TWI620468B - Brightness and color temperature adjustable led lighting drive system having high power factor and high efficiency - Google Patents

Abstract

The invention relates to an LED illumination driving system with high power factor and high efficiency dimming and color temperature, which mainly uses a high power LED to develop a lighting system to improve overall performance; and in driving source circuit design, The main module of the power supply adds an energy regeneration buffer to the flyback circuit to further reduce the loss. In the system control, the digital signal processor (DSP) is used as the core to realize the primary side detection method and the quasi-resonant switching. Conversion efficiency, reducing circuit volume; in the aspect of dimming, the phase-phase PWM circuit is combined with the sensor to have automatic brightness adjustment and color temperature functions; thereby, the driving source characteristics include a maximum efficiency of 89%. The power factor is 99.9%, the total harmonic distortion factor is 1.64%, and the system can automatically adjust the brightness, and the color temperature range can be adjusted from 2500K to 5500K. At the same time, the color rendering of the light source is between 73 and 91, and it is used in its entirety. More practical and effective features.

Description

LED lighting drive system with high power factor and high efficiency dimming and color temperature

The invention relates to an LED illumination driving system with high power factor and high efficiency dimming and color temperature, in particular to a driving source characteristic including a maximum efficiency of 89%, a power factor of 99.9%, and full load total harmonic distortion. The factor is 1.64%, and the system can automatically adjust the brightness, and can be adjusted from 2500K to 5500K in the color temperature range. At the same time, the color rendering of the light source is between 73 and 91, and the high performance of the utility model is enhanced in its overall implementation. LED lighting drive system for high efficiency dimmable and color temperature.

In order to reduce the damage to the environment, to achieve sustainable survival, improve transmission and conversion efficiency, and effectively use existing energy, has become an important research topic. From the perspective of green energy, the focus of future energy development is no longer to build power plants or find new energy sources, but to save energy consumption and recycling. In terms of reducing equipment power consumption, At present, various types of conversion equipment are mostly non-linear loads, which will cause distortion of the mains current, resulting in poor power factor and harmonic interference, and the efficiency of power transmission and distribution is reduced. Therefore, the power factor correction function must be added to the converter system to improve the power conversion and transmission efficiency, and meet the ENERGY STAR specifications.

The use of electric energy in lighting is an important indicator of the progress of human civilization. With the improvement of living standards, the people are no longer pursuing luminous efficiency, but a comfortable light source environment. Related studies indicate that color temperature affects the physiological and psychological responses of humans. In recent years, due to the advancement of LED production technology and materials, lighting applications in various occasions, such as indoor lighting, outdoor advertising billboards and various landscape decorations, are becoming more and more popular. Therefore, the characteristics and lighting quality of LED driving power supplies must be constantly Refined.

In addition, in addition to the drive source, the LED lighting system also affects the overall performance. Pulse dimming control (PWM) is most commonly used for LED dimming. However, in the process of power consumption, high-power LEDs are converted into light energy of only 15%-25%, and the rest of the energy is converted into heat energy. The increase in temperature leads to problems such as reduced luminous efficiency and light decay; therefore, lowering the LED temperature is a very important issue.

The reason is that the inventor has given this year's rich experience in design, development and actual production of the relevant industry, and has researched and improved the existing structure and defects to provide an LED with high power and high efficiency dimming and color temperature. Lighting drive systems for the purpose of achieving better practical value.

The main object of the present invention is to provide a high power factor and high efficiency dimming And the color temperature LED lighting drive system, mainly based on the drive source characteristics including the highest efficiency up to 89%, power factor 99.9%, full load total harmonic distortion factor of 1.64%, and the system can automatically adjust the brightness, and the color temperature range from 2500K It can be adjusted up to 5500K, and the color rendering of the light source is between 73 and 91, and it is more practical and useful in its overall application.

