This Application claims priority of Taiwan Patent Application No. 101141989, filed on Nov. 12, 2012, the entirety of which is incorporated by reference herein.
1. Field of the Invention
The present invention relates to a battery management system, and in particular to a battery management system for use in an electric vehicle (e.g. electric bikes, electric motorcycles, or cars).
2. Description of the Related Art
Currently, an electric vehicle may comprise a battery module and a battery management system. The present USB devices may have different types of charging specifications, and the required maximum charging currents of different charging specifications may be different. Although the conventional battery management system of an electric vehicle provides a charging function to charge a USB device, the conventional battery management system can not recognize the type of the USB device, and thus the USB device connected to the conventional battery management system can only be charged with a fixed charging current. Accordingly, it is not effective to charge a USB device by using the conventional battery management system.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
In an exemplary embodiment, a battery management system for use in an electric vehicle is provided. The battery management system comprises: a battery module, configured to provide power to drive the electric vehicle; and a charging module, configured to detect a type of a USB device coupled to the battery management system, and charge the USB device by using the power from the battery module according to the type of the USB device.
In another exemplary embodiment, an electric vehicle is provided. The electric vehicle comprises: a battery module, configured to provide power to the electric vehicle; a driving apparatus, configured to receive the power from the battery module to drive the electric vehicle; and a charging module, configured to detect a type of a USB device coupled to the battery management system, and charge the USB device by using the power from the battery module according to the type of the USB device.
The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
The charging module 130, coupled to the battery module 110, is configured to detect the type of the USB device 190 connected to the battery management system 100 automatically, and provide an optimal voltage/current to charge the USB device 190 with the power from the battery module 110 according to the detected type of the USB device 190.
In an embodiment, the charging module 130 may transmit a feature signal corresponding to a specific type to the USB device 190 when the USB device is connected to the battery management system 100, and detect the type of the USB device 190 according to a voltage level from the USB device 190 in response to the feature signal. Specifically, the charging module 130 may transmit a first feature signal corresponding to a first type to the USB device 190 when the USB device 190 is connected to the battery management system 100. Then, the charging module 130 may detect whether the USB device 190 conforms to the first type according a voltage level from the USB device 190 in response to the first feature signal. When the USB device 190 conforms to the first type, the charging module 130 may provided a first charging current to charge the USB device 190. When the USB device 190 does not conform to the first type, the charging module 130 may transmit a second feature signal corresponding to a second type to the USB device 190. Then, the charging module 130 may further determine whether the USB device conforms to the second type according to the voltage level from the USB device 190 in response to the second feature signal. When the USB device 190 conforms to the second type, the charging module 130 may provide a second charging current to charge the USB device 190. When the USB device 190 does not conform to the second type, the charging module 130 may further provide a third charging current corresponding to a third type to charge the USB device 190.
In an embodiment, the aforementioned first type and second type are model numbers or type numbers defined by a specific manufacturer (e.g. iPad, New iPad, or iPhone defined by Apple), but the invention is not limited thereto. The aforementioned first type and second type can be other model numbers or type numbers defined by other specific manufacturers, such as Blackberry, Samsung, or other brands. In addition, the aforementioned first charging current and second charging current may be 1 A and 2 A, respectively. In another embodiment, the aforementioned third type may be a model supporting the dedicated charging port (hereinafter as DCP) mode defined in the USB Battery Charging Specification (hereinafter as USB BCS). In addition, the aforementioned third charging current may be 1.5 A.
When a USB device is connected to a conventional charging module, the conventional charging module may use the standard downstream port (hereinafter as SDP) mode defined in the USB BCS to charge the USB device with a 0.5 A current without concern for what type of the USB device it is. Thus, there may be the issue of a long charging time for the conventional charging module. However, the charging module 130 may provide an appropriate current larger than 0.5 A to charge the USB device 190 according to the type of USB device 190, thereby achieving fast charging of the USB device 190. It should be noted that the voltage level of the differential signal pair (e.g. D+ and D− pins) of the USB device 190 should be set to a fixed specific voltage level when the USB device 190 is charged by a current larger than the current defined in the SDP mode (e.g. 0.5 A). Since there is no demand for data transmission during the charging of the USB device on the electric vehicle, the battery management system 100 may set the voltage level of the differential signal pair (e.g. D+ and D− pins) of the USB device 190 to a fixed voltage level when the USB device 190 is charged by the battery management system 100, so that it is more convenient for the battery management system 100 to select one of the first, second and third charging current to charge the USB device 190.
