CN103179755B - A kind of LED linear constant current driving governor with High Power Factor - Google Patents

Abstract

The invention belongs to the technical field of LED constant current control and provides an LED linear constant current drive controller with high power factor and an LED drive device. The LED linear constant current drive controller with high power factor samples the voltage output by the rectifier circuit through the voltage sampling circuit, and then the power factor correction circuit squares the sampled voltage or outputs it after equivalent processing, and then the constant current control circuit according to the power factor The voltage output by the correction circuit is used to control the constant current of the light-emitting diode unit as a load. Compared with the existing linear LED constant current drive control circuit with high power factor, while improving the power factor and reducing the pollution to the power grid, it also makes all the LEDs in the light-emitting diode unit light up at the same time, which improves the utilization of LEDs. rate; at the same time, the wide-range adjustment of the input voltage is realized by using the voltage regulation circuit, and it is safe and reliable.

Description

A LED linear constant current drive controller with high power factor

technical field

The invention belongs to the technical field of LED constant current control, in particular to an LED linear constant current drive controller with high power factor and an LED drive device.

Background technique

Knownly, there are currently two ways to implement LED driving devices with high power factor:

One is a flyback or DC-DC buck-boost switching power supply type constant current drive control circuit. Since there are energy storage components such as transformers or inductors in this circuit topology, and the high power factor circuit has a discrete valley filling circuit or a power factor correction circuit integrated in the controller, the input part and output part of the circuit are separate current loop, the output voltage (that is, the sum of the voltages of the LED units as the load) is not limited by the input voltage, so the input voltage can be varied in a wide range. However, this kind of constant current drive control circuit has a complex structure, occupies a large circuit board, and has high cost, which is not conducive to production and promotion.

Aiming at the deficiencies of the above-mentioned implementation methods, another linear LED constant current drive control circuit is proposed. There are no energy storage components such as transformers or inductors in the topological structure of this circuit, and the input part and output part are in the same current loop. Figure 1 shows a linear LED constant current drive control circuit with high power factor provided by the prior art. In this circuit, the multi-segment light-emitting diode units as the load are conducted in segments. When the input voltage amplitude is low When the input voltage is high, only some of the LED units light up or none of the LED units light up, and the output power decreases; The LED unit of the segment can still light up normally, but the loss on the constant current controller will increase, and it will even burn the constant current controller after working for a long time.

It can be seen that in the existing linear LED constant current drive control circuit with high power factor, the light-emitting diode units of each segment are not fully lit all the time, and their utilization rate is low. If the fixed power is output to the load, the input voltage Wide range adjustment is not possible.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a LED linear constant current drive controller with a high power factor, aiming at solving the problem of segmental conduction of light emitting diode units in the existing linear LED constant current drive control circuit with high power factor. The light-emitting diode units of each section are not fully bright all the time, and the utilization rate thereof is low.

The embodiment of the present invention is achieved in this way, a LED linear constant current drive controller with high power factor, the LED linear constant current drive controller includes:

The voltage sampling circuit is used for sampling the voltage output by the rectifier circuit in the LED driving device, and outputting the sampling result signal and the sampling voltage;

A voltage regulation circuit, configured to adjust the magnitude of the voltage output by the rectification circuit according to the sampling result signal, and output it to the positive input terminal of the light emitting diode unit;

A power factor correction circuit, configured to square the sampled voltage and then output it;

A constant current control circuit, configured to perform constant current control on the LED unit according to the voltage output by the power factor correction circuit;

The voltage regulation circuit includes a voltage selection circuit, and also includes a boost circuit and/or a step-down circuit;

The voltage selection circuit is configured to control the boost circuit to boost the voltage output by the rectifier circuit if the voltage output by the rectifier circuit is less than a second preset value according to the sampling result signal, and Outputting the boosted voltage of the booster circuit to the positive input terminal of the LED unit, and/or according to the sampling result signal, if the voltage output by the rectification circuit is greater than a first preset value, then controlling the step-down circuit to step down the voltage output by the rectifier circuit, and output the voltage after step-down processing by the step-down circuit to the positive input terminal of the light emitting diode unit;