The main purpose and effect of the LED lighting driving system with high power factor and high efficiency dimming and color temperature are achieved by the following specific technical means: the main signal system includes a signal processor and a forward-return converter. a dimming circuit and an LED; wherein: the signal processor (DSP) is electrically coupled to the forward flyback converter and the dimming circuit, respectively, so that the signal processor can be used to drive the forward flyback Transducing and regulating the dimming circuit; the forward flyback converter is connected to an energy regeneration buffer on a primary side of the isolation transformer, and the isolation transformer is provided with a forward winding N _Forward on the secondary side And a flyback winding N _Flyback , the first end of the _forward winding N _Forward is connected with the positive pole of the fast diode D ₁ , and the second end of the _forward winding N _Forward is coupled with the flyback winding N _Flyback The first end and the positive pole of the fast diode D ₂ , the second end of the output capacitor C _{o , and} the second end of the output load R _o are connected together for grounding, the negative pole of the fast diode D ₁ and the fast second The anode of the polar body D ₂ and the first of the output inductor L _o Terminal connected to a second end of winding of the flyback _Flyback positive electrode of the N-linked D ₃ of the fast diode, the anode of the fast diode D ₃ of the second end of the L _o of the output inductor, the output capacitance C _a first end of the output terminal R _o is connected to the first end of the isolation transformer; a winding N _p is disposed on a primary side of the isolation transformer, and an excitation parallel to the winding N _p is formed on a primary side of the isolation transformer The inductor L _p and the connected leakage inductance L _lk , and the leakage inductance L _lk formed on the primary side of the isolation transformer is connected to the first end of the crystal switch S _w ; the energy regeneration buffer is recovered by the capacitor C _r , the diode D ₄ , D ₅ and the return winding N _r are formed such that the anode of the recovery capacitor C _r is connected between the leakage inductance L _lk and the first end of the crystal switch S _w , and the recovery capacitor a cathode of C _r is connected to a second end of the diode D ₄ and a first end of the diode D _{5 , and} the first end of the diode D _{4 and} the primary side of the isolation transformer are formed magnetizing winding N _p and L _p is the inductance a first end connected to the input of the positive power source V _in, the diode D ₅ and the second end of the return A first connector terminal group of N _r, the return of the second end windings N _r are collectively connected to a second terminal of the switch S _w of the crystal to the input of the negative power supply V _in; the dimming circuit, which uses digital formula The phase-phase PWM dimming, and the color sensor is used to detect the brightness and color temperature of the feedback source to achieve precise brightness adjustment of the light source, and the dimming mode is realized by the signal processor and the related circuit, and The signal processor outputs a PWM signal, and the color sensor intercepts the color temperature for comparison. The LED is used to adjust the respective PWM control, and the duty cycle of the PWM is changed, that is, the color temperature control can be performed; the LED, and the LED The forward flyback converter and the dimming circuit are electrically coupled to drive the LED illumination using the forward flyback converter and the dimming circuit.

LED lighting driving system with high power factor and high efficiency dimming and color temperature A preferred embodiment of the system, wherein the dimming circuit has a regulation range of 2500K to 5500K.

A preferred embodiment of the LED illumination driving system with high power factor and high efficiency dimming and color temperature is provided, wherein the PWM pulse wave frequency is set at 400 Hz.

The preferred embodiment of the present invention has a high power factor and high efficiency dimming and color temperature LED illumination driving system, wherein the LED is a high power LED.

(1)‧‧‧Signal Processor

(2) ‧‧‧ forward flyback converter

(21)‧‧‧Isolation transformer

(22) ‧‧‧Energy regeneration buffer

(3) ‧‧‧ dimming circuit

(4)‧‧‧LED

First: Schematic diagram of the architecture of the present invention

Second figure: schematic diagram of the circuit of the forward-backward converter of the present invention

Third: Schematic diagram of detecting the primary side auxiliary winding of the present invention

Fourth: Schematic diagram of the circuit architecture of the single-stage power factor correction of the present invention

Figure 5: Waveform diagram of V _{Aux of the} present invention in different working intervals

Figure 6: Schematic diagram of the sampling time point of the ADC of the present invention

Figure 7: Schematic diagram of the LED of the present invention applied to a lighting fixture

Figure 8: Schematic diagram of the automatic dimming architecture of the LED of the present invention applied to a lighting fixture

For a more complete and clear disclosure of the technical content, the purpose of the invention and the effects thereof achieved by the present invention, it will be explained in detail below, and please refer to the illustrated figure. And the figure number: first, please refer to the first diagram of the schematic diagram of the present invention. The present invention mainly includes a signal processor (1), a forward-return type converter (2), a dimming circuit (3), and LED (4); wherein: the signal processor (DSP) (1) is electrically connected to the forward flyback converter (2) and the dimming circuit (3) respectively, so as to be able to use the signal processing The device (1) drives the forward flyback converter (2) and regulates the operation of the dimming circuit (3).