In an embodiment, the control circuit 140 may control the switches S3 and S1, so that the voltage source V1 having a first voltage level (e.g. 2.7V) is coupled to the D+ pin of the USB device. Meanwhile, the control circuit 140 may control the switches S4 and S2, so that the voltage source V2 having a second voltage level (e.g. 2.0V) is coupled to the D− pin of the USB device. Accordingly, the first detection circuit 150 may transmit the first feature signal by providing the first voltage level (e.g. 2.7V) and the second voltage level (e.g. 2.0V) to the differential signal pin (e.g. D+ and D− pins) respectively. When the USB device conforms to the first type and has received the first feature signal, the USB device may respond with voltage signals of 2.7V and 2.0V at the D+ pin and the D− pin, respectively. The voltage detection circuit 151 may determine whether the USB device conforms to the first type by detecting whether the voltage levels of the D+ and D− pins are the same with the 2.7V and 2.0V respectively, and store the determination result of the first type into a first register (not shown) by a control signal C1. Then, the control circuit 140 may read the data stored in the first register to perform corresponding actions, such as charging the USB device with the first charging current, or perform subsequent detection by the second detection circuit 160.
In another embodiment, the control circuit 140 may control the switches S5 and S1, so that the voltage source V3 having a third voltage level (e.g. 2.0V) is coupled to the D+ pin of the USB device. Meanwhile, the control circuit 140 may control the switches S6 and S2, so that the voltage source V4 having a fourth voltage level (e.g. 2.7V) is coupled to the D− pin of the USB device. Accordingly, the second detection circuit 160 may transmit the second feature signal by providing the third voltage level (e.g. 2.0V) and the fourth voltage level (e.g. 2.7V) to the differential signal pair (e.g. D+ and D− pins) respectively. When the USB device conforms to the second type and has received the second feature signal, the USB device may respond with respective voltage signals at 2.0V and 2.7V at the D+ pin and D− pin respectively. The voltage detection circuit 161 may determine whether the USB device conforms to the second type by detecting whether the voltage levels of the D+ and D− pins are the same with the 2.0V and 2.7V respectively. The detection circuit 161 may further store the determination result of the second type into a second register (not shown) by a control signal C2. Then, the control circuit 140 may read the data stored in the second register to perform corresponding actions, such as charging the USB device with the second charging current or the third charging current.
In view of the above, the control circuit 140 may control the charging circuit 170 to output an appropriate current through the VBUS pin of the USB device according to the type of USB device 190 detected by the first detection circuit 150 or the second detection circuit 160. The voltage detection circuit 151 in the first detection circuit 150 and the voltage detection circuit 161 in the second detection circuit 160 are configured to detect the voltage levels in response from the USB device, thereby determining whether the USB device conforms to the first type (e.g. Apple devices charged with a 2 A current) or the second type (e.g. Apple devices charged with a 1 A current). When the USB device does not conform to the first type and the second type, the control circuit 140 may control the charging circuit 170 to charge the USB device with a third charging current.
For example, in the second charging mode (e.g. 1 A charging mode), the voltage levels of the D+ and D− pins are at 2.0V and 2.7V, respectively. In the first charging mode (e.g. 2 A charging mode), the voltage levels of the D+ and D− pins are at 2.7V and 2.0V, respectively. In the following embodiment, the first charging mode having the 2 A current is regarded as the default charging mode for the purpose of description. When a USB device 190 is connected to the battery management system 100 through a USB interface (e.g. D+, D−, GND, and VBUS pins in
In step S250, the control circuit 140 may control the switches S1 and S2 to select the second detection circuit 160, and control the switches S5 and S6 to connect to the voltage sources V3 and V4, respectively. That is, the D+ and D− pins are connected to the voltage source V3 (e.g. 2.0V) and the voltage source V4 (e.g. 2.7V). The charging module 130 may transmit the second feature signal corresponding to a second type (e.g. 1 A charging mode) to the D+ and D− pins of the USB device 190 (step S255). The charging module 130 may also receive the voltage levels for responding to the second feature signal from the D+ and D− pins of the USB device 190 (step S260). Then, the voltage detection circuit 161 of the second detection circuit 160 may determine whether the responding voltage levels from the D+ and D− pins of the USB device 190 are the same with the second feature signal (i.e. determining whether the responding voltage levels at the D+ and D− pins are 2.0V and 2.7V, respectively). That is, the second detection circuit 160 may determine whether the USB device 190 conforms to the second type (step S270). If so (e.g. the responded voltage levels are the same with the second feature signal), it is determined that the USB device 190 supports the second charging mode, and the charging circuit 170 may charge the USB device 190 with the second charging current (e.g. 1.0 A) via the VBUS pin. If not, step S290 is performed.
