CN102223748A - Drive method and drive power source of light-emitting diode (LED) lamp with alternating current power supply - Google Patents

Abstract

The invention discloses a drive method and a drive power source of a light-emitting diode (LED) lamp with alternating current power supply. The drive method comprises the following steps: rectifying an alternating current power source into a positive pulsating power source; carrying out current limiting on the pulsating power source by utilizing series constant current diodes; and leading the LED to operate in a current-controlled state, wherein, the frequency of the pulsating power source is larger than 80Hz. The drive power source comprises a bridge-type rectifier circuit connected with an externally connected alternating current power source, and is characterized in that the output end of the bridge-type rectifier circuit is connected with at least one constant current diode in series. In the drive circuit provided by the invention, any capacitor does not need to be used, thus prolonging the whole service life of the circuit, and effectively improving the utilization efficiency of the power source.

Description

A kind of LED lamp driving method and driving power of Alternating Current Power Supply

Technical field

The present invention relates to a kind of LED lamp driving method and circuit, be specifically related to a kind of driving method of LED lamp of Alternating Current Power Supply, and the driving power that adopts this driving method.

Background technology

The LED lamp is compared with traditional incandescent lamp or contain hg fluorescent lamp, and plurality of advantages such as green, energy-conservation, power saving, life-span are long are arranged.Think in the prior art, because LED requires to work under DC low-voltage, if the employing mains powered then needs to be converted into the DC power supply that meets the LED job requirement (referring to the 364th page of People's Telecon Publishing House August in 2008 the 1st edition " new generation of green light source led and application technology thereof ") by suitable circuit topology.Therefore, the led drive circuit of present Alternating Current Power Supply all is converted to DC power supply with AC power, its basic structure is, AC power is carried out rectification after, at first carry out smothing filtering with electrolytic capacitor, offer the low pressure translation circuit again, output voltage stabilizing or constant current are so that the luminous work of LED.Because the working life of general electrolytic capacitor has only 3000～5000 hours, especially after temperature rise appears in operational environment, the life-span more will significantly shorten, and this and hundreds thousand of hours working life of LED are not complementary, and certainly will restrict long advantage of LED lamp life-span.

Summary of the invention

Goal of the invention of the present invention provides a kind of LED lamp driving method and driving power of Alternating Current Power Supply, improvement by method, in entire circuit, do not introduce capacitor, thereby effectively improve the working life of circuit, avoid of the harmful effect of the life-span of electrolytic capacitor the LED lamp life-span.

To achieve the above object of the invention, the technical solution used in the present invention is: a kind of LED lamp driving method of Alternating Current Power Supply, AC power is rectified into the forward pulsafeeder, utilize the current regulator diode of series connection that pulsafeeder is carried out current limliting, make LED be operated in current controlled state, the frequency of described pulsafeeder is greater than 80 hertz.

In the technique scheme, following condition is satisfied in the series connection number of described current regulator diode and the selection of constant current value, mated by effective operating current of pulsafeeder of current regulator diode current limliting and the rated current value of driven LED.

In the technique scheme, because the LED electroluminescent lamp is to be operated in pulse condition, in each voltage cycle, the unit group that LED series connection forms, its angle of flow are relevant with the LED number of series connection, what of quantity, determined its duty ratio in the single cycle, therefore, by selecting the suitable constant current value of current regulator diode, can guarantee the normally luminous of LED lamp.And, though think in the prior art, LED need be operated under the DC low-voltage, but the inventor finds, the shutoff of LED has the regular hour delay, when the frequency of pulsafeeder during greater than 80 hertz, LED can be near the illumination effect that reach under the direct current supply state, makes eyes look the flicker free sense.

Adopt the LED lamp driving power source of a kind of Alternating Current Power Supply of said method, comprise the bridge rectifier that is connected with external AC power supply, be in series with at least one current regulator diode at the output of described bridge rectifier.

In the technique scheme, following condition is satisfied in the series connection number of described current regulator diode and the selection of constant current value, mated by effective operating current of pulsafeeder of current regulator diode current limliting and the rated current value of driven LED.

Optimized technical scheme, described current regulator diode are the current regulator diode with negative temperature characteristic.

Because the technique scheme utilization, the present invention compared with prior art has following advantage:

1. in the drive circuit of the present invention, do not need to use any capacitor, thereby the bulk life time of circuit prolongs.

2. current regulator diode generally is applied in the DC power supply, be applied in the pulse power among the present invention, because the operating voltage of current regulator diode has certain scope of application, with the use that is together in series of a plurality of current regulator diodes, when voltage fluctuation, not only can bear the voltage power consumption that causes that raises increases, when electric voltage dropping, also can farthest reduce the power consumption that causes in the impedance, compare, can more effectively improve power utilization efficient with using the resistance step-down.

