TW201626848A - LED driver and driving method thereof - Google Patents

Abstract

An analog feed-forward control circuit generates a first processing signal in response to a load current, comprises an adder unit outputting a first control signal in response to the first processing signal and a second processing signal, wherein the first processing signal and the second processing signal determine an external specific frequency, and the external specific frequency determines a stability of the load current, and a voltage-to-current converter circuit outputting a second control signal in response to the first control signal to control the external specific frequency.

Description

Light-emitting diode driving circuit and driving method thereof

The invention relates to a light emitting diode driving circuit and a driving method thereof, in particular to a light emitting diode driving circuit including an analog feedforward control circuit.

Light-emitting diodes (LEDs) have the following advantages: long life (about 35,000 to 50,000 hours), low power consumption and high luminous efficiency (greater than 100 lm / W), so it has become the mainstream of new generation lighting. LED driver circuits are of course also expected to have long life, high stability and high efficiency.

The first figure shows a conventional LED driving circuit including an AC/DC power factor correction (PFC) converter and a DC/DC converter. Circuit diagram. The conventional LED driving circuit 1 has an AC/DC PFC converter 11, a busbar capacitor _Cbus , a DC/DC converter 12, and a plurality of LEDs 13 electrically connected in series.

The second figure shows a schematic circuit diagram of a conventional LED driving circuit including an AC/DC PFC converter. The conventional light emitting diode drive circuit 2 having an AC / DC PFC converter 11, an output capacitor C _o LED is connected electrically in series and a plurality of 13.

Usually, the LED driver needs to use an electrolytic capacitor. The AC/DC PFC converter makes the input current i _in follow the input voltage v _in , the input power P _in is a sine wave form, and the LED output power P _o is a continuous current form, which needs to be treated with an electrolytic capacitor. Energy difference. As shown in the third figure, it is a waveform diagram of the input power of the AC/DC power factor correction converter of a conventional LED driving circuit and the output power of the LED driving circuit with respect to time. When the input power is greater than the output power, the electrical energy is stored in the electrolytic capacitor. When the input power is less than the output power, the electrical energy stored in the electrolytic capacitor is released to the load, so that the output power is maintained at a stable level. However, if there is no electrolytic capacitor output, there will be a large current ripple on the LED, and the LED lifetime and light efficiency will decrease. However, on the other hand, the electrolytic capacitor limits the life of the LED driving circuit, which has a relatively short life (5,000 to 10,000 hours) and halve its lifetime due to a temperature rise of 10 °C.

Traditional methods of replacing electroless capacitors include: 1. Harmonic injection method: 3 ^rd and 5 ^th harmonics are injected into the input terminal to reduce the output current ripple, multipliers and dividers are required, the control circuit is complicated, and the power factor is poor. Not suitable for high-power applications; 2. Using bi-directional circuits: processing energy differences through bidirectional circuits, less efficient in high-power applications, more components, higher cost; 3. Digital feedforward control method: through digital feedforward control The device reduces the current chopping, and most of them are composed of digital components, and the cost is large. Therefore, how to overcome the above shortcomings and envisage a device and method for replacing the electroless capacitor is worth pondering.

For the sake of his position, the inventor, in view of the lack of prior art, is Considering the idea of improving the invention, the "light-emitting diode driving circuit and its driving method" of the present invention can be invented.

The main purpose of this case is to provide an analog feedforward Controlled electroless capacitor LED driver circuit, the front stage is AC/DC PFC converter to improve power factor, the latter stage is DC/DC converter, providing stable output current, suitable for high power applications, and has analog feedforward The control circuit is used to reduce the current chopping to replace the electrolytic capacitor. Since the control circuit is composed of analog components, it has the advantages of small volume and low cost.

Another main purpose of the case is to provide a light-emitting diode The body driving circuit comprises an AC to DC conversion circuit, and outputs a first feedback signal and a DC power signal in response to an AC power signal, and a power factor correction controller is electrically connected to the AC to DC conversion circuit and regulated The DC power signal is continuously converted to a DC conversion circuit, and the DC power signal is converted into a first current for supply to a light emitting diode device, and an analog feed forward control circuit detects the first current to obtain a second The feedback signal receives the first feedback signal and includes a first-stage adder, including an adding unit, adding the first feedback signal and the second feedback signal to output a first control signal and an inversion The amplifying unit outputs a second control signal in response to the first control signal, and a voltage-to-current conversion unit outputs a third control signal in response to the second control signal, wherein the third control signal has a second current And a DC controller that is always connected between the DC-to-DC conversion circuit and the analog feedforward control circuit And controlling the first current, wherein the DC-DC controller outputs a fourth control signal having a specific frequency in response to the third control signal, where the second control signal is used to regulate the second current, the third control The signal is used to regulate the specific frequency, and the specific frequency The rate is used to regulate the first current to maintain the stability of the first current.

