Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A fan structure comprises a first impeller and a second impeller, wherein the first impeller is composed of a first annular substrate, a plurality of first ribs and a plurality of first blades. The first ribs and the first blades are formed on the first annular substrate, each of the first ribs comprises an engaging hole, and a first accommodating space is formed between each of the adjacent first blades. The second impeller is composed of a hub, a second annular substrate, a plurality of second ribs, a plurality of second blades and at least one engaging member formed on the second ribs. The second ribs and the second blades are formed on the second annular substrate, and a second accommodating space is formed between each of the adjacent second blades. The first blades and the second blades are arranged in a staggered relationship.

Abstract: A fan structure at least includes a cap, an impeller, a bearing and a fixing shaft, wherein the cap comprises a bottom portion, a body and an accommodating space. The impeller comprises a hub and a coupling base having a ring wall and an accommodating slot. The bearing couples to the accommodating slot, and the fixing shaft penetrates through an axial hole of the bearing. The ring wall of the coupling base comprises at least one guidance hole exposing the fixing shaft. The guidance hole is in communication with the accommodating space and the accommodating slot. The lubricants can be collected inside the accommodating space of the cap through the guidance of the guidance hole to prevent the lubricants from leakage when the impeller is in rotation.

Abstract: A fan structure at least includes a bearing module and a rotor, the bearing module includes a hollow cylinder body, a bearing, a limiting member and a blocking member. The hollow cylinder body comprises a ring wall and an accommodating hole, wherein the bearing, the limiting member and the blocking member are disposed at the accommodating hole in sequence. The ring wall comprises an inner ring wall and a limiting slot recessed from the inner ring wall. The blocking member comprises a body portion and a blocking portion extendedly formed at the body portion, the body portion embedded into the limiting slot, and the blocking portion is in contact against the limiting member. A rotating shaft of the rotor penetrated through the limiting member and the bearing, and a plurality limiting plates of the limiting member inserted into a ring slot of the rotating shaft.

Abstract: A fan structure comprises a first impeller and a second impeller, wherein the first impeller is composed of a first annular substrate, a plurality of first ribs and a plurality of first blades. The first ribs and the first blades are formed on the first annular substrate, each of the first ribs comprises an engaging hole, and a first accommodating space is formed between each of the adjacent first blades. The second impeller is composed of a hub, a second annular substrate, a plurality of second ribs, a plurality of second blades and at least one engaging member formed on the second ribs. The second ribs and the second blades are formed on the second annular substrate, and a second accommodating space is formed between each of the adjacent second blades. The first blades and the second blades are arranged in a staggered relationship.

Abstract: A continuous sand filter has a tank provided therein with a first separation container and a second separation container. The continuous filtration of the waste water is carried out in the first separation container and the second separation container. The first separation container is provided with an arresting piece capable of enhancing the filtration effect. The light and the heavy impurities are treated separately in the first separation container. The further filtration process is carried out continuously in the second separation container.