JP2010142098A - Charger for mobile electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charger for mobile electronic equipment which detects that a connector has been connected and activates a charging circuit. <P>SOLUTION: A connector connection detecting means other than the charging circuit is provided in the charger for the mobile electronic equipment. The connector connection detecting means applies a higher voltage than a voltage of a built-in battery of the mobile electronic equipment to be charged to a charging terminal of a charging connector. As the applied voltage drops when the connector is connected, a connector connection is detected by the voltage drop and the charging circuit is activated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

Detailed Description of the Invention

  The present invention relates to a charger for portable electronic devices such as a mobile phone, a portable music player, and a portable electronic game machine, and more particularly to a charger using a dry battery or a secondary battery.

  AC chargers with AC 100V input / DC 5V output are used as chargers for portable electronic devices such as mobile phones, portable music players, and portable electronic game machines. If an AC outlet is not at hand, a battery is built in. The charger is convenient.

  As a charger for a portable electronic device with a built-in battery, a charger for a mobile phone is widely known and commercially available.

  Since the battery of a portable electronic device uses a nominal 3.7V lithium ion or lithium polymer battery, the charger must output a voltage of 3.7V or higher. For this reason, the charger for portable electronic devices includes voltage control means for stepping up or down the voltage of the built-in battery to a voltage suitable for charging.

  One problem of a portable electronic device charger that uses the energy of a built-in battery as charging energy is power consumption during standby.

  If the voltage control means for raising or lowering the voltage of the built-in battery to a voltage suitable for charging continues to operate continuously during standby, the built-in battery is consumed. Therefore, it is desirable that the voltage control means operates only when the connector of the portable electronic device is connected to the charging connector of the charger.

  As a method of operating the voltage control means by detecting the connection of the connector, a connector provided with a switch terminal in addition to two power supply terminals necessary for charging has been proposed (Patent Document 1, Patent Document 2).

  JP 2002-374545 A   Japanese Patent Publication No. Sho 63-110573

  As a connector having a switch terminal, there is an interface connector of a mobile phone. The connection of the interface connector is shown in FIG. FIG. 3 shows only a portion related to charging of the charger 31 and the mobile phone 32. Since the COM (common) terminal of the interface connector 323 on the mobile phone 32 side is connected to one terminal, two interfaces are connected. When the connector is connected, power is supplied to the voltage control means 312 of the charger 31, and the voltage control means 312 operates.

  In the case of a connector having no switch terminal, a method of providing a metal electrode functioning as a switch around the connector has been proposed (Patent Document 3).

  Published Patent Publication No. Hei 4-123775

  In some existing connectors, there is no space in the connector terminal, and the switch terminal may not be provided. A typical example is a USB connector.

  In such a case, as seen in [Patent Document 3], it is necessary to provide a metal electrode or a proximity switch that functions as a switch around the connector. In any case, the cost increases because it must be processed into a case.

  The present invention has been made to solve the above problems, and provides a charger for a portable electronic device that detects attachment / detachment of a connector with a power transmission terminal of the connector and operates a voltage control means when the connector is connected.

As shown in FIG. 3, the charging terminal of the portable electronic device is generally connected to a built-in battery via a backflow prevention means. Therefore, the charging terminal voltage during charging with the connector connected is the sum of the forward voltage drop of the backflow prevention means and the voltage of the built-in battery, and this voltage is hereinafter referred to as V _C.

  The charger of the present invention is made by paying attention to the voltage of the charging terminal, and its configuration is shown in FIG. In FIG. 1, 11 is a battery built in the charger 1, 12 is voltage control means for boosting or lowering the voltage of the battery 11, 13 is probe voltage generation means, 14 is voltage monitoring means, and 15 is voltage control. Means for activating means 12.

In the configuration of FIG. 1, a voltage higher than V _C , Vtest, is applied between the charging terminals 16 a and 16 b by the probe voltage generating means 13. When this voltage Vtest connector 16 is connected to the charging connector of the portable electronic device will be reduced to V _C. When this voltage drop is detected by the voltage monitoring means 14 and the voltage means 12 is activated by this, charging from the charger 1 to the portable electronic device is started.

