Abstract: A portable electronic device includes a battery, a central processing unit (CPU), and voltage converting circuit. The battery includes an erasable programmable read-only memory (EPROM) and a signal terminal connected to the EPROM. The CPU includes a read/write control terminal. The voltage converting circuit includes a first power terminal connected to a first power supply, a second power terminal connected to a second power supply, a first port connected to the read/write control terminal through a 1-wire bus, and a second port connected to the signal terminal.

Abstract: An earphone jack circuit includes an earphone jack configured to receive an earphone plug, a frequency modulation (FM) signal processing circuit electrically connected to the earphone jack, and an amplifying circuit. The FM signal processing circuit includes a first matching circuit electrically connected to the earphone jack, and an amplifying circuit electrically connected to the first matching circuit. The first matching circuit receives an initial FM signal from the earphone jack and executes a first filtering process for the initial FM signal when the earphone plug is inserted into the earphone jack. The amplifying circuit amplifies the filtered FM signal.

Abstract: A control circuit for light emitting diode (LED) of display includes a central processing unit (CPU), an AND gate, and a driving circuit. The CPU comprises a general purpose input output (GPIO) contact which outputs an instant high level voltage when a battery is installed into a portable electronic device. The AND gate includes a first input contact connected to the GPIO contact, a second input contact connected to a system power supply, and a first output contact. The system power supply outputs a low level voltage when the electronic device is powered off and outputs a high level voltage when the electronic device is powered on. The driving circuit includes a second output contact connected to an anode of the LED, a feedback contact connected to a cathode of the LED and an enable connected to the first output contact.

Abstract: A voltage conversion circuit for a charging device includes a voltage-stabilizing circuit and a switching circuit. The voltage-stabilizing circuit includes a voltage stabilizer circuit and a feedback resistor, the voltage stabilizer circuit comprises an input pin, an output pin, and a feedback pin. The switching circuit includes a switch and at least two divider resistors, the switch comprises at least two data input terminals, a data output terminal, and two control terminals. The input pin is connected to a power source, and the feedback resistor is connected between the feedback pin and ground. The data input terminals are respectively connected to the output pin through one of the divider resistors, the data output terminal is connected between the feedback pin and the feedback resistor, the two control terminals are capable of receiving control signals to control the data output terminal to selectively connect to one of the data input terminals.

Abstract: A portable electronic device includes an earphone jack circuit for receiving an earphone plug, a control circuit and a switch circuit. The control circuit sends audio to or receives audio from the earphone plug by the earphone jack. The switch circuit is set between the earphone jack and the control circuit including a first mode and a second mode. The control circuit identifies a type of the earphone plug, and switches the switch circuit to a corresponding mode according to the type of the earphone plug.

Abstract: A power management circuit for managing power of an electronic device includes a regulator and a protection circuit. The regulator converts an input voltage into a corresponding rated voltage and includes an enable pin and an output pin. The enable pin receives a voltage signal to enable or disable the regulator, and the output pin selectively outputs the rated voltage. When the electronic device is implemented as a slave universal serial bus (USB) device and the enable pin receives a low voltage signal, the regulator is disabled, and the protection circuit receives an output voltage. When the electronic device is implemented as a USB host and the enable pin receives a high voltage signal, the regulator is enabled, and the output protection circuit outputs the rated voltage.

Abstract: An earphone jack circuit includes an earphone jack configured to receive an earphone plug, a frequency modulation (FM) signal processing circuit electrically connected to the earphone jack, and an amplifying circuit. The FM signal processing circuit includes a first matching circuit electrically connected to the earphone jack, and an amplifying circuit electrically connected to the first matching circuit. The first matching circuit receives an initial FM signal from the earphone jack and executes a first filtering process for the initial FM signal when the earphone plug is inserted into the earphone jack. The amplifying circuit amplifies the filtered FM signal.

Abstract: A charging circuit includes a main control microchip, a charging integrated circuit, and a current control circuit. The main control microchip includes a power-on pin connected to a charging device. The charging integrated circuit comprises a power input pin and a current limit pin, wherein the power input pin is connected to the charging device, and the charging integrated circuit is capable of limiting current. The current control circuit comprises a transistor, a first current limiting resistor and a second current limiting resistor, a base of the transistor is connected to the main control microchip, the first current limiting resistor is connected between the current limit pin and ground, and the second current limiting resistor is connected between the current limit pin and a collector of the transistor, the main control microchip is operable to output control signals to enable or disable the transistor.

