Abstract: Methods for flyback converters are provided. The method, adopted by a flyback converter circuit including a transformer, including: determining an output voltage output from a secondary circuit of the transformer; feeding a feedback voltage based on the output voltage from the secondary circuit back to a primary circuit of the transformer; increasing a current limit and a switching frequency of a primary current with the feedback voltage; and supplying the primary current to a primary winding of the transformer.

Abstract: Disclosed is a power converter control circuit, comprising at least a power converter circuit and a control circuit. The power converter circuit is able to boost up an input voltage into a greater driving voltage and supply it to the driven device. Moreover, the power converter circuit is also able to generate a voltage signal and a current-sense signal separately, and then combine them into a joint voltage/current-sense signal. The control circuit receives the joint voltage/current-sense signal and resolves it into an over-voltage signal and a current-sense signal with the aid of a modulation signal. The two signals are separately fed into an over-voltage protection device and an over-current protection device for comparison; the outcomes are utilized to execute the over-voltage protection and the over-current protection.

Abstract: A light emitting diode (LED) backlight system and a driving apparatus and a driving method thereof are provided. The driving apparatus is suitable for an LED backlight system with N LED strings, where N is a positive integer greater than 1, and which includes an LED driver and a switching unit. The LED driver is configured to receive a dimming signal and time-divisionally generate N control signals in response to a counting clock and an enabling time and a period time both related to the dimming signal. The switching unit is coupled to the LED driver and the N LED strings, and is configured to respectively control an on-off time ratio of a current flowing through each of the LED strings in response to the N control signals.

Abstract: Disclosed is a power converter control circuit, comprising at least a power converter circuit and a control circuit. The power converter circuit is able to boost up an input voltage into a greater driving voltage and supply it to the driven device. Moreover, the power converter circuit is also able to generate a voltage signal and a current-sense signal separately, and then combine them into a joint voltage/current-sense signal. The control circuit receives the joint voltage/current-sense signal and resolves it into an over-voltage signal and a current-sense signal with the aid of a modulation signal. The two signals are separately fed into an over-voltage protection device and an over-current protection device for comparison; the outcomes are utilized to execute the over-voltage protection and the over-current protection.

Abstract: A flyback-based power conversion apparatus and a power conversion method thereof are provided. By switching first and second detection switches disposed in a control chip and coupled to a multi-function pin of the control chip at different timings, the present invention applies a collocation of a voltage-current detection auxiliary circuit and a current detection circuit at a certain timing to execute a detection of the AC input voltage received by a flyback power conversion circuit, and the present invention applies a collocation of the auxiliary voltage-current detection circuit, an over temperature protection unit and an over voltage protection unit at another timing to execute detections of an over temperature protection and an over voltage protection. As the result, a single multi-function detection pin of the control pin is corresponding to a plurality of related function detections, so as to reduce the production cost of manufacturing the control chip.

Abstract: A power factor correction (PFC) power conversion apparatus and a power conversion method thereof are provided. In the invention, by switching a detection switch disposed inside a control chip and connected to a detection pin of the control chip at a certain time, and performing a detection of an input voltage received by a boost power conversion circuit at the certain time through a collocation between a current detection auxiliary circuit and a current detection main circuit. Accordingly, an over current protection (OCP) point corresponding to whether an OCP mechanism is activated is compensated according to the detected result, and thus the detection manner of the OCP performed by the invention can be adaptively suitable for different input voltages. In the invention, according to the detected result, a brown out protection also can be performed, and the output of the boost power conversion circuit also can be changed or determined.

Abstract: A power detection apparatus is provided. The power detection apparatus includes a first current processing circuit and a second current processing circuit. The first current processing circuit is configured to provide a dynamic bias voltage at a bias terminal in response to a variation of a system power. The second current processing circuit is coupled to the first current processing circuit and is biased under the dynamic bias voltage for outputting a power good signal at an output terminal to represent that the system power is ready when the dynamic bias voltage is greater than a threshold voltage.

Abstract: A light-emitting-diode (LED) driving apparatus is provided, and which includes a power switch having a first terminal coupled to a first node and a second terminal coupled to a second node, wherein an LED string is coupled between a DC voltage and the first node; a first resistor coupled between the second node and a ground potential; and a control chip for generating a driving signal in response to a voltage on the second node and a bandgap voltage during an activation phase of the LED driving apparatus, so as to switch the power switch and thus making the LED string to be operated under a constant current for producing light, and further comparing a detection voltage obtained in response to a voltage on the first node with a predetermined voltage, so as to stop generating the driving signal when the detection voltage is greater than the predetermined voltage.

Abstract: A light emitting diode (LED) driving apparatus is provided, and which includes a first operational amplifier (OPA) having a positive input terminal receiving a predetermined voltage related to a current flowing through an LED string; a first resistor having a first end coupled to a negative input terminal of the first OPA and a second end coupled to a ground; a power transistor having a gate coupled to an output of the first OPA, a drain coupled to a cathode of the LED string and a source coupled to the first end of the first resistor; an error amplifier having a first input terminal coupled to the gate of the power transistor, a second input terminal receiving a reference voltage and an output terminal outputting a control voltage; and a power conversion stage providing a DC voltage to an anode of the LED string according to the outputted control voltage.

Abstract: A power conversion apparatus and a brown-out protection method are provided. The brown-out protection method includes sampling a rectification signal relating to an AC voltage received by the power conversion apparatus by adopting a discrete sampling means; and when a peak value of the sampled rectification signal has reached to a predetei mined value within a predetermined duration, making a pulse width modulation (PWM) control chip in the power conversion apparatus provide a PWM signal to switch a power switch in the power conversion apparatus, and thereby making the power conversion apparatus provide an output voltage to an electronic device; otherwise, making the PWM control chip to stop providing the PWM signal.

Abstract: A light emitting diode (LED) driving apparatus is provided, which includes a power conversion circuit for receiving and converting an input power so as to generate a DC voltage to simultaneously drive a plurality of LED strings arranged in parallel; and a plurality of current regulation chips each having a single regulation channel and respectively corresponding to the LED strings, wherein an ith current regulation chip is only used for regulating a current flowing through an ith LED string, where i is a positive integer.

Abstract: A power conversion apparatus and an over current protection (OCP) method thereof are provided. The OCP method includes generating a pulse-width-modulation (PWM) signal according to a loading status of an electronic device, so as to switch a power switch in the power conversion apparatus and thus making the power conversion apparatus providing an output voltage to the electronic device; generating an OCP reference signal with variable slope according to a feedback signal related to the loading status of the electronic device and a system operation voltage of a PWM controller chip in the power conversion apparatus that is used for generating the PWM signal; and comparing a sensing voltage corresponding to a current following through the power switch on a resistor, and the OCP reference signal with variable slope to determine whether to activate an OCP mechanism to control the PWM controller chip whether to generate the PWM signal.

Abstract: A frequency-jitter-controller for a power-converter is provided, and which includes a first and a second capacitance units, a first and a second charge-discharge control units, a comparing unit and a control unit. Both capacitance units are charged to a crossing-voltage during a charging phase and discharged to a reference voltage and a clamp voltage respectively during a discharging-phase in response to operations of both charge-discharge control units. The comparing unit outputs a pulse signal, compares voltages of both capacitance units during the charging phase, and compares the voltage of the first capacitance unit and the reference voltage during the discharging phase. The control unit generates a frequency jitter control signal according to the pulse signal to adjust a rising rate of the voltage on the second capacitance unit, so as to change a frequency of the pulse signal, and thus reduce EMI generated by switching switch-elements in the power-converter.