Semiconductor Components Industries, LLC

Fairchild (taiwan) Corporation

Rickhtek Tecnology Corp.

Chen-Hua Chiu

Mao-Sheng Lin

HyeongSeok Baek

Ta-Yung Yang

Gwan-Bon Koo

Guangchao Zhang

Moon-Ho Choi

Yuan-Pu Lee

Guang-Chao Zhang

Wei-Hsu Chang

Wei-Hsuan Huang

Sangcheol Moon

Jung-Sheng Chen

Chien-Yuan Lin

Kuo-Hsien Huang

Jhih-Da Hsu

Dan Chen

Ching-Jan Chen

Yung-I Chang

Chi-Chen Chung

Yong-Ann Ang

It may be desirable to limit the switching frequency of a pulse frequency modulated (PFM) resonant converter, however certain load conditions and/or startup condition require high switching frequencies to regulate an output voltage. The disclosed resonant converter can limit a maximum switching frequency while regulating an output voltage by shifting from PFM to phase-difference modulation based on a load condition. The appropriate modulation can be applied based on a comparison between a charge-control signal and a load-control signal.

Resonant converter with dual-mode control

A secondary side controlled control circuit for power converter with synchronous rectifier is provided. The secondary side controlled control circuit comprises a primary side controller and a secondary side controller. The primary side controller generates a primary side switching signal for switching a primary side switch of the power converter. The secondary side controller generates a secondary side switching signal for switching a switch of the synchronous rectifier of the power converter. The secondary side controller generates a primary side control signal to control the primary side controller for controlling the primary side switching signal.

Secondary side controlled control circuit for power converter with synchronous rectifier

In one embodiment, a control circuit may be configured to form a switching signal to switch a power transistor at a frequency to regulate an output voltage of the power supply to a target value wherein the control circuit is configured to operate in a normal operating mode and a start-up mode and wherein the control circuit is configured to switch the switching signal at a target frequency in response to operating in the normal operating mode. A first circuit may be configured to control the frequency of the switching signal to increase from a first frequency to a second frequency that is less than the target frequency in response to operating in the start-up mode.

Control circuit and method therefor

An LED driver is provided. The LED driver comprises a plurality of driving units and a fold circuit. The driving units are coupled to an LED string including a plurality of LEDs for driving the LEDs. The fold circuit is coupled to the LED string and divides the LED string into a plurality of LED segments when an input voltage is lower than a threshold voltage. The LED segments are coupled to each other in parallel, and the input voltage is supplied to the LED segments.

LED driver

In one general aspect, a control circuit for a power converter can include a feedback terminal configured to be coupled to a non-isolated feedback of the power converter when a feedback of the power converter is the non-isolated feedback, or configured to be coupled to a ground when the feedback of the power converter is an isolated feedback. The control circuit can include a detection circuit, coupled to the feedback terminal. The detection circuit can be configured to trigger a feedback voltage at the feedback terminal within an initial setting of the power converter. The feedback voltage can be high in response to the feedback terminal being coupled to the feedback of the power converter, and the feedback voltage can be low in response to the feedback terminal being coupled to the ground of the power converter.

Control circuit for power converter with isolated or non-isolated feedback

In a general aspect, a control circuit for a power converter can include an option selector circuit that is coupled with a detection pin. The option selector can, based on a voltage applied to the detection pin being greater than or less than a threshold voltage, respectively generate a first enable signal or generate a second enable signal. The control circuit can also include a first mode controller coupled with the option selector and the detection pin. The first mode controller can be configured to, in response to receiving the first enable signal, operate the power converter in a first mode of operation. The control circuit can further include a second mode controller coupled with the option selector and the detection pin. The second mode controller can being configured to, in response to receiving the second enable signal, operate the power converter in a second mode of operation.

Control circuits and control methods for power converters

A control circuit and a method for a programmable power supply are provided. The control circuit and the method modulate a switching frequency of a switching signal in response to a feedback signal and an output voltage of the programmable power supply. The switching signal is used for switching a transformer and regulating an output of the programmable power supply. The level of the feedback signal is related to the level of an output power of the programmable power supply. The output voltage of the programmable power supply is programmable. Further, the control circuit and the method modulate a maximum switching frequency of the switching signal in response to the output voltage of the programmable power supply for stabilizing the system.

Programmable frequency decrease circuit for a programmable power supply

A power converter in a powered device (PD) of Power-over-Ethernet (PoE) system and a control method are provided. The power converter includes a transformer, a PD interface, a primary-side controller and a detecting circuit. The PD interface receives an input voltage to determine a PoE protocol type of the input voltage, so as to generate a first power type signal. The primary-side controller receives the first power type signal to adjust a primary-side control signal, wherein a primary-side switch is controlled by the primary-side control signal. The detecting circuit detects a mapping signal generated in a secondary-side winding according to the primary-side control signal to generate a second power type signal, wherein the second power type signal indicates the PoE protocol type of the input voltage.

Power converter in powered device of power-over-ethernet system and control method thereof

A control circuit for LED and an active bleeder thereof are provided. The control circuit comprises an LED driver and the active bleeder. The LED driver drives at least one LED and generates a current-sense signal. The current-sense signal is correlated to an LED current. The active bleeder comprises a bleeder circuit. The bleeder circuit is coupled to the LED driver to receive the current-sense signal and sinks a bleeding current in accordance with the current-sense signal for keeping the current flowing through the dimmer higher than the holding current.

Control circuit for LED and active bleeder thereof

A control circuit of a power supply is provided. The control circuit includes a circuit and a PWM circuit. The circuit generates a limit signal in response to an output voltage of the power supply for limiting a switching current of a transformer of the power supply. The PWM circuit generates a switching signal in response to a feedback signal and the limit signal for switching the transformer and regulating the output voltage of the power supply. A level of the feedback signal is related to a level of the output voltage of the power supply. The output voltage of the power supply is programmable.

Programmable current limit circuit for a programmable power supply

A discharge circuit for an electromagnetic interference (EMI) filter is provided. The discharge circuit includes a switch circuit, a control circuit, and a detection circuit. The switch circuit is coupled to an X-capacitor of the EMI filter. The control circuit is coupled to the switch circuit and configured to turn on the switch circuit in a predetermined period to provide a discharge path. The detection circuit is coupled to the discharge path. In the predetermined period, the detection circuit detects whether a cross point occurs between a discharge voltage signal on the discharge path and a reference voltage signal to generate a detection signal which is provided to the control circuit. When the detection circuit detects that the cross point does not occur, the control circuit continuously turns on the switch circuit according to the detection signal after the predetermined period has elapsed.

Discharge circuits of discharge paths for electromagnetic interference filters

For a multiphase interleaved voltage regulator, an offset cancellation circuit is applied for each phase separately. The current loop gain of each phase is thus increased to mitigate the beat-frequency oscillation in phase currents when the beat frequency is below the bandwidth of the low-pass filter in the offset cancellation circuit, without introducing additional instability issue that is the drawback of increasing current-sensing gain.

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Taipei, Taiwan

Chen-Hua Chiu