Abstract: A low power oscillator circuit with temperature compensation is illustrated. A current supply unit of an oscillator used to output an output current which is proportional to a reference current. As the temperature is increased, both a first threshold and the reference current of a unidirectional conduct in the temperature compensation circuit are decreased. Because a delay time of the oscillating signal is proportional to the first threshold voltage, and the delay time is inversely proportional to the reference current, the effects of the first threshold voltage and the reference current on the delay time are canceled, and the delay time of the oscillating signal is not affected by the temperature.

Abstract: In a driving circuit, a drain of first NMOS transistor receives current with a positive temperature coefficient provided by current source, and a gate of first NMOS transistor and a gate of second NMOS transistor are electrically connected to the drain of first NMOS transistor. A drain and a source of second NMOS transistor respectively receive an input voltage and generate an output voltage for driving a load. Two ends of resistor are respectively electrically connected to a source of first NMOS transistor and an emitter of PNP bipolar junction transistor. A base of PNP bipolar junction transistor is electrically connected to a source of second NMOS transistor, and a collector of PNP bipolar junction transistor is electrically connected to a low voltage. By selecting the resistance value of the resistor, an overdrive voltage or a turned-on resistance value of second NMOS transistor is independent of a temperature variation.

Abstract: A comparator module for an oscillator is disclosed. The comparator module has a function provided by two independent comparators that are combined together to share the same bias current source, so that an operation current of the oscillator may be reduced, and the circuit area and power consumption may be effectively reduced. Further, compared to the conventional design that one of the two comparators compares a first voltage with a reference voltage and the other one of the two comparators compares a second voltage with the reference voltage and the time points at which the first voltage and the second voltage are a logic high level are different, three transistors of the disclosed comparator module are designed into two equivalent differential pairs and share a bias current source.

Abstract: An oscillator equipped with a temperature compensation circuit is illustrated. Through the temperature compensation circuit, a transistor of a current mirror circuit of the oscillator which outputs a reference current to a voltage matching circuit is controlled by the temperature compensation voltage. Both of the temperature compensation voltage and a reference current decrease as the temperature rises, and a delay time of the oscillation voltage is proportional to the temperature compensation voltage and inversely proportional to the reference current. Therefore, the effects of temperature on the delay time just cancel each other out. The delay time of the oscillating voltage is related to the frequency of the clock signal. Therefore, if the delay time of the oscillating voltage is not affected by temperature, the frequency of the clock signal will not be affected by temperature.

Abstract: An amplifier circuit has an output stage, a first current source, a second current source, a third current source, a fourth current source, and a voltage clamping voltage. The output stage has a first P-type transistor and a first N-type transistor. The voltage clamping circuit receives a first bias voltage and a second bias voltage, and has a first end and a second end. When a second input current is positive current and the input current is a negative current or a zero current, the first end provides a first clamping voltage greater than the first bias voltage to a gate of the first P-type transistor. When the first input current is positive and the second input current is a negative current or zero current, the second end provides a second clamping voltage lower than the second bias voltage to a gate of the first N-type transistor.

Abstract: A constant power control circuit driving an external device receiving an input voltage and generating an output voltage is provided. A first conversion circuit converts the voltage difference between the input voltage and the output voltage to generate a charge current. An energy storage circuit is charged during a charging period by the charge current to provide a stored voltage. The charging period is terminated in response to the stored voltage reaching a predetermined voltage. A control circuit adjusts a control signal according to a length of the charging period. A second conversion circuit generates a counting voltage according to the control signal. The counting voltage is inversely proportional to the voltage difference. A third conversion circuit converts the counting voltage into a limitation current. A driving circuit compares the setting current and the limitation current to generate a driving signal and send it to the external device.

