TWM412574U - Driving circuit of light emitting diode - Google Patents

Abstract

A driving circuit of a light emitting diode (LED) including an AC power, a rectifier, a power converter, a waveform sampler, and a control circuit is provided. The AC power provides an AC signal. The rectifier is coupled to the AC power and outputs a driving signal. The power converter is coupled to the rectifier. The power converter includes an LED and outputs a first signal positive correlated with a current passing through the LED. The waveform sampler is coupled between the AC power and the rectifier, and outputs a second signal directly proportional to the AC signal. The control circuit is coupled between the waveform sampler and the power converter, and outputs a control signal according to a comparison between the first signal and the second signal to the power converter.

Description

M412574 100-5-16 V. New description: [New technical field] This creation is related to a driving circuit, and in particular to a driving circuit for a light emitting diode (LED). [Prior Art] Light-emitting diodes (LEDs) are small in size, power-saving and durable, and with the mature technology of process technology, products with light-emitting diodes as light sources have become more and more popular. Since the slight change of the bias voltage causes a large change in the operating current within the operating range of the light-emitting diode, the light-emitting diode must be driven at a constant current, otherwise the current will exceed the rated value, which will result in a light-emitting diode. The body burned. FIG. 1 is a schematic diagram of a conventional driving circuit of a light emitting diode. Referring to Fig. 1, the driving circuit 100 includes an alternating current (AC) voltage source 1 and a buck converter 102 and a buck converter. The AC voltage source 101 drives the LEDs 103' by the bridge rectifiers 1', wherein the LEDs 104' and the diodes 1'5 are lightly connected in a loop. The clock generator 106 provides a clock signal to the set terminal s of the SR flip-flop 108 to trigger the set terminal s of the SR flip-flop 108 each time the pulse pulse is made, thereby turning on the switch Qm. . When the switch Qm is turned on, the current flowing through the light-emitting diode ι〇3 and the inductor 1〇4 gradually increases. At this time, the diode 1〇5 is reverse biased and is not turned on. Therefore, the current Isw flowing through the resistor Rsen is equivalent to the electric current of the light-emitting diode 1 〇3 passing through the light-emitting diode ι3 to the voltage across the resistor Rsen 5 M412574 100-5-16, when Vref is passed (For example, 〇·5ν), the comparator 1〇7 will trigger the reset terminal R of the sr positive and negative and the switch Qm is turned off. When the switch is turned off, the current of the light-emitting body 103 is circulated in a loop formed by the light-emitting diode 1〇3, the electrical minus 1〇4, and the diode 105, and the current will follow the light-emitting diode 103 The energy is dissipated and gradually decreases 'until the next clock pulse is generated. Therefore, the current of the light-emitting diode (9) exhibits a periodic ore tooth waveform and is substantially a stable value. On the other hand, in order to ensure that the current of the light-emitting diode 103 is continuous, a large capacitance Cm is commonly coupled between the bridge rectifier 102 and the buck converter 110, which is, for example, a 47 microfarad (//F) capacitor. The Cin is used to maintain the input direct current (DC) voltage Vein such that the DC voltage Vein is kept larger than the on-voltage vf of the light-emitting diodes 1〇3. However, an excessively large capacitor Cin results in a narrower conducting phase angle and a poor input power factor. To improve the power factor of a conventional LED driver circuit, a solution It is a power factor correction (PFC) pre-stage circuit. As shown in Fig. 2, the driving circuit 100' of the LED of Fig. 2 includes a power factor correction boost (b〇ost PFC) control circuit 12' to boost the power factor. However, as shown in Fig. 2, although the driving circuit of Fig. 2 has a higher power factor, this driving circuit is much more complicated and more space-consuming than the driving circuit of Fig. 1. However, in many small lighting diode lighting devices, there is not enough space to accommodate the extra circuit components of Figure 2. M412574 100-5-16 [New content] This creation provides a driving circuit for a light-emitting diode with a good power factor. The present invention proposes a driving circuit for a light-emitting diode, which comprises an intersection, a rectifier, a power converter, a waveform sampler, and a 'circuit. The AC power source has a first end and a second end, and provides an AC signal through the first end and the second end. The rectifier has a third end, a reed, and a fifth end. The third end and the fourth end respectively reduce the first end and the third end, and the rectification fast outputs a driving signal through the fifth end. The power converter has a sixth end, and the sixth end is coupled to the fifth end. The power converter includes a photodiode and outputs a first signal positively related to a current through the light emitting diode through a seventh terminal. The waveform sampler has an eighth end and an eighth end. The eighth end is coupled between the AC power source and the rectifier, and the waveform sampling state outputs a second signal proportional to the AC signal through the ninth terminal. The control circuit has a tenth end. The control circuit is coupled between the ninth end of the waveform sampler and the seventh end of the power converter, and is output through the tenth end-control signal

