Abstract: An electronic device includes a MCU, and a power control circuit. The power control circuit includes a first switch unit connected between a power source and the MCU, and a second switch unit connected between a control terminal of the first switch unit and the MCU. In a first status, the second switch unit outputs a first control signal to switch on the first switch to connect the MCU to the power source for enabling the MCU to receive power; and further outputs a boot signal to the MCU to power the electronic device. Switched to a second status, a shutdown signal is output to the MCU to shutdown the electronic device; and the second switch module further outputs a second control signal to switch off the first switch after a determined time period, to cut power consumption to nil at the end of that period.

Abstract: A light-emitting diode (LED) driving circuit includes a constant current module, a current follower module and a LED indicator. The constant current module is connected to a power supply output for stabilizing the output current from the power supply at a preset value. The current follower module is connected between the constant current module and the LED indictor for further stabilizing the current output from the constant current module. The LED driving circuit makes sure the current through the LED indicator invariable, thereby keeping brightness of the LED indicator invariable.

Abstract: An antistatic switch connected between a micro control unit and a power supply of an electronic device includes six terminals. A first terminal is left vacant and a third terminal is connected to the power supply. A second terminal is public access terminal connected to the micro control unit and selectively connected to the first terminal or the second terminal. The fourth terminal, the fifth terminal, and the sixth terminal are all grounded to remove the static electricity flowing to the electronic device.

Abstract: An electronic device with video in/out switching function using one port when connected with an external electronic apparatus includes a video switch circuit; an LCD; a processing unit, to decode and output video signals to the LCD; and an interface unit. In a video in mode, the video switch circuit connects the processing unit to the external electronic apparatus via the interface unit, thereby video signals from the external electronic apparatus are decoded and then output to the LCD. In a video out mode, the video switch circuit connects a video source to the external electronic via the interface unit, thereby video signals from the video source are output to the external electronic apparatus.

Abstract: A charging status display circuit is used in an electronic device. The electronic device includes a power supply circuit, a rechargeable battery, and an interface circuit capable of electrically connecting with the rechargeable battery. The electronic device is powered by either the power supply circuit or the rechargeable battery. The rechargeable battery is charged by the power supply circuit via the interface circuit. The charging status display unit includes a light emitting diode for indicating whether the rechargeable battery is being charged, and a surface-contact diode for clamping a voltage between the light emitting diode and the interface unit at a predetermined value. The light emitting diode is connected in series between the power supply circuit and the interface circuit. The surface-contact diode is connected in parallel with the light emitting diode.

Abstract: A power conversion circuit includes a pulse width modulator, a feedback module, a negative voltage producing module, a voltage regulating module, a path switch, and a rectifier module. The path switch is connected to a power port connected to a power source. The feedback module produces a feedback signal according to the voltage of a positive voltage input port of a power amplifier. The pulse width modulator receives the feedback signal, and outputs a pulse signal with a corresponding duty cycle according to the feedback signal to the path switch, then producing a switching power supply signal; the rectifier module converts the switching power supply signal to a direct current signal with a suitable positive voltage. The negative voltage producing module produces corresponding negative voltage when the path switch is turned on or off. The voltage regulating module regulates the negative voltage to a suitable negative voltage.

Abstract: A power regulation circuit is connected to a voltage supply unit for receiving a power-on voltage supplied by the voltage supply unit and to a voltage management unit for enabling an enable port thereof. The power regulation circuit includes a first regulation unit and the second regulation unit. The first regulation unit is used for outputting an enable signal to the enable port when the power-on voltage is lower than a threshold value such that the voltage management unit can output a first working voltage to a load via a first output port thereof. The first regulation unit stops outputting the enable signal after the expiry of a certain period of time following the drop in a power supply to a level which is below a certain threshold value for a predetermined period.

Abstract: A protection circuit for protecting light-emitting diodes of a laser emitter is provided. The laser emitter includes a first LED for reading multimedia data stored in a first media and a second LED for reading multimedia data stored in a second media. Cathodes of the first LED and the second LED are grounded, and anodes of the first LED and the second LED are connected with soldering tin. The protection circuit includes a first protection element with a first breakdown voltage and a second protection element with a second breakdown voltage. One end of each of the first protection element and the second protection element is grounded. When the circuit is connected to the laser emitter, residual ends of the first protection element and the second protection element are respectively connected to the anodes of the first LED and the second LED.

Abstract: A protection circuit includes a relay, a reset switch, a voltage conversion circuit, and a rectifier circuit. The voltage conversion circuit is connected to an AC power supply via the reset switch, and converts a voltage of the AC power supply to a low AC voltage. The rectifier circuit converts the low AC voltage to a direct current voltage and powers a coil of the relay. At least one item of electronic apparatus is powered by the AC power supply via contacts of the relay or the reset switch. If the main power is lost, the relay releases, and the power connection must be re-established by pressing the reset switch after the AC power supply has been restored, thus energizing the relay to latch on the AC power supply.

