Abstract: A flyback converter, a constant-current control method, and a lighting system are provided. The constant-current control method includes: sampling a loop current in a resonant loop to obtain a first sampling signal; obtaining zero crossing time of an excitation current in the resonant loop; and turning off a first switch tube when the first sampling signal reaches a reference value, and turning off a second switch tube after the zero crossing time of the excitation current in the resonant loop to control an average value of the excitation current to keep constant. The present disclosure can achieve a constant average value of an excitation current in each switching cycle based on a loop current in a resonant loop on the primary side of the converter, thereby realizing constant-current control of an output current of the converter.

Abstract: A buffer circuit for an LED driver circuit, a LED driver circuit, and a control method, the buffer circuit includes a first control switch connected in series in a rectified input loop and a feedback control module connected to the rectified input loop to obtain a loop current in the rectified input loop for generating a first control signal to the first control switch according to the loop current and a reference signal. The first control switch switches between a fully conducting state and a non-fully-conducting state based on the first control signal and restrains the loop current when the first control switch is in the non-fully-conducting state. The buffer circuit enhances the effect of restraining the current change rate and can effectively restrain current spikes in a circuit, resulting in higher safety and reliability.

Abstract: A frequency regulating circuit for a switching circuit, a frequency regulating method, and the switching circuit are provided. The frequency regulating circuit includes a charging current generating module configured to receive a first signal characterizing an output power and a second signal characterizing an input voltage to generate a charging current and a signal generating module configured to output a third signal according to the charging current. The third signal is used to adjust the maximum operating frequency of the switching circuit so that the maximum operating frequency decreases with the increase of the input voltage. Therefore, the frequency regulating circuit increases the maximum operating frequency of the switching circuit under the condition of low voltage input, which decreases the maximum operating frequency of the switching circuit under the condition of high voltage input to reduce the switching loss of the switching circuit with wide input voltage and improve efficiency.

Abstract: A light-emitting diode (LED) drive method, an LED drive circuit, and an LED lighting device are disclosed. The method includes: setting preset values of a maximum on-time parameter and a current limit parameter, where the preset values are in at least two sets; selecting a set of the preset values of the maximum on-time parameter and the current limit parameter after a value of a voltage signal on a direct current (DC) bus is detected; controlling a drive current flowing through an LED load based on a selected maximum on-time parameter and a selected current limit parameter. The maximum on-time parameter and the current limit parameter of the system can be adaptively adjusted according to an input voltage, so that the system can have a preferred dimming schedule and dimming depth while realizing a constant current in a wider input voltage range.

Abstract: A leakage protection circuit and a dimming drive circuit are provided. A leakage detection circuit is configured to detect whether leakage occurs between two input terminals that receive an external signal. When leakage occurs, leakage protection measures are taken. A pulse generation circuit receives the sampling signal characterizing the voltage between the two input terminals to compare the sampling signal with two thresholds to control a detection path of the leakage detection circuit to be turned on or off according to a comparison result. The leakage detection path is enabled to be turned on twice by setting two pulse signals in a power frequency period, which can consider the leakage detection of the front-edge phase-cutting dimming and rear-edge phase-cutting dimming of the dimming drive circuit and has a wide range of applications.

Abstract: Disclosed is an asymmetric half-bridge flyback converter and a control method, comprising: in an initial switching cycle of the asymmetric half-bridge flyback converter, obtaining a pre-turnoff time of the second switch transistor, and controlling the second switch transistor to be turned off after a delay which lasts for a first time and starts at the pre-turnoff time of the second switch transistor; in a non-initial switching cycle of the asymmetric half-bridge flyback converter, obtaining a judgment result by judging whether the first switch transistor is operated with zero-voltage switching in a current switching cycle, and adjusting a length of the first time based on the judgment result. The present disclosure can realize zero-voltage switching of the asymmetric half-bridge flyback converter, and at the same time, satisfy a requirement for achieving more ideal dead-time setting under a wider range of input voltage and a wider range of output voltage.

