Abstract: Disclosed a drive method, a drive circuit for a power switch and a power supply system. During the turning-on period of the power switch, which can be roughly divided into three processes, a current limiting module is used to limit the current flowing through the power switch for preventing current overshoot, a logic control module is used for controlling the current limiting module not to operate before the turning-on period and the control terminal of the power switch is turned off; during the turning-on period, a feedback circuit adjusts the gate voltage of the power switch for controlling the current flowing through the power switch to reach a predetermined limited value quickly and then maintain at the limited value until the power switch is fully turned on. The current limiting module can be employed in various embodiments.

Abstract: A circuit and a method for detecting a current zero-crossing point, and a circuit and method for detecting a load voltage are disclosed. The circuit for detecting current zero-crossing point includes: a load power supply circuit, a voltage-dividing resistor, a transistor switch, a zero-crossing detection circuit; the load power supply circuit includes: a load, a diode, and a transformer; one end of a primary winding of the transformer is connected with the operating voltage input terminal, the other end of the primary winding of the transformer is connected with a first end of the transistor switch and a first end of the voltage-dividing resistor, a second end of the voltage-dividing resistor and a second end of the transistor switch are connected with the ground, the load voltage is controlled by the transistor switch.

Abstract: Disclosed a control circuit for a lighting circuit. In the control circuit, an AC input signal provided at an AC input terminal is rectified to obtain a rectified voltage, a low potential end of the rectified voltage is used as a reference ground, a load of the lighting circuit is composed of N strings connected in series, and N is a natural number greater than or equal to 2, when the control circuit detects that the AC input terminal is connected to a dimmer, the control circuit controls the N strings to be simultaneously turned on, when the control circuit detects that the AC input terminal is not connected to the dimmer, the control circuit controls the N strings to be individually turned on in accordance with the rectified voltage. According to the present disclosure, the lighting circuit can obtain a high power factor and is compatible with the dimmer, and the scheme is simple and easy to implement.

Abstract: Disclosed a battery balance circuit, a control method for battery balance and a battery system. The battery balance circuit is implemented on basis of a circuit structure having a plurality of cascaded balance modules, in which a judgement of abnormal states of batteries or balance modules is realized together with synchronizations of the detection of battery states and battery balance. When the judgement of abnormal states of batteries (including the abnormal states of battery voltages, battery temperatures and battery currents) is made, the balance modules stop balancing by transferring signals, meanwhile, when the balance modules restore from the abnormal state, they restore balance. The disclosure increases the judgement of abnormal states, and implements detection and alarm at abnormal states.

Abstract: A protection circuit and an illumination driving circuit are described herein. The protection circuit comprises a detection circuit, detecting a current flowing through a first switch to obtain a current detection signal and determining whether there is leakage at an input terminal according to the current detection signal; a control circuit, controlling the first switch to switch on intermittently, detecting the current flowing through the first switch by the detection circuit during a switch-on period of the first switch, and keeping the load at a disconnection state if the detection circuit determines there is leakage; and the first switch, connected to the input terminal, and a control terminal of the first switch being connected to the control circuit, and the first switch being controlled by the control circuit to be switched on intermittently. The present invention has the protection function and enhances safety during load removing and installation processes.

Abstract: The present invention provides a synchronous rectification control circuit, a method and a flyback switching circuit. A drive circuit outputs a drive signal to control the turn-on and turn-off of a synchronous rectification transistor; a threshold comparison circuit controls the drive circuit to output a pull-up drive signal to turn on the synchronous rectification transistor when a drain-source voltage is lower than a preset low threshold voltage and controls the drive circuit to output a pull-down drive signal to turn off the synchronous rectification transistor when the drain-source voltage is higher than or equal to a preset high threshold voltage; a voltage regulation control circuit controls the drive circuit to output a drive signal for pulling up a voltage of the drive signal to a preset pull-up voltage high value when the drain-source voltage is lower than a preset voltage regulation reference value.