The voltage selection circuit includes: N-channel MOS transistor Q1, N-channel MOS transistor Q2, N-channel MOS transistor Q3, N-channel MOS transistor Q4, N-channel MOS transistor Q5, and gate U3 , inverter U4, NOR gate U5 and NOR gate U6;

The drain of the N-channel MOS transistor Q4, the drain of the N-channel MOS transistor Q3, and the drain of the N-channel MOS transistor Q1 are connected to the output end of the rectification circuit ; the source of the N-channel MOS transistor Q5, the source of the N-channel MOS transistor Q3 and the source of the N-channel MOS transistor Q2 are connected, and are commonly connected to the LED unit positive input terminal; the gate of the N-channel MOS transistor Q4 is connected to the gate of the N-channel MOS transistor Q5, and is commonly connected to the output terminal of the AND gate U3; the N-channel MOS transistor The gate of Q1 is connected to the gate of the N-channel MOS transistor Q2, and is commonly connected to the output terminal of the NOR gate U6; the gate of the N-channel MOS transistor Q3 is connected to the NOR gate U5 The output terminal of the AND gate U3 is connected to an input terminal of the NOR gate U5 and an input terminal of the NOR gate U6, and is commonly connected to the output terminal of the voltage sampling circuit; the The other input terminal of the AND gate U3 is connected to the input terminal of the inverter U4 and the other input terminal of the NOR gate U6, and is commonly connected to the output terminal of the voltage sampling circuit; The output end is connected to the other input end of the NOR gate U5; the source of the N-channel MOS transistor Q4 and the drain of the N-channel MOS transistor Q5 are connected to the step-down voltage, and the N-channel The source of the N-channel MOS transistor Q1 and the drain of the N-channel MOS transistor Q2 are connected to the booster circuit.

Another object of the embodiments of the present invention is to provide an LED driving device, which includes a rectification circuit, and the LED driving device further includes the LED linear constant current driving controller with high power factor as described above.

The LED linear constant current drive controller with high power factor provided by the embodiment of the present invention samples the voltage output by the rectifier circuit through the voltage sampling circuit, and outputs the sampling result signal and the sampling voltage; the sampling result signal is input to the voltage regulation circuit, if If the voltage output by the rectifier circuit is too high or too low, it will be regulated by the voltage regulating circuit, and then output to the positive input terminal of the light-emitting diode unit as the load, and the sampling voltage is input to the power factor correction circuit, and the power factor correction circuit will sample The voltage is output after square or equivalent processing, and then the constant current control circuit performs constant current control on the light-emitting diode unit as the load according to the voltage output by the power factor correction circuit. Compared with the existing linear LED constant current drive control circuit with high power factor, while improving the power factor and reducing the pollution to the power grid, it also makes all the LEDs in the light-emitting diode unit light up at the same time, which improves the utilization of LEDs. rate; at the same time, the wide-range adjustment of the input voltage is realized by using the voltage regulation circuit, and it is safe and reliable.

Description of drawings

1 is a schematic diagram of a linear LED constant current drive control circuit with high power factor provided by the prior art;

Fig. 2 is a schematic circuit diagram of an LED linear constant current drive controller with high power factor provided by an embodiment of the present invention;

Fig. 3 is a circuit schematic diagram of a voltage regulating circuit in Fig. 2;

Fig. 4 is in Fig. 2, the circuit diagram of voltage sampling circuit;

Fig. 5 is in Fig. 3, the circuit diagram of voltage selection circuit;

Fig. 6 is in Fig. 2, the circuit diagram of power factor correction circuit;

Fig. 7 is in Fig. 2, the circuit diagram of constant current control circuit;

FIG. 8 is a circuit diagram of the LED unit in FIG. 2 .

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Aiming at the problems existing in the prior art, the present invention proposes a LED linear constant current drive controller with a high power factor, which samples the voltage output by the rectifier circuit through a voltage sampling circuit, and outputs a sampling result signal and a sampling voltage; the sampling result The signal is input to the voltage regulation circuit. If the output voltage of the rectification circuit is too high or too low, it will be regulated by the voltage regulation circuit and output to the positive input terminal of the light-emitting diode unit as the load. The sampling voltage is input to the power factor correction The power factor correction circuit performs square or equivalent processing on the sampled voltage and then outputs it, and then the constant current control circuit performs constant current control on the light-emitting diode unit as a load according to the voltage output by the power factor correction circuit.

