Abstract: A driving circuit for a single-string light-emitting diode (LED) lamp includes a push-pull converter. The push-pull converter converts an input low DC voltage (such as 12-19V) to a high DC voltage (such as above 200V) to supply power to the single-string LED lamp. The driving circuit controls a lamp current flowing through the single-string LED lamp by constant current and adjusts brightness of the single-string LED lamp by pulse-width modulation (PWM) dimming. In addition, the single-string LED lamp provides the standardization design for connectors of the driving circuit used to connect to the single-string LED lamp so that the driving circuit has a better common-use characteristic. Moreover, the driving circuit does not need a current balance circuit and only needs a cheaper and general-purpose integrated circuit to control the push-pull converter to reduce design cost of the driving circuit.

Abstract: A driving circuit for an LED lamp including no more than 4 strings each having an input and an output terminals outputs a DC voltage of no more than 70V to the input terminals. The driving circuit includes constant current circuits each coupled between the output terminal of a corresponding string and ground. An on-off control signal controls whether the constant current circuits work to control whether the LED lamp works. A dimming control signal controls a duty cycle of working of to the constant current circuits to control a brightness of the LED lamp. The driving circuit further includes an overvoltage protection circuit and a switch. When a voltage at one input terminal is too high or a short circuit occurs in one string, the overvoltage protection circuit outputs an overvoltage control signal and accordingly the switch forces the on-off control signal to control the constant current circuits not to work.

Abstract: A driving circuit for a single-string light-emitting diode (LED) lamp includes a push-pull converter. The push-pull converter converts an input low DC voltage (such as 12-19V) to a high DC voltage (such as above 200V) to supply power to the single-string LED lamp. The driving circuit controls a lamp current flowing through the single-string LED lamp by means of constant current and adjusts brightness of the single-string LED lamp by means of pulse-width modulation (PWM) dimming. In addition, the single-string LED lamp provides the standardization design for connectors of the driving circuit used to connect to the single-string LED lamp so that the driving circuit has better common-use characteristic. Moreover, the driving circuit does not need a current balance circuit and only needs a cheaper and general-purpose integrated circuit to control the push-pull converter to reduce design cost of the driving circuit.

Abstract: An LED lamp tube includes a plurality of primary light emitting units connected in series. Each of the primary light emitting units includes a plurality of light emitting sub-units connected in parallel. Each of the light emitting sub-units includes at least one light emitting diode. A liquid crystal display device includes the LED lamp tube, a drive circuit, an optical module and a liquid crystal layer.

Abstract: A driving circuit for an LED lamp including no more than 4 strings each having an input and an output terminals outputs a DC voltage of no more than 70V to the input terminals. The driving circuit includes constant current circuits each coupled between the output terminal of a corresponding string and ground. An on-off control signal controls whether the constant current circuits work to control whether the LED lamp works. A dimming control signal controls a duty cycle of working of to the constant current circuits to control a brightness of the LED lamp. The driving circuit further includes an overvoltage protection circuit and a switch. When a voltage at one input terminal is too high or a short circuit occurs in one string, the overvoltage protection circuit outputs an overvoltage control signal and accordingly the switch forces the on-off control signal to control the constant current circuits not to work.