Abstract: An earphone jack drive circuit applied in an electronic device is provided. The earphone jack drive circuit includes a mute circuit; a micro-controller including a detect pin and a control pin; a delay switch circuit including a resistance, a capacitance, an npn transistor and a first current-limiting resistance. During the plugging in or the unplugging out of the earphone, any momentary logic high of the detect pin charges the capacitance, the capacitance discharges when the detect pin is set to be logic low. For a period, the npn transistor is kept on, the connector of the npn transistor is set to be logic low, the input port of the mute circuit is set to be logic low, thereby the mute circuit is controlled to perform the mute mode during the period to eliminate the popping noises of connection and disconnection.

Abstract: The power management circuit includes a sampling unit, a reference voltage unit, a comparator, and a power managing unit. The sampling unit divides an input voltage from the power supply to generate a sampling voltage. The reference voltage unit receives the input voltage and generates a reference voltage when the input voltage is larger than a predetermined value. The comparator compares the sampling voltage with the reference voltage, generates a first signal when the sampling voltage is larger than the reference voltage, and generates a second signal when the sampling voltage is smaller than the reference voltage. The power managing unit establishes an electrical connection between the power supply and the load according to the first signal, and cuts off the electrical connection between the power supply and the load according to the second signal. A related electronic device is also provided.

Abstract: An electronic device includes a power supply, a load, and a switch circuit controlling the power supply. The switch circuit includes a control unit and a key switch capable of establishing an electrical connection between the power supply and the control unit in response to an operation by a user. When the key switch establishes the electrical connection, the control unit receives a supply voltage from the power supply and is charged-up by the supply voltage to generate a first control signal, the first control signal enables the power supply to power the load.

Abstract: A power circuit includes a power input port, a power output port, and a three-terminal regulator. A voltage regulating circuit and a charge/discharge circuit are connected to the power output port. The three-terminal regulator detects a voltage value of the output port and enables the input port if the detected voltage value is less than a predetermined voltage value and disables the input port if the detected voltage value is not less than the predetermined value. If the input port of the three-terminal regulator is enabled, the charge/discharge circuit is charged by the current provided by a power supply connected to the power input port. If the input port of the three-terminal regulator is disabled, the charge/discharge circuit discharges to an electronic device connected to the power output port with the voltage regulating circuit.

Abstract: A voltage stabilizing circuit includes an input terminal that receives an external input voltage, a three terminal voltage regulator including an input pin and an output pin; and a voltage reduction unit. The voltage reduction unit reduces the external input voltage and outputs the reduced external input voltage to the input pin. The three terminal voltage regulator regulates the reduced external input voltage to a stabilized supply voltage, and outputs the stabilized supply voltage through the output pin for powering a load.

Abstract: An exemplary charge indicator circuit indicates the state of charge of a battery. The charge indicator circuit includes a connection jack, an indicator module, a voltage detection module, a charger IC, and a path connection module. The indicator module includes an indicator. The indicator is on when the battery is being charged. The voltage detection module is to output a first response signal when the connection jack is connected to the power supply. The charger IC is to manage the charging of the battery, and output a low level signal when a condition of the battery is satisfied. The path connection module is in a shunt circuit of the indicator module, and enables the shunt circuit of the indicator module to cause the indicator to be on when the voltage detection module outputs the first response signal and the charger IC outputs the low level signal.

Abstract: An earphone jack drive circuit applied in an electronic device is provided. The earphone jack drive circuit includes a mute circuit; a micro-controller including a detect pin and a control pin; a delay switch circuit including a resistance, a capacitance, an npn transistor and a first current-limiting resistance. During the plugging in or the unplugging out of the earphone, any momentary logic high of the detect pin charges the capacitance, the capacitance discharges when the detect pin is set to be logic low. For a period, the npn transistor is kept on, the connector of the npn transistor is set to be logic low, the input port of the mute circuit is set to be logic low, thereby the mute circuit is controlled to perform the mute mode during the period to eliminate the popping noises of connection and disconnection.

Abstract: A device is used for measuring an output voltage of a battery. The device includes a detecting circuit, an encoding circuit, a control circuit, and a processing circuit. The detecting circuit is configured for detecting the output voltage of the battery and generating a first signal, a second signal, and a third signal accordingly. The encoding circuit is configured for generating a first code and a second code according to the first signal and the second signal. The control unit is configured for modifying the second code when the third signal indicates that the output voltage is lower than a predetermined value. The processing unit is configured for generating and outputting display control signals according to the first and second codes. The display control signals are used to control a display panel to display information of the output voltage of the battery.

Abstract: An exemplary reset circuit includes a first connection jack connected to a first power supply, a second connection jack connected to a second power supply, a reset IC, a voltage response module, and a control module. The voltage response module outputs a first response signal when the voltage provided by the second power supply is abnormal, and then the control module outputs a first voltage which is less than the voltage provided by the first power supply. The voltage response module outputs a second response signal when the voltage provided by the second power supply is normal, and then the control module outputs a second voltage which is equal to the voltage provided by the first power supply. When the voltage received by the reset IC is changed from the first voltage to the second voltage, the reset IC outputs a reset signal to reset the processing IC.