• To the power converter. U - In the present embodiment, the waveform sample 上述 includes a -th resistor and a second resistor. The _ terminal of the first resistor is an AC power source, and the other end of the resistor is connected to the ninth terminal of the waveform sampler. The second resistor is connected to the ninth end of the waveform resistor and the other end of the waveform is connected to the ground terminal. In the present invention, the driving circuit of the light emitting diode includes a third resistor and a fourth resistor. One end of the third resistor is interleaved 7 M412574 100-5-16% of the first end of the source and the other end is lightly connected to the first resistor. The first end is connected to the third resistor, and the other end is connected to the AC power source. In one embodiment of the present invention, the driving of the LED is = terminal. Include a capacitor. The capacitor is coupled to the fifth end of the rectifier and the grounding circuit. In one embodiment of the present invention, the power converter and the current sensor are described above. The switch is coupled to the light emitting diode. The device is coupled to the switch and a ground terminal, and the current sensor is transmitted through the m "IL sensing - the chip is at the seven-terminal output of the Q-th is an electric house. In an embodiment of the present invention, the above-mentioned First, in an embodiment of the present invention, the current sensor includes a fifth resistor. The fifth resistor is coupled in series with the light emitting diode. In one embodiment of the present invention, the power converter described above is a buck converter. In one embodiment of the present invention, the power converter described above is a fly back converter. In one embodiment of the present invention, the power converter described above is a forward converter.

In one embodiment of the present invention, the control circuit includes a clock generator, an SR flip-flop, and a comparator. An SR flip-flop coupled to the eSR flip-flop between the clock generator and the power converter has a set terminal and a reset terminal, and receives a clock signal through the set terminal. The comparator has a positive terminal, a negative terminal, and an output terminal. The seventh end of the positive terminal coupled to the power converter is coupled to the ninth end of the waveform sampler, and the output is coupled to the reset end of the SR M412574 100-5-16 flip-flop. In one embodiment of the present invention, the rectifier described above is a bridge rectifier. Based on the above, the embodiment of the present invention captures the second signal by directly coupling the waveform sampler to the AC power source, so that the captured second signal is very close to the AC signal and is not affected by the back end load component. In turn, a power factor of more than 13⁄4 can be provided. To make the above-described features and advantages of the present invention more comprehensible, the following detailed description is made in conjunction with the accompanying drawings. [Embodiment] FIG. 3 is a schematic view showing a driving circuit of a light-emitting diode according to a first embodiment of the present invention. Referring to FIG. 3, the driving circuit 3 of the light emitting diode includes an AC power source 310, a rectifier 320, a power converter 330, a waveform sampler 340, and a control circuit 350. The AC power source 310 has a first end E1 and a second end E2, and provides an AC signal Vac through the first end E1 and the second end E2 to drive the LED. The AC signal Vac of the present embodiment is, for example, an AC voltage. As shown in Fig. 3, the rectifier 32 of the present embodiment is, for example, a bridge rectifier. In detail, the rectifier 32 has a third end E3, a fourth end E4 and a fifth end E5, wherein the third end E3 and the fourth end E4 are respectively coupled to the first end E1 and the second end E2 of the AC power source 310. In addition, the rectifier 320 outputs a driving signal Idr through the fifth end E5, and the driving signal 9 M412574 100-5-16

