Abstract: A highly integrated switching power supply and a control circuit are provided. The switching power supply includes a transformer, the transformer comprises a primary winding, a secondary winding and an auxiliary winding, and the control circuit includes: a power switch transistor, configured to control disconnection and conduction of the primary winding of the transformer; a primary current sampling module, configured to sample a current of the primary winding to generate a sampling voltage; and a voltage stabilization control module, configured to turn on or turn off the power switch transistor according to an input voltage, an output voltage of the switching power supply system, and the sampling voltage.

Abstract: A highly integrated switching power supply and a control circuit are provided. The switching power supply includes a transformer, the transformer comprises a primary winding, a secondary winding and an auxiliary winding, and the control circuit includes: a power switch transistor, configured to control disconnection and conduction of the primary winding of the transformer; a primary current sampling module, configured to sample a current of the primary winding to generate a sampling voltage; and a voltage stabilization control module, configured to turn on or turn off the power switch transistor according to an input voltage, an output voltage of the switching power supply system, and the sampling voltage.

Abstract: A control circuit and a control method of a switching power supply, according to feedback signals on a pin FB and a pin CS, a constant current control module generates and outputs a control signal to control an output current of the switching power supply, thereby regulating duty cycle of a first transistor adaptively and controlling an output current Io of a power supply system to be constant; according to the feedback signals on the pin FB and on the pin CS, a constant current precision compensation module adaptively regulates circuit parameters of the constant current control module and a sample-and-hold module, preventing precision of constant current output from being influenced by change of a working mode and/or by variation of input conditions; when an output voltage changes, QR mode keeps unchanged or depth of a CCM keeps approximately constant.

Abstract: A primary controller of a switching power supply and the switching power supply are provided. The primary controller includes an input voltage detection module which receives a detected signal and generates a detection signal; a controller module which receives a feedback signal and a current sampling signal of the switching power supply, and generates a control signal according to the feedback signal and the current sampling signal; a PWM signal generation module, receive the detection signal and the control signal, generate a PWM signal according to the control signal when the detection signal is the second level, and stop generating the PWM signal when the detection signal is the first level; and a power switch transistor, having a control terminal coupled with an output terminal of the PWM signal generation module.

Abstract: What disclosed are a control circuit and a control method of a switching power supply, according to feedback signals on a pin FB and a pin CS, a constant current control module generates and outputs a control signal to control an output current of the switching power supply, thereby regulating duty cycle of a first transistor adaptively and controlling an output current Io of a power supply system to be constant; according to the feedback signals on the pin FB and on the pin CS, a constant current precision compensation module adaptively regulates circuit parameters of the constant current control module and a sample-and-hold module, preventing precision of constant current output from being influenced by change of a working mode and/or by variation of input conditions; when an output voltage changes, QR mode keeps unchanged or depth of a CCM keeps approximately constant.

Abstract: Disclosed is a high voltage power system with enable control, comprising a high voltage start-up circuit, a PWM control module, and a driving module; the high voltage start-up circuit comprises a first transistor, a third transistor, a fourth transistor, a resistor, a diode, a VDD detection unit and an I/O interface unit; the high voltage start-up circuit is controlled by an input of a pin EN; when the pin EN is set, the high voltage start-up circuit stops working; the power system is shut off and doesn't restart, and enters a zero standby state; when the pin EN is reset, the high voltage start-up circuit restores to work, and the power system restarts and enters a normal working state. The power system having the high voltage start-up circuit with enable control has characteristics that the standby input power consumption and standby input current are both close to zero.

Abstract: Disclosed are a control method and a control circuit for a switching power supply, said switching power supply comprises a secondary side controller and a secondary side MOS transistor connected between a load and a secondary side winding of a transformer. The present invention is used for detecting a working state of the secondary side winding of a transformer and a type of a communication signal transmitted by a load, and for generating a switching pulse signal VG in a Reset Time interval of an on/off cycle according to the type of the communication signal; the primary side controller detects a variation amplitude of the transiently varied signal of the voltage drop at the pin feedback (FB) in the Reset Time interval; if the variation amplitude of the transiently varied signal is greater than a pre-set value ?Vref, the primary side controller judges that the signal is a communication signal, and records the communication signal.

Abstract: A switching power supply is provided which includes: an output port; a transformer; a first voltage divider circuit, configured to divide a feedback voltage to obtain a first divided voltage; and a primary controller, configured to control a current of the primary winding of the transformer; where the primary controller includes: a first comparison module, configured to compare the first divided voltage with a first reference voltage to obtain a first comparison result; a second comparison module, configured to compare the power supply voltage with a second reference voltage to obtain a second comparison result; and an open circuit protection module, configured to generate an open circuit protection signal, where the primary controller is configured to stop control of the primary winding in response to the open circuit protection signal. The present disclosure can efficiently detect disconnection of the up-sampling resistor of the switching power supply and provide open-circuit protection.

