[embodiment]
As depicted in figs. 1 and 2, be a kind of LED driving circuit that receives the alternating current input that the embodiment of the invention provided, electrical couplings is in an AC power AC, and wherein AC power AC has one first output V1 and one second output V2, and electrical couplings is to drive circuit.
As shown in Figure 1, this drive circuit comprises one first light-emitting diode 111a and one second light-emitting diode 112a, one first diode 121 and one second diode 122.
As shown in Figure 1, the first light-emitting diode 111a, first diode 121, the second light-emitting diode 112a, and second diode 122 be connected into a cyclic loop in regular turn, and the first light-emitting diode 111a, first diode 121, the second light-emitting diode 112a, and second diode 122 all have identical forward bias voltage drop direction.Forward bias voltage drop direction shown in Figure 2 be clockwise direction only for convenience of description shown in, the configuration that is actually clockwise or counterclockwise need looks side circuit decides.
Anode A 21 electrical couplings of first diode 121 are in the negative electrode C11 of the first light-emitting diode 111a, and the negative electrode C21 electrical couplings of first diode 121 is in the anode A 12 of the second light-emitting diode 112a.
Anode A 22 electrical couplings of second diode 122 are in the negative electrode C12 of the second light-emitting diode 112a, and the negative electrode C22 electrical couplings of second diode 122 is in the anode A 11 of the first light-emitting diode 111a.
With the PN junction rectifier is example, the anode of aforementioned (luminous) diode and cloudy and be respectively the P type side and the N type side of (luminous) diode, but the form of (luminous) diode is not exceeded with the PN junction rectifier, also can be (luminous) diode of other form, anode to the direction of negative electrode is the forward bias voltage drop direction, when anode is bestowed positive voltage and negative electrode when being bestowed negative voltage, (luminous) diode is a forward bias voltage drop and can being switched on; Anti-, when anode is bestowed negative voltage and negative electrode when being bestowed positive voltage, (luminous) diode is that reverse biased and can presenting opens circuit.
As depicted in figs. 1 and 2, the first output V1 electrical couplings is in the anode A 11 of the first light-emitting diode 111a and the negative electrode C22 of second diode 122, and the second output V2 electrical couplings is in the anode A 12 of the second light-emitting diode 112a and the negative electrode C21 of first diode 121.
As shown in Figure 3, make the first output V1 be output as positive voltage Vin and the second output V2 when being output as negative voltage Vout when the output cycle of AC power, first diode 121 is bestowed forward bias voltage drop and conducting, and second diode 122 is bestowed reverse biased and opened circuit.This moment, positive voltage Vin can pass through the first light-emitting diode 111a, made the first light-emitting diode 111a bear forward bias voltage drop and luminous.Simultaneously, because of second diode 122 for opening circuit, so electric current is by the second light-emitting diode 112a, therefore the second light-emitting diode 112a does not burn because of bearing reverse biased.
As shown in Figure 4, make the first output V1 be output as negative voltage Vout and the second output V2 when being output as positive voltage Vin when the output cycle of AC power, first diode 121 is bestowed reverse biased and is opened circuit, and second diode 122 is bestowed forward bias voltage drop and conducting.This moment, positive voltage Vin can pass through the second light-emitting diode 112a, made the second light-emitting diode 112a bear forward bias voltage drop and luminous.Simultaneously, because of first diode 121 for opening circuit, so electric current is by the first light-emitting diode 111a, therefore the first light-emitting diode 111a does not burn because of bearing reverse biased.
The drive circuit that first embodiment of the invention provided, can directly receive the input of alternating current, make in each time point, all have at least a part of light-emitting diode to bear forward bias voltage drop and luminous, and can not cause light-emitting diode to bear reverse biased to burn, thereby have simplified the power system of drive circuit because of the output of alternating current changes.The voltage cycle of alternating current changes and lifting repeatedly, and among first embodiment, the first light-emitting diode 111a and the second light-emitting diode 112a light and shade repeatedly switch.Yet, the about 60Hz of frequency of general family expenses alternating current, and for human eye as long as switching frequency is not less than 30Hz and just can experience the light and shade variation, so the embodiment of the invention still can be effective as general lighting or Backlight For Liquid Crystal Display Panels.