Abstract: An amplifier circuit has an output stage, a first current source, a second current source, a third current source, a fourth current source, and a voltage clamping voltage. The output stage has a first P-type transistor and a first N-type transistor. The voltage clamping circuit receives a first bias voltage and a second bias voltage, and has a first end and a second end. When a second input current is positive current and the input current is a negative current or a zero current, the first end provides a first clamping voltage greater than the first bias voltage to a gate of the first P-type transistor. When the first input current is positive and the second input current is a negative current or zero current, the second end provides a second clamping voltage lower than the second bias voltage to a gate of the first N-type transistor.

Abstract: A voltage converting apparatus includes a comparison circuit, a compensation signal generator, and a voltage converter. The comparison circuit generates a comparison result according to an output voltage, an input voltage, and a compensated feedback signal. The compensation signal generator provides a compensation signal held to be equal to a reference voltage at a first time interval in an enable period in a working cycle and sets the compensation signal to be a ramp signal at a second time interval in the enable period. The compensation signal generator generates the compensated feedback signal according to a feedback signal and the compensation signal. The voltage converter generates a control signal according to the comparison result, performs a voltage converting operation through an inductor according to the control signal, and generates the output voltage. The feedback signal is generated according to a current on the inductor.

Abstract: A constant power control circuit driving an external device receiving an input voltage and generating an output voltage is provided. A first conversion circuit converts the voltage difference between the input voltage and the output voltage to generate a charge current. An energy storage circuit is charged during a charging period by the charge current to provide a stored voltage. The charging period is terminated in response to the stored voltage reaching a predetermined voltage. A control circuit adjusts a control signal according to a length of the charging period. A second conversion circuit generates a counting voltage according to the control signal. The counting voltage is inversely proportional to the voltage difference. A third conversion circuit converts the counting voltage into a limitation current. A driving circuit compares the setting current and the limitation current to generate a driving signal and send it to the external device.

Abstract: A voltage converting apparatus includes a comparison circuit, a compensation signal generator, and a voltage converter. The comparison circuit generates a comparison result according to an output voltage, an input voltage, and a compensated feedback signal. The compensation signal generator provides a compensation signal held to be equal to a reference voltage at a first time interval in an enable period in a working cycle and sets the compensation signal to be a ramp signal at a second time interval in the enable period. The compensation signal generator generates the compensated feedback signal according to a feedback signal and the compensation signal. The voltage converter generates a control signal according to the comparison result, performs a voltage converting operation through an inductor according to the control signal, and generates the output voltage. The feedback signal is generated according to a current on the inductor.

Abstract: A power switching device is provided. A first transmitting switch transmits an input voltage to an output node when the first transmitting switch is turned on. When the current passing through the first transmitting switch exceeds a predetermined value, a current limiting circuit turns off the first transmitting switch. When a short circuit occurs between the output node and a ground node, a short protection circuit turns off the first transmitting switch. The short protection circuit includes a first comparator and a first set circuit. The first comparator compares a voltage of the output node and a first reference voltage to generate a first comparison result to turn off the first transmitting switch. The first set circuit generates the first reference voltage according to the voltage of the output node. The first reference voltage is less than the voltage of the output node.

Abstract: A power switching device is provided. A first transmitting switch transmits an input voltage to an output node when the first transmitting switch is turned on. When the current passing through the first transmitting switch exceeds a predetermined value, a current limiting circuit turns off the first transmitting switch. When a short circuit occurs between the output node and a ground node, a short protection circuit turns off the first transmitting switch. The short protection circuit includes a first comparator and a first set circuit. The first comparator compares a voltage of the output node and a first reference voltage to generate a first comparison result to turn off the first transmitting switch. The first set circuit generates the first reference voltage according to the voltage of the output node. The first reference voltage is less than the voltage of the output node.

Abstract: A charging circuit including a transformer, a storage element, a switch element, a first resistor, and a current detection unit is provided. The transformer includes a primary coil and a secondary coil. The storage element is coupled to the secondary coil. The switch element is coupled to the primary coil. The first resistor is coupled to the primary coil. The current detection unit detects current flowing through the first resistor. When the current reaches a set current, the current detection unit sends a full signal to de-activate the switch unit.