FIG. 2 shows the circuit principle of the LED linear constant current drive controller with high power factor provided by the embodiment of the present invention. For the convenience of illustration, only the parts related to the embodiment of the present invention are shown.

In detail, the LED linear constant current drive controller with high power factor provided by the embodiment of the present invention includes: a voltage sampling circuit 12, the input end of the voltage sampling circuit 12 is connected to the output end of the rectification circuit, and is used for sampling the LED driving device. , the voltage Vinp output by the rectification circuit, and output the sampling result signal and the sampling voltage; the voltage regulation circuit 11, the input terminal of the voltage regulation circuit 11 is connected to the first output terminal of the voltage sampling circuit 12, and the power supply terminal of the voltage regulation circuit 11 is connected to the rectification circuit The output terminal of the voltage regulating circuit 11 is connected to the positive input terminal of the light-emitting diode unit as the load, and is used to adjust the voltage Vinp output by the rectifier circuit according to the sampling result signal, and output it to the positive input terminal of the light-emitting diode unit. Input terminal; power factor correction circuit 14, the input terminal of power factor correction circuit 14 is connected to the second output terminal of voltage sampling circuit 12, and is used for outputting after square or equivalent processing to sampled voltage; Constant current control circuit 13, constant current The first input end of the control circuit 13 is connected to the negative input end of the light-emitting diode unit, and the second input end of the constant current control circuit 13 is connected to the output end of the power factor correction circuit 14, which is used for outputting the voltage according to the power factor correction circuit 14. The LED unit performs constant current control.

The LED linear constant current drive controller with high power factor provided by the embodiment of the present invention samples the voltage output by the rectifier circuit through the voltage sampling circuit, and outputs the sampling result signal and the sampling voltage; the sampling result signal is input to the voltage regulation circuit, if If the voltage output by the rectifier circuit is too high or too low, it will be regulated by the voltage regulating circuit, and then output to the positive input terminal of the light-emitting diode unit as the load, and the sampling voltage is input to the power factor correction circuit, and the power factor correction circuit will sample The voltage is output after being squared or equivalently processed, and then the constant current control circuit performs constant current control on the light emitting diode unit as a load according to the voltage output by the power factor correction circuit 14. Compared with the existing linear LED constant current drive control circuit with high power factor, while improving the power factor and reducing the pollution to the power grid, it also makes all the LEDs in the light-emitting diode unit light up at the same time, which improves the utilization of LEDs. rate; at the same time, the wide-range adjustment of the input voltage is realized by using the voltage regulation circuit 11, and it is safe and reliable.

FIG. 3 shows the circuit principle of the voltage regulation circuit 11 in FIG. 2 .

Specifically, the voltage regulation circuit 11 may include: a voltage selection circuit 111 , and further includes a boost circuit 112 and/or a voltage drop circuit 113 . The input terminal of the voltage selection circuit 111 is connected to the output terminal of the voltage sampling circuit 12 as the input terminal of the voltage regulation circuit 11, and the power supply terminal of the voltage selection circuit 111 is connected to the output terminal of the rectifier circuit as the power supply terminal of the voltage regulation circuit. The output terminal is connected as the positive input terminal of the light-emitting diode unit as the load as the output terminal of the voltage regulating circuit 11, and the control terminal of the voltage selection circuit 111 is connected with the boost circuit 112 and/or the step-down circuit 113, and the voltage selection circuit 111 is used for sampling As a result of the signal, if the voltage Vinp output by the rectifier circuit is less than the second preset value, the booster circuit 112 is controlled to boost the voltage Vinp output by the rectifier circuit, and the voltage boosted by the booster circuit 112 is output to the light emitting diode. The positive input terminal of the diode unit, and/or according to the sampling result signal, if the voltage Vinp output by the rectifier circuit is greater than the first preset value, the step-down circuit 113 is controlled to step down the voltage Vinp output by the rectifier circuit, and the step-down The voltage after the step-down processing of the voltage circuit 113 is output to the positive input terminal of the light emitting diode unit, and the voltage selection circuit 111 is also used for according to the sampling result signal, if the voltage Vinp output by the rectification circuit is not greater than the first preset value and not less than the second If it is a preset value, the voltage Vinp output by the rectification circuit is directly output to the positive input end of the light emitting diode unit.