Abstract: A current limiting circuit of a switching circuit, and a switching circuit are provided. The switching circuit uses a gallium nitride (GaN) power transistor as a main power transistor. The current limiting circuit includes a first terminal connected with a drain of the GaN power transistor, and a second terminal connected with a controller of the switching circuit. The current limiting circuit is configured to limit a current flowing out of a power supply terminal of the controller. The current limiting circuit suppresses a negative current flowing through the controller.

Abstract: Disclosed is a flyback converter and a control method thereof. The flyback converter comprises: a transformer; a power switch; a driver; a synchronous rectifier; and a feedback control module, wherein the feedback control module is configured to output a primary-side turn-on signal when a new switching cycle is started; in each switching cycle, the feedback control module is configured to turn off a primary-side power switch according to a voltage across the synchronous rectifier and an output voltage of the flyback converter. The flyback converter only needs a single isolation device to achieve lossless equivalent peak current control and driving interlocking of primary side and the secondary side, and the synchronous rectifier can effectively prevent driving shoot-through of the primary side and the secondary side in terms of control without reducing a drive voltage, which further improves system efficiency and reliability.

Abstract: The present disclosure provides a manufacture method of an LDMOS. The manufacture method includes: forming a drift region in a substrate; forming a gate structure on the substrate, the gate structure defining a source region and a drain region which are separated from each other, and the gate structure including a gate oxide layer and a gate conductor layer which are successively stacked on the substrate; forming a first doped region in the source region, wherein the first doped region is surrounded by the drift region; forming a first barrier layer with a first opening on the source region and in connect with sidewall of the gate structure; forming a first implantation region in the source region through self-aligned implantation on the basis of the first opening of the first barrier layer; and forming a second implantation region and a third implantation region respectively.

Abstract: A charging control method of power supply equipment and power supply equipment are provided. The power supply equipment includes a power stage circuit and a battery. An input power supply charges the battery through the power stage circuit. The power stage circuit includes a linear regulator and a switched capacitor converter. The linear regulator is connected with the switched capacitor converter. The linear regulator and/or the switched capacitor converter are/is selected for charging management according to charging power of the battery and/or a voltage of the battery. The charging control method can achieve relatively high charging efficiency when the battery is charged with a large current, and can achieve accurate control of the voltage of the battery when the battery is charged with a small current.

Abstract: A single live line switch circuit includes a single live line connecting end, a switch unit, two wire channels, an on-state power obtaining circuit, an off-state power obtaining circuit, and an energy storage element. The single live line connecting end is connected to an external single live line. The on-state power obtaining circuit is connected to the single live line connecting end. The switch unit includes a fixed connecting end and a movable connecting end, and the fixed connecting end is connected to the on-state power obtaining circuit. The two wire channels are provided with a first connecting end and a second connecting end, respectively, and the movable connecting end of the switch unit is in contact with the first connecting end or the second connecting end. A control method of the single live line switch circuit is provided.

Abstract: Disclosed is a switch protection circuit and a power converter, configured to set upper and lower limit-value current signals which can be adjusted along with an input voltage, so that instantaneous power of a main power switch can be prevented from being too high, and the main power switch can always be operated within a safe operating range, thereby solving the problem that the power converter is easy to be damaged in applications under a high-current circumstance.

Abstract: A control method of a switching circuit, a control circuit of the switching circuit and the switching circuit are provided. The control circuit includes a slope buffer and a first operational amplifier. The slope buffer receives a first voltage reference, and controls slopes of a rising edge and a falling edge to generate a second voltage reference. The first operational amplifier receives an output feedback voltage and a reference voltage, and performs an operational amplification to obtain a compensation voltage. When the first voltage reference has the falling edge, the reference voltage is coupled to the first voltage reference through a first switch, and the second voltage reference is coupled to an output voltage through a second switch. When the first voltage reference has the rising edge, the reference voltage is coupled to the second voltage reference through a third switch.