Another main purpose of the case is to provide a light-emitting diode The driving method of the body driving circuit comprises the steps of: outputting a first feedback signal and a direct current power signal in response to an AC power signal; converting the DC power signal into a first current to be supplied to a light emitting diode device; Detecting the first current to obtain a second feedback signal, and receiving the first feedback signal; adding the first feedback signal and the second feedback signal to output a first control signal; responding to the first control signal And outputting a second control signal, wherein the second control signal has a second current; and outputting a third control signal having a specific frequency in response to the second control signal, wherein the first control signal is used to regulate the a second current, the second control signal is used to regulate the specific frequency, and the specific frequency is used to regulate the first current to maintain the stability of the first current.

The main purpose of this case is to provide an analog feedforward The control circuit generates a first processing signal according to a load current, and includes an adding unit for outputting a first control signal according to the first processing signal and a second processing signal, wherein the first processing signal and the first processing signal The second processing signal determines an external specific frequency, and the external specific frequency determines one of the load current stability, and a voltage-to-current conversion unit outputs a second control signal in response to the first control signal to control The extrinsic specific frequency.

In order to achieve the above objects, features, and advantages of the present invention It is more obvious and easy to understand. The preferred embodiments are described below, and the detailed description is as follows:

1‧‧‧ A conventional LED driving circuit comprising an AC/DC PFC converter and a DC/DC converter

11‧‧‧AC/DC PFC Converter

12‧‧‧DC/DC Converter

13‧‧‧Multiple LEDs connected in series

2‧‧‧Light-emitting diode driving circuit including an AC/DC PFC converter

3‧‧‧Light emitting diode driving circuit of the first preferred embodiment of the present invention

31‧‧‧Boost PFC Converter

32‧‧‧LLC resonant converter

33‧‧‧ analog feedforward control circuit

331‧‧‧secondary adder

332‧‧‧voltage to current conversion unit

333‧‧‧compensation circuit

3331‧‧‧Compensator circuit

3332‧‧‧Photocoupler

34‧‧‧PFC controller

35‧‧‧Resonance controller

4‧‧‧Light emitting diode driving circuit of the second preferred embodiment of the present invention

41‧‧‧PFC converter with buck/boost/return/return architecture

411‧‧‧Buck/Lifting/Reducing/Returning Architecture

5‧‧‧Light-emitting diode driving circuit of the third preferred embodiment of the present invention

51‧‧‧Resonant converter with SRC/PRC architecture

511‧‧‧SRC/PRC Architecture

6‧‧‧Light-emitting diode driving circuit of the fourth preferred embodiment of the present invention

61‧‧‧DC/DC converter with buck/return architecture

611‧‧‧Buck/Return Architecture

62‧‧‧DC-DC controller

7. The light-emitting diode driving circuit of the fifth preferred embodiment of the present invention

71‧‧‧DC/DC converter with buck/return architecture and other forms of load

711‧‧‧Other forms of load

8. The light-emitting diode driving circuit of the sixth preferred embodiment of the present invention

81‧‧‧Control integrated circuit of resonant converter

82‧‧‧voltage circuit

9‧‧‧Light-emitting diode driving circuit of the seventh preferred embodiment of the present invention

91‧‧‧LLC architecture

92‧‧‧Two-way AC current ripple canceller

93‧‧‧ Pulse width modulation controller

94‧‧‧ analog feedback circuit

First: It shows a schematic circuit diagram of a conventional LED driving circuit including an AC/DC power factor correction converter and a DC/DC converter.

Second: It shows a schematic circuit diagram of a conventional LED driving circuit including an AC/DC power factor correction converter.

Fig. 3 is a waveform diagram showing the input power of an AC/DC power factor correction converter of a conventional LED driving circuit and the output power of the LED driving circuit with respect to time.

Fourth FIG. 4 is a circuit diagram showing a light emitting diode driving circuit according to a first preferred embodiment of the present invention.

Fig. 5 is a circuit diagram showing a light-emitting diode driving circuit according to a second preferred embodiment of the present invention.