FIG. 4 shows the circuit of the voltage sampling circuit 12 in FIG. 2 .

Specifically, the voltage sampling circuit 12 may include: a resistor R0 , a resistor R1 , a resistor R2 , a resistor R3 , a comparator U1 and a comparator U2 . Wherein, the resistor R3, the resistor R2, the resistor R1 and the resistor R0 are sequentially connected in series between the output terminal of the rectifier circuit and the ground, and the end of the resistor R3 not connected to the resistor R2 is used as the input terminal of the voltage sampling circuit 12; the resistor R3 and the resistor R2 One end of the connection is connected to the non-inverting terminal + of the comparator U1 at the same time, and the inverting terminal - of the comparator U1 is connected to the first reference voltage Vrh; the end connected to the resistor R2 and the resistor R1 is simultaneously connected to the non-inverting terminal + of the comparator U2, and the inverting terminal of the comparator U2 Inverting terminal - connected to the second reference voltage Vrl; one end connected to the resistor R1 and the resistor R0 is simultaneously used as the second output terminal of the voltage sampling circuit 12 and connected to the input terminal of the power factor correction circuit 14; the output terminal of the comparator U1 and the comparator The output terminals of U2 serve as the first output terminal of the voltage sampling circuit 12 and are connected to the input terminal of the voltage selection circuit 111 .

FIG. 5 shows the circuit of the voltage selection circuit 111 in FIG. 3 .

Specifically, the voltage selection circuit 111 may include: an N-channel metal-oxide-semiconductor field effect transistor (hereinafter referred to as a MOS transistor) Q1, an N-channel MOS transistor Q2, an N-channel MOS transistor Q3, and an N-channel MOS transistor. Tube Q4, N-channel MOS tube Q5, AND gate U3, inverter U4, NOR gate U5 and NOR gate U6. Wherein, the drain of the N-channel MOS transistor Q4, the drain of the N-channel MOS transistor Q3 and the drain of the N-channel MOS transistor Q1 are connected, and are jointly connected to the output end of the rectifier circuit; the N-channel MOS The source of the transistor Q5, the source of the N-channel MOS transistor Q3, and the source of the N-channel MOS transistor Q2 are connected, and are commonly connected to the positive input terminal of the light-emitting diode unit; the gate of the N-channel MOS transistor Q4 Connect the gate of the N-channel MOS transistor Q5, and jointly connect the output terminal of the AND gate U3; the gate of the N-channel MOS transistor Q1 is connected to the gate of the N-channel MOS transistor Q2, and jointly connect the NOR gate The output terminal of U6; the gate of the N-channel MOS transistor Q3 is connected to the output terminal of the NOR gate U5; an input terminal of the AND gate U3 is connected to an input terminal of the NOR gate U5 and an input terminal of the NOR gate U6, And connect the output end of voltage sampling circuit 12 commonly, with reference to Fig. 4, then connect the output end of comparator U1; Another input end of AND gate U3 connects the input end of inverter and another input end of NOR gate U6, And connect the output end of voltage sampling circuit 12 commonly, referring to Fig. 4, then connect the output end of comparator U2; The output end of inverter U4 connects another input end of NOR gate U5; The MOS transistor Q4 of N channel The source and the drain of the N-channel MOS transistor Q5 are connected to the step-down voltage 113 , and the source of the N-channel MOS transistor Q1 and the drain of the N-channel MOS transistor Q2 are connected to the boost circuit 112 .

FIG. 6 shows the circuit of the power factor correction circuit 14 in FIG. 2 .

Specifically, the power factor correction circuit 14 may include: a multiplier 141, the input terminal of the multiplier 141 is used as the input terminal of the power factor correction circuit 14, and the output terminal of the multiplier 141 is used as the output terminal of the power factor correction circuit 14, for The sampled voltage is output after square or equivalent processing. The multiplier circuit belongs to the well-known technology in the art, and will not be repeated here.

