Abstract: A power supply device for eliminating overcurrent protection malfunctions includes a first transformer, a power switch element, an output stage circuit, a detection circuit, a feedback compensation circuit, a PWM (Pulse Width Modulation) IC (Integrated Circuit), a second transformer, and a control circuit. The first transformer generates an induced voltage according to an input voltage. The output stage circuit generates an output current according to the induced voltage. The detection circuit monitors the output current and generates a detection voltage according to the output current. The feedback compensation circuit includes a linear optical coupler and a voltage regulator. The feedback compensation circuit generates a coupling current. The second transformer generates a control voltage according to the coupling current. The control circuit selectively enables or disables the linear optical coupler and the voltage regulator according to the detection voltage and the control voltage.

Abstract: A power supply device with low loss includes an input switch circuit, a transformer, a first capacitor, an output stage circuit, and a detection and control circuit. The input switch circuit generates a switching voltage according to an input voltage. The output stage circuit generates an output voltage. The output stage circuit includes a first rectifying switch element and a second rectifying switch element. The detection and control circuit detects a first output current flowing through the first rectifying switch element so as to generate a first control voltage, and it detects a second output current flowing through the second rectifying switch element so as to generate a second control voltage. The first rectifying switch element is selectively closed or opened according to the first control voltage. The second rectifying switch element is selectively closed or opened according to the second control voltage.

Abstract: A boost converter with high power factor includes a bridge rectifier, a divider and filter circuit, a capacitive adjustment circuit, an induction circuit, a multiplier, a power switch element, a PWM (Pulse Width Modulation) IC (Integrated Circuit), an output stage circuit, and a feedback circuit. The bridge rectifier generates a rectified voltage according to a first input voltage and a second input voltage. The divider and filter circuit generates a divided voltage according to the rectified voltage. The output stage circuit generates an output voltage. The feedback circuit generates a feedback voltage according to the output voltage. The multiplier generates a product voltage difference according to the divided voltage and the feedback voltage. The capacitive adjustment circuit is enabled or disabled according to the feedback voltage. The induction circuit selectively provides a compensation current according to the product voltage difference.

Abstract: A power supply device with low loss includes an input switch circuit, a transformer, a first capacitor, an output stage circuit, and a detection and control circuit. The input switch circuit generates a switching voltage according to an input voltage. The output stage circuit generates an output voltage. The output stage circuit includes a first rectifying switch element and a second rectifying switch element. The detection and control circuit detects a first output current flowing through the first rectifying switch element so as to generate a first control voltage, and it detects a second output current flowing through the second rectifying switch element so as to generate a second control voltage. The first rectifying switch element is selectively closed or opened according to the first control voltage. The second rectifying switch element is selectively closed or opened according to the second control voltage.

Abstract: A power supply device for eliminating the ringing effect includes a bridge rectifier, a first transformer, a second transformer, a third transformer, a power switch element, a delay and stabilization circuit, an output stage circuit, and a controller. The bridge rectifier generates a rectified voltage according to a first input voltage and a second input voltage. The first transformer generates an induced voltage according to the rectified voltage. A magnetizing inductor is built in the first transformer. A parasitic capacitor is built in the power switch element. The second transformer generates a control voltage according to a resonant voltage between the magnetizing inductor and the parasitic capacitor. The output stage circuit includes a plurality of discharge paths and generates an output voltage. The discharge paths are selectively enabled or disabled according to the control voltage.

Abstract: A power factor calibration circuit includes a multiplier, a boost inductor, an auxiliary winding, a detection resistor, a compensation capacitor, a comparator, and an auxiliary switch. The comparator is configured to detect inductor current flowing through the boost inductor. When the detected inductor current is too small, the energy stored in the compensation capacitor is transmitted to the auxiliary winding for generating compensation current, thereby enhancing the level of the inductor current.

Abstract: A boost converter includes a voltage divider circuit, a first comparator, a tunable inductive element, a power switch element, a second comparator, an output stage circuit, and a controller. The voltage divider circuit receives an input voltage. The tunable inductive element is coupled to the voltage divider circuit. The total inductance of the tunable inductive element is controlled by the first comparator. The output stage circuit is coupled to the tunable inductive element and the power switch element. The output stage circuit includes a tunable resistive element. The total resistance of the tunable resistive element is controlled by the second comparator. When the boost converter operates in a first mode, an output voltage of the output stage circuit has a relatively high voltage level. When the boost converter operates in a second mode, the output voltage of the output stage circuit has a relatively low voltage level.

