to these solutions, an embodiment of the solution enables the charging power to be completely switched off when the battery is already full.

[0027] The electrical device may refer to any kind of battery operated device that may be charged with a charger. The present embodiments may be suitable for chargers of, for example, smartphones or mobile phones, tablets, computers, cameras, game consoles, laptop computers, domestic electrical devices, electrical toothbrushes, vacuum cleaners with battery, and such devices.

[0028] FIG. 1 illustrates a schematic representation of a block diagram of a device 100 for charging according to an embodiment. The device may be referred to as a charger 100. The charger 100 enables automatic disconnecting of power of a charging circuit when there is no need for charging.

[0029] The charger 100 comprises a primary circuit 10 and a secondary circuit 20. The two circuits 10, 20 may be coupled to a protection unit 50 such as to mains protection. The charger 100 may be connected to a power supply 40 to receive power. The power supply 40 may be, for example, a socket providing a mains current of 110 or 230 V AC. The power may also be received from other suitable sources than the mains power source.

[0030] The primary circuit 10 comprises a primary rectifier 12 configured to provide auxiliary voltage for operations in the primary circuit 10. The primary circuit 10 further comprises a power control unit 14 configured to control a power switch 30. The power control unit 14 operates in response to signals indicating that an electrical device is connected to the charger 100. The signals are received from the secondary circuit 20, and they may indicate if an electrical device is connected to the charger or if the battery of the electrical device has reached a sufficient charge level. The power switch 30 is arranged to interconnect the primary 10 and secondary 20 circuits. The power switch 30 interfaces the two circuits 10, 20 of different voltages together without one electrically affecting the other. A controller 18 is configured to determine when the battery of the electrical device is substantially fully charged. In response to the determination, the controller 18 is further configured to activate a hold unit 16. The hold unit 16 is configured to ground a signal from the secondary circuit 20, and cause the power switch 30 to switch off. The controller 18 may receive its operating voltage from the secondary circuit 20.

[0031 ] The secondary circuit 20 comprises a secondary rectifier 22 configured to convert the supplied AC voltage from the power supply 40 to DC voltage. A transformer 24 is configured to transform the rectified high voltage to an operating voltage level. The secondary circuit comprises a detector 26 configured to determine the operating current values. The detector 26 is further configured to provide the current values to the controller 18. A connector 28 is configured to provide connection means for an electrical device to connect to the charger 100 for charging. The connector 28 is also configured to indicate to the power control unit 14 when the electrical device is connected to the connector 28.

[0032] FIGS. 2A-2C provide a more specified example of the structure and operation of the charger 100. The illustrated components and values are for illustrative purposes only, and they should not be understood as a limitation. The charger 100 may be configured to operate at different voltages, and some of the components may be replaced or removed. For convenience, the sections receiving current in each operation are provided with bold frames.

[0033] FIG. 2A illustrates a schematic representation of a block diagram of the charger 100 when an electronic device is connected to the charger 100. Connecting the electrical device to the charger 100 triggers the operations to switch on power to the secondary circuit 20 for charging.

[0034] When the charger 100 is connected to the power supply 40, but there is no electrical device connected to the charger 100, the power switch 30 and the secondary circuit 20 are switched off. Concurrently, the primary rectifier 12 provides auxiliary voltage for the primary circuit, which may be, for example, 12 V. The auxiliary voltage may be regulated, and constant DC voltage produced with, for example, a bridge rectifier and a zener coupling. The power switch 30 may be, for example, an opto-triac or other opto-isolator. The power switch 30 may comprise a led coupled to the primary circuit 10 and a triac coupled to the secondary circuit 20. At this point, no current is flowing through the led in the opto-triac 30. Thus, the power switch 30 is switched off, and no power is supplied to the secondary rectifier 22. Since there is no noteworthy load when only the primary rectifier 12 is operating, the consumption of the charger 100 is negligible. The consumption may be, for example, less than 0,1 mW, while the stand-by consumption of conventional chargers may be 20 mW.

[0035] The connector 28 may be a USB connector and comprise data pins. The data pins provide differential data signals, D+ and D-. When the electrical device is connected to the connector 28, either D+ or D- may be pulled up with bias resistors to high voltage, thus indicating that a device is connected to the connector 28. Once the electrical device is connected, the data pins may operate as a voltage divider, and a route to the ground is provided for the current through the data pins. Thus, a sufficient voltage may be provided to activate a transistor in the power control unit 14, and the transistor starts conducting. Now that the current may flow through the led of the opto-triac, the power switch 30 is switched on and the secondary circuit 20 starts operating.

[0036] The secondary rectifier 22 may convert, for example, the supplied 230 AC voltage to 230 DC voltage. The secondary rectifier 22 may be a bridge rectifier with a smoothing capacitor. Thereafter the voltage is lowered, for example, to a 5 V operating voltage with the isolated transformer 24. Thus, the charging current may be provided for the connected electrical device.

[0037] FIG. 2B illustrates a schematic representation of a block diagram of operation of the charger when the electrical device is substantially fully charged. The operations may be initiated when the controller 18 determines that the battery of the electrical device has reached a sufficient charge level, such as over 90 percent of the battery capacity.