As shown in Figure 5 and Figure 6, the quantity of the first light-emitting diode 111a and the second light-emitting diode 112a can be several, forms first light emitting diode matrix 111 and second light emitting diode matrix 112 respectively.
First light emitting diode matrix 111 and second light emitting diode matrix 112 comprise some with the first light-emitting diode 111a and several second light-emitting diodes 112a respectively.As shown in Figure 5, the first light-emitting diode 111a and the second light-emitting diode 112a can be series connection; As shown in Figure 6, the first light-emitting diode 111a and the second light-emitting diode 112a can be parallel connection.Certainly also can be several and the serial that connects.The first light-emitting diode 111a of first light emitting diode matrix 111 has identical forward bias voltage drop direction, and second light-emitting diode of second light-emitting diode 112 has identical forward bias voltage drop direction.
Among above-mentioned first embodiment, have only the lumination of light emitting diode of half in each time point, and the switching light and shade state that replaces of light-emitting diode.In preferred embodiment of the present invention, light-emitting diode can be all simultaneously luminous, so that the luminous power of light-emitting diode is utilized fully.
As shown in Figure 7, for the disclosed a kind of LED driving circuit that receives the alternating current input of second embodiment of the invention, comprise one first light emitting diode matrix 211 and one second light emitting diode matrix 212, one first diode 221 and one second diode 222, one the 3rd diode 223 and one the 4th diode 224, one the 5th diode 225 and one the 6th diode 226.Aforesaid first light emitting diode matrix 211 and second light emitting diode matrix 212 can be single light-emitting diode, or the light-emitting diode of several serial or parallel connections.
As shown in Figure 7, first light emitting diode matrix 211, first diode 221, second light emitting diode matrix 212, and second diode 222 be connected into a cyclic loop, and first light emitting diode matrix 211, first diode 221, second light emitting diode matrix 212, and second diode 222 have identical forward bias voltage drop direction.
As shown in Figure 7, the 3rd diode 223, the 4th diode 224 are connected into a cyclic loop with this first light emitting diode matrix 211, and first light emitting diode matrix 211, the 3rd diode 223, and the 4th diode 224 have identical forward bias voltage drop direction.The negative electrode C24 electrical couplings of the anode A 24 of anode A 23 electrical couplings of the 3rd diode 223 in the negative electrode C23 electrical couplings of the negative electrode C11 of first light emitting diode matrix 211, the 3rd diode 223 in the 4th diode 224, the 4th diode 224 is in the anode A 11 of first light emitting diode matrix 211.
As shown in Figure 7, the 5th diode 225 and the 6th diode 226 are connected into a cyclic loop with this second light emitting diode matrix 212, and second light emitting diode matrix 212, the 5th diode 225, and the 6th diode 226 have identical forward bias voltage drop direction.The negative electrode C26 electrical couplings of the anode A 26 of anode A 25 electrical couplings of the 5th diode 225 in the negative electrode C25 electrical couplings of the negative electrode C12 of second light emitting diode matrix 212, the 5th diode 225 in the 6th diode 226, the 6th diode 226 is in the anode A 12 of second light emitting diode matrix 222.
As shown in Figure 7, the first output V1 electrical couplings is in the anode A 24 of the negative electrode C23 and the 4th diode 224 of the 3rd diode 223, thereby electrical couplings is in the anode A 11 of first light emitting diode matrix 211 and the negative electrode C22 of second diode 222 indirectly.And the second output V2 electrical couplings is in the anode A 26 of the negative electrode C25 and the 6th diode 226 of the 5th diode 225, thereby electrical couplings is in the anode A 12 of second light emitting diode matrix 212 and the negative electrode C21 of first diode 221 indirectly.