Abstract: A switching power supply includes a rectifier circuit, a converter, a detecting unit, a control unit, a switching unit, and a protection unit. The rectifier circuit is used for rectifying an input voltage into a first direct current voltage. The converter is configured for generating a first current according to the first direct current voltage. The detecting unit is used for generating a detected voltage according to the first current. The control unit is configured for generating a control signal. The switching unit is used for enabling the converter, and conducting the first current to the detecting unit when receiving the control signal. The protection unit is configured for shunting the first current with the detecting unit when the first current becomes a large current surge. The control unit stops generating the control signal when determining that the detected voltage is equal to or higher than a predetermined value.

Abstract: An exemplary power supply system is used to provide one or more operation voltages to a plurality of loads individually. The power supply system includes a timing circuit configured to control a starting time that the corresponding loads start to receive their corresponding operation voltages. The timing circuit includes a first capacitor arranged to be charged by the corresponding DC voltage, and the starting time is determined according to a charging characteristic of the first capacitor.

Abstract: A power supply protection device for an electric appliance includes a switching circuit for establishing an electrical connection to receive an external voltage from the external power supply and output the external voltage to the electric appliance, a detecting circuit for disabling the switch circuit to break the electrical connection when determining the external voltage is equal to or higher than a predetermined value, and an alert circuit for generating an alert signal when the electrical connection is broken and outputting the alert signal to a user.

Abstract: An exemplary charging control circuit includes a signal shaping unit, a first switch unit, and a second switch unit. The signal shaping unit receives a control signal, and is capable of reshaping the received control signal to have a time interval transited from a first state to a second state. The first switch unit receives the shaped control signal, and generates a first switching signal. The second switch unit receives the first switching signal, and is capable of being turned on based on the first switching signal for allowing electrical power to be outputted to a battery.

Abstract: The power management circuit includes a sampling unit, a reference voltage unit, a comparator, and a power managing unit. The sampling unit divides an input voltage from the power supply to generate a sampling voltage. The reference voltage unit receives the input voltage and generates a reference voltage when the input voltage is larger than a predetermined value. The comparator compares the sampling voltage with the reference voltage, generates a first signal when the sampling voltage is larger than the reference voltage, and generates a second signal when the sampling voltage is smaller than the reference voltage. The power managing unit establishes an electrical connection between the power supply and the load according to the first signal, and cuts off the electrical connection between the power supply and the load according to the second signal. A related electronic device is also provided.

Abstract: A device is used for measuring an output voltage of a battery. The device includes a detecting circuit, an encoding circuit, a control circuit, and a processing circuit. The detecting circuit is configured for detecting the output voltage of the battery and generating a first signal, a second signal, and a third signal accordingly. The encoding circuit is configured for generating a first code and a second code according to the first signal and the second signal. The control unit is configured for modifying the second code when the third signal indicates that the output voltage is lower than a predetermined value. The processing unit is configured for generating and outputting display control signals according to the first and second codes. The display control signals are used to control a display panel to display information of the output voltage of the battery.

Abstract: A switching power supply includes a rectifier circuit, a converter, a detecting unit, a control unit, a switching unit, and a protection unit. The rectifier circuit is used for rectifying an input voltage into a first direct current voltage. The converter is configured for generating a first current according to the first direct current voltage. The detecting unit is used for generating a detected voltage according to the first current. The control unit is configured for generating a control signal. The switching unit is used for enabling the converter, and conducting the first current to the detecting unit when receiving the control signal. The protection unit is configured for shunting the first current with the detecting unit when the first current becomes a large current surge. The control unit stops generating the control signal when determining that the detected voltage is equal to or higher than a predetermined value.

Abstract: A power supply protection device for an electric appliance includes a switching circuit for establishing an electrical connection to receive an external voltage from the external power supply and output the external voltage to the electric appliance, a detecting circuit for disabling the switch circuit to break the electrical connection when determining the external voltage is equal to or higher than a predetermined value, and an alert circuit for generating an alert signal when the electrical connection is broken and outputting the alert signal to a user.

Abstract: An electronic device includes an operation circuit, a positive input terminal, a negative input terminal, a resistor, and a field effect transistor. The negative input terminal is used for cooperating with the positive input terminal to receive an input voltage. The field effect transistor includes a source connected to the positive input terminal, a drain connected to the operation circuit, and a gate connected to the positive input terminal and the operation circuit via the resistor.

Abstract: An exemplary charging control circuit includes a signal shaping unit, a first switch unit, and a second switch unit. The signal shaping unit receives a control signal, and is capable of reshaping the received control signal to have a time interval transited from a first state to a second state. The first switch unit receives the shaped control signal, and generates a first switching signal. The second switch unit receives the first switching signal, and is capable of being turned on based on the first switching signal for allowing electrical power to be outputted to a battery.