Fig. 6 is a circuit diagram showing a light-emitting diode driving circuit according to a third preferred embodiment of the present invention.

Figure 7 is a circuit diagram showing a light-emitting diode driving circuit according to a fourth preferred embodiment of the present invention.

Figure 8 is a circuit diagram showing a light-emitting diode driving circuit according to a fifth preferred embodiment of the present invention.

Figure 9 is a circuit diagram showing a light-emitting diode driving circuit in accordance with a sixth preferred embodiment of the present invention.

Fig. 10 is a circuit diagram showing a light-emitting diode driving circuit according to a seventh preferred embodiment of the present invention.

The fourth figure is a circuit diagram of a light emitting diode driving circuit according to a first preferred embodiment of the present invention. In the fourth figure, the LED driving circuit 3 includes a boosting power factor correction converter (boost PFC converter) 31, an LLC resonant converter 32, an analog feedforward control circuit 33, and a The PFC controller is coupled to a resonant controller 35. The analog feedforward control circuit 33 includes a two-stage adder 331, a voltage-to-current conversion unit 332 (which is an emitter follower, and the emitter follower is a bipolar transistor emitter with coupling) a compensation circuit 333 and a blocking capacitor C _block .

In the fourth figure, the boosting PFC converter 31 outputs a first feedback signal v _feed and a DC power signal V _{bus in} response to an AC power signal v _ac , and the PFC controller 34 is electrically connected to the boost PFC. The converter 31 regulates the DC power signal V _bus , and the LLC resonant converter 32 converts the DC power signal V _bus into a first current I _LED for supply to a light emitting diode device (which is a plurality of series devices) Connected LED13 and a voltage divider resistor). The plurality of serially connected LEDs 13 are electrically connected in series to one end of the voltage dividing resistor, the other end of the voltage dividing resistor is grounded, and the analog feedforward control circuit 33 detects the first current I _LED to obtain a second feedback. Signal v _LED and receive the first feedback signal v _feed . The adding unit (including resistors R8, R9, and R10) included in the second adder 331 adds the first feedback signal v _feed and the second feedback signal v _LED to output a first control signal, and The inverting amplifying unit (including the resistors R11 and R12) included in the second-stage adder 331 outputs a second control signal v _{crtl in} response to the first control signal, and the voltage-to-current converting unit 332 includes a transistor and The resistors R6 and R7 output a third control signal in response to the second control signal v _crtl , wherein the third control signal has a second current, and the resonant controller 35 is electrically connected to the LLC resonant converter 32 and the Analogously controlling the first current between the feedforward control circuit 33, wherein the resonant controller 35 outputs a fourth control signal having a specific frequency in response to the third control signal, wherein the second control signal is used to regulate The second current, the third control signal is used to regulate the specific frequency, and the specific frequency is used to regulate the first current to maintain the stability of the first current.

As shown in FIG. 4, the boost PFC converter 31 has a first and a second output terminal, a first voltage dividing circuit (including resistors R ₃ and R ₄ and an output terminal) and a bus capacitor C. _Bus , the first voltage dividing circuit and the bus bar capacitor C _bus are electrically connected in parallel to the first and second output ends, and the first voltage dividing circuit is configured to generate an output voltage signal v _fb , the analogy The feedforward control circuit 33 further includes a blocking capacitor C _block , and the blocking capacitor C _block receives the output voltage signal v _fb and blocks the DC component of the output voltage signal to obtain the first wave with a 120 Hz chopping a feedback signal v _feed , the LLC resonant converter 32 has a first and a second output end and an output capacitor C _o , the output capacitor C _{o is} electrically connected in parallel to the LED device 13 and the LLC resonant conversion The first and the second output of the device 32. The bus bar capacitor C _bus and the output capacitor C _o are both a non-electrolytic capacitor.

Referring to the fourth figure, the compensation circuit 333 includes a compensator circuit 3331 and a photocoupler 3332. The compensation circuit 333 receives the second feedback signal v _LED and outputs a compensated second feedback signal v _LED to the addition. The compensator circuit 3331 includes a compensator having an input end and an output end, and a comparator having an inverting input terminal, a non-inverting input terminal and an output terminal, and the photocoupler 3332 has An input terminal and an output terminal, wherein the inverting input terminal is electrically connected to the input end of the compensator, and receives the second feedback signal v _LED , and the non-inverting input terminal receives a reference voltage I _ref to two feedback signal v _LED comparator, the output terminal of the comparator of the output terminal of the compensator is the sum of the optocoupler to the input terminal is electrically connected to 3332 of, and the output terminal of the photocoupler 3332 of the addition unit is electrically Connected to output the compensated second feedback signal v _LED .