As shown in Figure 8, make the first output V1 be output as positive voltage Vin and the second output V2 when being output as negative voltage Vout when the output cycle of AC power, the 4th diode 224, first diode 221, and the 5th diode 225 bestowed forward bias voltage drop and conducting; Second diode 222, the 3rd diode 223, and the 6th diode 226 bestowed reverse biased and opened circuit.Positive voltage Vin can pass through the 4th diode 224, first light emitting diode matrix 211, first diode 221, second light emitting diode matrix 212, reach the 225 formed series loops of the 5th diode this moment, made first light emitting diode matrix 211 and second light emitting diode matrix 212 bear forward bias voltage drop simultaneously and luminous.
As shown in Figure 9, make the first output V1 be output as negative voltage Vout and the second output V2 when being output as positive voltage Vin when the output cycle of AC power, second diode 222, the 3rd diode 223, and the 6th diode 226 bestowed forward bias voltage drop and conducting; The 4th diode 224, first diode 221, and the 5th diode 225 bestowed reverse biased and opened circuit.Positive voltage Vin can pass through the 6th diode 226, second light emitting diode matrix 212, second diode 222, first light emitting diode matrix 211, reach the 223 formed series loops of the 3rd diode this moment, made first light emitting diode matrix 211 and second light emitting diode matrix 212 bear forward bias voltage drop simultaneously and luminous.
The drive circuit that second embodiment of the invention provided, can directly receive the input of alternating current, in each time point, can make all light-emitting diodes bear forward bias voltage drop simultaneously and luminous, and can not change because of the output of alternating current causes light-emitting diode to bear reverse biased, because all light-emitting diodes can both be simultaneously luminous, all light-emitting diodes have therefore more effectively been used.
Among aforementioned second embodiment, the brightness of light-emitting diode the light and shade variation occurs with the cycle of alternating current.Aforementioned light and shade changes except promoting ac frequency, make its be not less than 30Hz outside, also can improve by circuit modification.
As shown in figure 10, variation example for second embodiment of the invention, wherein this drive circuit comprises that more one first decides electric current assembly 231 and one second and decides electric current assembly 232, one first decides electric current assembly 231 and one second decides the RC circuit that electric current assembly 232 can be respectively capacitor or comprise capacitor, decides electric current output by the effect generation that discharges and recharges of repetitiousness.
First two ends of deciding electric current assembly 231 respectively electrical couplings make first decide electric current assembly 231, the 3rd diode 223, the 4th diode 224, and first light emitting diode matrix, 211 series connection formation cyclic loops in the 3rd diode 223 and the 4th diode 224.Second two ends of deciding electric current assembly 232 respectively electrical couplings make second decide electric current assembly 232, the 5th diode 225, the 6th diode 226, and second light emitting diode matrix, 212 series connection formation cyclic loops in the 5th diode 225 and the 6th diode 226.
Make the first output V1 be output as positive voltage Vin when the output cycle of AC power, make the 4th diode 224, first diode 221, and the 5th diode 225 quilts are bestowed forward bias voltage drop and conducting, positive voltage Vin decides 221 chargings of electric current electricity assembly to second earlier, decide electric current electricity assembly 221 by second again and emit metastable electric current, by the 4th diode 224, first light emitting diode matrix 211, first diode 221, second light emitting diode matrix 212, and the 6th diode 226 formed series loops, make first light emitting diode matrix 211 and second light emitting diode matrix 212 receive metastable electric current, the light and shade that reduces luminosity changes.
Make the second output V2 be output as positive voltage Vin when the output cycle of AC power, make second diode 222, the 3rd diode 223, and the 6th diode 226 bestowed forward bias voltage drop and during conducting, positive voltage Vin decides 221 chargings of electric current assembly to first earlier, decide electric current assembly 221 by first again and emit metastable electric current, by the 6th diode 226, second light emitting diode matrix 212, second diode 222, first light emitting diode matrix 211, first diode 221, and the 3rd diode 223 formed series loops, make first light emitting diode matrix 211 and second light emitting diode matrix 212 receive metastable electric current, the light and shade that reduces luminosity changes.
The present invention is connected into cyclic loop by light-emitting diode and general diode with identical forward bias voltage drop direction, makes that alternating current is constant to put on light-emitting diode with forward bias voltage drop.Therefore, do not need and direct current is provided outward or exchange changes DC circuit, simplified the drive circuit of light-emitting diode.