Wr is, for example, a drive current. In addition, the biggest feature is that the AC signal Vac is directly taken as the signal control, and the value of the capacitor C1 of the driving circuit 300 can be reported as small (about 0.1 microfarad (VF)), wherein the capacitor C1 is used as the high frequency filter capacitor. use. However, if the DC power supply of the rectifier 320 is used for signal control, the value of the capacitor C1 of the driving circuit 300 needs to be about 1 microfarad to stabilize the DC power signal and avoid signal distortion caused by the load effect, thereby avoiding the power factor (p0wer fact). 〇r) reduction. Referring to FIG. 3, the power converter 330 has a sixth end E6, and the sixth end E6 is coupled to the fifth end E5 of the rectifier 320. In addition, the power converter 330 includes a light emitting diode 332 (only three are schematically shown), and the power converter 330 outputs a signal VI through the seventh end E7, wherein the signal VI is positively related to the current passing through the light emitting diode 332. II ^ That is, the higher the current II through the light-emitting body 332, the larger the signal vi, and the signal VI of the present embodiment is, for example, a voltage signal. Further, in the present embodiment, the power converter 330 is, for example, a buck converter. In detail, in addition to the light-emitting diode 332, the power converter 33A further includes a diode D, an inductor L1, a switch Q1, and a current sensor 334. The current sensor 334 is coupled to the switch Q1 and the ground, and the current sensor 334 outputs the signal V through the seventh end E7. The current sensor 334 includes the resistor Res and the resistor RCS and the LED The bodies 332 are coupled in series. The size of the L number vi is equivalent to the voltage across the resistor Rcs. In other words, the resistor Res is adapted to convert the current n through the light-emitting diode 332 into an electrical waste signal (ie, signal VI)' and provide a voltage signal VI » 100 at the end of the resistor Rcs (corresponding to the seventh end E7). 5-16, the waveform sampler 340 has an eighth end E8 and a ninth end E9. The eighth end E8 is coupled between the AC power source 31〇 and the rectifier 32〇, and the waveform sample 340 is output through the ninth end E9. A signal V2 proportional to the AC signal yac. The signal V2 is, for example, a voltage signal, and is a divided voltage of the AC signal Vac. As shown in FIG. 3, the waveform sampler 34A includes a resistor illusion and R2. In detail, one end of the resistor R1 is lightly connected to the AC power source 31〇, and the other end of the resistor R1 is coupled to the ninth end E9 of the waveform sampler 340. Resistor • One end of the R2 handle is connected to the ninth terminal E9 of the waveform sampler, and the other end of the resistor R2 is connected to the ground. On the other hand, the driving circuit 300 of the light emitting diode further includes resistors R3 and R4. One end of the resistor R3 is connected to the first end of the AC power source 310, and the other end of the resistor is connected to the resistor. The end of the resistor R4 is connected to the resistor R3, and the other end of the resistor R4 is subtracted from the second terminal E2 of the parent power source 310. As can be seen from the above, the resistors R1 to R4 are =-divider-voltage circuits. Therefore, the signal V2 is proportional to the parent current 彳s number Vac of the AC power source 31. It is worth mentioning that since the waveform sampler 34 is directly coupled to the AC power source 310, rather than through the rectifier 32, and then connected to the AC power source 310, the letter of the compressor is less likely to be affected. The end element (such as the rectifier 320 or the capacitor C1 or other electronic components) is shaped, so that the waveform of the signal W can be close to the waveform of the riding Vae. Please continue to refer to FIG. 3. The control circuit 350 of the embodiment is coupled to the waveform. The ninth end E9 of the sampler 340 and the seventh end E7 of the power converter 33' are outputted to the power converter 330 through the tenth end E10. The control circuit 350 is configured to turn the switch Q1 on or off according to the comparison result of the signals V1 and V2 to turn the power down converter on or off. 11 M412574 100-5-16 In detail, the