The forward flyback converter (2), please refer to the second diagram of the present invention, which is shown in the schematic diagram of the circuit of the flyback converter, which is connected to the primary side of the isolation transformer (21) with energy regeneration buffer. (22), the isolation transformer (21) is provided with a forward winding N _Forward and a flyback winding N _Flyback on the secondary side, and the first end of the _forward winding N _Forward is connected with a fast diode D _a positive pole of the forward winding N _Forward , a first end of the _Flyback winding N _Flyback and a positive pole of the fast diode D ₂ , a second end of the output capacitor C _o , and an output load R The second end of the _o is connected and grounded, and the negative pole of the fast diode D _{1 and} the negative pole of the fast diode D ₂ are connected to the first end of the output inductor L _o , and the flyback winding N _Flyback The second end is connected to the anode of the fast diode D _{3 ,} the cathode of the fast diode D ₃ is connected to the second end of the output inductor L _{o ,} the first end of the output capacitor C _o , and the output load _Ro The first end is connected; the primary side of the isolation transformer (21) is provided with a winding N _p , and the primary side of the isolation transformer (21) There into parallel with the magnetizing inductance of the phase winding N _p and L _p is connected to the leakage inductance L _lk of _the leakage inductance L _lk and S _w of transistor switch and to the isolation transformer (21) is formed of a first primary side The energy regenerative buffer (22) is composed of a recovery capacitor C _r , a diode D ₄ , a D ₅ and a return winding N _r , such that the anode of the recovery capacitor C _r is connected to the leakage inductance L _lk Between the first end of the crystal switch S _w and the negative end of the recovery capacitor C _r is connected to the second end of the diode D _{4 and} the first end of the diode D ₅ , the diode The first end of the body D _{4 and} the first end of the isolation transformer (21) form a first end of the winding N _p and the magnetizing inductance L _p connected to the anode of the input power source V _in , and the second end of the diode D ₅ the first end and the return end of the winding connected to N _r, the return of the second end windings N _r are collectively connected to a second terminal of the transistor switch S _w V _in the power supply to the input of the negative electrode.

Please refer to the third figure for the detection of the primary side auxiliary winding and the fourth figure of the present invention. The circuit diagram of the single-stage power factor correction of the present invention is shown, and the forward flyback converter is assumed. (2) Rated power 50W, input voltage range 110V±20%, input power frequency 60Hz, efficiency 89%, switching frequency 25~27kHz, output current 1.25A, output voltage 40V, output voltage chopping 0.5%, voltage regulation rate 1%, the output pulse frequency is 400Hz, so the parameters of the isolation transformer (21) and other main components are determined as follows:

1. Isolation transformer peak current: The relationship between inductor current and voltage is as shown in equation (1):

It can be seen that in the discontinuous mode, the crystal switch S _w rises from zero to the peak value ( I _pp ) during the on-time ( T _on ), so the minimum input voltage ( V _in(min) ) can be written as:

(2) where V _in is the DC input voltage, L _p is the isolation transformer magnetizing inductance, and I _pp is the primary side peak current of the isolation transformer.

Where D _max is the maximum duty cycle, f _s is the switching frequency, and the minimum input voltage V _in(min) can be obtained by bringing (3) into equation (2 ₎ :

In addition, in the discontinuous mode, the output power ( P _out ) is equal to the average stored energy of the magnetizing inductance L _p in each cycle, and the equation is as follows:

Divide (5) by (4) to get:

By rewriting (6), the peak current I _{pp of the} primary winding current can be obtained as shown in equation (7):

The minimum input voltage V _in(min) can be obtained by the equation (8), where the voltage of 20V is subtracted to increase the margin of the input voltage minimum:

The maximum input DC voltage is:

If the flyback winding N _Flyback and the forward winding N _{Forward are} each half of the output load power, the power output of the _flyback winding N _Flyback is 25W. Assuming the maximum duty cycle D _max = 0.45, the primary side peak current I _pp can be obtained:

Therefore, when the crystal switch S _w is turned on, the 汲 terminal of the power transistor must be able to withstand this current before it can operate normally.

2. for the Minimum duty D _min: the flyback converter (2), by adjusting the duty cycle of transistor switch S _w to obtain a stable output voltage at the front. When the input voltage range is from V _{in (min)} to V _{in (max)} , the relationship between the minimum and maximum duty cycle is as in (11):

Where K is the ratio of Vin _(min) and Vin _(max) . Bringing equations (8) and (9) into equation (11):

Assuming D _max = 0.45, and substituting the K value of (12) into equation (11) can be obtained:

It can be seen that when the input DC voltage range is 104V-187V, the duty cycle of the forward flyback converter (2) will operate between 0.31 and 0.45.

