Abstract: A low-pin count fan speed control system and a method thereof include primarily an activation unit to drive a fan to operate. When the fan starts completely, the fan slows down to a pre-determined rotation speed through an idle speed regulation unit. After achieving a pre-determined temperature through a temperature transition unit, the fan speed beings to increase from the idle speed. When the fan is operating, the rotation speed is properly increased in proportion to the temperature, using a positive temperature regulation slope unit. Therefore, through this method, the rotation speed will not be decreased by foreign objects when the fan is operating and a computer host can be provided with proper heat dissipation.

Abstract: The present invention discloses a quasi-resonant valley voltage detecting method, comprising the steps of: generating a valley detection signal by detecting a valley of a first quasi-resonant signal; generating a count value by counting the valley detection signal; and determining a level transition instance of a gating signal according to the count value, wherein the level transition instance of the gating signal is pulled back by the valley detection signal to trace the valley of the first quasi-resonant signal. The present invention also provides a quasi-resonant valley voltage detecting apparatus.

Abstract: A primary-side feedback control device for a power converter includes a control unit, a comparator and a sample-and-hold unit. The control unit is utilized for generating a pulse signal according to a feedback signal for controlling on and off states of a switching transistor of the power converter. The comparator is coupled to an auxiliary winding of a primary side of the power converter, and is utilized for generating at least one control signal according to a voltage on the auxiliary winding. The sample-and-hold unit is coupled to the auxiliary winding, the comparator and the control unit, and is utilized for generating the feedback signal according to the voltage on the auxiliary winding and the at least one control signal.

Abstract: An automated power supply is formed primarily by electrically connecting a power supply system and a chip management module. The chip management module includes a data storage module, a transmission module, a protocol circuit module and a power detecting module. The protocol circuit module includes at least one power output/input pin for transmitting an electric signal, and a grounding pin. Therefore, not only a requirement of an internal driving power can be reduced, but also a size of the chip and electric power consumption can be diminished significantly.

Abstract: The present invention discloses a cascade device with a voltage regulating effect. The cascade device can be applied to a power supply of a cascade structure and includes a comparing element and a power control element. The comparing element provides for inputting a sampling voltage and a reference voltage, and outputs a control signal to the power control element when the sampling voltage is larger than the reference voltage. Next, the power control element can control an input voltage to be outputted to grounding, according to the control signal. Therefore, a control circuit can be provided with a stable voltage source, without requiring an extra rectifying device.

Abstract: The present invention discloses a control circuit with frequency compensation, which can be applied to an open-loop control system. The control circuit includes an oscillator which is additionally connected to a first comparator including a first input end, a second input end and a first output end. The first input end provides for inputting a sampling current, the second input end provides for inputting a total voltage of a reference voltage and a DC-level voltage, and the first output end outputs a down-conversion signal. When the sampling current is larger than the total voltage, the first comparator will generate the down-conversion signal to the oscillator to reduce a frequency of the oscillator, such that a current of the open-loop control system can be controlled effectively to prevent an electronic element form being burned down.

Abstract: A system corrected programmable integrated circuit is applied to a power supply and includes a comparator unit, a digital output unit and a programming unit. The comparator unit includes an external feedback voltage input end and a reference voltage input end for inputting a feedback voltage and a reference voltage respectively, such that when the feedback voltage equals the reference voltage, the comparator unit transmits a control signal to the digital output unit. When receiving the control signal, the digital output unit stops outputting the reference voltage and the current reference voltage is recorded as a programming voltage for outputting to the programming unit. When receiving the programming voltage, the programming unit programs the programming voltage and transmits the voltage to the reference voltage input end. Accordingly, the present invention automatically detects and compensates a system error to reduce external element, yet still achieving a qualified range of product specification.

Abstract: The present invention discloses a minimum on-time reduction method for a switching power conversion, comprising the steps of: generating a first reset signal and an over-supply pulse signal according to a current sensing signal and a reference signal; generating a blanking signal according to a count number of the over-supply pulse signal; and generating a second reset signal by performing Logic-AND operation on the first reset signal and the blanking signal. Furthermore, the present invention also provides a minimum on-time reduction apparatus for a power conversion, and a system using the minimum on-time reduction apparatus for a power conversion.

Abstract: The present invention discloses a peak magnetic flux regulation method for a power conversion via magnetic flux transformation through an inductive component, comprising the steps of: generating an adaptive reference voltage according to voltage comparison of a current sensing voltage and an expected peak voltage; and generating a PWM signal according to voltage comparison of said current sensing voltage and said adaptive reference voltage. Furthermore, the present invention also provides a peak magnetic flux regulation apparatus for a power conversion, and a system using the peak magnetic flux regulation apparatus for a power conversion.

Abstract: A comparator module applied to a voltage level clamping circuit which can be implemented in an integrated circuit (IC) is provided. The IC includes a parasitic diode coupled between a first voltage source and a second voltage source. The voltage level clamping circuit includes a switch module and a comparator module. The comparator module has an output terminal, a first input terminal coupled to a first voltage source, and a second input terminal coupled to a second voltage source. The comparator module includes a current source module, a first voltage level adjusting circuit module, a second voltage level adjusting circuit module, and a comparing circuit module.