FIG. 7 shows the circuit of the constant current control circuit 13 in FIG. 2 .

Specifically, the constant current control circuit 13 includes: an error amplifier U7, an N-channel MOS transistor Q6 and a resistor R4. Wherein, the non-inverting terminal of the error amplifier U7 is connected to the output terminal of the power factor correction circuit 14 as the second input terminal of the constant current control circuit 13, the inverting terminal of the error amplifier U7 is grounded through the resistor R4, and the output terminal of the error amplifier U7 Connect the gate of the MOS transistor Q6 of the N-channel; the drain of the MOS transistor Q6 of the N-channel is used as the first input end of the constant current control circuit 13 to connect the negative input end of the light-emitting diode unit; the MOS transistor Q6 of the N-channel The source is connected to the inverting terminal - of the error amplifier U7.

FIG. 8 shows the circuit of the LED unit in FIG. 2 .

In the embodiment of the present invention, the light-emitting diode unit as a load may include at least one set of light-emitting diode groups. If the light-emitting diode unit includes two or more light-emitting diode groups, the two or more light-emitting diode groups are mutually connected in parallel. Each light emitting diode group includes at least one light emitting diode. If the light emitting diode group includes two or more light emitting diodes, the two or more light emitting diodes are connected in sequence from end to end. The anode of the LED group is used as the positive input terminal of the LED unit, and the cathode of the LED group is used as the negative input terminal of the LED unit.

In the embodiment of the present invention, the boost circuit 112 can be realized by using an existing charge pump structure, and can adopt a one-stage or multi-stage boost structure, and the specific structure is well known in the art, and will not be described in detail here; the step-down circuit 113 An existing structure of a linear voltage regulator can be used, and the specific structure is well known in the art, and will not be repeated here. The working principle of the above circuit will be described in detail below in conjunction with Fig. 4 to Fig. 8:

Assume that the first preset value is VH, the second preset value is VL, and VH>VL. For the voltage sampling circuit 12, when the output voltage Vinp of the rectifier circuit is lower than the second preset value VL, that is, when the resistance divided voltage is lower than the second reference voltage Vrl of the inverting terminal of the comparator U2, the output voltage of the comparator U2 Level EN1 is low level (denoted as 0), at this time the output voltage Vinp of the rectifier circuit is lower than the first preset value VH, and the resistor divider is lower than the first reference voltage Vrh at the inverting terminal of the comparator U1, so the comparator The output level EN2 of U1 is low level (marked as 0), then the sampling result signal output by the voltage sampling circuit 12 is 00; when the output voltage Vinp of the rectifying circuit is less than or equal to the first preset value VH and greater than or equal to the first When the second preset value is VL, that is, the resistance divided voltage is lower than the first reference voltage Vrh at the inverting terminal of the comparator U1, so the output level EN2 of the comparator U1 is low level (denoted as 0), and the resistance divided voltage When higher than the second reference voltage Vrl of the inverting terminal of the comparator U2, so the output level EN1 of the comparator U2 is a high level (marked as 1), then the sampling result signal output by the voltage sampling circuit 12 is 10; When the output voltage Vinp of the rectifier circuit is higher than the first preset value VH, that is, the resistor divided voltage is higher than the first reference voltage Vrh at the inverting terminal of the comparator U1, so the output level EN2 of the comparator U1 is high level ( Denoted as 1), at this time the output voltage Vinp of the rectifier circuit is higher than the second preset value VL, that is, the resistor divided voltage is higher than the second reference voltage Vrl of the inverting terminal of the comparator U2, so the output level of the comparator U2 If EN1 is at high level (denoted as 1), the sampling result signal output by the voltage sampling circuit 12 is 11.