In the fourth figure, the boost PFC converter 31 further includes a rectifier having four diodes and electrically connected to the rectifying circuit of alternating current v _ac power supply, electrically connected in parallel to a capacitance C _in the input of the rectifier circuit, a second voltage dividing circuit having resistors R ₁ and R ₂ and electrically connected in parallel to the input capacitor C _in , and having an inductor L, a switch S1 and a diode D1, and electrically connected in parallel to the first The boosting architecture of the two-divider circuit.

In the fourth figure, the LLC resonant converter 32 further includes a A half bridge switching device having switches S2 and S3, a resonant inductor Lr, a resonant capacitor Cr, a magnetizing inductor Lm, a transformer T1 and diodes D2 and D3. As shown in the fourth figure, the PFC controller 34 is electrically connected to the gate of the switch S1, the output end of the first voltage dividing circuit and the output end of the second voltage dividing circuit. The resonant controller 35 is electrically connected to the gate of the switch S2 The gate of the switch S3 and one end of the resistor R7 of the emitter follower 332.

The fifth figure is a second preferred embodiment in accordance with the inventive concept A schematic diagram of a circuit of a light-emitting diode driving circuit. The LED driving circuit 4 shown in FIG. 5 is different from the LED driving circuit 3 shown in FIG. 4 in that the boosting PFC converter 31 in the fourth figure is A PFC converter 41 having a step-down buck-boost/return architecture 411 is replaced. The PFC converter 41 is selected from the group consisting of a boost type power factor correction converter, a step-down power factor correction converter, a buck-boost type power factor correction converter and a flyback type power factor correction converter. One of the groups.

The sixth figure is a third preferred embodiment in accordance with the inventive concept A schematic diagram of a circuit of a light-emitting diode driving circuit. The LED driving circuit 5 shown in FIG. 6 is different from the LED driving circuit 4 shown in FIG. 5 in that the LLC resonant converter 32 in the fifth figure is The resonant converter 51 having the SRC/PRC architecture 511 is replaced. The resonant converter 51 is an SRC resonant converter or a PRC resonant converter.

The seventh figure is a fourth preferred embodiment in accordance with the inventive concept A schematic diagram of a circuit of a light-emitting diode driving circuit. The LED driving circuit 6 shown in the seventh figure is different from the LED driving circuit 5 shown in FIG. 6 in that the resonant converter 51 in the sixth figure is The DC-to-DC conversion circuit 61 of the buck/return architecture 611 is replaced, and the resonance controller 35 is taken by a DC-DC controller 62. generation. Of course, the DC-to-DC converter circuit 61 may also be one selected from the group consisting of a boost converter, a buck converter, a buck-boost converter, and a flyback converter.

The eighth figure is a fifth preferred embodiment in accordance with the inventive concept A schematic diagram of a circuit of a light-emitting diode driving circuit. The LED driving circuit 7 shown in the eighth figure is different from the LED driving circuit 6 shown in FIG. 7 in the plurality of LEDs electrically connected in series in the seventh figure. 13 is replaced by a other form of load 711. Of course, the "other form of load 711" means that it is not the plurality of LEDs 13 connected in series.

Figure 9 is a circuit diagram of a light emitting diode driving circuit in accordance with a sixth preferred embodiment of the present invention. In the ninth diagram, the LED driving circuit 8 includes an integrated circuit 81 for controlling a resonant converter, the analog feedforward control circuit 33 and a voltage dividing circuit 82. The integrated circuit includes a chip L6599, a resistor R _{f (limit)} and a capacitor C _f , wherein the resistor R _{f (limit) is} used to control an operating frequency f _{s of} the resonant converter. The voltage dividing circuit 82 has two voltage dividing resistors R _fb1 and R _fb2 and an output terminal, and one end of the voltage dividing resistor R _fb1 receives the DC bus voltage V _{DC_bus} , and the output terminal of the voltage dividing circuit 82 One end of the blocking capacitor C _block is electrically connected, and the function of the voltage dividing circuit 82 is the same as the second voltage dividing circuit included in the boosting PFC converter 31 in the fourth figure.