In step S290, since the USB device 190 does not support the first charging mode (e.g. 2 A charging mode) or the second charging mode (e.g. 1 A charging mode), the control circuit 140 may short-circuit the D+ pin and the D− pin, such that the D+ pin and the D− pin have the same voltage level. In the present embodiment, the control circuit 140 may control the switches S1 and S2 to select the first detection circuit 150, and control the switches S3 and S4 to connect to a resistance R5, so that the D+ pin and the D− pin are short-circuited. In addition, the control circuit 140 may optionally control the switches S1 and S2 to select the second detection circuit 160, and control the switches S5 and S6 to connect to a resistance R6, so that the D− pin and the D+ pin are short-circuited. Meanwhile, the charging circuit 170 may provide the third charging current (e.g. 1.5 A) through the VBUS pin to charge the USB device 190 (step S295). Generally, there is no demand for data transmission when the USB device 190 is being charged in an electric vehicle. Thus, the charging module 130 may short-circuit the D+ and D− pins which are used for data transmission, so that the USB device 190 can be charged in the third charging mode with the third charging current which is larger than the charging current (e.g. 0.5 A for USB 2.0, and 0.7 A for USB 3.0) defined in the SDP mode. The aforementioned third charging mode may be the DCP mode or another specific charging mode for the USB devices defined by other specific manufacturers. When the USB device 190 is charged in the DCP mode or another specific charging mode defined by other specific manufacturers, the voltage levels of the D+ and D− pins of the USB device 190 should be set to a specific fixed voltage level respectively. Accordingly, the D+ pin and the D− pin are short-circuited in step S290, and thus the voltage level of the D+ pin is identical to that of the D− pin, so that the USB device 190 can be charged with the third charging current, which is greater than the current defined in SDP mode, in step S295. Note that although the charging circuit 170 provides the third charging current at the VBUS pin to charge to the USB device 190, the charging current received by the USB device 190 still depends on the limitation of the charging mode defined by the USB interface specification of the USB device 190. For example, the USB device 190 may only support the SDP mode without supporting the DCP mode. Although the third charging current provided by the charging module 130 is greater than the charging current supported by the SDP mode, the maximum value of the charging current for charging the USB device 190, which only supports the SDP mode, is 0.5 A. Only when the USB device 190 supports the DCP mode, the maximum value of the charging current can be raised to 1.5 A. In addition, when the D− and D+ pins are short-circuited and the USB device 190 has been charged via the charging current (e.g. 1.5 A) of the DCP mode for more than a predetermined time period (e.g. 10 seconds), the control circuit 140 may restore the switches S1˜S6 to the connections of the default charging mode (e.g. 1 A charging mode or 2 A charging mode). That is, D+ and D− pins are restored to the connections of the default charging mode. Meanwhile, the charging circuit 170 may still keep charging the USB device 190 without affecting by the connection restoration of the switches S1˜S6 by the control circuit 140.
It should be noted that the 2 A charging mode is regarded as the default charging mode in the aforementioned embodiment. Alternatively, the 1 A charging mode can also be regarded as the default charging mode, and reference can be made to steps S250˜S280 in the aforementioned embodiment for the details of the procedure. In another embodiment, steps S210˜S240 or S250˜S280 in
In view of the above, the battery management system 100 may recognize the type of USB device, and provide a more appropriate charging current to charge the USB device according to the recognized type. Since the battery management system can be applied to an electronic vehicle, there is no demand for transmitting differential packets at the differential signal pair (e.g. D− and D+ pins) of the USB device when the USB device is charged by the battery management system of the electric vehicle of the invention. Accordingly, the battery management system of the invention may provide a corresponding fixed voltage on the differential signal pair, and provide a larger charging current at the VBUS pin of the USB interface to charge the USB device. In addition, the battery management system of the invention may directly charge the USB device without entering a “suspend” status.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
Number | Date | Country | Kind |
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101141989 | Nov 2012 | TW | national |