Abstract: An electronic device with video in/out switching function using one port when connected with an external electronic apparatus includes a video switch circuit; an LCD; a processing unit, to decode and output video signals to the LCD; and an interface unit. In a video in mode, the video switch circuit connects the processing unit to the external electronic apparatus via the interface unit, thereby video signals from the external electronic apparatus are decoded and then output to the LCD. In a video out mode, the video switch circuit connects a video source to the external electronic via the interface unit, thereby video signals from the video source are output to the external electronic apparatus.

Abstract: A light-emitting diode (LED) driving circuit includes a constant current module, a current follower module and a LED indicator. The constant current module is connected to a power supply output for stabilizing the output current from the power supply at a preset value. The current follower module is connected between the constant current module and the LED indictor for further stabilizing the current output from the constant current module. The LED driving circuit makes sure the current through the LED indicator invariable, thereby keeping brightness of the LED indicator invariable.

Abstract: A power-off protection circuit includes a power-off detection module and a delay module. The power-off detection module is connected to a system power port of an electronic device and determines when the system power port is at a low voltage, as an indication that the electronic device is being powered off. A power-off signal is produced when the system power port is at a low voltage. The delay module transmits the voltage from the system power port to a processing unit and an EEPROM when the electronic device is powered on, and provides a voltage to the processing unit and the EEPROM for a period of time when the electronic device is powered off, allowing the processing unit and the EEPROM to continue working for the period of time, thus enabling the processing unit controls to store parameters set but not yet stored by a user into the EEPROM.

Abstract: An anti-static protection circuit includes a first discharge unit and a second discharge unit. The first discharge unit is connected to a port of an electronic device, and includes a number of first sharp turning points. The first sharp turning points absorb static electricity flowing to the first discharge unit from the port, and discharge part of the static electricity to the air. The second discharge unit is grounded and includes a number of second sharp turning points spaced apart from and directly opposing to the corresponding first sharp turning points of the first discharge unit. The second sharp turning points absorb part of the static electricity on the first sharp turning points, and discharges the part of the static electricity to the ground. A related electronic device employing the protection circuit is also provided.

Abstract: An electronic device includes a MCU, and a power control circuit. The power control circuit includes a first switch unit connected between a power source and the MCU, and a second switch unit connected between a control terminal of the first switch unit and the MCU. In a first status, the second switch unit outputs a first control signal to switch on the first switch to connect the MCU to the power source for enabling the MCU to receive power; and further outputs a boot signal to the MCU to power the electronic device. Switched to a second status, a shutdown signal is output to the MCU to shutdown the electronic device; and the second switch module further outputs a second control signal to switch off the first switch after a determined time period, to cut power consumption to nil at the end of that period.

Abstract: A power conversion circuit includes a pulse width modulator, a feedback module, a negative voltage producing module, a voltage regulating module, a path switch, and a rectifier module. The path switch is connected to a power port connected to a power source. The feedback module produces a feedback signal according to the voltage of a positive voltage input port of a power amplifier. The pulse width modulator receives the feedback signal, and outputs a pulse signal with a corresponding duty cycle according to the feedback signal to the path switch, then producing a switching power supply signal; the rectifier module converts the switching power supply signal to a direct current signal with a suitable positive voltage. The negative voltage producing module produces corresponding negative voltage when the path switch is turned on or off. The voltage regulating module regulates the negative voltage to a suitable negative voltage.

Abstract: An electronic component includes a component body and at least one guiding element. The component body includes a number of sides. The at least one guiding element is placed on at least one side of the component body. A user can quickly and easily determine orientation of the electronic component by touch when mounting the electronic component in a socket.

Abstract: A power source detection circuit includes a voltage conversion module and a signal producing module. The voltage conversion module is connected to a power port, and is used to convert a voltage of a power source to a detection voltage. The signal producing module is connected to the voltage conversion module and a processing unit, and is used to compare the detection voltage with a reference voltage, and produces a high voltage signal to trigger the processing unit to control to display a remaining power of the battery when determining the detection voltage is lower than the reference voltage. The signal producing module is also used to produce a low voltage signal to trigger the processing unit to not display the remaining power of the battery when determining the detection voltage is higher than the reference voltage.

Abstract: A protection circuit for protecting light-emitting diodes of a laser emitter is provided. The laser emitter includes a first LED for reading multimedia data stored in a first media and a second LED for reading multimedia data stored in a second media. Cathodes of the first LED and the second LED are grounded, and anodes of the first LED and the second LED are connected with soldering tin. The protection circuit includes a first protection element with a first breakdown voltage and a second protection element with a second breakdown voltage. One end of each of the first protection element and the second protection element is grounded. When the circuit is connected to the laser emitter, residual ends of the first protection element and the second protection element are respectively connected to the anodes of the first LED and the second LED.

Abstract: A printed circuit board (PCB) includes at least two vias and at least two bonding pads corresponding to the vias. Each bonding pad is arranged on the surface of the PCB around the corresponding one of the at least two vias. Between two adjacent bonding pads, a through hole is arranged for preventing molten solder overflowing from one bonding pad to the other.

Abstract: The present disclosure provides a printed circuit board (PCB) with grounding protection. The PCB includes a grounding element. A predetermined number of via through holes or a predetermined number of soldering tin joints are distributed around the grounding element to generate a good grounding protection for the PCB.