For the voltage regulating circuit 11, when the sampling result signal is 00, the N-channel MOS transistor Q1 and the N-channel MOS transistor Q2 inside the voltage selection circuit 111 are turned on, and the output voltage Vinp of the rectifier circuit passes through the N-channel MOS transistor Q2. The voltage V1a transmitted by the tube Q1 is input to the boost voltage 112, and the boost circuit 112 boosts the input voltage V1a, and the output voltage V1b is output to the positive input terminal Voutp of the light-emitting diode unit through the N-channel MOS tube Q2 . When the sampling result signal is 10, the N-channel MOS transistor Q3 inside the voltage selection circuit 111 is turned on, and the output voltage Vinp of the rectifier circuit is output to the positive input terminal Voutp of the LED unit through the N-channel MOS transistor Q3. When the sampling result signal is 11, the N-channel MOS transistor Q4 and the N-channel MOS transistor Q5 inside the voltage selection circuit 111 are turned on, and the output voltage Vinp of the rectifier circuit is the voltage V2a after being transmitted by the N-channel MOS transistor Q4 Input to the step-down voltage 113, after the step-down circuit 113 steps down the input voltage, the output voltage V2b is output to the positive input terminal Voutp of the LED unit through the N-channel MOS transistor Q5. Through the processing of the voltage regulating circuit 11, the output voltage Vinp of the light-emitting diode single rectification circuit can be changed between the first preset value VH and the second preset value VL, thereby realizing wide-range adjustable input voltage and ensuring The circuit will not be burned out due to excessive voltage fluctuations.

For the power factor correction circuit 14, the correction principle of its power factor is: assume that after being rectified by the rectifier circuit, the instantaneous value of the voltage input to the LED linear constant current drive controller with high power factor is Vinp (t), and the peak value is Vp, the half-wave sine signal is |sin wt|; after being rectified by the rectifier circuit, the instantaneous value of the current input to the LED linear constant current drive controller with high power factor is Iin(t); The output instantaneous power of the LED linear constant current drive controller is pout(t), the input instantaneous power of the LED linear constant current drive controller with high power factor is pin(t), the LED linear constant current with high power factor The efficiency of drive controller is η; This has the instantaneous value of the output current of the LED linear constant current drive controller of high power factor (that is the instantaneous current of load is iout (t); The sum of the voltage drop of load is Vled; k= Vp·Ip·η represents a fixed constant, the cycle of the AC mains is Tac, and the average value of the output current of the half-wave sine signal within one cycle is Iout_avg(T).

Then the half-wave sinusoidal signal of the AC mains after the rectification circuit can be expressed as: Vinp(t)=Vp·|sin wt|. To achieve a high power factor, it is required that the input voltage and input current of the LED linear constant current drive controller with high power factor change in the same phase, so that the instantaneous value of the input current is also required to be a sinusoidal half-wave signal in the same phase, which means It is: Iin(t)＝Ip·|sin wt|. It can be seen from the power calculation formula that pout(t)=pin(t)·η, namely: Vp·|sin wt|·Ip·|sin wt|·η=iout(t)·Vled, then the high power The instantaneous value iout(t) of the output current of the LED linear constant current drive controller satisfies:

$\mathrm{<span\; class="notranslate">\; iout</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Vp</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; wt</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; IP</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; wt</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&eta;</span>}}{\mathrm{<span\; class="notranslate">\; Vled</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; sin</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; wt</span>}$

Then the average value Iout_avg(T) of the output current of the half-wave sinusoidal signal in one cycle satisfies: $\mathrm{Iout}\_\mathrm{avg}\left(T\right)={\&Integral;}_0^{\frac{\mathrm{Tac}}{2}}\frac{\mathrm{iout}\left(t\right)\mathrm{dt}}{\frac{\mathrm{Tac}}{2}},$ Based on the above formulas, we can get: $\mathrm{Iout}\_\mathrm{avg}\left(T\right)=\frac{1}{2}\&Center\; Dot;k.$

It can be seen from the above analysis that as long as the instantaneous value of the output current of the LED linear constant current drive controller with high power factor is the square signal of the input sine half-wave signal, the input voltage and the input current can be in the same phase, thereby obtaining high power factor. At the same time, the average value of the output current is also constant, realizing constant current control. In the embodiment of the present invention, the output voltage Vs2 of the power factor correction circuit 14 satisfies: This voltage is a constant in the half-wave sine cycle, and this voltage is input to the constant current control circuit 13, it can be seen that the average value of the output current of the LED linear constant current drive controller with high power factor is a fixed value, thereby realizing constant current. flow control while meeting high power factor requirements.