Figure 11 is a circuit diagram of a light-emitting diode driving circuit in accordance with a seventh preferred embodiment of the present invention. In the tenth figure, the LED driving circuit 9 includes a boost PFC converter 31 and an LLC resonant converter 32 (including an LLC architecture 91, an output capacitor Co, and a plurality of series connected LEDs 13 and one). Voltage divider resistor), an analog feedforward control circuit 33, a PFC controller 34, a resonant controller 35, a bidirectional AC current ripple eliminator 92, a pulse width modulation controller 93 and an analog feedback circuit 94. The LED driving circuit 9 has an input power P _in and an output power P _o . The bidirectional AC current chopping eliminator 92 includes an inductor L _B , a capacitor C _B , two switching switches S ₄ and S _{5 ,} and a voltage dividing circuit having voltage dividing resistors R5 and R6, and the electrical connection relationship is as follows. Ten figures are shown. The voltage dividing circuit is electrically connected in parallel to the two output ends of the bidirectional AC current chopper canceler 92, and generates a voltage division of an output voltage of the LED driving circuit 9. The analog compensation circuit 94 receives the divided voltage and generates a feedback signal to the pulse width modulation controller 93. The pulse width modulation controller 93 outputs two complementary switching signals for controlling the two switching switches S ₄ and S ₅ , respectively. The bidirectional alternating current chopper canceller 92 is configured to store excess energy into the bidirectional alternating current chopper canceler 92 when the input power P _in > the output power P _o , and when the input power P _in <At the output power P _o , the insufficient energy is supplied to the load (the plurality of series-connected LEDs 13 or the other type of load 711) by the energy stored by the bidirectional AC current chopper canceller 92. Due to the action of the bidirectional alternating current ripple canceller 92, the output ripple is very small, so only a very small output capacitance C _{o is required} . Similarly, the bidirectional AC current chopper canceller 92 can also be added to the second to fifth preferred embodiments according to the present invention in the same connection manner, that is, electrically connected to the output capacitor C _o and the plurality of Between the LED 13 connected in series and the voltage dividing resistor, or electrically connected between the output capacitor C _o and the other type of load 711 and the voltage dividing resistor, the same function can be used: "The output ripple is very small. Therefore, only a very small output capacitor C _o " is required.

Example:

A light-emitting diode driving circuit comprising: an AC-to-DC conversion circuit that outputs a first feedback signal and a DC power signal in response to an AC power signal; and a power factor correction controller electrically connected to the AC a DC-to-DC conversion circuit that regulates the DC power signal; a DC-DC conversion circuit that converts the DC power signal into a first current for supply to a light-emitting diode device; and an analog feedforward control circuit that detects the first a current to obtain a second feedback signal, receiving the first feedback signal, and comprising: a first-stage adder, comprising: an adding unit, adding the first feedback signal and the second feedback signal to output one a first control signal; and an inverting amplifying unit that outputs a second control signal in response to the first control signal; and a voltage to current conversion unit that outputs a third control signal in response to the second control signal, wherein the The third control signal has a second current; a DC-to-DC controller electrically connected between the DC-to-DC conversion circuit and the analog feedforward control circuit, and controlling the first current, wherein the DC-DC controller outputs a response in response to the third control signal a fourth control signal of a specific frequency, the second control signal is used to regulate the second current, the third control signal is used to regulate the specific frequency, and the specific frequency is used to regulate the first current to maintain the first The current is stable.

2. The LED driving power according to Embodiment 1 The circuit, wherein the AC to DC conversion circuit has a first output terminal and a second output terminal, a voltage dividing circuit and a bus bar capacitor, and the voltage dividing circuit and the bus bar capacitor are electrically connected in parallel to the first and the second The second output end, the voltage dividing circuit is configured to generate an output voltage signal, the analog feed control circuit further includes a blocking capacitor, the blocking capacitor receives the output voltage signal, and is used to block the output voltage signal Flow component to obtain the first feedback signal with only 120 Hz chopping, the DC to DC conversion circuit has a first output and a second output end and an output capacitor, and the output capacitor is electrically connected in parallel to the light emitting diode The first device and the second output end of the body device and the DC to DC conversion circuit.

