Abstract: An automatic bandwidth control system for any switching frequency of a power converter is provided. A pulse generator outputs a preset clock signal according to a comparing signal. A control circuit controls a first switch and a second switch according to frequencies of the preset clock signal and an external clock signal. A first current mirror is connected to an input voltage source and a first terminal of the first switch. A second comparator compares an output voltage of a second reference voltage source with an output voltage of the first current mirror to output the comparing signal. A second current mirror is connected to the input voltage source, an error amplifier and a first terminal of the second switch. A transconductance gain of the error amplifier is controlled by a current of the second current mirror to adjust a bandwidth of the power converter.

Abstract: A detection circuit and a switch module using the same is provided. The detection circuit includes a comparison circuit. A first input end of the comparison circuit is coupled to an output end of a power supply, and a second input end of the comparison circuit is coupled to an input end of a switch circuit. The comparison circuit compares voltage information or current information obtained via its first input end and it second input end, and accordingly generates an output signal. The output signal indicates whether there is an external resistor between the power supply and the switch circuit. According to the output signal, the switch circuit determines how a current provided by the power supply is to be detected, and accordingly continues or stops providing the current to a load.

Abstract: A fast transient current mode control circuit and a method thereof are provided. The circuit includes a slope detector circuit and a switch controller circuit. The slope detector circuit detects an output voltage signal of a power convertor. When a voltage of the output voltage signal drops sharply and a slope of the output voltage signal is larger than a slope threshold, the slope detector circuit outputs a transient enhanced signal. The switch controller circuit outputs a switch control signal to an upper bridge switch of the power convertor according to the transient enhanced signal to turn on the upper bridge switch during a duty cycle of a pulse wave of the transient enhanced signal, such that a current flowing through an inductor of the power convertor increases to be equal to a current flowing through a load of a system.

Abstract: An overshoot reduction circuit for a buck converter includes an operational amplifier, a first sampler circuit, a pulse generator circuit, a pulse calculator circuit, a second sampler circuit and a comparator. The operational amplifier outputs an operation amplified signal according to a buck converted signal of the buck converter and a voltage feedback signal of the operational amplifier. The first sampler circuit samples a first capacitor voltage signal according to a lower bridge conducted signal of the buck converter. The pulse generator circuit outputs a pulse signal. The pulse calculator circuit outputs a first sample compared signal according to the first capacitor voltage signal and the pulse signal. The second sampler circuit samples a second capacitor voltage signal according to the lower bridge conducted signal. The comparator compares the second capacitor voltage signal with the first sample compared signal to output a comparing signal to the buck converter.

Abstract: A charging device and a control method thereof are provided. The charging device includes an adapter, an energy storage unit and a charging module. The adapter provides an adapter current. The charging module receives the adapter current and provides a first charging current to charge the energy storage unit, or an output current to charge an electronic device. When the input current is larger than a first preset current and the first charging current is equal to or less than a third preset current, the charging module operates in a boost mode, such that the energy storage unit provides a second charging current to the charging module. When the second charging current is larger than the third preset current, the charging module enters a buck mode such that the energy storage unit is charged by the first charging current.

Abstract: A multi-phase DC-DC power converter includes an error amplifier, a comparator, a phase selection circuit, a plurality of phase circuits and a width detecting circuit. The plurality of phase circuits are each associated with a phase of the multi-phase DC-DC power converter, each including a turn-on clock generation circuit, a first switching transistor, a second switching transistor, an output inductor, and a control logic. In a load transition state, when the width detecting circuit detects that a comparison output signal exceeds a predetermined width, the phase selection circuit adjusts one of the plurality of phase signals based on a force trigger signal, and outputs, corresponding to a force trigger signal, one of the plurality of on-signals.