Abstract: A circuit and a method for detecting a current zero-crossing point, and a circuit and method for detecting a load voltage are disclosed. The circuit for detecting current zero-crossing point includes: a load power supply circuit, a voltage-dividing resistor, a transistor switch, a zero-crossing detection circuit; the load power supply circuit includes: a load, a diode, and a transformer; one end of a primary winding of the transformer is connected with the operating voltage input terminal, the other end of the primary winding of the transformer is connected with a first end of the transistor switch and a first end of the voltage-dividing resistor, a second end of the voltage-dividing resistor and a second end of the transistor switch are connected with the ground, the load voltage is controlled by the transistor switch.

Abstract: Disclosed a control circuit for a lighting circuit. In the control circuit, an AC input signal provided at an AC input terminal is rectified to obtain a rectified voltage, a low potential end of the rectified voltage is used as a reference ground, a load of the lighting circuit is composed of N strings connected in series, and N is a natural number greater than or equal to 2, when the control circuit detects that the AC input terminal is connected to a dimmer, the control circuit controls the N strings to be simultaneously turned on, when the control circuit detects that the AC input terminal is not connected to the dimmer, the control circuit controls the N strings to be individually turned on in accordance with the rectified voltage. According to the present disclosure, the lighting circuit can obtain a high power factor and is compatible with the dimmer, and the scheme is simple and easy to implement.

Abstract: A circuit and a method for detecting a current zero-crossing point, and a circuit and method for detecting a load voltage are disclosed.

Abstract: The present disclosure relates to a circuit and a method for overcurrent control and a power supply system including the same. When the system operates normally, a reference voltage has a constant value. When a short circuit or an overcurrent occurs at an output of the system, the reference voltage will be pulled down,. When the system is recovered from the short circuit or the overcurrent state, the reference voltage increases slowly up to a steady value. A feedback signal of an output voltage follows the reference voltage and increases slowly. Thus, an overshoot of the output voltage can be effectively eliminated to avoid damages to the system.

Abstract: A power supply protection circuit and a method is described herein. The power supply protection circuit comprises a current control unit, a voltage feedback unit, and a current pull-up unit. The voltage feedback unit is connected to the current control unit, the voltage feedback unit obtains a feedback voltage of an output voltage and feeds back the feedback voltage to the current control unit, and the current control unit uses the feedback voltage to control the current control unit to regulate an output current. The current pull-up unit is connected to a feedback terminal of the voltage feedback unit, and the current pull-up unit provides the voltage feedback unit with a pull-up current to determine whether the feedback terminal of the voltage feedback unit is short-circuited.

Abstract: The present invention provides a control circuit and a control method for a switch circuit and a switching-mode power supply circuit. The control method comprises following steps: detecting an output voltage or an output current, and adjusting an upper limit value and a lower limit value of an inductor current according to a result of comparing the output voltage or the output current with the corresponding reference; and sampling the inductor current, and controlling a main switch transistor in the circuit to be switched off when a sampling current rises to the upper limit value, and controlling the main switch transistor to be switched on when the sampling current drops to the lower limit value. In the present invention, the inductor current is fast in response without overshoot, the output voltage drops very little, there is no overshoot in a process of voltage recovery, and circuit transient response is fast.

Abstract: There is provided a dimming circuit, a dimming method and a LED driving circuit. On the basis of the dimming of a dimmer, the circuit according to the disclosure generates a plurality of current reference signals corresponding to a plurality of loads in accordance with a dimming signal, to change a ratio of load currents of the plurality of loads, so that, the adjustment of color temperature is implemented, wherein the dimming signal represents the changes of switching operation or dimming speed of the dimmer, and the ratio of current load currents of the plurality of loads is latched or a predetermined ratio of load currents is latched. According to the disclosure, the dimmer can be used for directly adjusting color temperature, without the need for a MCU, so that, the system compatibility is improved and the cost is decreased.