For the constant current control circuit 13, the value of Vs2 and the resistance of the resistor R4 determine the constant current working current of the LED unit, assuming that the constant current working current is I _led , then I _led =Vs2/R4.

The embodiment of the present invention also provides an LED driving device, including a rectification circuit, and the LED linear constant current driving controller with high power factor as described above. Among them, the rectification circuit includes a rectification bridge. Compared with other existing LED drive devices, there is no need for high-voltage electrolytic capacitors to process the output voltage of the rectification circuit between the rectification circuit and the LED linear constant current drive controller with high power factor. , prolong the service life of the LED driver.

In summary, the LED linear constant current drive controller with high power factor provided by the embodiment of the present invention samples the voltage output by the rectifier circuit through the voltage sampling circuit, and outputs the sampling result signal and sampling voltage; the sampling result signal is input to Voltage regulation circuit, if the voltage output by the rectifier circuit is too high or too low, it will be regulated by the voltage regulation circuit, and output to the positive input terminal of the light-emitting diode unit as the load, and the sampling voltage is input to the power factor correction circuit, and the power The factor correction circuit performs square or equivalent processing on the sampled voltage and outputs it, and then the constant current control circuit performs constant current control on the LED unit as a load according to the voltage output by the power factor correction circuit 14 . Compared with the existing linear LED constant current drive control circuit with high power factor, while improving the power factor and reducing the pollution to the power grid, it also makes all the LEDs in the light-emitting diode unit light up at the same time, which improves the utilization of LEDs. rate; at the same time, the wide-range adjustment of the input voltage is realized by using the voltage regulation circuit 11, and it is safe and reliable. In addition, in the LED drive device using the LED linear constant current drive controller with high power factor, no high-voltage electrolytic capacitor is needed between the rectifier circuit and the LED linear constant current drive controller with high power factor to carry out the voltage output from the rectifier circuit. treatment, prolonging the service life of the LED driver.

Those of ordinary skill in the art can understand that all or part of the steps in the methods of the above embodiments can be implemented by controlling related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage Media such as ROM/RAM, magnetic disk, optical disk, etc.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (7)

1. there is a LED linear constant current driving governor for High Power Factor, it is characterized in that, described in there is High Power Factor LED linear constant current driving governor comprise:

Voltage sampling circuit, for the voltage that rectification circuit in LED drive device of sampling exports, and exports sampled result signal and sampled voltage;

Voltage regulator circuit, for according to described sampled result signal, after regulating, exports to the positive input terminal of light emitting diode to the size of the voltage that described rectification circuit exports;

Power factor correction circuit, exports after described sampled voltage being done to square process;

Constant-current control circuit, for the voltage exported according to described power factor correction circuit, carries out current constant control to described light emitting diode;

Described voltage regulator circuit comprises voltage selecting circuit, also comprises booster circuit and/or reduction voltage circuit;

Described voltage selecting circuit is used for according to described sampled result signal, if the voltage that described rectification circuit exports is less than the second preset value, then control described booster circuit and boosting process is carried out to the voltage that described rectification circuit exports, and the voltage after described booster circuit boosting process is exported to the positive input terminal of described light emitting diode, and/or according to described sampled result signal, if the voltage that described rectification circuit exports is greater than the first preset value, then control described reduction voltage circuit and step-down process is carried out to the voltage that described rectification circuit exports, and the voltage after described reduction voltage circuit step-down process is exported to the positive input terminal of described light emitting diode,

Described voltage selecting circuit comprises: the metal-oxide-semiconductor Q5 of metal-oxide-semiconductor Q4, N raceway groove of metal-oxide-semiconductor Q3, N raceway groove of metal-oxide-semiconductor Q2, N raceway groove of metal-oxide-semiconductor Q1, N raceway groove of N raceway groove, with door U3, inverter U4, NOR gate U5 and NOR gate U6;