3. Calculate the isolation transformer's magnetizing inductance value L _p :

4. Select the core: Select HL24D iron core, the saturation magnetic flux B _sat is 3600G at 100 °C. If the saturation magnetic density is set to the maximum working magnetic flux density B _{max to} be half of B _sat , then:

5. Calculate the primary winding N _{p of the} isolation transformer: Substituting I _pp and L _p of equations (10) and (14) into the primary side flux linkage formula of the isolation transformer can obtain N _P :

Taking an integer is N _P =63T.

6. Isolation transformer secondary side forward winding N _Forward : When the input voltage is the smallest and the duty cycle is maximum, the secondary side voltage Vs is calculated as (17):

Then the secondary side forward winding N _Forward is:

Take the integer N _Forward = 55T.

7. Isolation transformer secondary side flyback winding N _Flyback : When the input voltage is the smallest and the duty cycle is the largest, the secondary side voltage Vs is calculated as (19):

By substituting known data, a secondary side flyback winding N _Flyback can be obtained:

8. Calculate the isolation transformer auxiliary winding N _Aux [please refer to the third diagram of the present invention for the detection of the primary side auxiliary winding schematic diagram]: The secondary winding voltage V _{a is} calculated as follows:

The auxiliary winding output voltage is set to 15V to provide the IC power supply voltage V _CC , so the number of turns of the auxiliary winding N _{Aux is} as shown in equation (22):

9. Output inductor L _o : Let the output inductor L _o operate at full load in DCM mode as shown in equation (23):

Substituting the forward winding output power to P _{o, Forward} = 25W, then

From practical experience and testing, the output inductor L _{o is} 0.6mH.

10. Reply winding N _r : the ratio of the primary side winding N _p and the return winding N _r of the isolation transformer n _r (n _r =N _r /N _p ), the value of n _r must be less than 1, when the crystal switch S _w is on The return winding voltage V _{Nr is} smaller than the recovery capacitor voltage V _cr . Integrating N _Aux in Nr saves the amount of copper in the winding, and the n _r formula is as in (25):

Let n _r =0.7 then N _r is calculated as (26):

11. Recovering capacitor C _r : It can be obtained by the principle of flux balance (27):

Where L _lk is the leakage inductance and its value is 10uH after the test. Referring to the above formula and practical experience, the capacitor C _{r is a} capacitor with 12nF and 275V.

12. Calculate the air gap length l _g : Since the isolation transformer uses only half of the saturation magnetic flux, the flux will only change in the first quadrant. In order to make the hysteresis loop flat, an air gap is used on the flux path to prevent the isolation transformer from saturating. The length of the air gap is as shown in (28):

13. Inductance L _{b of the} boost/buck type power factor corrector (please refer to the fourth circuit diagram of the circuit diagram of the single-stage power factor correction of the present invention according to the fourth embodiment): to ensure the inductor current I _Lb When working in DCM, the input current waveform will naturally follow the input voltage waveform. According to (29), the L _b inductance value of the boost/buck type can be known:

In the above formula, η is the efficiency of the design specifications of the present invention.

14. Crystal switch (S _w ) and fast diode (D ₁ , D ₂ and D ₃ ): The crystal switch S _{w of} the forward flyback converter must be able to withstand the maximum voltage V _DS(max) To avoid burning due to overvoltage. Let the voltage reflected from the secondary side of the isolation transformer to the primary side be V _R , and its formula is as shown in equation (30):

If the voltage spike ΔV generated by the leakage inductance L _lk is 20% of V _R +V _in(max) , the voltage spike ΔV is 82.7V, and V _DS(max) can be calculated by the formula (31): V _DS(max) =V _in(max) +V _R +△V=187+82.7+55=323.7V (31)

Based on the above formula, and considering the randomness of the transient surge, the present invention selects a crystal switch S _w capable of withstanding 500V, and its model is IRFP450. In addition, the three fast diodes (D ₁ , D ₂ , D ₃ ) have the maximum withstand voltage formulas as shown in equations (32) to (34):

In consideration of an appropriate margin, the present invention selects the D ₂ model as MUR3040, its reverse repeat peak voltage V _RRM is 400V, and the D ₁ and D ₃ models are STTH3002CT, which has a V _RRM =200V.