Abstract: An X-capacitor discharge method applied to a switched-mode power supply, wherein the switched-mode power supply comprises an X-capacitor, a rectifier circuit and a switching circuit; the X-capacitor discharge method comprises: arranging a first diode, wherein an anode of the first diode is connected to a first end of the X-capacitor, and a cathode of the first diode is configured as a first node; when it is detected that a voltage of the first node is higher than a first voltage threshold, pulling down the first node through a first sampling current, and performing a timing; and if a time for which the voltage of the first node continues to be higher than the first voltage threshold reaches a first threshold time, pulling down the first node through a first pull-down current. An X-capacitor discharge circuit applied to the switched-mode power supply is provided.

Abstract: An inductive current simulation circuit of a switching circuit, an inductive current simulation method of the switching circuit, and a switched-mode power supply are provided. The inductive current simulation method includes the following steps: based on an error amplification circuit, performing, by the error amplification circuit, an error amplification on a first sampling signal representing a current of a synchronous rectifier and a second sampling signal representing an inductive current simulation signal when the synchronous rectifier is turned on to obtain an error amplification signal; and reconstructing an inductive current according to the error amplification signal when the synchronous rectifier is turned on and a first current when a main power transistor is turned on to obtain the inductive current simulation signal.

Abstract: A synchronous rectification control circuit and method, and a flyback switched-mode power supply (SMPS) are provided. A voltage adjustment circuit is used to adjust a value of a first voltage signal that represents an output voltage, such that a voltage-second product of a difference between the output voltage and a drain-source voltage of a secondary-side synchronous rectifier can be zeroed in time in a transient process, and no false accumulation occurs. In this way, when a primary-side transistor switch is turned on, the secondary-side synchronous rectifier is turned off, to avoid a case in which the primary-side transistor switch and the secondary-side synchronous rectifier are simultaneously turned on.

Abstract: A switching-type regulation driver comprises a transformer, a controller, a synchronous rectifier and a drive control module. The drive control module is connected to the synchronous rectifier and the non-homonymous end of the secondary winding respectively, and is used to detect a target parameter of the voltage at both power ends of the synchronous rectifier when the synchronous rectifier disconnects the conductive path between the non-homonymous end of the secondary winding and the reference ground. When it is detected that the target parameter of the voltage at both power ends of the synchronous rectifier meets a preset condition, the controller controls a switching action of the first transistor so that the primary winding transmits power to the secondary winding. According to the present disclosure, the pre-stage chip may be matched with to realize a function of dynamic acceleration, and the dependence on the output pin may be reduced.

Abstract: The present disclosure provides a manufacture method of an LDMOS. The manufacture method includes: forming a drift region in a substrate; forming a gate structure on the substrate, the gate structure defining a source region and a drain region which are separated from each other, and the gate structure including a gate oxide layer and a gate conductor layer which are successively stacked on the substrate; forming a first doped region in the source region, wherein the first doped region is surrounded by the drift region; forming a first barrier layer with a first opening on the source region and in connect with sidewall of the gate structure; forming a first implantation region in the source region through self-aligned implantation on the basis of the first opening of the first barrier layer; and forming a second implantation region and a third implantation region respectively.

Abstract: A flyback switching circuit and control method thereof is disclosed, by setting a reference value greater than zero configured for controlling a turn-off time of a first transistor of the flyback switching circuit, a drain-source voltage of a main power transistor of the flyback switching circuit is consistent with the reference value greater than zero before the main power transistor is turned on, so that a turn-on power consumption of the main power transistor is reduced and a system efficiency is improved.

Abstract: Disclosed is a semiconductor structure and a method for manufacturing the same. The semiconductor structure includes a substrate; an N-type doped region in the substrate; a metal structure located on a surface of the substrate and including a middle portion and an edge portion, wherein the middle portion is in contact with the N-type doped region so as to form an SBD; a first P-type well region which is located in the N-type doped region, in contact with the edge portion and separates the edge portion from the N-type doped region; and a first P-type contact region located in the first P-type well region and separated from the edge portion. A doping concentration of the first P-type contact region is higher than a doping concentration of the first P-type well region. In a state that the first P-type contact region is grounded, the first P-type well region receives an anode voltage of the SBD.