Abstract: A system and a method for improving continuous load transition of a DC-DC converter are provided. The system includes a conduction detector circuit, a counter circuit, a depth control circuit and a slope generator. The conduction detector circuit detects a phase signal of the DC-DC converter to generate a pulse signal. The counter circuit counts the number of pulse waves of the pulse signal to output a counting signal. The depth control circuit generates a pulled-down depth signal. The slope generator generates a slope signal according to the pulled-down depth signal. The pulled-down depth signal is pulled down by a first depth each time the switch circuit is conducted, but when the number of times that the switching circuit is conducted reaches a conduction number threshold, the pulled-down depth signal is pulled down by a second depth that is larger than the first depth.

Abstract: Disclosed are a non-narrow voltage direct current (NON-NVDC) charger and a control method thereof. In the present disclosure, a proper target voltage, related to a turn-on voltage of a switch circuit, is determined according to an output voltage of a load, a storage voltage of an energy storage device and a turn-on resistance value of the switch circuit. Then, according to the determined target voltage, the NON-NVDC charger can enter a supplement mode at an appropriate time. The NON-NVDC charger can be operated stably and has excellent operation efficiency even when a current flowing through a transformer close to a maximum safe current.

Abstract: A method of driving an LED string is provided and includes steps of: (a) determining whether or not a detected voltage of a control terminal of a transistor is lower than a first reference voltage by a first comparator, if not, raising a voltage of the LED string by a power supply device and performing step (a), if yes, performing step (b); (b) determining whether or not the detected voltage is lower than a second reference voltage by a second comparator, if not, determining that a short circuit occurs, if yes, performing step (c); (c) increasing an output current of the LED string by an input current source; and (d) determining whether or not a current of the LED string reaches a maximum current that is adjustable by a light controller, if yes, determining that a short circuit occurs, if not, returning to step (c).

Abstract: A device and a method for automatically detecting an initial position of a rotor of a motor are provided. The device includes an initial position detector, a lookup table module and a controller. The initial position detector detects input voltages of the motor. The controller compares the input voltages with each other to determine the initial position of the rotor of the motor. The controller obtains a waveform pattern from the lookup table module to construct an activating waveform signal to be outputted to one of steps of the motor that corresponds to the initial position of the rotor to control the motor to run.

Abstract: A system and a method for demodulating a frequency shift keying signal are provided. The system includes a power transmitter and a power receiver. The power transmitter generates a frequency shift keying signal including a power signal and a power modulation instruction message. The power receiver detects a non-modulation period of the power signal within a waiting time, and then modulates a frequency of the power signal according to the power modulation instruction message to generate a pulse width modulated signal. The power receiver then calculates a full period of the pulse width modulated signal and then subtracts the non-modulation period from the full period of the pulse width modulated signal to obtain an undemodulated signal.

Abstract: A multi-channel power system and a method of controlling a phase shift of the same are provided. The multi-channel power system includes one or more first DC to DC converters and one or more second DC to DC converters. The first DC-DC converter outputs a first pulse width modulated signal having a first default frequency. When the first DC-DC converter receives a reference clock signal, it outputs the first pulse width modulated signal having a frequency that is the same as that of the reference clock signal. The first DC-DC converter outputs a phase-shifted clock signal having a preset phase shift relative to the first pulse width modulated signal. The second DC-DC converter outputs a second pulse width modulated signal having a second default frequency. The second DC-DC converter outputs the second pulse width modulated signal having the preset phase shift according to the phase shift clock signal.

Abstract: An abnormal power failure control system and a method thereof are provided. The system includes a first comparator, a boost-buck control circuit, a logic control circuit, a switch circuit, a current sensor circuit, a current slope comparator circuit, a second comparator, and a mode switching circuit. The first comparator compares a stored power with a first reference voltage source to output a first voltage compared signal. The boost-buck control circuit outputs a boost-buck control signal and the logic control circuit accordingly controls the switch circuit. The current slope comparator circuit determines change of a slope of a current of the switch circuit. The second comparator compares the stored power with the second reference voltage to output a second voltage compared signal. The mode switching circuit instructs the logic control circuit to control the switch circuit.