15. Output Capacitor C _o : The principle of selecting the output capacitor, in addition to the effect of voltage regulation, must also withstand the peak-packed full-wave rectified voltage formed by the secondary side inductor current of the isolation transformer. When the output voltage chop is set to 0.5V, the minimum output capacitance value can be obtained by (35):

In the above formula, f _L is the commercial frequency of 60 Hz, and the actual output capacitance C _{o (min)} = 3400 uF.

Primary side output voltage control: Primary-Side Regulation (PSR) technology is used to improve overall efficiency. When the crystal switch S _w is turned off, the output voltage V _o will reflect the voltage to the auxiliary winding N _Aux , and the voltage signal on the auxiliary winding N _Aux is fed back to the signal processor ( 1 ) to achieve the output voltage regulation. The purpose is to use the output voltage of the auxiliary winding at the same time, which can be used as a power supply IC and peripheral circuits.

The forward flyback converter (2) operate in a discontinuous conduction mode [DCM]; can be divided into three operating states: (1) during transistor switch S _w is turned on, (2) transistor switch S _w OFF period, (3 When the crystal switch S _w is turned off, the energization of the magnetizing inductance L _{p is} completed. Please refer to the fifth diagram of the V _{Aux of the} present invention as shown in the waveform diagram of different working sections. When the crystal switch S _{w is} at d _1T , the voltage V _{Aux_Da} on the auxiliary winding N _Aux is as shown in (36):

In order to make the feedback signal conform to the voltage range of the analog-to-digital converter input of the signal processor (1), the sampled circuit is processed by an ADC (Analog to Digital Converter, ADC) sampling circuit, please Referring to the sixth diagram, the sampling time point of the ADC of the present invention is shown, and the sampling time points are at t _n and t _n+1 . The feedback signal V _{Aux_ADC is} sent to the signal processor (1) for ADC sampling. Since the resolution of the ADC is 12 bits and the maximum allowable input voltage range is 3.3V, the conversion gain (G _ADC ) and The V _ADC equations are shown in equations (37) and (38):

The dimming circuit (3) adopts digital phase-phase PWM dimming, and uses a color sensor to detect the brightness and color temperature of the feedback source to achieve precise brightness adjustment of the light source, and the dimming mode thereof is adopted by the The signal processor (1) is implemented by the related circuit. In addition, the signal processor (1) outputs a PWM signal, and the color sensor intercepts the color temperature for comparison, and the LED (4) of a plurality of different models (color temperature) is used. [eg: three primary color LEDs] to adjust the phase of each PWM control, change the duty cycle of the PWM, that is, the color temperature control, the regulation range is 2500K to 5500K. In order to avoid flickering of the LED (4), the PWM pulse frequency is set at 400 Hz.

The LED (4) is a high-power LED (4), and the LED (4) is electrically connected to the forward flyback converter (2) and the dimming circuit (3) to utilize the front The LED (4) is driven to the flyback converter (2) and the dimming circuit (3), and has a rated voltage of 2.8 V, a forward current of 700 mA, and a color rendering property (CRI) of 70 or more.

When the present invention is applied to the driving of a lighting fixture, please refer to the seventh diagram. The LED of the present invention is applied to the schematic diagram of the lighting fixture structure, so that each string of the LED (4) is connected in series with the switching component, and the voltage is used. The coupler is used to limit the current, and the signal processor (1) transmits the PWM signal through the dimming circuit (3) for dimming. Taking the first group of the LED (4) circuit as an example, when the reference voltage V _pwm1 is the low voltage level V _L1 , the switching element Q1 operates in the cut-off region, at which time there is no current on the LED (4); When V _pwm1 is the high voltage level V _H1 , the comparator output is at a high level, the switching element Q1 operates in the ohmic region, and a current flows through the LED (4). The phase-phase PWM control mode can adjust the brightness and color temperature of the LED (4), and use the color sensor to detect the brightness and color temperature of the returned light source to achieve precise light source control.

In addition, when the present invention is to achieve automatic dimming, please refer to the eighth diagram. The LED of the present invention is applied to the automatic dimming architecture diagram of the lighting fixture, and is supplied by the forward flyback converter (2). LED (4) array power supply, and then the color sensor intercepts the ambient brightness for comparison. When the external light source is bright, the color sensor transmits a signal to the signal processor (1) to convert the forward-return type. (2) The voltage is turned down; conversely, when the external light source is dark, the voltage is increased, so that the brightness of the LED (4) is regulated within the indoor illumination specification range.