Abstract: A magnetic sensing switch includes switch body having a hollow tube and an opening. A magnetic reed switch is disposed in the tube and includes two conductive points. The plug having an elastic clamping force is fixed in the opening by interference fit. The plug including a sealant injection portion and a retaining portion communicating with the tube. The two wires are inserted in the tube, one end of each wire is connected to one conductive point, and the other end passes through the retaining portion to protrude out of the tube. A sealant is injected into the tube via the sealant injection portion to entirely wrap the magnetic reed switch and the wires inside the tube, and the sealant partially protrudes out of the sealant injection portion.

Abstract: A charging circuit including a transformer, a storage element, a switch element, a first resistor, and a current detection unit is provided. The transformer includes a primary coil and a secondary coil. The storage element is coupled to the secondary coil. The switch element is coupled to the primary coil. The first resistor is coupled to the primary coil. The current detection unit detects current flowing through the first resistor. When the current reaches a set current, the current detection unit sends a full signal to de-activate the switch unit.

Abstract: A charging device for providing an output voltage to charge a flash capacitor is provided. A transformer includes a primary winding and a secondary winding. The transformer generates a primary voltage according to an input voltage and generates a secondary voltage according to the primary voltage. A diode coupled between the secondary winding of the transformer and the flash capacitor provides the output voltage according to the secondary voltage. A current detector detects a current flowing through the primary winding of the transformer and generates a detection signal. A determining circuit generates a determining signal according to the primary voltage, the secondary voltage and a reference voltage. A control circuit switches a switch coupled between the primary winding of the transformer and a ground according to the detection signal and the determining signal, so as to control the transformer to charge the flash capacitor.

Abstract: A charging device for providing an output voltage to charge a flash capacitor is provided. A transformer includes a primary winding and a secondary winding. The transformer generates a primary voltage according to an input voltage and generates a secondary voltage according to the primary voltage. A diode coupled between the secondary winding of the transformer and the flash capacitor provides the output voltage according to the secondary voltage. A current detector detects a current flowing through the primary winding of the transformer and generates a detection signal. A determining circuit generates a determining signal according to the primary voltage, the secondary voltage and a reference voltage. A control circuit switches a switch coupled between the primary winding of the transformer and a ground according to the detection signal and the determining signal, so as to control the transformer to charge the flash capacitor.

Abstract: An electronic device having a stretchable USB receptacle is provided. An extending connecting cable is added to the USB receptacle on the electronic device. In normal condition, the connecting cable is accommodated in a cable reel to make the USB receptacle accommodated in an accommodating recess of the electronic device to keep consistency of the appearance. In using condition, the USB receptacle may be taken out and used in a needed place by drawing out the connecting cable. This overcomes the disadvantage that the conventional adjacent USB receptacles may be interfered with each other, and the scope of use also increases.

Abstract: An electronic device having a stretchable USB receptacle is provided. An extending connecting cable is added to the USB receptacle on the electronic device. In normal condition, the connecting cable is accommodated in a cable reel to make the USB receptacle accommodated in an accommodating recess of the electronic device to keep consistency of the appearance. In using condition, the USB receptacle may be taken out and used in a needed place by drawing out the connecting cable. This overcomes the disadvantage that the conventional adjacent USB receptacles may be interfered with each other, and the scope of use also increases.

Abstract: The invention provides a voltage generating apparatus for powering at least one amplifier. The voltage generating apparatus comprises a voltage source, a switched capacitor voltage converter and a voltage detector. The voltage source supplies a first voltage to a positive voltage input terminal of the at least one amplifier. The first voltage is a positive DC voltage. The switched capacitor voltage converter is coupled to the voltage source for outputting an output voltage to a negative voltage input terminal of the at least one amplifier according to the first voltage and a predetermined voltage. The output voltage is a negative DC voltage. The voltage detector is coupled to the switched capacitor voltage converter for determining a switching frequency corresponding to the predetermined voltage according to the output voltage.