Abstract: An LED control circuit, comprising: an isolated DC-DC circuit having a first current loop and a voltage loop, said circuit being used for outputting a stable direct current voltage; and a buck circuit having a control unit; wherein the control unit is used for controlling the buck circuit to output constant current, so as to supply power to an LED load, and also used for controlling the buck circuit to not operate when the direct current voltage is less than a preset voltage, and controlling the buck circuit to operate when the direct current voltage is greater than or equal to the preset voltage.

Abstract: An LED drive circuit, comprising: a Flyback circuit that has a current-limiting mode and a constant-voltage mode, a non-isolated DC-DC circuit, and a control circuit. The control circuit is used to detect the output voltage of the Flyback circuit, and, when the output voltage of the Flyback circuit is greater than or equal to a first preset voltage value, control the Flyback circuit to operate in the constant-voltage mode; the control circuit is further used to detect the switch transistor current or output current of the Flyback circuit, and, when the output current of the Flyback circuit is greater than a first preset current value, control the Flyback circuit to operate in the current-limiting mode.

Abstract: An LED control circuit, comprising: an isolated DC-DC circuit having a first current loop and a voltage loop, said circuit being used for outputting a stable direct current voltage; and a buck circuit having a control unit; wherein the control unit is used for controlling the buck circuit to output constant current, so as to supply power to an LED load, and also used for controlling the buck circuit to not operate when the direct current voltage is less than a preset voltage, and controlling the buck circuit to operate when the direct current voltage is greater than or equal to the preset voltage.

Abstract: An LED drive circuit, comprising: a Flyback circuit that has a current-limiting mode and a constant-voltage mode, a non-isolated DC-DC circuit, and a control circuit. The control circuit is used to detect the output voltage of the Flyback circuit, and, when the output voltage of the Flyback circuit is greater than or equal to a first preset voltage value, control the Flyback circuit to operate in the constant-voltage mode; the control circuit is further used to detect the switch transistor current or output current of the Flyback circuit, and, when the output current of the Flyback circuit is greater than a first preset current value, control the Flyback circuit to operate in the current-limiting mode.

Abstract: An integrated magnetic device includes a bobbin having a through hole. A center column magnetic core groove is arranged in the middle of the bobbin to divide the bobbin into a first bobbin and a second bobbin, the center column magnetic core groove is inserted with a center column magnetic core, the first bobbin and the second bobbin are both provided with a side magnetic core for forming a closed loop with the center column magnetic core, the side magnetic core includes a center column inserted in the through hole, a first winding groove for winding a magnetic device winding of a Boost circuit is provided between side walls of the first bobbin, and a second winding groove for winding a magnetic device winding of an LLC circuit is provided between side walls of the second bobbin.

Abstract: A resonant converter includes a resonant current truncating unit, a resonant current processing unit and a driving control unit. The resonant current truncating unit is connected in series in a current loop of a resonance circuit and is configured to periodically truncate to acquire a sampling interval and acquire a sampling signal characterizing a resonant current in the sampling interval. The resonant current processing unit is configured to perform an averaging process on the sampling signal to acquire a feedback signal. The driving control unit is configured to control a switching state of the main switch of the primary circuit based on the feedback signal, to make the resonant converter output a stable current.

Abstract: A resonant converter includes a resonant current truncating unit, a resonant current processing unit and a driving control unit. The resonant current truncating unit is connected in series in a current loop of a resonance circuit and is configured to periodically truncate to acquire a sampling interval and acquire a sampling signal characterizing a resonant current in the sampling interval. The resonant current processing unit is configured to perform an averaging process on the sampling signal to acquire a feedback signal. The driving control unit is configured to control a switching state of the main switch of the primary circuit based on the feedback signal, to make the resonant converter output a stable current.

Abstract: A control circuit in a power factor correction (PFC) circuit includes: a multiplier, used for multiplying a voltage sampling signal by a feedback signal, and outputting a first signal; and a waveform generating module, used for generating a second signal related to a filter capacitor connected in parallel to an input end and/or an output end of a rectifier bridge. A control signal for controlling a state of a main switch transistor is generated by using the first signal, the second signal, and a current sampling signal of the main switch transistor in the PFC circuit.

Abstract: Disclosed are a method and circuit for reducing a ripple of a current output by a current source. The circuit for reducing a ripple of a current output by a current source comprises a tube with adjustable impedance and a control circuit.

Abstract: Disclosed is a constant current drive for an LED light source, including a main power supply loop and at least one backup power supply loop. The main power supply loop at least includes a power conversion circuit. The power conversion circuit outputs a constant current to an LED light source. The backup power supply loop at least includes a power conversion backup circuit. The power conversion backup circuit outputs a constant current to the LED light source. When the power conversion circuit and the power conversion backup circuit operate normally, any one thereof operates in a nominal state or a derating state, and the output ends thereof are connected in parallel and then supply power to the LED light source simultaneously. When any one of the power conversion circuit and the power conversion backup circuit is invalid, the invalid circuit will not affect the normal operation of the remaining circuit.

Abstract: An auxiliary power supply circuit of a two wire dimmer, comprising: an auxiliary source capacitor (20) and a cutoff switch (30) constituting a series branch, a chopper switch (10) parallel-connected to the series branch, and a control device (40) connected to the chopper switch (10) and to the cutoff switch (30). The control device (40) measures an auxiliary source voltage and receives a chopper voltage control signal (Vg), and outputs signals (V1 and V2), on the basis of the result of a comparison between the auxiliary source voltage and a preset voltage and of the state of the chopper voltage control signal (Vg), to control the on and off of the chopper switch (10) and of the cutoff switch (30) for controlling the charging of the auxiliary source capacitor (20). The auxiliary power supply circuit has low losses, high efficiency, and is not limited by minimum chopper angle, and has low electromagnetic interference.

