Bus power device and power-source control method

Abstract

To include a USB connector (150) that is connected to a high-power USB port (11) (or a low-power USB port (12)) of a USB-corresponding device (10) corresponding to a USB interface standard, a current / voltage detecting unit (107) that detects current / voltage supplied from the USB-corresponding device (10) to a bus power line (151) via the high-power USB port (11) (or the low-power USB port (12)) and the USB connector (150), and a power assisting unit (108) that assists a current to the bus power line (151) based on a result of comparison between a current detected by the current / voltage detecting unit (107) and a threshold current, and assists a voltage as much as the deficient amount to the bus power line (151) based on a result of comparison between a detected voltage and a threshold voltage.

Description

technical field [0001] The present invention relates to such as USB (Universal Serial Bus: Universal Serial Bus) and IEEE (Institute of Electronic and Electronics Engineers: Institute of Electrical and Electronics Engineers) 1394 and other interface standards as the basis of the bus power (Bus Power) device, particularly to avoid A bus power supply device and a power supply control method capable of grasping the remaining battery level corresponding to the operating state when the operation cannot be performed due to a voltage drop, and further enabling rapid charging. Background technique [0002] In recent years, USB interface standards have attracted attention as an interface for connecting peripheral devices to personal computers. This USB interface standard has the feature that a maximum of 127 USB devices can be connected in a tree. [0003] FIG. 7 is a block diagram showing the configuration of a conventional bus power supply device 20 . In this figure, a USB compat...

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Problems solved by technology

[0015] On the other hand, when the judgment result of step SA3 is "No", that is, when the USB connector 30 is connected to the low-power USB port 12, because the USB-compatible device 10 is connected to the low-power device 20 Each unit of each unit only provides low power (100mA / 5V), so in step SA6, can not use bus power unit 20

[0016] Here, in the bus power supply device 20 shown in FIG. 7 , depending on the operating conditions, there may be the following cases: after the USB connector 30 is connected to the USB compatible device 10, there may be an inrush current due to the initial rotation of the hard disk 23. If the bus power supply line 31 flows, the following problem occurs: the current supplied from the USB corresponding device 10 to the bus power supply device 20 exceeds the specified value (500mA), causing malfunction or inoperability

[0039] For example, when the voltage of the high-power USB port 11 is 5V and the operating guaranteed voltage of the hard disk 23 is 4.75 to 5.25V, if the above-mentioned voltage drop exceeds 0.25V, the voltage supplied to the hard disk 23 is insufficient for the guaranteed operating voltage of 4.75V. (5-0.25) V, the hard disk 23 cannot work

[0040] However, in the current assist method of the bus power supply device 40, since only the current flowing through the bus power supply line 31 is used as the detection object, there is a problem that the operation cannot be avoided due to a voltage drop.

[0041] In addition, in the conventional bus power supply device 40, because it corresponds to the operating state of the bus power supply device 40 (charging, access to the hard disk 23, data transfer), regardless of the load (battery voltage) of the secondary battery 41, it is relatively stable. The battery voltage of the secondary battery 41 and a threshold value are used to display the remaining battery level on the battery remaining level display unit 47 based on the comparison result, so there is a problem that the correct battery level cannot be grasped.

[0042] In addition, in the conventional bus power supply device 40, since the charging current from the charging unit 45 to the secondary battery 41 is constant, there is a problem that rapid charging cannot be performed even if charging is required for a short time.

[0043] In addition, in the conventional bus power supply device 50 shown in FIG. 10 , when it is connected to the low-power USB port 12, another power supply (AC / DC adapter) is required, and it cannot be used without another power supply. The problem

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