[0038] The detector 26 measures current values supplied to the electrical device. The current values are signaled to the controller 18. The controller 18 may comprise an algorithm configured to detect when the battery of the electrical device is substantially fully charged. The controller 18 may then initiate operations to switch off power of the secondary circuit 20. Thus, the voltage in the secondary circuit 20 is not maintained needlessly. If the secondary circuit was not shut down, the charger 100 would be constantly charging, e.g. every time the battery level drops even slightly, such as by 1 %. With the two separate rectifiers 12, 22 it is not necessary to maintain electricity in the secondary circuit 20 configured to provide the charging power. [0039] In response to detecting that the battery of the electrical device is substantially fully charged, the controller 18 may control the hold unit 16 to be switched on. In an embodiment, the controller 18 may initiate a voltage pulse to the hold unit 16. In response, the hold unit 16 is activated and starts conducting. As a result, the hold unit 16 is able to hold a certain voltage level. The hold unit 16 is configured to ground the control signal received from the connector 28. Consequently, from the power control unit’s 14 perspective the electrical device is disconnected, and the transistor is therefore cut-off. Futher, the led in the opto-triac stops receiving the current, and the power supply to the secondary circuit 20 is disconnected. Because the controller 18 is arranged to receive its power from the secondary circuit 20, the controller 18 is turned off at the same time as the secondary circuit 20 immediately after the controller 18 has activated the hold unit 16. The hold unit 16 is configured to hold the voltage until the electrical device is disconnected from the connector 28.

[0040] FIG. 2C illustrates a schematic representation of a block diagram of the charger 100 when the electrical device is disconnected from the charger. When the electrical device is disconnected from the charger 100, the secondary circuit automatically turns off.

[0041 ] By disconnecting the electrical device from the connector 28, the base current of the transistor has no longer route to the ground, and therefore the transistor switches to the off mode. Thus, the led of the opto- isolator stops receiving current, and the power switch 30 is switched off. In case the power switch 30 had been disconnected earlier due to the battery of the electrical device being substantially fully charged, disconnecting the electrical device from the connector 28 resets the hold unit 16.

[0042] The functionality described herein can be performed, at least in part, by one or more computer program product components such as software components. Any range or device value given herein may be extended or altered without losing the effect sought. Also any embodiment may be combined with another embodiment unless explicitly disallowed. [0043] Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.

[0044] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item may refer to one or more of those hems. The term‘and/or’ may be used to indicate that one or more of the cases it connects may occur. Both, or more, connected cases may occur, or only either one of the connected cases may occur.

[0045] Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought.

[0046] The term 'comprising' is used herein to mean including the method, blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

[0047] It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

1. A charger device (100), comprising:

a secondary circuit (20) configured to provide charging power;

a primary circuit (10) configured to connect and disconnect supply power (40) to the secondary circuit (20);

wherein the primary circuit (10) connects or disconnects the supply power based on signals received from the secondary circuit (20) indicating a charging demand; and

wherein the primary circuit (10) is configured to provide an auxiliary voltage from the supply power (40) for a power switch (30) interfacing the primary and the secondary circuits for connecting or disconnecting the supply power (40) to the secondary circuit (20).

2. The charger device (100) of claim 1, wherein the primary circuit (10) is configured to:

connect the supply power in response to a signal indicating that an electrical device is connected to the device (100).

3. The charger device (100) of claim 1 or 2, wherein the primary circuit (10) is configured to:

disconnect the supply power in response to a signal indicating that the electrical device is substantially fully charged.

4. The charger device (100) of any of the claims 1 - 3, wherein the primary circuit (10) is configured to:

disconnect the supply power in response to a signal indicating that the electrical device is disconnected from the device (100).

5. The charger device (100) of any of the claims 1 - 4, wherein the device (100) comprises the power switch (30) interfacing the primary (10) and secondary circuit (20) configured to switch on and off the power to the secondary circuit (20); and

the primary circuit (10) further comprises a power control unit (14) configured to control the power switch (30) in response to the signals.

6. The charger device of any of the claim 1 - 5, wherein the secondary circuit (20) comprises a connector (28) configured to provide connection means for the electrical device to connect to the device (100), and to provide signals to the primary circuit (10) indicating when the electrical device is connected.

7. The charger device (100) of claim 3, wherein the primary circuit (10) comprises a controller (18) configured to:

receive current value signals from the secondary circuit (20);

detect when the electrical device is substantially fully charged based on the current values; and

control the operation of the primary circuit (10) to disconnect the supply power.

8. The charger device (100) of claim 7, wherein the secondary circuit (20) comprises a detector (26) configured to determine charging current values and provide the charging current values to the controller (18).

9. The charger device (100) of any of the preceding claims, wherein the primary circuit (10) comprises a primary rectifier (12) configured to provide a constant voltage when the device (100) is connected to a power supply (40).

10. The charger device (100) of any of the preceding claim, wherein the secondary circuit (20) comprises a secondary rectifier (22) configured to provide operating current for the connector (28) and the controller (18).

11. The charger device (100) of any of the claims 7 - 10, wherein the controller (18) is configured to actuate a hold unit (16) configured to cause the power control unit (14) to switch off the power switch (30) in response to detecting that the electrical device is substantially fully charged.

12. The charger device (100) according to any preceding claim, wherein the auxiliary voltage comprises constant DC voltage, which is substantially lower that a voltage of the supply power (40).

13. The charger device (100) according to any preceding claim, wherein the power switch (30) comprises a led and an opto-isolator, wherein based on the auxiliary voltage and the led controls the opto-isolator for connector or disconnecting the supply power (40).

14. The charger device (100) according to any preceding claim, wherein a connection to a chargeable device is configured operate as a voltage divider and provide a connection to a ground for a transistor in the power control unit (14) so as to provide current to the led of the power switch (30).