control circuit 350 outputs the control signal Sct1 to the power converter 330 through the tenth terminal E10 to turn the power converter 330 on or off. As shown in FIG. 3, the control circuit 350 includes a clock generator 352, an SR flip-flop 354, and a comparator 356. The SR flip-flop 354 is coupled between the clock generator 352 and the power converter 330. The SR flip-flop 354 has a set terminal S, a reset terminal R, and an output terminal Q. The clock generator 352 is coupled to the set terminal S of the SR flip-flop 354 to cause the SR flip-flop 354 to receive the clock signal Sdk through the set terminal S. The output terminal Q of the SR flip-flop 354 is coupled to the switch φ, and outputs a control signal s c t丨 through the output terminal Q to turn the power converter 330 on or off. The comparator 356 includes a positive terminal Ep, a negative terminal EN, and an output terminal 〇ρι. The positive terminal EP is coupled to the seventh end E7 of the power converter 33A for receiving the signal VI. The negative terminal EN is coupled to the ninth terminal E9 of the waveform sampler 34A for receiving the signal V2. The output terminal 0P1 is coupled to the reset end scale of the SR flip-flop. When the voltage level of the signal VI is higher than the voltage level of the signal V2, the output terminal OP1 of the comparator triggers the reset terminal R of the SR flip-flop 354. In detail, the clock generator 352 outputs the set terminal s of the clock signal Sclk to the SR forward and reverse 354. At each clock generation, the set terminal s is triggered to enable the output of the SR flip-flop 354 to cause the switch Q1 to pass. When the switch qi is turned on, the current η of the light-emitting diode 332 is equivalent to the current through the switch Q1 and the current sense I! 334, that is, the current Ies. At this time, the diode D1 is reverse biased and not turned on. The current II flowing through the light-emitting diode 332 and the sense L1 increases with the increase of the voltage Vsw of the sixth terminal E6 until the signal V1 is higher than the voltage signal %, and then the output terminal 0P1 of the comparator triggers the SR flip-flop The reset terminal R of 354, the output terminal Q of the SR flip-flop 12 M412574 100-5-16 outputs a control signal Sctl to cause the switch Q1 to be worn. When switch Q1 is turned off, current Ics drops to zero. At this time, the current II of the light-emitting diode 332 flows in the loop formed by the light-emitting diode 332, the inductor L1, and the diode D1, and gradually decreases due to the power dissipation of the light-emitting diode 332 until the next A clock pulse from the clock generator 352 appears once. 4A is a schematic diagram showing a current path of the driving circuit 3 of the LED of FIG. 3 when the AC power source 310 is at a positive voltage Vac+. As shown in FIG. 4A, when the parent >'il power source 310 provides a positive voltage Vac+, the path P1 through which part of the current iacl passes is the first terminal m, the resistor R3, the waveform sampler 340, the ground terminal, and the second. The pole body D2 and the second end E2. When the current Iacl flows through the resistor R2 of the waveform sampler 340, a signal V2 corresponding to the positive voltage vac+ is generated at the negative terminal EN of the comparator 356, and a signal V2 is supplied to the comparator 356 for comparison, thereby turning the power on or off. Converter 33〇. It should be noted that since the waveform sampler 34A of the present embodiment is directly coupled to the AC power source 310, instead of being indirectly coupled to the AC power source 310 through the rectifier 32 or the capacitor ci, that is, the rectifier 320 and the capacitor C1 are not Lightly connected between the waveform sampler 340 and the AC power source 310, the current iaci is less affected by other loads such as the capacitor C1 or the rectifier 320, so that the signal V2 output by the waveform sampler 340 is closer to positive. Voltage Vac+. Since the signal V2 to be captured is closer to the source (ie, the positive voltage Vac+), the current waveform switched by the current Ics is closer to the voltage waveform of the positive voltage Vac+, thereby causing the driving current I (jr waveform and current Iacl). The waveform is closer to the positive voltage Vac+ waveform, resulting in a more power factor. On the other hand, compared