From the above description, the implementation of the present invention shows that the present invention is mainly based on the prior art means, the main characteristics of the driving source include a maximum efficiency of 89%, a power factor of 99.9%, and a full load total harmonic. The distortion factor is 1.64%, and the system can automatically adjust the brightness, and the color temperature range can be adjusted from 2500K to 5500K. The color rendering of the light source is between 73 and 91, and it is more practical and useful in its overall application.

However, the above-described embodiments or drawings are not intended to limit the structure or the use of the present invention, and any suitable variations or modifications of the invention will be apparent to those skilled in the art.

In summary, the embodiments of the present invention can achieve the expected use efficiency, and the specific structure disclosed therein has not been seen in similar products, nor has it been disclosed before the application, and has completely complied with the provisions of the Patent Law. And the request, the application for the invention of a patent in accordance with the law, please forgive the review, and grant the patent, it is really sensible.

Claims (4)

An LED lighting driving system with high power factor and high efficiency dimming and color temperature, mainly comprising a signal processor, a forward-returning converter, a dimming circuit and an LED; wherein: the signal processor [DSP] And electrically connecting to the forward flyback converter and the dimming circuit, respectively, so that the signal processor can be used to drive the forward flyback converter and the dimming circuit is controlled; the forward returning The converter is connected to the primary side of the isolation transformer with an energy regeneration buffer. The isolation transformer is provided with a forward winding N _Forward and a flyback winding N _Flyback on the secondary side, the forward winding N _Forward the first end connected to the positive electrode of the fast diode D _1, the forward end of the second winding and the positive electrode of the N _forward back to the first end of the fly-winding and fast N _Flyback diode D _2, the output The second end of the capacitor C _{o and} the second end of the output load R _o are connected together for grounding, the negative pole of the fast diode D _{1 and} the negative end of the fast diode D ₂ and the first end of the output inductor L _o Connection, the second end of the _flyback winding N _Flyback is connected with a fast two a cathode of the diode D _{3 ,} the cathode of the fast diode D ₃ is connected to the second end of the output inductor L _{o ,} the first end of the output capacitor C _{o , and} the first end of the output load R _o ; the primary side of the isolation transformer has a winding N _p, and are formed in parallel to the leakage inductance L _lk has the magnetizing inductance of the phase winding N _p and L _p is connected to the primary side of the isolation transformer _and the isolation transformer in the The leakage inductance L _lk formed on the primary side is connected to the first end of the crystal switch S _w ; the energy regeneration buffer is composed of a recovery capacitor C _r , a diode D ₄ , a D ₅ and a return winding N _r , The anode of the recovery capacitor C _r is connected between the leakage inductance L _lk and the first end of the crystal switch S _w , and the cathode of the recovery capacitor C _r is opposite to the second end of the diode D ₄ and the The first end of the diode D ₅ is connected, and the first end of the diode D _{4 and} the first end of the winding N _p and the magnetizing inductance L _p formed on the primary side of the isolation transformer are connected to the input power source V _in the positive electrode, the second end of the diode D ₅ N _r of a first end of the winding is connected to the return of the reply to the second end of the winding and the N _r The second end of the body of the switch S _w collectively connected to the input of the negative power supply V _in; the dimming circuit, which uses digital phase PWM dimming type sequence, and using the color sensor and the color temperature of the light source luminance detection timing of the back To achieve precise brightness control of the light source, and the dimming mode is realized by the signal processor and the related circuit, and the PWM signal is outputted by the signal processor, and then the color temperature is intercepted by the color sensor for comparison. The LED is sequentially adjusted to adjust the PWM, and the duty cycle of the PWM is changed, that is, the color temperature control can be performed; the LED is electrically connected to the forward flyback converter and the dimming circuit to utilize the forward direction. The flyback converter and the dimming circuit drive the LED illumination. For example, the LED lighting driving system with high power factor and high efficiency dimming and color temperature as described in claim 1 of the patent scope, wherein the dimming circuit has a regulation range of 2500K to 5500K. High power factor and high efficiency dimming and color temperature as described in item 1 of the patent application scope LED lighting drive system, wherein the PWM pulse frequency is set at 400 Hz. For example, the LED lighting driving system with high power factor and high efficiency dimming and color temperature as described in claim 1 of the patent scope, wherein the LED is a high power LED.