3. when the current regulator diode of preferred negative temperature characterisitic, in use, raising appears in ambient temperature, also can not make the power consumption of the LED lamp in the work surpass prescribed limit, has avoided the light decay of LED and life-span to reduce.

Description of drawings

Fig. 1 is the circuit diagram of embodiment one.

Fig. 2 is a pulsafeeder voltage waveform view among the embodiment one.

Fig. 3 is the circuit diagram of embodiment two.

Embodiment

Below in conjunction with drawings and Examples the present invention is further described:

Embodiment one: referring to shown in Figure 1, a kind of LED lamp driving power source of Alternating Current Power Supply comprises the bridge rectifier that is connected with external AC power supply, is in series with n current regulator diode at the output of described bridge rectifier.The LED number of connecting in the size of n and the power supply unit is relevant, and is general in 1～8 scope.

Referring to accompanyingdrawing 1, insert the AC AC power, behind bridge rectifier, become a forward pulsating voltage.

After m LED series connection, during its normally, the voltage that need apply is that the pressure drop of rectifier diode in 3.3V * m(bridge heap can be ignored), for the input pulsating voltage, when having only V 〉=3.3V * m, LED just enters normal operating conditions.

Shown in accompanying drawing 2, have only when being applied to LED(string) during total voltage after greater than the LED series connection of the positive half cycle voltage magnitude of pulsation after the rectification at two ends, the LED(string) just have electric current and flow through, conducting is luminous.

The sinusoidal wave expression formula of alternating current is V=V_PeakSin θ is when θ=90 °, promptly during 1/4 cycle, V reaches the peak value of voltage, when mains frequency was 50Hz, the cycle was 20ms, and 1/4 cycle was 5ms, if LED(string) the angle of flow is θ ' (θ ' less than 90 °), at this moment time corresponding is T ', and then, the time of conducting is 5ms-T ' in 1/4 cycle, thereby, can calculate duty ratio briefly

Flow through the electric current I of LED_Arg=I_PeakD can go here and there LED() operate as normal sets under the direct current supply state current value is I_Arg, I so_PeakThe current regulator diode constant current value that need provide just.

Need the quantity of the current regulator diode of serial connection, can be by V_PeakThe result of-V goes to be removed by the highest working voltage of the permission of current regulator diode and obtain.

Adopt such circuit,, not only eliminated, also reduced because the phase shift of capacitor and the electromagnetism Harmonic Interference that charge and discharge process brings to electrical network to short worry of electrochemical capacitor life-span owing to there is not capacitor.

Current regulator diode in the present embodiment is good with the current regulator diode that employing has negative temperature characteristic.

Embodiment two: referring to shown in Figure 3, a kind of LED lamp driving power source of Alternating Current Power Supply, comprise the bridge rectifier that is connected with external AC power supply, be provided with the multiple series series current regulator diode group of mutual parallel connection at the output of described bridge rectifier, each road series connection current regulator diode group is used for can being provided with the LED of a plurality of series connection in each LED unit group to a LED unit group power supply.

In each road, the number of the current regulator diode of series connection is complementary with the LED number of powering in this road, and its computational methods and embodiment one are similar.

Claims (5)

1. the LED lamp driving method of an Alternating Current Power Supply, it is characterized in that: AC power is rectified into the forward pulsafeeder, utilize the current regulator diode of series connection that pulsafeeder is carried out current limliting, make LED be operated in current controlled state, the frequency of described pulsafeeder is greater than 80 hertz.

2. the LED lamp driving method of Alternating Current Power Supply according to claim 1, it is characterized in that: following condition is satisfied in the series connection number of described current regulator diode and the selection of constant current value, mated by effective operating current of pulsafeeder of current regulator diode current limliting and the rated current value of driven LED.

3. the LED lamp driving power source of an Alternating Current Power Supply comprises the bridge rectifier that is connected with external AC power supply, it is characterized in that: the output at described bridge rectifier is in series with at least one current regulator diode.

4. the LED lamp driving power source of Alternating Current Power Supply according to claim 3, it is characterized in that: following condition is satisfied in the series connection number of described current regulator diode and the selection of constant current value, mated by effective operating current of pulsafeeder of current regulator diode current limliting and the rated current value of driven LED.

5. the LED lamp driving power source of Alternating Current Power Supply according to claim 3, it is characterized in that: described current regulator diode is the current regulator diode with negative temperature characteristic.

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