Abstract: A primary-side feedback control device for a power converter includes a control unit for generating a pulse signal according to a feedback signal for controlling on and off states of a switching transistor of the power converter, a comparator coupled to an auxiliary winding of a primary side of the power converter for generating at least one control signal according to a voltage on the auxiliary winding and a reference voltage, a sample-and-hold unit coupled to the auxiliary winding, the comparator, and the control unit for generating the feedback signal according to the voltage on the auxiliary winding and the at least one control signal, and a voltage generator coupled to the control unit, the comparator, and the sample-and-hold unit for generating the reference voltage according to the feedback signal.

Abstract: A light source driver circuit includes a voltage input terminal, a light source module, a transformer module, a voltage regulator module, a first switch and a control module. The voltage input terminal receives an input voltage. The light source module includes a plurality of light-emitting units. The transformer module is electrically connected to the light-emitting units. The voltage regulator module connected to the voltage input terminal provides a stable output voltage. The first switch electrically connected to the transformer module and the voltage regulator module receives the stable output voltage to determine whether the first switch is to be turned on or off. The control module is electrically connected to the first switch. The control module and the first switch are controlled so that the light source module the input voltage can be drived by the input voltage.

Abstract: A digital overcurrent protection device for a power supply device includes a receiving end for receiving a current sensing signal, a digital reference voltage generator for digitally generating a reference voltage, a comparator coupled between the receiving end and the digital reference voltage generator for comparing the current sense signal with the reference voltage in order to generate a comparison result, and a control unit coupled to the comparator for controlling a power switch of the power supply device according to the comparison result.

Abstract: This patent discloses an efficient PWM controller for generating a pulse signal in response to a feedback signal, capable of operating in a normal mode or a green mode, comprising: a capacitor for building a saw-tooth signal by current integration, the saw-tooth signal having a ramp-up period and a ramp-down period; a first composite current source for the ramp-up period, detachable into a first constant current source and a first variable current source; and a second composite current source for the ramp-down period, detachable into a second constant current source and a second variable current source; wherein, the first variable current source is attached to the first constant current source and the second variable current source is attached to the second constant current source respectively in the green mode.

Abstract: “An active-load dominant circuit for common-mode glitch interference cancellation, biased between a first voltage potential and a second voltage potential with an accompanying common-mode glitch interferer. The active-load dominant circuit includes a pair of pull-up networks and a pair of active-load networks. The common-mode glitch interferer is cancelled out due to a symmetric structure of the pair of pull-up networks. At least one set signal and at least one reset signal are provided to a latch in response to a clock signal or a complemented clock signal. At least one of the set signal and the reset signal can be pulled up to the first voltage potential or pulled down to the second voltage potential. The voltage difference of the set signal and the reset signal is large enough for a latch.

Abstract: An overcurrent protection device for a power supply device includes a receiving end for receiving a current sensing signal, a compensating current unit coupled to the receiving end for compensating the current sensing signal in order to generate a current sense compensation signal, a first reference voltage generator for generating a first reference voltage, a comparator coupled between the compensating current unit and the first reference voltage generator for comparing the current sense compensation signal with the first reference voltage in order to generate a comparison result, a control unit coupled to the comparator for controlling a power switch of the power supply device according to the comparison result.

Abstract: An active-load dominant circuit for common-mode glitch interference cancellation, biased between a first voltage potential and a second voltage potential with an accompanying common-mode glitch interferer. The active-load dominant circuit includes a pair of pull-up networks and a pair of active-load networks. The common-mode glitch interferer is cancelled out due to a symmetric structure of the pair of pull-up networks. At least one set signal and at least one reset signal are provided to a latch in response to a clock signal or a complemented clock signal. At least one of the set signal and the reset signal can be pulled up to the first voltage potential or pulled down to the second voltage potential. The voltage difference of the set signal and the reset signal is large enough for a latch.

Abstract: A voltage level clamping circuit which can be implemented in an integrated circuit (IC) and a high-speed comparator module, wherein the IC includes a parasitic diode coupled between a first voltage source and a second voltage source. The voltage level clamping circuit includes a switch module coupled between the first voltage source and the second voltage source and a comparator module having an output terminal coupled to the switch module, a first input terminal coupled to the first voltage source, and a second input terminal coupled to the second voltage source, for comparing a voltage level of the first voltage source with a voltage level of the second voltage source to generate an output signal, and transmitting the output signal to the switch module to control a conducting state of the switch module to selectively clamp the voltage level of the second voltage source.

Abstract: A method for an adjustable leading edge blanking device in a power supply device includes generating a detection signal according to a leading edge and a trailing edge of a spike signal, generating a blanking signal according to the detection signal, for blanking the spike signal between the leading edge and the trailing edge, and controlling output states of the power supply device according to the blanking signal.

Abstract: A current-level controlling device for a power supply includes a reception end for receiving a current sense signal, a reference voltage generator for generating a reference voltage, an adaptive reference voltage generator, coupled to the reference voltage generator and the reception end, for adjusting the reference voltage according to variation of peak values of the current sense signal, so as to generate an adaptive reference voltage, a comparator, coupled to the reception end and the adaptive reference voltage generator, for comparing the current sense signal and the adaptive reference voltage, to generate a comparison result, and a control unit, coupled to the comparator, for controlling a switch transistor of the power supply according to the comparison result.