Abstract: A boost converter with high power factor includes a bridge rectifier, a divider and filter circuit, a capacitive adjustment circuit, an induction circuit, a multiplier, a power switch element, a PWM (Pulse Width Modulation) IC (Integrated Circuit), an output stage circuit, and a feedback circuit. The bridge rectifier generates a rectified voltage according to a first input voltage and a second input voltage. The divider and filter circuit generates a divided voltage according to the rectified voltage. The output stage circuit generates an output voltage. The feedback circuit generates a feedback voltage according to the output voltage. The multiplier generates a product voltage difference according to the divided voltage and the feedback voltage. The capacitive adjustment circuit is enabled or disabled according to the feedback voltage. The induction circuit selectively provides a compensation current according to the product voltage difference.

Abstract: A boost converter for improving output stability includes a transformer, a detection circuit, a first resistor, a power switch element, an output stage circuit, a feedback compensation circuit, a controller, an inverter, and a multiplier. The transformer includes a main coil and a secondary coil. The main coil receives an input voltage. The detection circuit is coupled to the secondary coil. The detection circuit generates a detection voltage. The first resistor is coupled to the main coil. The output stage circuit generates an output voltage. The feedback compensation circuit generates a feedback voltage according to the output voltage. The inverter generates an inverted oscillation voltage. The multiplier generates a compensation voltage difference according to the detection voltage, the inverted oscillation voltage, and the feedback voltage. The compensation voltage difference is applied to the first resistor.

Abstract: A power supply device for eliminating the ringing effect includes a bridge rectifier, a first transformer, a second transformer, a third transformer, a power switch element, a delay and stabilization circuit, an output stage circuit, and a controller. The bridge rectifier generates a rectified voltage according to a first input voltage and a second input voltage. The first transformer generates an induced voltage according to the rectified voltage. A magnetizing inductor is built in the first transformer. A parasitic capacitor is built in the power switch element. The second transformer generates a control voltage according to a resonant voltage between the magnetizing inductor and the parasitic capacitor. The output stage circuit includes a plurality of discharge paths and generates an output voltage. The discharge paths are selectively enabled or disabled according to the control voltage.

Abstract: A power conversion device is provided. The power conversion device includes a main transformer circuit, a power switch, an auxiliary transformer, a resonant circuit, and a switch circuit. When the power switch is turned on, the switch circuit is enabled according to energy stored in an output capacitor of the main transformer circuit, so that energy associated with a secondary side of a main transformer is coupled to the resonant circuit via the auxiliary transformer so the resonant circuit obtains coupling energy. When the power switch is turned off, the resonant circuit and a parasitic capacitor of the power switch form a resonant tank coupled to a grounding terminal of a power supply side based on the coupling energy.

Abstract: A power supply device includes a switch circuit, a resonant circuit, a first transformer, an output rectifier, a feedback circuit, and a controller. The switch circuit generates a switch voltage according to an input voltage, a first clock voltage, and a second clock voltage. The resonant circuit includes a variable capacitor and a variable inductor. The resonant circuit generates a resonant voltage according to the switch voltage, a first control voltage, and a second control voltage. The first transformer generates a transformation voltage according to the resonant voltage. The output rectifier generates an output voltage according to the transformation voltage. The feedback circuit and the controller detect a sensing voltage relative to the output rectifier. The feedback circuit determines the first control voltage according to the sensing voltage. The controller determines the second control voltage according to the sensing voltage.

Abstract: A boost converter includes a first inductor, a first switch element, a second switch element, a tuning circuit, and an output stage circuit. A first parasitic capacitor is built in the first switch element. The first switch element selectively couples the first inductor to a ground voltage according to a first control voltage. A second parasitic capacitor is built in the second switch element. The second switch element selectively couples the first inductor to the output stage circuit according to a second control voltage. The tuning circuit includes a second inductor, a third inductor, and a discharge path. The first parasitic capacitor resonates with the second inductor and is coupled through the discharge path to the ground voltage, or the second parasitic capacitor resonates with the third inductor and is coupled through the discharge path to the ground voltage.

Abstract: A power supply device for eliminating the ringing effect includes a transformer, an output stage circuit, a power switch element, a pulse width modulation integrated circuit, and a control circuit. The transformer includes a main coil, a secondary coil, and an auxiliary coil. A leakage inductor is built in the transformer. The main coil receives an input voltage through the leakage inductor. The secondary coil generates an induced voltage. The output stage circuit generates an output voltage according to the induced voltage. A first parasitic capacitor is built in the power switch element. The control circuit includes an auxiliary inductor coupled to the auxiliary coil. The control circuit monitors the power switch element. If the power switch element is switched from an enable state into a disable state, the control circuit will couple the auxiliary inductor to the main coil and the leakage inductor of the transformer.