Abstract: A control circuit for light emitting diode (LED) of display includes a central processing unit (CPU), an AND gate, and a driving circuit. The CPU comprises a general purpose input output (GPIO) contact which outputs an instant high level voltage when a battery is installed into a portable electronic device. The AND gate includes a first input contact connected to the GPIO contact, a second input contact connected to a system power supply, and a first output contact. The system power supply outputs a low level voltage when the electronic device is powered off and outputs a high level voltage when the electronic device is powered on. The driving circuit includes a second output contact connected to an anode of the LED, a feedback contact connected to a cathode of the LED and an enable connected to the first output contact.

Abstract: A portable electronic device includes a battery, a central processing unit (CPU), and voltage converting circuit. The battery includes an erasable programmable read-only memory (EPROM) and a signal terminal connected to the EPROM. The CPU includes a read/write control terminal. The voltage converting circuit includes a first power terminal connected to a first power supply, a second power terminal connected to a second power supply, a first port connected to the read/write control terminal through a 1-wire bus, and a second port connected to the signal terminal.

Abstract: A charging circuit includes a main control microchip, a charging integrated circuit, and a current control circuit. The main control microchip includes a power-on pin connected to a charging device. The charging integrated circuit comprises a power input pin and a current limit pin, wherein the power input pin is connected to the charging device, and the charging integrated circuit is capable of limiting current. The current control circuit comprises a transistor, a first current limiting resistor and a second current limiting resistor, a base of the transistor is connected to the main control microchip, the first current limiting resistor is connected between the current limit pin and ground, and the second current limiting resistor is connected between the current limit pin and a collector of the transistor, the main control microchip is operable to output control signals to enable or disable the transistor.

Abstract: A power management circuit for managing power of an electronic device includes a regulator and a protection circuit. The regulator converts an input voltage into a corresponding rated voltage and includes an enable pin and an output pin. The enable pin receives a voltage signal to enable or disable the regulator, and the output pin selectively outputs the rated voltage. When the electronic device is implemented as a slave universal serial bus (USB) device and the enable pin receives a low voltage signal, the regulator is disabled, and the protection circuit receives an output voltage. When the electronic device is implemented as a USB host and the enable pin receives a high voltage signal, the regulator is enabled, and the output protection circuit outputs the rated voltage.

Abstract: A voltage conversion circuit for a charging device includes a voltage-stabilizing circuit and a switching circuit. The voltage-stabilizing circuit includes a voltage stabilizer circuit and a feedback resistor, the voltage stabilizer circuit comprises an input pin, an output pin, and a feedback pin. The switching circuit includes a switch and at least two divider resistors, the switch comprises at least two data input terminals, a data output terminal, and two control terminals. The input pin is connected to a power source, and the feedback resistor is connected between the feedback pin and ground. The data input terminals are respectively connected to the output pin through one of the divider resistors, the data output terminal is connected between the feedback pin and the feedback resistor, the two control terminals are capable of receiving control signals to control the data output terminal to selectively connect to one of the data input terminals.

Abstract: A portable electronic device includes an earphone jack circuit for receiving an earphone plug, a control circuit and a switch circuit. The control circuit sends audio to or receives audio from the earphone plug by the earphone jack. The switch circuit is set between the earphone jack and the control circuit including a first mode and a second mode. The control circuit identifies a type of the earphone plug, and switches the switch circuit to a corresponding mode according to the type of the earphone plug.

Abstract: A touch screen device comprises a coordinate correction module, a controller and a notice module. The controller is initialized when the controller receives an initiation command from a sensor. The notice module sends a control command to the controller, the controller notices the sensor to acquire coordinates of sensing points of the touch device and a pressure sensor to acquire pressure of the sensing points.

Abstract: A power supply regulating device for supplying electric power to a wireless data card includes an interface, a first voltage regulator connected to the interface, a second voltage regulator connected to the first voltage regulator; and a capacitor connected to both the first voltage regulator and the second voltage regulator. The interface is connected to a power supply and the wireless data card is connected to the second voltage regulator. The first voltage increases the voltage applied on the interface by the power supply, the second voltage regulator regulates the increased voltage to a working voltage provided to the wireless data card and generating a working current in the wireless data card. The capacitor charged by the increased voltage and is capable of discharging to generate a supplementary current provided to the wireless data card.

Abstract: An electronic device and a white balance adjustment method for the electronic device installed with a camera unit are provided. The camera unit is installed with a light sensor and a digital signal processor (DSP). The light sensor senses light that strikes the electronic device, to determine a source of the light, and acquires illumination parameters of the light source. The DSP adjusts white balance settings of the camera unit according to the illumination parameters, and converts an image of an object captured by a charge coupled device into a user recognizable image. The user recognizable image is displayed on a display device of the electronic device.