[0022] The bypass circuit proposed by the present invention mainly includes a thyristor, a first impedance element and a second impedance element. The thyristor is connected in parallel with the electronic element, and the first impedance element and the second impedance element are connected in parallel with the electronic element in series. The gate of the thyristor is further coupled between the first impedance element and the second impedance element, wherein the terminal voltage of the electronic element can be divided by the first impedance element and the second impedance element, as the thyristor Gate voltage. When an electronic component fails and causes an open circuit, its terminal voltage is the largest, and the divided gate voltage will be greater than the threshold voltage of the thyristor, which will trigger the thyristor to conduct. In this way, the current that should have passed through the failed electronic component will be changed to flow through the thyristor, so that other electronic components on the same string can maintain normal operation. In addition, when the power is cut off, that is, when the current is zero, the thyristor will be turned off again.
[0023] The following embodiments will take the light-emitting diode string using this bypass circuit as an example to illustrate its specific implementation structure. It should be noted that the following embodiments are only examples, and are not intended to limit the application scope of the bypass circuit of the present invention. In other words, the above-mentioned electronic components widely include light-emitting elements, display elements, etc., and all other light-emitting diode display panels with similar series circuit structures, light-emitting diode array surface light sources, or electronic devices using other types of electronic element arrays. The bypass circuit of the present invention can be applied to improve the reliability of the overall circuit.
[0024] Figure 2A 2B illustrates a light-emitting diode array with bypass function according to an embodiment of the present invention. In this embodiment, the LED array 200 includes a plurality of LED strings 210 arranged side by side, and each LED string 210 is formed by a plurality of LEDs 212 connected in series. The LED array 200 can be applied to products such as a backlight module of a liquid crystal display, a general lighting fixture or a LED display panel, for example. Each light emitting diode string 210 is, for example, coupled between the boost circuit 220 and the constant current source circuit 230, and drives the light emitting diode 212 on each light emitting diode string 210 to emit light with current. In addition, in order to realize the bypass function, each light emitting diode 212 is connected in parallel with a switching element 240.
[0025] Such as Figure 2A As shown, if each light-emitting diode 212 on the light-emitting diode array 200 operates normally, the switching element 240 connected in parallel with it will be in an open-circuit state, allowing current to flow through each light-emitting diode 212 on the light-emitting diode string 210 to drive the light-emitting diode 212 shines. In addition, as shown in FIG. 2B, when one of the light-emitting diodes 212' in a certain light-emitting diode string 210' fails (such as burned) and forms an open circuit, the switching element 240' connected in parallel with the failed light-emitting diode 212' will Turning on allows current to flow through the switching element 240' and maintain the normal operation of other LEDs 212 on the same LED string 210'.
[0026] In addition to the above applications, the above embodiments can also actively control the on and off of the light emitting diode 212. In more detail, even if the light emitting diode 212 does not fail, you can still choose to turn on the switch next to the specific light emitting diode 212 to turn off some specific light emitting diodes 212. In other words, the LED array 200 can be dynamically driven, for example, it can provide a dynamic light source when applied to a backlight module or a lighting fixture, and can provide a dynamic display effect when used as a light-emitting diode display panel.
[0027] Figure 3A versus 3B It further illustrates the structure of a bypass circuit according to an embodiment of the present invention, which can be used as the aforementioned switching element to achieve the aforementioned effect of bypassing current. As shown in FIG. 3, a light-emitting diode string 310 integrated with a bypass circuit is, for example, formed by a plurality of light-emitting diodes 312 connected in series and coupled to a voltage source Vdc. Each light emitting diode 312 has a first end 312a and a second end 312b for connecting in parallel with the bypass line 340, and the bypass line 340 includes a thyristor 342, a first impedance element 344, a second impedance element 346, etc. element. The thyristor 342 has an anode 342a, a cathode 342b, and a gate 342c. The anode 342a is coupled to the first end 312a of the corresponding light emitting diode 312, and the cathode 342b is coupled to the second end of the corresponding light emitting diode 312.端312b. The first impedance element 344 is coupled between the gate 342c of the thyristor 342 and the first end 312a of the light emitting diode 312. The second impedance element 346 is coupled between the gate 342c of the thyristor 342 and the second end 312b of the light emitting diode 312.
[0028] Such as Figure 3A As shown, in a general state, the thyristor 342 is in a closed state, and the current Idc provided by the voltage source Vdc can smoothly flow through each of the LEDs 312 on the LED string 310. The first impedance element 344 and the second impedance element 346 can divide the terminal voltage Vf of the light emitting diode 312 as the gate voltages Vg1˜Vgn of the thyristor 342.
[0029]In this embodiment, the threshold voltage of the thyristor 342 can be set to achieve the bypass effect. Assuming that the resistance of the first impedance element 344 is R1, the resistance of the second impedance element 346 is R2, and the threshold voltage of the thyristor 342 is Vgth, the threshold voltage Vgth of the thyristor 342 can be set as: Vgth≤Vf ×R2/(R1+R2).
[0030] In more detail, such as Figure 3B As shown, when the light-emitting diode 312' fails and causes an open circuit, the gate voltage Vg2 of the divided terminal voltage Vf will be greater than the threshold voltage of the thyristor 342', which will trigger the thyristor 342' to turn on. In this way, the current that should pass through the failed LED 312' will be changed to flow through the thyristor 342' of the bypass line 340', so that other LEDs 312 in the same string can maintain normal operation. It is worth noting that based on the latch characteristics of the thyristor 342', when the thyristor 342' is turned on, as long as there is current passing, even if the gate voltage Vg2 is lower than the threshold voltage, the gate will be turned on. The thyristor 342' continues to maintain the state of the path until the current Idc supplied by the voltage source Vdc is zero, the thyristor 342' will be closed again.
[0031] Also, please refer to Figure 4 , Which illustrates a bypass circuit structure according to another embodiment of the present invention. In order to prevent the current flowing through the thyristor 342 from being too large, a third impedance element 348 may be further arranged between the anode 342a of the thyristor 342 and the voltage source Vdc in this embodiment to control the magnitude of the current passing through the thyristor 342. Other components of this embodiment are similar to the above-mentioned embodiment, and similar effects can be achieved. For the description, please refer to the above-mentioned embodiment, which will not be repeated here.
[0032] The thyristors mentioned in the foregoing embodiments include various types of elements. For example, silicon-controlled rectifiers, bipolar junction transistors, or metal oxide semiconductor field effect transistors, etc., all have latches. ) Characteristics, but can achieve the same effect of the element. In addition, although the foregoing embodiment only shows a series of light-emitting diodes for illustration, in practical applications, the aforementioned series of light-emitting diodes can also be arranged side by side to form a structure such as Figure 2A The light-emitting diode array shown.
[0033] In summary, the bypass circuit proposed by the present invention can be used in various electronic devices to bypass failed electronic components on the electronic component series, so that other electronic components can maintain normal operation. In addition, applying the present invention to backlight modules or area array light sources (such as lighting fixtures) can not only improve product reliability, but also generate dynamic light sources through the operation of bypass lines. In addition, if the bypass circuit is applied to the display panel, the normal display of the screen can also be maintained, and more display effects can be provided through the operation of the bypass circuit.
[0034] Although the present invention has been disclosed as above in the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be as defined in the claims.
