Abstract: An LED driving system and a closed-loop control method for LED driving are provided; the LED driving system includes an LED load, a constant-current control module, an electrolytic capacitor, a discharging-voltage measuring module, a bus-voltage measuring module and a charging-current control module, wherein the charging-current control module is connected to an output of the discharging-voltage measuring module, the bus-voltage measuring module and a lower plate of the electrolytic capacitor; the charging current of the electrolytic capacitor is adjusted based on the control signal of the discharging-voltage measuring module and the measured voltage of the bus-voltage measuring module, wherein the charging current of the electrolytic capacitor is reduced by an subtraction operation performed by the addition and subtraction counter, and the charging current of the electrolytic capacitor is increased by an addition operation performed by the addition and subtraction counter.

Abstract: An LED driving system and a closed-loop control method for LED driving are provided; the LED driving system includes an LED load, a constant-current control module, an electrolytic capacitor, a discharging-voltage measuring module, a bus-voltage measuring module and a charging-current control module, wherein the charging-current control module is connected to an output of the discharging-voltage measuring module, the bus-voltage measuring module and a lower plate of the electrolytic capacitor; the charging current of the electrolytic capacitor is adjusted based on the control signal of the discharging-voltage measuring module and the measured voltage of the bus-voltage measuring module, wherein the charging current of the electrolytic capacitor is reduced by an subtraction operation performed by the addition and subtraction counter, and the charging current of the electrolytic capacitor is increased by an addition operation performed by the addition and subtraction counter.

Abstract: A LED driving circuit and method for balancing efficiency and a power factor. The circuit comprises a voltage input module, an LED load, a constant current control module and a current turn-off slope control module for adjusting the turn-off slope of the current flowing through the LED load, such that a compromise between efficiency and power factor is achieved. When an input voltage is higher than a setting voltage, the current flowing through the LED load is turned off, such that the power consumption is reduced; in addition, the efficiency and power factor are balanced by adjusting the turn-off slope of the current. According to the present invention, a compensation capacitor is used to control the average current in an alternating current period and to limit peak current, thereby implementing constant power output within a wide range of input voltage.

Abstract: A LED driving circuit and method for balancing efficiency and a power factor. The circuit comprises a voltage input module, an LED load, a constant current control module and a current turn-off slope control module for adjusting the turn-off slope of the current flowing through the LED load, such that a compromise between efficiency and power factor is achieved. When an input voltage is higher than a setting voltage, the current flowing through the LED load is turned off, such that the power consumption is reduced; in addition, the efficiency and power factor are balanced by adjusting the turn-off slope of the current. According to the present invention, a compensation capacitor is used to control the average current in an alternating current period and to limit peak current, thereby implementing constant power output within a wide range of input voltage.

Abstract: A single-segment linear constant-power LED driving circuit and method. The circuit comprises: a voltage input module, an LED load, a power switch tube, a sampling resistor, an over-voltage control module for detecting the voltage at a drain terminal of the power switch tube, a current control module for limiting a peak current of the LED load, and a comparison module. When an input voltage is greater than a turn-on voltage of the LED load, the current control module limits the peak current so that the current average value in different input voltage periods is constant. When the input voltage is greater than a set value, current flowing through the LED load is turned off, thereby reducing power consumption. When the input voltage is less than the turn-on voltage of the LED load, the LED load is turned off.

Abstract: A single-segment linear constant-power LED driving circuit and method. The circuit comprises: a voltage input module, an LED load, a power switch tube, a sampling resistor, an over-voltage control module for detecting the voltage at a drain terminal of the power switch tube, a current control module for limiting a peak current of the LED load, and a comparison module. When an input voltage is greater than a turn-on voltage of the LED load, the current control module limits the peak current so that the current average value in different input voltage periods is constant. When the input voltage is greater than a set value, current flowing through the LED load is turned off, thereby reducing power consumption. When the input voltage is less than the turn-on voltage of the LED load, the LED load is turned off.

Abstract: A controller for a switched mode power supply (SMPS) is provided. The SMPS is equipped with a transformer having a primary side winding, a secondary winding, and an auxiliary winding. The controller includes a detection circuit for detecting a transition from a first output load condition to a second output load condition of the SMPS and a control circuit coupled to the detection circuit and being configured to output one or more control signals in response to the detected output load transition. Depending on the embodiment, the one or more control signals include a first control signal for turning on a power switch to cause a current flow in a primary winding of the SMPS and/or one or more second control signals for turning off one or more functional circuit blocks in the controller.

Abstract: A power converter includes a primary winding for providing a primary current, a secondary winding for providing an output current and an output voltage, and a current sense node for receiving a current sense signal related to the primary current. The power converter also includes a control circuit configured to limit the current sense signal to be lower than or equal to a predetermined reference peak current. Moreover, the power converter includes a first circuit configured to modify the current sense signal using a first signal related to the output voltage to cause an variation in the output current.

Abstract: A controller for a switched mode power supply (SMPS) is provided. The SMPS is equipped with a transformer having a primary side winding, a secondary winding, and an auxiliary winding. The controller includes a detection circuit for detecting a transition from a first output load condition to a second output load condition of the SMPS and a control circuit coupled to the detection circuit and being configured to output one or more control signals in response to the detected output load transition. Depending on the embodiment, the one or more control signals include a first control signal for turning on a power switch to cause a current flow in a primary winding of the SMPS and/or one or more second control signals for turning off one or more functional circuit blocks in the controller.

Abstract: A power converter includes a primary winding for providing a primary current, a secondary winding for providing an output current and an output voltage, and a current sense node for receiving a current sense signal related to the primary current. The power converter also includes a control circuit configured to limit the current sense signal to be lower than or equal to a predetermined reference peak current. Moreover, the power converter includes a first circuit configured to modify the current sense signal using a first signal related to the output voltage to cause an variation in the output current.

Abstract: A paper corner protector includes a corner reinforcement body (1) which consists of a cardboard (2) and a cavity (3), wherein the cavity (3) is formed by folding the cardboard (2) end to end. The present utility model enhances the convenience of cost during its transportation and decreases its storage space. Furthermore, a Kraft board is used as the raw material, which is recoverable and reusable and has water-absorbing capacity, so it meets the requirement of environmental protection. It can be expediently folded to become packaging corner protectors so as to be placed on the corners of a packing container such that it can provide favorable protective actions to the corners of the product in the container, such as buffer action, shockproof action and moisture proof action.