Abstract: A constant current control circuit with PFC function and its PFC circuit are provided. The PFC circuit comprises a valley-filled PFC circuit and a harmonic compensation circuit, whose output signal is supplied to the current control circuit. By adding the harmonic compensation circuit to the PFC circuit, the distortion of input current is decreased and the power factor is enhanced. Moreover, the whole circuit is simplified and its cost is reduced.

Abstract: Disclosed are a method and circuit for reducing a ripple of a current output by a current source. The circuit for reducing a ripple of a current output by a current source comprises a tube with adjustable impedance and a control circuit.

Abstract: A control circuit in a power factor correction (PFC) circuit includes: a multiplier, used for multiplying a voltage sampling signal by a feedback signal, and outputting a first signal; and a waveform generating module, used for generating a second signal related to a filter capacitor connected in parallel to an input end and/or an output end of a rectifier bridge. A control signal for controlling a state of a main switch transistor is generated by using the first signal, the second signal, and a current sampling signal of the main switch transistor in the PFC circuit.

Abstract: A device and system for load driving. The device includes: an electric energy supplying unit including at least two units with output voltage adjustable; a sampling unit, with the input thereof connected to either end of a load unit for sampling the current of that end and sending the sampled current to an output voltage controller; the output voltage controller, with the input thereof connected to the output of the sampling unit for outputting voltage control signal to each unit with output voltage adjustable, according to the sampled current, so as to control the difference between the output voltage of each unit with output voltage adjustable and the maximum load voltage in a load branch to be not greater than a preset difference threshold, with the difference threshold being greater than or equal to zero. The device and system for load driving can improve the reliability of the driving device and can reduce the complexity of the circuit.

Abstract: A load driving device and system, and a limiting point control method and device. The load driving device comprising: a voltage/current regulative main circuit placed under the control of an output current controller, for use in conducting a voltage conversion on an input voltage, and in supplying electric power to a subsequent load unit; a sampling unit connected to an output terminal of the main circuit, for use in sampling an output feature parameter of the main circuit; the output current controller, for use in controlling a limiting point of the main circuit, and on the basis of the adjustment direction of the limiting point and on changes of the output feature parameters of the main circuit before and after an adjustment, determining a steady working point for the main circuit, and controlling the main circuit to work at the steady working point. The load driving device and system enable an increase in driver reliability and a reduction in circuit complexity.

Abstract: A multi-path constant current driving circuit. In the multi-path constant current driving circuit, a current sharing transformer (T31, T32, T33, T3(n?1)) is provided in power supply circuits which are provided with adjacent rectifier and filter units (Z31, Z32, Z33, Z3n). A first winding of the current sharing transformer (T31, T32, T33, T3(n?1)) is connected between a first terminal of a secondary winding of a first power supply circuit and the rectifier and filter unit (Z31, Z32, Z33, Z3n) of the first power supply circuit. A second winding of the current sharing transformer (T31, T32, T33, T3(n?1)) is connected between a first terminal of a secondary winding of a second power supply circuit and the rectifier and filter unit (Z31, Z32, Z33, Z3n) of the second power supply circuit. In-phase current flows through the dotted terminal of the first winding and the synonym terminal of the second winding of the current sharing transformer (T31, T32, T33, T3(n?1)).

Abstract: Provided in an embodiment of the present invention are an LED driver, and method and device for controlling the fixed value of the LED driver, the method comprising: detecting whether an existing terminal of an LED driver inputs a control signal; when the control signal is detected, determining the fixed value of the LED driver according to the control signal; when the LED driver is an LED driver having no dimming function, the fixed value is the rated current of the LED driver; when the LED driver is an LED driver having a dimming function, the fixed value includes the upper limit or lower limit of the output current value of the LED driver. The method, device and the LED driver provided in the embodiment of the present invention can save LED driver costs.

Abstract: The present invention discloses a power supply circuit for multi-path light-emitting diode (LED) loads. The two ports of the second diode are connected in parallel with the first switch tube, and the two ports of the forth diode are connected in parallel with the second switch tube. The conduction mode of the second and forth diodes is controlled by controlling the switch status of the first and second switch tubes. When the system is on a normal state, the first and second switch tubes are both switched off. When the load output of any path needs to be turned off, the corresponding switch tube should be controlled to switch on, which makes the diode connected in parallel with the switch tube short-circuited. The present invention can avoid a strong impulse current produced in filtering capacitor when the load of any path is directly short-circuited. Therefore, the present invention can reduce the current stress in circuits, improve the reliability of circuits, and reduce the cost.

Abstract: A open-circuit protection circuit of a constant current driving circuit for light emitting diodes is disclosed, which includes that: a transformer (Ta1), which has at least one secondary winding (WT1), is connected to at least two load branches (A1, A2); a commutating loop is composed of each load branches (A1, A2) and one secondary winding (WT1), wherein the secondary winding (WT1) has tap ends; a current sharing transformer (T1) is set in two neighbor load branch (A1, A2); each load branch (A1, A2) is separately connected to one open-circuit protection module (10).