3. LED driving according to embodiment 1 or 2 The circuit further comprises a bidirectional AC current chopper canceler with two switchers, a pulse width modulation controller and an analog feedback circuit, wherein the LED driving circuit has an input power, an output voltage and An output power, the analog feedback circuit receives a partial voltage of the output voltage from the bidirectional AC current chopper canceler, and outputs a feedback signal, the pulse width modulation The controller receives the feedback signal and outputs two complementary switching signals for controlling the two switching switches. The bidirectional alternating current chopper canceler is electrically connected in parallel to the output capacitor, and the LED device is electrically connected in parallel. Connected to the bidirectional alternating current chopper canceller, the bidirectional alternating current chopper canceller is configured to store excess energy into the bidirectional alternating current chopper canceler when the input power > the output power, and when When the input power is <the output power, the insufficient energy is supplied to the light emitting diode device by the energy stored by the bidirectional alternating current chopper canceler to reduce the output chopping of the output capacitor, the bus bar capacitance and The output capacitor is a non-electrolytic capacitor, the AC to DC converter circuit is a power factor correction converter, the DC to DC converter circuit is a resonant converter, the DC to DC controller is a resonant controller, the illumination The diode device includes a plurality of LEDs electrically connected in series and a voltage dividing resistor having a first end and a second end, the voltage dividing resistor The second end is electrically connected to the plurality of series connected electrically connected LEDs at a first contact, the second end of the voltage dividing resistor is grounded, the first contact outputs the second feedback signal, and the voltage is turned The current conversion unit is an emitter follower.

4. The LED driving according to any of the above embodiments a power circuit, wherein the power factor correction converter is selected from the group consisting of a boost type power factor correction converter, a step-down power factor correction converter, a step-up and step type power factor correction converter, and a flyback type power factor correction One of the groups of converters, the resonant converter is selected from the group consisting of an LLC resonant converter, an SRC resonant converter and a PRC resonant converter, and the emitter is coupled The device is a bipolar transistor emitter follower.

5. The LED driving according to any of the above embodiments The dynamic circuit, wherein the DC-to-DC conversion circuit is one selected from the group consisting of a boost converter, a buck converter, a buck-boost converter, and a flyback converter.

6. The LED driving according to any of the above embodiments a dynamic circuit, wherein the analog output circuit further includes a compensation circuit, the compensation circuit receives the second feedback signal, and outputs a compensated second feedback signal to the adding unit, the compensation circuit includes an input a compensator with an output terminal, a comparator having an inverting input terminal, a non-inverting input terminal and an output terminal, and a photocoupler having an input terminal and an output terminal, the inverting input terminal The input end of the compensator is electrically connected to receive the second feedback signal, and the non-inverting input terminal receives a reference voltage for comparison with the second feedback signal, the output of the comparator, the output of the compensator The terminal is electrically connected to the input end of the photocoupler, and the output end of the photocoupler is electrically connected to the adding unit to output the compensated second feedback signal.

A driving method of a light emitting diode driving circuit, comprising the steps of: outputting a first feedback signal and a direct current power signal in response to an alternating current power signal; converting the direct current power signal into a first current to supply to a light emitting a diode device; detecting the first current to obtain a second feedback signal, and receiving the first a feedback signal; the first feedback signal and the second feedback signal are added to output a first control signal; and the second control signal is output in response to the first control signal, wherein the second control signal has a first And outputting, according to the second control signal, a third control signal having a specific frequency, wherein the first control signal is used to regulate the second current, and the second control signal is used to regulate the specific frequency, and The specific frequency is used to regulate the first current to maintain stability of the first current.

8. The driving method according to embodiment 7, wherein the LED driving circuit comprises an AC-to-DC conversion circuit, a DC-DC conversion circuit, an analogy with a two-stage adder and a voltage-to-current conversion unit. a feedforward control circuit and a DC to DC controller disposed between the DC to DC conversion circuit and the analog feedforward control circuit, the AC to DC conversion circuit outputs the first feedback signal in response to the AC power signal And the DC power signal, the DC to DC conversion circuit converts the DC power signal into the first current for supply to the LED device, and the analog feedforward control circuit detects the first current to obtain the first The second feedback signal receives the first feedback signal, and the second adder adds the first feedback signal and the second feedback signal to output the first control signal, and the voltage-to-current conversion unit responds to the first Controlling the signal and outputting the second control signal, the DC to DC controller is configured to control the first current, and the DC to DC controller responds The second control signal And outputting the third control signal having the specific frequency.

An analog feedforward control circuit for generating a first processing signal according to a load current, comprising: an adding unit, for outputting a first control signal according to the first processing signal and a second processing signal, The first processing signal and the second processing signal determine an external specific frequency, and the external specific frequency determines one of the load current stability; and a voltage-to-current conversion unit outputs the response according to the first control signal A second control signal to control the external specific frequency.

