LED apparatus and light-emitting diode string with stable voltage control
A LED string with stable voltage control receives a DC voltage. The LED string includes a plurality of LED apparatuses and a controller. The plurality of LED apparatuses sequentially receives a plurality of data signals externally provided by the controller through a signal path. The controller preferentially supplies power to the LED apparatus that directly receives the DC voltage via the positive voltage end, and the remaining LED apparatuses are supplied power sequentially. When the plurality of LED apparatuses does not receive the plurality of data signals, a bypass path is enabled to bypass the signal path so that no current flowing through the signal path; otherwise, when the plurality of LED apparatuses receives the plurality of data signals, the bypass path is disabled to make the plurality of data signals be transmitted through the signal path.
1 . A light-emitting diode (LED) string with stable voltage control, configured to receive a DC voltage, the LED string comprising:
a plurality of LED apparatuses, each LED apparatus comprising a positive voltage end, a negative volage end, a data input end, and a data output end, wherein each LED apparatus is coupled to a LED, and
a controller, comprising a positive polarity end, a negative polarity end, and a data end, wherein the positive polarity end is coupled to the DC voltage and the negative polarity end is coupled to a ground end,
wherein the plurality of LED apparatuses sequentially receives a plurality of data signals externally provided by the controller through a signal path, and the controller is configured to first supply power to the LED apparatus that directly receives the DC voltage via the positive voltage end, and the remaining LED apparatuses are supplied power sequentially so that the plurality of LED apparatuses are sequentially driven by a drive voltage,
wherein when the plurality of LED apparatuses does not receive the plurality of data signals, a bypass path is enabled to bypass the signal path so that no current flowing through the signal path to perform a constant-voltage compensation for the light-emitting operation of the LED apparatus; when the plurality of LED apparatuses receives the plurality of data signals, the bypass path is disabled to make the plurality of data signals be transmitted through the signal path so that the plurality of LED apparatuses is stably supplied power under the constant-voltage compensation by the drive voltage.
2 . The LED string as claimed in claim 1 , wherein the plurality of LED apparatuses forms a series-connected structure or a parallel-series-connected structure; the negative voltage end of the first LED apparatus is coupled to the negative polarity end of the controller, and the positive voltage end of the last LED apparatus is coupled to the DC voltage.
3 . The LED string as claimed in claim 2 , wherein the series-connected structure is a one-by-n array structure,
wherein the sequence that the controller provides the plurality of data signals is the first LED apparatus, the second LED apparatus, until the last LED apparatus,
wherein the sequence that the controller controls the power supply of the DC voltage is the last LED apparatus, the second to last LED apparatus, until the first LED apparatus.
4 . The LED string as claimed in claim 2 , wherein the parallel-series-connected structure is a m-by-n matrix structure,
wherein the sequence that the controller provides the plurality of data signals is the first LED apparatus, the second LED apparatus, until the last LED apparatus,
wherein the sequence that the controller controls the power supply of the DC voltage is n LED apparatuses in the last row, n LED apparatuses in the second to last row, until the n LED apparatuses in the first row.
5 . The LED string as claimed in claim 1 , wherein the plurality of LED apparatuses forms a series-connected structure or a parallel-series-connected structure; the positive voltage end of the first LED apparatus is coupled to the DC voltage, and the negative voltage end of the last LED apparatus is coupled to the negative polarity end.
6 . The LED string as claimed in claim 5 , wherein the series-connected structure is a one-by-n array structure,
wherein the sequence that the controller provides the plurality of data signals is the first LED apparatus, the second LED apparatus, until the last LED apparatus,
wherein the sequence that the controller controls the power supply of the DC voltage is the first LED apparatus, the second LED apparatus, until the last LED apparatus.
7 . The LED string as claimed in claim 5 , wherein the parallel-series-connected structure is a m-by-n matrix structure,
wherein the sequence that the controller provides the plurality of data signals is the first LED apparatus, the second LED apparatus, until the last LED apparatus,
wherein the sequence that the controller controls the power supply of the DC voltage is n LED apparatuses in the first row, n LED apparatuses in the second row, until the n LED apparatuses in the last row.
8 . The LED string as claimed in claim 1 , wherein each LED apparatus further comprises:
a first bypass circuit, comprising:
a first switch and a second switch, coupled to the drive voltage, and the second switch configured to provide the bypass path, and
an inverting unit, coupled to the first switch and the second switch, wherein the first switch and the second switch are turned on and turned off in complementary by operating the inverting unit.
9 . The LED string as claimed in claim 8 , wherein the first bypass circuit is arranged at the data output end of each of the LED apparatuses.
10 . The LED string as claimed in claim 8 , wherein the first bypass circuit is arranged at the data input end of each of the LED apparatuses.
11 . The LED string as claimed in claim 8 , wherein when the plurality of LED apparatuses do not receive the plurality of data signals, the first switch is turned off and the second switch is turned on so that the bypass path is enabled; when the plurality of LED apparatuses receive the plurality of data signals, the first switch is turned on and the second switch is turned off so that the plurality of data signals is transmitted through the signal path provided by the first switch.
12 . The LED string as claimed in claim 1 , wherein each LED apparatus further comprises:
a second bypass circuit, comprising:
a first switch and a second switch, coupled to the drive voltage, wherein the first switch is coupled to the LED in series, and
an inverting unit, coupled to the first switch and the second switch, wherein the first switch and the second switch are turned on and turned off in complementary by operating the inverting unit.
13 . The LED apparatus as claimed in claim 12 , wherein the second bypass circuit further comprises:
an impedance matching component, coupled to the first switch and the LED in series, wherein the impedance matching component is configured to provide an impedance characteristic corresponding to the LED.