Leadtrend Technology Corporation

Grenergy Opto Inc.

Yu-Yun Huang

Yi-Lun Shen

Ren-Yi Chen

A controller for generating jitters in a quasi resonant mode includes a feedback pin, a voltage generation unit, a pulse generator, and a comparator. The feedback pin is used for receiving a feedback voltage from a secondary side of a power converter. The voltage generation unit is used for generating a first voltage according to the feedback voltage and a pulse. The pulse generator is used for generating the pulse when a control signal controlling a power switch of a primary side of the power converter is enabled. The comparator is used for controlling enabling and disabling of a switching signal according to the first voltage and a variable reference voltage. The variable reference voltage is monotonously swung within a predetermined range according to a digital signal.

Controller for generating jitters in a quasi resonant mode and method for generating jitters in a quasi resonant mode

A power supply has an inductor and determines loading state of the power supply according to a compensation signal. When the loading state is determined to be a light loading state or a no-loading state, a switch is operated at a low operating frequency. When the loading state is determined to be a heavy loading state, the switch is operated at a high operating frequency. If the compensation signal exceeds a critical value, it is determined that the loading state is an overloaded state. When the overloaded state continues past a tolerable duration, the switch is turned off. The tolerable duration is determined by an external capacitor and is independent of the operating frequency.

Controlling method, power controller, and power controlling method

A controller for generating jitters in a constant current mode of a power converter includes a current pin, an auxiliary pin, a constant current control unit, and a control signal generation unit. The current pin is used for receiving a primary side voltage determined according to a resistor and a primary side current flowing through the power converter. The auxiliary pin is used for receiving a voltage corresponding to an auxiliary winding of the power converter. The constant current control unit is used for generating an adjustment signal according to the primary side voltage, a discharge time corresponding to the voltage, and a reference voltage. The reference voltage has a predetermined range jitter voltage. The control signal generation unit is used for adjusting a period of a gate control signal according to the adjustment signal.

Controller for generating jitters in a constant current mode of a power converter and method thereof

Power controllers and related primary-side control methods are disclosed. A disclosed power controller has a comparator and an ON-triggering controller. The comparator compares a feedback voltage with an over-shot reference voltage. Based on an inductance-coupling effect, the feedback voltage represents a secondary-side voltage of a secondary winding. Coupled to the comparator, the ON-triggering controller operates a power switch at about a first switching frequency when the feedback voltage is lower than the over-shot reference voltage. The ON-triggering controller operates the power switch at about a second switching frequency when the feedback voltage exceeds the over-shot reference voltage. The second switching frequency is less than the first switching frequency.

Methods and power controllers for primary side control

A quasi-resonant (QR) converter introduces soft transition for valley switching and valley locking. One exemplifying QR converter is capable of performing valley switching, but has the valley switching in a specific signal valley of one switching cycle softly transit to the valley switching in another signal valley of a later switching cycle, via at least one switching cycle performing no valley switching.

Switching mode power supply capable of achieving soft transition for valley switching, or performing valley locking

Controllers and related control methods for a switched mode power supply are disclosed. The switched mode power supply has an inductive device and a power switch connected in series. An output current estimator in a controller is configured for receiving a current-sense signal representing an inductor current flowing through the inductive device and a discharge-time signal indicating a discharge time of the inductive device. The output current estimator generates a charge current in response to the discharge-time signal and the current-sense signal, thereby the charge current substantially corresponding to an output current that the switched mode power supply outputs to a load. The charge current is limited not to exceed a maximum value. A current limiter is configured for limiting the current-sense signal when the charge current is the maximum value.

Controllers and related control methods for generating signals representing an output current to a load in a switched mode power supply

Herein is disclosed a constant current control unit and a control method, for a switched mode power supply with primary side control. The switched mode power supply comprises a power switch and an inductive device. A reflective voltage of the inductive device is detected to generate a feedback voltage signal. By delaying the feedback voltage signal, a delayed signal is generated. According to the feedback voltage and the delayed signal, a discharge time of the inductive device is determined when the power switch is OFF. According to the discharge time and a current-sense signal, a maximum average output current of the switched mode power supply is stabilized. The current-sense signal represents a current flowing through the inductive device.

Constant current control units and control methods thereof for primary side control

Embodiments disclose control methods and control apparatuses for a switched mode power supply. The switched mode power supply comprises a current-controllable device. A driving current is provided to turn ON the current-controllable device. A conduction current passing through the current-controllable device is detected. The driving current is controlled according to the conduction current. The higher the conduction current the higher the driving current.

Control methods and apparatuses for switching mode power supplies

Disclosure includes control methods and power controllers with load compensation adapted for a power supply powering a load. A disclosed power controller comprises a converter and a control circuit. The converter converts the load signal at a first node to output a load-compensation signal at a second node. The load signal corresponds to an output power provided from the power supply to the load, and the converter includes a low-pass filter coupled between the first and second nodes. The control circuit is coupled to an inductive device via a feedback node, for controlling the output power to make a cross voltage of the inductive device approach a target voltage, based on a feedback voltage at the feedback node. The higher the load-compensation signal the higher the target voltage.

Control methods and power controllers with load compensation adapted for a power supply

The disclosure provides a power controller and related control method for a switch mode power supply operating in a quasi-resonant mode. The switched mode power supply has a power switch and an auxiliary winding. The power controller has a feedback pin connected to the auxiliary winding. A clamp circuit is connected to the feedback pin and configured for clamping a voltage at the feedback pin by providing a clamp current. A peak hold circuit is connected to the clamp circuit for generating a peak record substantially corresponding to a peak value of the clamp current. A valley detector is configured for providing an entry signal indicating a start of a voltage valley. A delay circuit provides a trigger signal a delay time after the entry signal is provided. The delay time varies in response to the peak record, and the trigger signal is capable of turning on the power switch.

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Hsin-Chu, Taiwan

Yu-Yun Huang