10. The analog feedforward control circuit according to Embodiment 9 is for a driving circuit, wherein the driving circuit is used for driving a load, and the driving circuit comprises an AC to DC conversion circuit and a switching circuit. a DC-to-DC conversion circuit, the load generates the load current, the DC-to-DC conversion circuit generates the first processing signal, and the AC-to-DC conversion circuit generates the second processing signal according to an AC power signal, and the external processing The specific frequency is one of the switching frequencies of the switching circuit.

11. The analog feedforward control circuit of embodiment 9 or 10, wherein the load is a light emitting diode device

In summary, the present invention provides an electroless capacitor LED driving circuit with analog feedforward control, the front stage is an AC/DC PFC converter to improve the power factor, and the latter stage is a DC/DC converter to provide stability. Output current, suitable for high power applications, and analog feedforward control circuit to reduce current chopping instead of electrolytic capacitor, because the controller is It is composed of analog components and has the advantages of small volume and low cost, so it is novel and progressive.

Therefore, even though the present invention has been described in detail by the above-described embodiments, it can be modified by those skilled in the art, and is not intended to be protected as claimed.

13‧‧‧Multiple LEDs connected in series

3‧‧‧Light emitting diode driving circuit of the first preferred embodiment of the present invention

31‧‧‧Boost PFC Converter

32‧‧‧LLC resonant converter

33‧‧‧ analog feedforward control circuit

331‧‧‧secondary adder

332‧‧‧voltage to current conversion unit

333‧‧‧compensation circuit

3331‧‧‧Compensator circuit

3332‧‧‧Photocoupler

34‧‧‧PFC controller

35‧‧‧Resonance controller

Claims (11)