In general, since the voltage of the built-in battery 11 is lower than V _C , it is recommended to use a step-up DC / DC converter for the probe voltage generating means 13. In particular, the step-up charge pump circuit can achieve low power consumption, and is therefore suitable as the probe voltage generating means 13 of the present invention.

  A wide variety of charging connectors are used in portable electronic devices. The present invention can be applied to a wide variety of connectors, and is useful for providing a charger for a portable electronic device that is extremely convenient.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or equivalent parts are denoted by the same reference numerals as those in FIG.

FIG. 2 is a configuration diagram of an embodiment of the charger for portable electronic devices of the present invention. As the voltage control means 12, a general step-up DC / DC converter is used. Since the details are not necessary for explaining the technical contents of the present invention, only the positive terminal V _{DD of} the power source, the negative terminal V _{SS of the} power source, and the boost output terminal V _out are shown.

  The probe voltage generating means 13 is a charge pump circuit comprising two inverters 13C and 13D, two diodes 13A and 13B, a resistor 13a, capacitors 13b, 13c and 13d, and includes two inverters 13C and 13D and a resistor 13a. The capacitor 13b is a relaxation oscillator.

The capacitor 13c is charged to V _B −V _D with the polarity shown in the relaxation oscillation half cycle in which the output voltage of the relaxation oscillator inverter 13D becomes zero. Here, V _B is the voltage of the battery 11, and V _D is the forward voltage drop of the diode 13A. While the output of the inverter 13D becomes V _{B in the} next half cycle, the capacitor 13d is charged to 2 (V _B −V _D ) with the polarity shown. Here, the forward voltage drop of the diode 13B is also assumed that V _D.

Therefore, when a portable electronic device is not connected, Vtest = 2 (V _B −V _D ) is applied as a probe voltage between the terminals 16 a and 16 b of the connector 16.

The voltage monitoring unit 14 includes a transistor 14A and resistors 14a, 14b, and 14c. Resistor 14a and 14b, the transistor 14A is turned on when the voltage across the terminals of the connector 16 is Vtest, so that the terminal voltage of the portable electronic device is connected a connector 16 turns off the transistor 14A when reduced to _{V C} Selected.

  The starting means 15 is composed only of an nMOS transistor 15A whose gate is connected to the output of the voltage monitoring means 14. When the transistor 14A of the voltage monitoring means 14 is on, that is, when the voltage between the terminals of the connector 16 is Vtest, the nMOS transistor 15A is off, and the charge control means 12 has a battery voltage. Is not applied, the voltage control means 12 does not operate.

  On the other hand, when the portable electronic device is connected to the connector 16, the transistor 14A is turned off, the nMOS transistor 15A is turned on, the voltage of the battery 11 is applied to the voltage control means 12, and the voltage control means 12 is activated to transfer to the portable electronic device. Start charging.

In this embodiment, it is assumed that the battery voltage V _B is 2 (V _B −V _D )> V _C. However, if the battery voltage V _B is low and this condition cannot be satisfied, the charge pump circuit is used. Connect or use DC / DC converter with large step-up ratio.

  If the voltage control means 12 is provided with an enable function, it can be activated using this enable function.

The structure of the charger for portable electronic devices of this invention. Embodiment of the charger for portable electronic devices of this invention. Conventional cellular phone and charger connector connection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,31 ... Charger of portable electronic device 2,32 ... Portable electronic device 11 …… Battery 12 …… Voltage control means 13 …… Probe voltage generation means 14 …… Voltage monitoring means 15 …… Starting means 16 …… Connector

Claims (2)

A battery charger for a portable electronic device incorporating a battery and its voltage control means,
By probe voltage generating means for applying a voltage higher than the built-in battery of the portable electronic device that charges the power transmission terminal of the connector of the charger, voltage monitoring means for monitoring the voltage of the power transmission terminal, and the voltage monitoring means A portable electronic device charger comprising: means for activating the voltage control means.   The charger for a portable electronic device according to claim 1, wherein a boosting charge pump or a boosting DC / DC converter is used as the probe voltage generating means.

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