to the conventional circuit of Figure 1, 13 M412574 100-5-16 since the comparator 107 of Figure 1 receives a The fixed reference voltage Vref' is such that the current Isw of the graph i cannot follow the waveform of the positive voltage snap + to obtain a good power factor. In the embodiment, since the waveform sampler 34 is directly coupled to the source, the comparator is made. The signal V2 received by 356 can change with the positive voltage Vae+, so the current waveform switched by the current Ies will be connected to the positive voltage Vac+ waveform, so that the waveform of the current Iac is closer to the waveform of the positive voltage Vac+, thereby obtaining good power. Figure 4B is a schematic diagram of the current path of the driving circuit 3 of the light-emitting diode of Figure 3 when the AC power source 310 is at a negative voltage Vac-. As shown in Figure 4B, when the AC power source 310 is provided with a negative power. The path P2 through which the portion of the current Iac2 passes is sequentially the second terminal E2, the resistor R4, the waveform sampler 340, the ground terminal, the diode D3, and the first terminal m. When the current/'il is waveform When the resistor R2 of the sampler 340 is generated, a signal V2 corresponding to the negative voltage Vac_ is generated at the negative terminal EV of the comparator 356, and a signal v2 is supplied to the comparator 356 for comparison, thereby turning the power converter Mo on or off. Since the waveform sampler 340 is directly coupled to the AC power source 31, the signal V2 to be operated is close to the source (ie, the negative voltage vac), so that the supplied signal V2 can be changed with the negative voltage vac-, Let the current waveform switched by the electric & Ics be closer to the negative electric vac•• waveform, and finally make the Iac2 current shape closer to the negative voltage Vac-waveform, and get a good power factor. Compared with the conventional circuit of Fig. 1 In other words, since the comparator 107 of FIG. 1 receives a fixed reference dust Vref, the current Isw of the graph cannot follow the negative voltage Vac_ waveform to obtain a good power factor. Sampler 340 is directly coupled At the source, 14 M412574 100-5-16 allows the supplied signal V2 to change with the negative voltage vac_, so that the current waveform switched by the current ICS is closer to the voltage waveform of the negative voltage Vac—finally making the waveform of the current Iac2 more The waveform of the negative voltage Vac- is obtained, and a good power factor is obtained. Fig. 5 is a waveform diagram of the alternating current signal Vac and the signal V2 of the driving circuit 300 of the light emitting diode of Fig. 3. As can be seen from Fig. 5, in this embodiment, Since the signal V2 captured by the waveform sampler 340 is close to the AC signal Vac provided by the AC power source 310, the driving circuit 300 of the LED can provide a good power factor. It should be noted that, in this embodiment, regardless of whether the AC signal Vac is a positive voltage Vac+ or a negative voltage Vac-', the waveform V2 extracted by the waveform sampler 340 is a DC voltage and is, for example, positive. In other words, in the present embodiment, before the signal V2 is intercepted, the rectifier signal for rectifying the AC signal Vac can be additionally configured to obtain the DC signal V2 for use by the comparator 356, thereby saving the configuration space of the circuit. SECOND EMBODIMENT Fig. 6 is a schematic view showing a driving circuit of a light-emitting diode according to a second embodiment of the present invention. The driving circuit 400 is similar to the driving circuit 3A of the light-emitting diode of Fig. 3. The main difference is that the power converter 430 of the present embodiment is a flyback converter. As shown in FIG. 6, the power converter 430 includes a transformer 432, wherein the switch Q1 and the current sensor 334 are located on the primary side of the transformer 432, and the light emitting diode 332, the capacitor C2 and the diode D4 are located in the transformer. The secondary side of 432. In detail, the 'diode D4 _ is connected to the capacitor 匸 2 15 M412574 100-5-16 and the light-emitting diode 332, and the capacitor C2 and the light-emitting diode 332 are coupled in parallel with each other. The primary side of the transformer 432 provides a fixed power (Vsw*Itr), and converts the fixed power (Vsw*Itr) to the secondary side to form the same power as the primary side (V ed*I2), and further A current 12 is supplied to the light emitting diode 332 to cause the light emitting diode 322 to emit light, wherein Vied is a voltage across the three light emitting diodes 332. In addition, when the switch Q1 is turned on, since the diode D4 is reverse biased and not turned on, when the switch Q1 is turned off, the diode D4 is turned on and turned on. Since the related operation principle can be referred to the first embodiment, it will not be described here. Third Embodiment Fig. 7 is a schematic view showing a driving circuit of a light-emitting diode according to a third embodiment of the present invention. The driving circuit 500 is similar to the driving circuit 400 of the light emitting diode of FIG. 6, but the main difference is that the power converter 530 of the present embodiment is a forward converter. As shown in FIG. 7, the power converter 530 includes a transformer 532, wherein the switch Qi and the current sensor 334 are located on the primary side of the transformer 532, and the light emitting diode 332 and the diodes D5 D D6 are located on the secondary side of the transformer 532. . As shown in FIG. 7, the diode D5 is connected to the diode D6 and the inductor L3' is connected to the LED 332, and the diode D6 and the inductor L3 form a loop with the LED 332. The primary side of the transformer 532 provides a fixed power (Vsw*Itr)' and converts this fixed power (Vsw*Itr) to the secondary side to form the same power as the primary side (Vled*I3), thereby providing current. 13 is applied to the light-emitting diode 332 to cause the light-emitting diode 322 to emit light, wherein Vled is a cross-pressure of three M412574 100-5-16 light-emitting diodes 332. In addition, when the switch qi is turned on, the diode D5 is turned on by the forward bias. When the switch qi is turned off, the diode D5 is reverse biased and not turned on. Since the related operation principle can be referred to the first embodiment, it will not be described here. In summary, the embodiment of the present invention captures the divided signal by directly coupling the waveform sampler to the AC power source, so that the divided voltage signal is very close to the AC signal and is not affected by the back end load component. In this way, the input current (such as current Iacl or Iac2) can be made closer to the input AC signal, thus providing a higher power factor. In addition, since the circuit design is not complicated and the size of the capacitor is greatly reduced, the size of the circuit architecture can be reduced. Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention to anyone having ordinary knowledge in the art, and may make some changes and refinements without departing from the spirit and scope of the present invention. The scope of protection of this creation is subject to the definition of the scope of the patent application attached. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a conventional driving circuit of a light-emitting diode. 2 is a schematic diagram of a conventional driving circuit of a light emitting diode. Fig. 3 is a schematic view showing the driving circuit of the light-emitting diode of the first embodiment. 4A is a schematic view showing a current path of a driving circuit of the light-emitting diode of FIG. 3 at an alternating current lightning voltage. 4B is a schematic diagram showing the current path of the driving circuit of the light-emitting diode of FIG. 3 at an alternating current negative voltage. 17 M412574 100-5-16 Figure 5 is a waveform diagram of the AC signal and signal of the driving circuit of the LED of Figure 3. Fig. 6 is a schematic view showing the driving circuit of the light-emitting diode of the second embodiment. Fig. 7 is a schematic view of a light-emitting diode according to a third embodiment of the present invention. [Description of main component symbols] Driving circuit 100, 100', 300, 400, 500 of light emitting diode: 110: buck converter ιοί: AC voltage source 102: bridge rectifier 104, L1: inductance 105, D1 ~ D6 Diodes 103, 332: Light-emitting diodes 108, 354: SR flip-flop 120. PFC boost control circuit 310: AC power source 320: Rectifiers 330, 430, 530: Power converter 334: Current sensor 340 : Waveform Sampler 350: Control Circuit 352: Clock Generator M412574 100-5-16