An LED driving circuit comprises: an AC to DC conversion circuit, which outputs a first feedback signal and a DC power signal in response to an AC power signal; and a power factor correction controller electrically connected to the AC to DC Converting the circuit and regulating the DC power signal; continuously flowing the DC conversion circuit, converting the DC power signal into a first current for supplying to a light emitting diode device; and comparing the first current with the analog feedforward control circuit Receiving the first feedback signal, and receiving the first feedback signal, and comprising: a first-stage adder, comprising: an adding unit, adding the first feedback signal and the second feedback signal to output a first a control signal; and an inverting amplifying unit that outputs a second control signal in response to the first control signal; and a voltage to current converting unit that outputs a third control signal in response to the second control signal, wherein the third The control signal has a second current; and the DC controller is always flowing, electrically connected to the DC-to-DC conversion circuit and the analogy Between the feed control circuit, and controlling the first current, wherein the DC-DC controller in response to the third control signal to output a fourth control signal having a particular frequency, the second control signal to the regulation of The second current, the third control signal is used to regulate the specific frequency, and the specific frequency is used to regulate the first current to maintain the stability of the first current. The illuminating diode switching circuit of claim 1, wherein the ac switching circuit has a first output terminal and a second output terminal, a voltage dividing circuit and a bus bar capacitor. The circuit and the busbar capacitor are electrically connected in parallel to the first and second output terminals, and the voltage dividing circuit is configured to generate an output voltage signal, and the analog feedforward control circuit further comprises a blocking capacitor, the blocking capacitor Receiving the output voltage signal and blocking the DC component of the output voltage signal to obtain the first feedback signal with only 120 Hz chopping, the DC-to-DC conversion circuit having a first output and a second output An output capacitor electrically connected in parallel to the first and second output ends of the LED device and the DC to DC converter circuit. The illuminating diode driving circuit of claim 2, further comprising a bidirectional alternating current chopper eliminator having two switching switches, a pulse width modulation controller and an analog feedback circuit, wherein The LED driving circuit has an input power, an output voltage and an output power. The analog feedback circuit receives a partial voltage of the output voltage from the bidirectional AC current chopper canceler, and outputs a feedback signal. The pulse width modulation controller receives the feedback signal and outputs two complementary switching signals for controlling the two switching switches. The bidirectional alternating current chopper canceler is electrically connected in parallel to the output capacitor. The diode device is electrically connected in parallel to the two-way intersection a current-carrying chopper canceller for storing excess energy into the bi-directional alternating current chopper canceler when the input power > the output power, and when the input power is < At the output power, insufficient energy is supplied to the LED device by the energy stored by the bidirectional AC current chopper canceler to reduce output chopping of one of the output capacitors, and the bus capacitor and the output capacitor are both For a non-electrolytic capacitor, the AC to DC conversion circuit is a power factor correction converter, the DC to DC conversion circuit is a resonant converter, the DC to DC controller is a resonant controller, and the LED device a plurality of series-connected light-emitting diodes and a voltage dividing resistor having a first end and a second end, wherein the first end of the voltage-dividing resistor is electrically connected in series to the plurality of series-connected light-emitting diodes The pole body is grounded at a first contact, the second end of the voltage dividing resistor is grounded, the first contact outputs the second feedback signal, and the voltage to current conversion unit is an emitter follower. The illuminating diode driving circuit of claim 3, wherein the power factor correction converter is selected from the group consisting of a boost type power factor correction converter, a step-down power factor correction converter, and a buck-boost voltage One of a group consisting of a power factor correction converter and a flyback type power factor correction converter selected from the group consisting of an LLC resonant converter, an SRC resonant converter and a PRC resonant converter One of the group is formed, and the emitter follower is a bipolar transistor emitter follower. The light-emitting diode driving circuit according to claim 1, wherein The DC to DC conversion circuit is selected from the group consisting of a boost converter, a buck converter, a buck-boost converter and a flyback converter. The illuminating diode driving circuit of claim 1, wherein the analog feedforward control circuit further comprises a compensation circuit, the compensation circuit receives the second feedback signal, and outputs a compensated second feedback signal. To the adding unit, the compensation circuit includes a compensator having an input end and an output end, a comparator having an inverting input terminal, a non-inverting input terminal and an output terminal, and an input terminal An output photocoupler, the inverting input is electrically connected to the input end of the compensator, and receives the second feedback signal, the non-inverting input receiving a reference voltage for comparison with the second feedback signal, The output end of the comparator, the output end of the compensator is electrically connected to the input end of the photocoupler, and the output end of the photocoupler is electrically connected to the adding unit to output the compensated first Second feedback signal. A driving method of a driving diode driving circuit, comprising the steps of: outputting a first feedback signal and a DC power signal in response to an AC power signal; converting the DC power signal into a first current to be supplied to a light emitting diode The device detects the first current to obtain a second feedback signal, and receives the first feedback signal; Adding the first feedback signal and the second feedback signal to output a first control signal; and outputting a second control signal in response to the first control signal, wherein the second control signal has a second current; And outputting, according to the second control signal, a third control signal having a specific frequency, wherein the first control signal is used to regulate the second current, and the second control signal is used to regulate the specific frequency, and the specific frequency is used for the specific frequency. The first current is regulated to maintain the stability of the first current. The driving method of claim 7, wherein the LED driving circuit comprises an AC to DC conversion circuit, a DC to DC conversion circuit, a DC adder and a voltage to current conversion unit. An analog feedforward control circuit and a DC to DC controller disposed between the DC to DC conversion circuit and the analog feedforward control circuit, the AC to DC conversion circuit outputs the first feedback in response to the AC power signal And the DC power conversion signal, the DC to DC conversion circuit converts the DC power signal into the first current for supply to the LED device, and the analog feedforward control circuit detects the first current to obtain the signal The second feedback signal receives the first feedback signal, and the second adder adds the first feedback signal and the second feedback signal to output the first control signal, and the voltage-to-current conversion unit responds to the first Outputting the second control signal by a control signal, the DC to DC controller is configured to control the first current, and the DC to DC control The device responds to the second control signal and loses The third control signal having the specific frequency is output. An analog feedforward control circuit generates a first processing signal according to a load current, comprising: an adding unit, corresponding to the first processing signal and a second processing signal, to output a first control signal, wherein the The first processing signal and the second processing signal determine an external specific frequency, and the external specific frequency determines one of the load current stability; and a voltage-to-current conversion unit outputs a first in response to the first control signal Two control signals to control the external specific frequency. The analog feedforward control circuit as described in claim 9 is for a driving circuit, wherein the driving circuit is used for driving a load, and the driving circuit comprises an AC to DC conversion circuit and a switching a DC-to-DC conversion circuit of the circuit, the load generates the load current, the DC-to-DC conversion circuit generates the first processing signal, and the AC-to-DC conversion circuit generates the second processing signal according to an AC power signal, and the external processing signal At a specific frequency is one of the switching circuits switching frequencies. An analog feedforward control circuit as described in claim 10, wherein the load is a light emitting diode device.