Abstract: A battery charging circuit for charging a battery is provided. The battery charging circuit includes a control module and a charging mode adjusting module. The charging mode adjusting module adjusts a charging mode according to a voltage value or a current value or an internal resistor of the battery. The charging mode adjusting module includes a charging unit and a detecting unit. The charging unit provides a charging current or a charging voltage to charge the battery. The detecting unit is electrically connected to the charging unit to detect the voltage value or the current value or the internal resistor of the battery.

Abstract: Disclosed is a current sensing circuit to sense a current flowing through a load switch. The load switch receives a supply voltage to generate an output voltage. The current sensing circuit includes a first circuit and a second circuit. The first circuit is coupled the load switch through a first resistor, and senses the current flowing through the load switch. The second circuit is coupled to the first circuit and the load switch, senses the output voltage, and generates an adjusting current according to the output voltage. The second circuit generates the adjusting current when the output voltage is smaller than a threshold voltage, such that the ratio of the current flowing through the load switch to a current flowing through the first circuit is maintained at certain ratio, but the second circuit is disabled when the output voltage is larger than or equal to the threshold voltage.

Abstract: A motor driving circuit according to the present disclosure includes a driving voltage generation circuit, a duty detection circuit, a calibration circuit and a multiplier. The calibration circuit is coupled to the duty detection circuit and the multiplier is coupled to the driving voltage generation circuit and the calibration circuit. A motor driving method according to the present disclosure includes: detecting a duty cycle signal provided by a system terminal through the duty detection circuit; generating an adjustment signal according to the duty cycle signal through the calibration circuit; and multiplying the predetermined driving voltage by the adjustment signal through the multiplier to generate a driving voltage to a motor. The waveform of the coil current of the motor will be a sine wave. The adjustment signal represents a ratio at which the predetermined driving voltage needs to be adjusted under a specific duty of the motor.

Abstract: The present disclosure illustrates a demodulation circuit disposed in a wireless charging device. The demodulation circuit comprises a detection unit, a delay unit, a demodulation unit, a switch unit, an amplifier, an ADC, a control unit and a digital demodulation unit. The detection unit detects a pulse width modulation signal received by a coil, and outputs a modulation signal. The delay unit delays the modulation signal to generate a delay signal. The demodulation unit compares the modulation signal with the delay signal to generate a first demodulation signal. When the control unit detects the first demodulation signal is lower than a demodulation success rate in a time period, the control unit outputs a first switch signal to the switch unit. When the control unit detects a second demodulation signal is lower than the demodulation success rate in the time period, the control unit outputs a second switch signal to the switch unit.

Abstract: A power switch circuit includes a first switch circuit, a second switch unit and a capacitor. The capacitor has a first terminal coupled to a node between the first and second switch units. In addition, the capacitor has a second terminal coupled to the first and second switch units, a charge pump and a charging circuit. When the power switch circuit is coupled to a load, the charging circuit pre-charges the capacitor. Once the load is enabled, the first and second switch units are turned on by only a small voltage increase at the second terminal of the capacitor by the charge pump to allow power to be supplied to a load through the first and second switch units from a power supply.

Abstract: A battery charging circuit adjusts a voltage proportional relationship between a turned-on voltage of a charging transistor and a turned-on voltage of a first transistor according to a first voltage corresponding to a charging current and a second voltage corresponding to the charging current, so that a ratio between the charging current and a first current sensing the charging current is a constant value or close to a constant value.

Abstract: A fast-locking phase locked loop and a fast locking method are provided. The fast locking method includes dividing a frequency of an oscillation signal by a preset divisor to output a divided signal, detecting a frequency difference between the divided signal and a reference signal, tracking whether a divided frequency of the divided signal falls within a locked frequency range or not, if not, tracking the divided frequency, and if yes, locking the divided frequency, detecting a divided phase difference between a divided phase of the divided signal and a reference phase of the reference signal, recording the phase difference as a tracking reference phase difference, tracking a next divided phase according to the tracking reference phase difference, and determining whether the divided phase falls within a locked phase range, and if not, tracking the divided phase, and if yes, locking the divided phase.