356: Comparator 432, 532: Transformer Vref: Reference voltage Vsw, Vled: Voltage Vf: On-voltage Vein: DC voltage Vac: AC signal Vac+: Positive voltage Vac-: Negative battery V Bu V2: Signal

Isw, II, Ics, Iacl, Iac2, Itr: Current

Idr: drive signal

Sctl: control signal

Sclk: Clock signal OP Bu Q: Output R: Reset

S : setting end

Cin, a~C2: capacitor

Qm, Q1: switches R1 to R4, Res, Rsen: resistors P1 to P2: path EP: positive terminal EN: negative terminal E1 · first terminal 19 M412574 100-5-16 E2: second terminal E3: third terminal E4: fourth end E5: fifth end E6: sixth end E7: seventh end E8: eighth end E9: ninth end E10: tenth end 20

Claims (1)

M412574 100-5-16 VI. Patent Application Range: L A driving circuit of a light-emitting diode, comprising: a parent current power source having a first end and a second end, and passing through the second and second sides Providing an alternating current signal; a first end, a fourth end, and a fifth end, the second end and the fourth end are respectively coupled to the first end and the second end, and the rectifier transmits the first end Five-terminal output a driving signal; a power converter having a sixth end, and the sixth end is connected to the fifth end, the i-Hail power converter includes a light-emitting diode, and outputs a positive correlation through the light-emitting diode through a seventh end a first signal of the current of the polar body; - the waveform sampler has - a first end and a ninth end, the eighth end is switched between the alternating current power supply and the rectifying port, and the waveform sampler passes through the 5 The ninth terminal outputs a second signal proportional to the AC signal; and a control circuit having a tenth end, the control circuit being coupled to the ninth end of the wave sampler and the power converter A control signal is outputted to the power converter through the tenth end. 2. The driving circuit of the light-emitting diode according to claim 1, wherein the waveform sampler comprises: - a first-resistor, the other end of which is connected to the waveform sampler The ninth terminal; and: the second resistor 'the end of the first resistor and the ninth end of the waveform sampler, and the other end of which is coupled to a ground terminal 3 The driving of the light-emitting diode 21 M412574 100-5-16 is a third resistor, one end of which is coupled to the first end of the AC power source, and the other end of which is coupled to the first resistor; and a fourth resistor, The other end is coupled to the second end of the AC power source. 4. The driving circuit of the light emitting diode according to claim 1, further comprising a capacitor coupled between the fifth end and the ground end of the rectifier. 5. The driving circuit of the light-emitting diode of claim 1, wherein the power converter further comprises: a switch coupled to the light-emitting diode; and a current sensor coupled to the light-emitting diode The switch and a ground end, the current sensor outputs the first signal through the seventh end. 6. The driving circuit of the light emitting diode according to claim 5, wherein the first signal is a voltage signal. 7. The driving circuit of the light emitting diode according to claim 6, wherein the current sensor comprises a fifth resistor, and the fifth resistor is coupled in series with the light emitting diode. 8. The driving circuit of the light emitting diode according to claim 5, wherein the power converter is a buck converter. 9. The driving circuit of the light emitting diode according to claim 5, wherein the power converter is a flyback converter. 10. The driving circuit of the light emitting diode according to claim 5, wherein the power converter is a forward converter. 11. The circuit of claim 22, wherein the control circuit comprises: a clock generator; an SR flip-flop coupled to the clock generation. Between the device and the power converter, the SR flip-flop has a set terminal and a reset terminal, and receives a clock signal through the set terminal; and a comparator having a positive terminal, a negative terminal and an output terminal The positive end is coupled to the seventh end of the power converter, the negative end is coupled to the ninth end of the waveform sampler, and the output end is coupled to the reset end of the SR flip-flop. 12. The driving circuit of a light-emitting diode according to claim 1, wherein the rectifier is a bridge rectifier. twenty three