Abstract: Disclosed is a short-circuit protection circuit for a voltage sampling resistor of a primary side converter, comprising a high voltage power transistor, a high voltage starting resistor, a first voltage dividing resistor of a port VDD, a second voltage dividing resistor of the port VDD, an NMOS transistor, a diode, a first comparator, a second comparator, a third comparator, a time delay circuit, a filter, a first logic circuit, a second logic circuit, a current supply, a first AND gate and a first inverter. The chip of the present disclosure is capable of correctly and effectively detecting whether the sampling resistor is shorted or not before the chip works normally, thereby avoiding the risk of damaging the chip by large current from the voltage feedback port FB due to turn-on of the switching transistor when the upper voltage sampling resistor is shorted, and greatly reducing the input power.

Abstract: Disclosed are a control method and a control circuit for a switching power supply, said switching power supply comprises a secondary controller and a secondary MOS M2 connected between a load and a secondary winding of a transformer. The present invention is used for detecting a working state of the secondary winding of a transformer and a type of a communication signal transmitted by a load, and for generating a switching pulse signal VG in a Reset Time of an on/off cycle according to the type of the communication signal; the primary controller detects a variation amplitude of the transiently varied signal of the voltage drop at the pin FB in the Reset Time; if the variation amplitude of the transiently varied signal is greater than a pre-set value ?Vref, the primary controller judges that the signal is a communication signal, and records the communication signal.

Abstract: Disclosed is a high voltage power system with enable control, comprising a high voltage start-up circuit, a PWM control module, and a driving module; the high voltage start-up circuit comprises a first transistor, a third transistor, a fourth transistor, a resistor, a diode, a VDD detection unit and an I/O interface unit; the high voltage start-up circuit is controlled by an input of a pin EN; when the pin EN is set, the high voltage start-up circuit stops working; the power system is shut off and doesn't restart, and enters a zero standby state; when the pin EN is reset, the high voltage start-up circuit restores to work, and the power system restarts and enters a normal working state. The power system having the high voltage start-up circuit with enable control has characteristics that the standby input power consumption and standby input current are both close to zero.

Abstract: The present disclosure relates to a circuit structure for enhancing EFT immunity of primary side converter, including a power ground and a feedback voltage detecting block, a feedback current detecting block, a controller, a PWM driving block, a high voltage starting block, a starting unit, a circuit for enhancing EFT immunity of primary side converter, a power MOS transistor, and an OR gate configured to perform a logical OR of an off-time calculated theoretically and an off-time output by an off-time control block. The present disclosure enhances EFT immunity effectively and improves the dynamic characteristics of the primary side converter.

Abstract: A compensation circuit for constant output voltage is disclosed. The compensation circuit comprises a current source, a first switch, a controllable current source, a second switch, a logic NOT gate, a CV loop control module, and an input voltage detection module. The compensation circuit ensures a normal start-up, and substantially no additional power dissipation of the converter is generated at no load. Furthermore, the compensation circuit adjusts a compensation current according to at least one of a detected input voltage of the power supply converter and a working mode of the transformer, to obtain better precision of constant output voltage. The compensation circuit can be applied to occasions where extremely small standby input power dissipation or extremely high precision of constant output voltage is required.

Abstract: Disclosed is a short-circuit protection circuit for a voltage sampling resistor of a primary side converter, comprising a high voltage power transistor, a high voltage starting resistor, a first voltage dividing resistor of a port VDD, a second voltage dividing resistor of the port VDD, an NMOS transistor, a diode, a first comparator, a second comparator, a third comparator, a time delay circuit, a filter, a first logic circuit, a second logic circuit, a current supply, a first AND gate and a first inverter. The chip of the present disclosure is capable of correctly and effectively detecting whether the sampling resistor is shorted or not before the chip works normally, thereby avoiding the risk of damaging the chip by large current from the voltage feedback port FB due to turn-on of the switching transistor when the upper voltage sampling resistor is shorted, and greatly reducing the input power.

Abstract: The present disclosure relates to a circuit structure for enhancing EFT immunity of primary side converter, including a power ground and a feedback voltage detecting block, a feedback current detecting block, a controller, a PWM driving block, a high voltage starting block, a starting unit, a circuit for enhancing EFT immunity of primary side converter, a power MOS transistor, and an OR gate configured to perform a logical OR of an off-time calculated theoretically and an off-time output by an off-time control block. The present disclosure enhances EFT immunity effectively and improves the dynamic characteristics of the primary side converter.

Abstract: A high voltage start-up circuit with adjustable start-up time, wherein, the drain electrode of the first NMOS transistor is connected with a first terminal of the first resistor, a gate electrode of the second NMOS transistor and a negative terminal of the diode; a source electrode of the first NMOS transistor, together with a positive terminal of the diode, is connected to the power ground; a drain electrode of the second NMOS transistor, together with a second terminal of the first resistor, is connected with a port SW of a chip; a source electrode of the second NMOS transistor, together with a first terminal of the second resistor, is connected with a power port VDD of the chip. The circuit can adjust the start-up time and the restart time of the chip flexibly.