System and method for current control. As an example, the system for current control includes: a transistor including a drain terminal, a gate terminal, and a source terminal, the drain terminal being coupled to one or more light emitting diodes; a resistor coupled to the source terminal of the transistor and configured to generate a resistor voltage related to a current flowing through the one or more emitting diodes; a voltage detector configured to receiver a first input voltage related to a second input voltage received by the one or more light emitting diodes; and a voltage controller coupled to the voltage detector, the resistor, and the gate terminal of the transistor; wherein the voltage detector is further configured to: detect the first input voltage; and generate a control signal based at least in part on the first input voltage.

The present disclosure provides a power factor improvement circuit with a DC/DC converter including an arithmetic circuit. A first voltage having a full-wave rectified waveform is received by an input voltage detection terminal of the power factor improvement circuit. A second voltage is generated by amplifying an error between a first detection voltage and a reference voltage according to an output voltage of the DC/DC converter. A third voltage is generated by multiplying the first voltage by the second voltage. The arithmetic circuit adds an offset voltage to a third voltage to generate a fourth voltage. A comparator is configured to compare a second detection voltage with the fourth voltage. A drive circuit is configured to turn on/off drive of the switching transistor according to an output of the comparator. When the second detection voltage is higher than the fourth voltage, the switching transistor is turned off.

The present disclosure provides a power factor improvement circuit with a DC/DC converter including an arithmetic circuit. A first voltage having a full-wave rectified waveform is received by an input voltage detection terminal of the power factor improvement circuit. A second voltage is generated by amplifying an error between a first detection voltage and a reference voltage according to an output voltage of the DC/DC converter. A third voltage is generated by multiplying the first voltage by the second voltage. The arithmetic circuit adds an offset voltage to a third voltage to generate a fourth voltage. A comparator is configured to compare a second detection voltage with the fourth voltage. A drive circuit is configured to turn on/off drive of the switching transistor according to an output of the comparator. When the second detection voltage is higher than the fourth voltage, the switching transistor is turned off.

A light emitting element driving device includes a light emitting element to emit light in response to a supply of a first current, a first switching element to turn ON/OFF the first current supplied to the light emitting element, a second switching element to turn ON/OFF a second current not supplied to the light emitting element, a constant current circuit to adjust a total current amount of the first current and the second current to be constant, and a control circuit. The control circuit turns ON the first switching element in a state of flowing the second current to the second switching element by turning ON the second switching element, and after turning ON the first switching element, flows the first current to the light emitting element and the first switching element by turning OFF the second switching element.

A light emitting element driving device includes a light emitting element to emit light in response to a supply of a first current, a first switching element to turn ON/OFF the first current supplied to the light emitting element, a second switching element to turn ON/OFF a second current not supplied to the light emitting element, a constant current circuit to adjust a total current amount of the first current and the second current to be constant, and a control circuit. The control circuit turns ON the first switching element in a state of flowing the second current to the second switching element by turning ON the second switching element, and after turning ON the first switching element, flows the first current to the light emitting element and the first switching element by turning OFF the second switching element.

A dual-line cascade application system for simultaneously supplying electrical power and transmitting data, including a controller, cascade chips connected to the controller, and LED lights connected to the cascade chips. Each cascade chip is provided with a voltage clamp module, an electrical power supply module, a data storage module, a PWM constant current output driving circuit, an R end (Red LED output end), a G end (Green LED output end), a B end (Blue LED output end), a W end (White LED output end), a VCC/DATA end and a GND/DATA end, as well as a data sampling and calibration module, a power line data sampling and transmission module, a chip initial address setting by command module, a module which determines if E-fuse address of the chip is identical to an address of received data, and an E-fuse module which are sequentially connected. A method using the system is also provided.

A dual-line cascade application system for simultaneously supplying electrical power and transmitting data, including a controller, cascade chips connected to the controller, and LED lights connected to the cascade chips. Each cascade chip is provided with a voltage clamp module, an electrical power supply module, a data storage module, a PWM constant current output driving circuit, an R end (Red LED output end), a G end (Green LED output end), a B end (Blue LED output end), a W end (White LED output end), a VCC/DATA end and a GND/DATA end, as well as a data sampling and calibration module, a power line data sampling and transmission module, a chip initial address setting by command module, a module which determines if E-fuse address of the chip is identical to an address of received data, and an E-fuse module which are sequentially connected. A method using the system is also provided.

A light emitting element driving device includes a light emitting element to emit light in response to a supply of a first current, a first switching element to turn ON/OFF the first current supplied to the light emitting element, a second switching element to turn ON/OFF a second current not supplied to the light emitting element, a constant current circuit to adjust a total current amount of the first current and the second current to be constant, and a control circuit. The control circuit turns ON the first switching element in a state of flowing the second current to the second switching element by turning ON the second switching element, and after turning ON the first switching element, flows the first current to the light emitting element and the first switching element by turning OFF the second switching element.

A light emitting element driving device includes a light emitting element to emit light in response to a supply of a first current, a first switching element to turn ON/OFF the first current supplied to the light emitting element, a second switching element to turn ON/OFF a second current not supplied to the light emitting element, a constant current circuit to adjust a total current amount of the first current and the second current to be constant, and a control circuit. The control circuit turns ON the first switching element in a state of flowing the second current to the second switching element by turning ON the second switching element, and after turning ON the first switching element, flows the first current to the light emitting element and the first switching element by turning OFF the second switching element.

An LED tube lamp comprises: a glass lamp tube; a light diffusion layer disposed on a surface of the glass lamp tube; an LED light strip, which comprises a fixing portion and an extending portion disposed in the glass lamp tube; a plurality of LED light sources mounted on the fixing portion of the LED light strip; a fixing structure disposed between the fixing portion and the inner circumferential surface the glass lamp tube; a power supply module disposed on the fixing structure and electrically connecting to the LED light strip and two end caps attached to two ends of the glass lamp tube respectively. The fixing structure comprises a first end fixedly connected to the inner circumferential surface of the glass lamp tube and a second end fixedly connected to the fixing portion of the LED light strip and not connected to the extending portion of the LED light strip.