The drain electrode of the drain electrode of the metal-oxide-semiconductor Q4 of described N raceway groove, the metal-oxide-semiconductor Q3 of described N raceway groove is connected with the drain electrode of the metal-oxide-semiconductor Q1 of described N raceway groove, and the common output connecting described rectification circuit; The source electrode of the source electrode of the metal-oxide-semiconductor Q5 of described N raceway groove, the metal-oxide-semiconductor Q3 of described N raceway groove is connected with the source electrode of the metal-oxide-semiconductor Q2 of described N raceway groove, and the common positive input terminal connecting described light emitting diode; The grid of the metal-oxide-semiconductor Q4 of described N raceway groove connects the grid of the metal-oxide-semiconductor Q5 of described N raceway groove, and common connection is described and the output of door U3; The grid of the metal-oxide-semiconductor Q1 of described N raceway groove connects the grid of the metal-oxide-semiconductor Q2 of described N raceway groove, and the common output connecting described NOR gate U6; The grid of the metal-oxide-semiconductor Q3 of described N raceway groove connects the output of described NOR gate U5; Describedly be connected an input of described NOR gate U5 and an input of described NOR gate U6 with an input of door U3, and the common output connecting described voltage sampling circuit; Describedly be connected the input of described inverter U4 and another input of described NOR gate U6 with another input of door U3, and the common output connecting described voltage sampling circuit; The output of described inverter U4 connects another input of described NOR gate U5; The source electrode of the metal-oxide-semiconductor Q4 of described N raceway groove is connected described step-down voltage with the drain electrode of the metal-oxide-semiconductor Q5 of described N raceway groove, and the source electrode of the metal-oxide-semiconductor Q1 of described N raceway groove is connected described booster circuit with the drain electrode of the metal-oxide-semiconductor Q2 of described N raceway groove.

2. there is the LED linear constant current driving governor of High Power Factor as claimed in claim 1, it is characterized in that, described voltage selecting circuit is also for according to described sampled result signal, if the voltage that described rectification circuit exports is not more than the first preset value and is not less than the second preset value, then the direct positive input terminal voltage that described rectification circuit exports being exported to described light emitting diode.

3. have the LED linear constant current driving governor of High Power Factor as claimed in claim 1, it is characterized in that, described voltage sampling circuit comprises: resistance R0, resistance R1, resistance R2, resistance R3, comparator U1 and comparator U2;

Between the output that described resistance R3, described resistance R2, described resistance R1 and described resistance R0 are connected on described rectification circuit successively and ground; One end that described resistance R3 is connected with described resistance R2 connects the in-phase end of described comparator U1 simultaneously, and the end of oppisite phase of described comparator U1 connects the first reference voltage; One end that described resistance R2 is connected with described resistance R1 connects the in-phase end of described comparator U2 simultaneously, and the end of oppisite phase of described comparator U2 connects the second reference voltage; One end that described resistance R1 is connected with described resistance R0 connects the input of described power factor correction circuit simultaneously; Output and the output of described comparator U2 of described comparator U1 are connected the input of described voltage selecting circuit jointly.

4. have the LED linear constant current driving governor of High Power Factor as claimed in claim 1, it is characterized in that, described constant-current control circuit comprises: the metal-oxide-semiconductor Q6 of error amplifier U7, N raceway groove and resistance R4;

The in-phase end of described error amplifier U7 connects the output of described power factor correction circuit, and the end of oppisite phase of described error amplifier U7 is by described resistance R4 ground connection, and the output of described error amplifier U7 connects the grid of the metal-oxide-semiconductor Q6 of described N raceway groove; The drain electrode of the metal-oxide-semiconductor Q6 of described N raceway groove connects the negative input end of described light emitting diode; The source electrode of the metal-oxide-semiconductor Q6 of described N raceway groove connects the end of oppisite phase of described error amplifier U7.

5. have the LED linear constant current driving governor of High Power Factor as claimed in claim 1, it is characterized in that, described power factor correction circuit comprises:

Multiplier, exports after described sampled voltage being done to square process.

6. there is the LED linear constant current driving governor of High Power Factor as claimed in claim 1, it is characterized in that, described light emitting diode comprises at least one group of light-emitting diode group parallel with one another, and each light-emitting diode group comprises the light-emitting diode that at least one head and the tail connects in turn.

7. a LED drive device, comprises rectification circuit, it is characterized in that, described LED drive device also comprises the LED linear constant current driving governor with High Power Factor as described in any one of claim 1 to 6.