Abstract: A power supply device for eliminating the ringing effect includes a transformer, an output stage circuit, a power switch element, a pulse width modulation integrated circuit, and a control circuit. The transformer includes a main coil, a secondary coil, and an auxiliary coil. A leakage inductor is built in the transformer. The main coil receives an input voltage through the leakage inductor. The secondary coil generates an induced voltage. The output stage circuit generates an output voltage according to the induced voltage. A first parasitic capacitor is built in the power switch element. The control circuit includes an auxiliary inductor coupled to the auxiliary coil. The control circuit monitors the power switch element. If the power switch element is switched from an enable state into a disable state, the control circuit will couple the auxiliary inductor to the main coil and the leakage inductor of the transformer.

Abstract: A power supply apparatus including a protection circuit and a power conversion circuit is provided. The protection circuit includes a control circuit, an auxiliary capacitor, and a switching circuit. The control circuit receives an AC voltage from an AC power source and generates a pulsating voltage and a control signal accordingly. The auxiliary capacitor receives the pulsating voltage and provides a first voltage accordingly. The switching circuit is coupled to the auxiliary capacitor to receive the first voltage and coupled to the control circuit to receive the control signal. The switching circuit transmits the first voltage to the power conversion circuit in response to the control signal. The power conversion circuit converts the first voltage to an output voltage. When the switching circuit is switched to an on state in response to the control signal, the auxiliary capacitor reduces an input inrush current from the AC power source.

Abstract: A boost converter includes a first inductor, a power switch element, a tuning circuit, and an output stage circuit. The first inductor is configured to receive an input voltage. A parasitic capacitor is built in the power switch element. The power switch element selectively couples the first inductor to a ground voltage according to a clock voltage. The output stage circuit is configured to generate an output voltage. The tuning circuit includes a second inductor, a third inductor, and a current-limiting path. The second inductor is coupled to the first inductor and the power switch element. The third inductor is coupled through the current-limiting path to the output stage circuit. The first inductor, the second inductor, and the third inductor are mutually coupled to each other, so as to form an equivalent transformer.

Abstract: A charging device supporting PD (Power Delivery) includes a bridge rectifier, a first capacitor, a transformer, a power switch element, an output stage circuit, a feedback compensation circuit, a PWM (Pulse Width Modulation) IC (Integrated Circuit), a discharging circuit, and a controller. The bridge rectifier generates a rectified voltage according to a first input voltage and a second input voltage. The transformer includes a main coil and a secondary coil. The main coil receives the rectified voltage, and the secondary coil generates an induced voltage. The output stage circuit generates an output voltage according to the induced voltage and a first control voltage. The controller generates the first control voltage and a second control voltage according to the output voltage. The discharging circuit selectively reduces the voltage level of the output voltage according to the second control voltage.

Abstract: A power supply device for eliminating overcurrent protection malfunctions includes a first transformer, a power switch element, an output stage circuit, a detection circuit, a feedback compensation circuit, a PWM (Pulse Width Modulation) IC (Integrated Circuit), a second transformer, and a control circuit. The first transformer generates an induced voltage according to an input voltage. The output stage circuit generates an output current according to the induced voltage. The detection circuit monitors the output current and generates a detection voltage according to the output current. The feedback compensation circuit includes a linear optical coupler and a voltage regulator. The feedback compensation circuit generates a coupling current. The second transformer generates a control voltage according to the coupling current. The control circuit selectively enables or disables the linear optical coupler and the voltage regulator according to the detection voltage and the control voltage.

Abstract: A buck converter includes a bridge rectifier, a power switch element, an output stage circuit, a first diode, a first inductor, and a detection and compensation circuit. The bridge rectifier generates a rectified voltage according to the first input voltage and the second input voltage. The power switch element selectively couples the bridge rectifier to the ground voltage according to the clock voltage. The output stage circuit generates an output voltage. The first inductor is coupled between the detection and compensation circuit and the output stage circuit. The detection and compensation circuit monitors and compares the rectified voltage and the output voltage. If it is detected that the rectified voltage is lower than the output voltage, the detection and compensation circuit will readjust the rectified voltage so that it is higher than or equal to the output voltage.