Abstract: A control method, a control circuit and a device for a switching circuit are disclosed, for fixing a frequency of the switching circuit when the switching circuit is operated under CCM. The present disclosure is suitable to various switching circuits, and an application scope of the control method of the switching circuit can be extended. The control method comprises: starting measuring time at a rising edge of a turn-on signal of the first switch; reducing a turn-on time or a turn-off time of the first switch when a first measured time is reached, and the rising edge in a next cycle of the turn-on signal has not arrived; increasing the turn-on time or the turn-off time of the first switch when the rising edge in the next cycle of the turn-on signal arrives but the first measured time is not reached.

Abstract: The present invention provides a control method and a control circuit for a switch circuit and a corresponding switch circuit device. The control circuit comprises: an acquiring module, configured to acquire first time; a comparing module, connected with the acquiring module and configured to compare first time with first fixed time; and an adjusting module, connected with the comparing module. The adjusting module adjusts a cycle of a turn-on signal of a first switch transistor to second fixed time when the first time is less than the first fixed time. The adjusting module adjusts the sum of second time and the first fixed time to the second fixed time to achieve spread spectrum when the first time is more than the first fixed time. The control circuit for the switch circuit provided by the present invention is used for controlling the switch circuit for spread spectrum.

Abstract: For controlling a switch power supply, an adjustment module produces a first control voltage by comparing a period of a switch signal with a reference period. A current source module generates a first charging current according to the first control voltage. A pulse signal generating module converts the first charging current into an on time signal or off time signal of a switch transistor. A driving module produces the switch signal according to the on time or off time signal of the switching transistor, so as to control the turn on and turn off signal of a switching transistor. A time measurement module obtains a time parameter according to the switch signal, and generates a periodic adjustment signal according to the time parameter. The adjustment module adjusts the reference period according to the periodic adjustment signal to adjust the period of the switch signal.

Abstract: This invention provides a switch control circuit and a switch circuit. When a main transistor on-time reaches a constant on-time, whether an inductor current reaches an instruction current is detected; if the inductor current fails to reach the instruction current, the main transistor on-time is prolonged; the main transistor is turned off and the auxiliary transistor is turned on until the inductor current reaches the instruction current or exceeds the instruction current by a certain threshold; when the main transistor is turned off and the auxiliary transistor is turned on, the inductor current is detected in real time to check whether the inductor current is smaller than the instruction current, and the auxiliary transistor is turned off and the main transistor is turned on again if yes.

Abstract: The present invention discloses a bleeder circuit; solutions of the present invention may be applied in linear driving and switch driving solutions; a threshold voltage is a zero crossing value, and when the input voltage is zero crossing, the load current at this time is zero; a bleeder current is generated to make the input current greater than a holding current of a TRIAC dimmer, to maintain turning-on of the TRIAC dimmer, and a second time is set as a delay time, which reduces power consumption. In the application of switch driving solution, the current regulating circuit is controlled to be enabled according to the waveform features of the previous and latter halves of periods of the sine wave as well as the size of the input current of the driving circuit.

Abstract: The present disclosure discloses a bleeder circuit and a control method thereof, and an LED control circuit. The present disclosure is applied in an LED control circuit of TRIAC dimming, directly or indirectly detects cross-zero point of input voltage; after cross-zero point of the input voltage is delayed by a second time, the bleeder module works to generate bleeder current, and a time between turn-on time of the TRIAC and a time that a driving circuit input current achieves a predetermined value (maintaining current of TRIAC) is a first time. During the first time, the bleeder circuit generates losses; when the first time is greater than a predetermined value, the second time is prolonged; when the first time is smaller than the predetermined value, the second time is reduced, such that the first time is close to or equal to the predetermined value.

Abstract: The present invention provides an isolating switch circuit and a control method. The present invention takes first time information as a characteristic to control and adjust primary and secondary sides The primary side identifies the first time information by detecting the voltage between two ends of a main power switch transistor, and the secondary side compares a sampling output voltage or/and output current with a corresponding reference signal to obtain a first control signal representing the first time information. The present invention does not need to use the optical coupler to carry out isolated transmission of primary and secondary signals, which reduces the cost of the circuit, and the freewheeling time of a parasitic diode of a synchronous rectification transistor is taken as a characteristic to carry out identifying and controlling, such that power consumption is low and the control and adjustment is more precisely.