TWI586210B - Lighting driving circuit and lighting apparatus - Google Patents

Description

Light-emitting drive circuit and light-emitting device

The present invention relates to a light-emitting driving circuit and a light-emitting device, and more particularly to an active self-regulating current light-emitting driving circuit and a light-emitting device.

Traditional luminaires and illuminating diode lamps usually use Triode for Alternating Current (TRIAC) as a dimmer, while triacs (TRIAC) are used in a Single Controlled Rectifier (SCR). Based on the development, it is a Thyristor consisting of two SCRs in parallel with the common gate, and it can be triggered by only one trigger circuit. It is an ideal AC switching element.

The incandescent lamp used in traditional lamps is a purely resistive load. The general power range is from 25W to 100W. It is easy to meet the working conditions of the three-terminal bidirectional AC component (TRIAC), so it will not encounter the three-terminal bidirectional AC component (TRIAC). The problem of insufficient current is maintained. However, the driving circuit power of the LED lamp is generally less than 20W, and the capacitor and the inductor energy storage component are in the driving circuit, and the input energy is not continuously consumed during the entire working cycle. It is the reason for the high efficiency of the driving circuit of the LED lamp, but it causes the sustain current of the triac (TRIAC) to be insufficient, which causes the LED in the LED lamp to flicker.

At present, the industry generally uses the phase-shift circuit (RC) charging and discharging characteristics, which will generate a holding current throughout the working cycle, but it will cause the efficiency of the driving circuit of the light-emitting diode lamp to be reduced, and affect the service life of the lamp.

Therefore, how to provide an illumination driving circuit and a light-emitting device capable of actively adjusting current has become one of important topics.

In view of the above problems, an object of the present invention is to provide an illumination driving circuit suitable for use in a light emitting device having at least one light emitting unit and a power supply circuit, wherein the power supply circuit sends a system current from an output terminal to drive The light emitting unit, and the light emitting driving circuit comprises a switching unit and a comparator. The switching unit is disposed between an output current path and a feedback current path, the output current path is electrically connected to the output end of the power supply circuit, and the current on the feedback current path is fed back to the power supply circuit, and the output current is The path does not pass through the lighting unit. The comparator is electrically connected to the switch unit, and compares a system current-related voltage and a reference voltage to output a control signal to control the switch unit. The potential of the system current-dependent voltage is determined according to the current value of the system current, wherein the comparator When the current value of the system current is less than a threshold value, a switching signal having a first state is output to make the switching unit substantially short-circuit, and when the current value of the system current is greater than a critical value, a switching signal having a second state is output to cause the switching unit Substantial disconnection.

In an embodiment, the switching unit and the comparator are disposed in an integrated circuit, and the integrated circuit has a first pin and a second pin electrically connected to the output current path and the feedback current path, respectively. And the switch unit is electrically connected to the first pin and the second pin respectively; a third pin is electrically connected to a negative pressure node on the feedback current path; and a fourth pin is electrically connected to the light The unit, and the system current flowing through the light unit flows from the fourth pin to the integrated circuit and from the second pin to the feedback current path.

In one embodiment, the illumination driving circuit further includes a detecting resistor disposed on the feedback current path, the detecting resistor has a first end electrically connected to the second pin, and the detecting resistor has a The second end is electrically connected to the negative pressure node.

In an embodiment, the integrated circuit further includes a reference voltage source electrically coupled to a first input of the comparator to provide a reference voltage, and a reference current source electrically coupled to the second of the comparator The input terminal provides a reference current: and an internal resistor having a first end and a second end electrically connected to the third pin and the second input of the comparator, wherein the reference current flows through the internal resistor, A system current related voltage is generated at the second input of the comparator.

In an embodiment, the illumination driving circuit further includes a protection diode to protect The diode has an anode end and a cathode end electrically connected to the power supply circuit and the light emitting unit, respectively, wherein the system current flows through the protective diode to the light emitting unit.

In order to achieve the above object, a lighting device according to the present invention includes a power supply circuit electrically connected to a working power supply and providing a system current from an output terminal; and an illumination unit electrically connected to the power supply circuit to Receiving system current, and being driven according to system current, and the system current is fed back to the power supply circuit through a feedback current path after passing through the illumination unit; a switching unit is disposed between an output current path and a feedback current path, The output current path is electrically connected to the output end of the power supply circuit, and the output current path does not pass through the light emitting unit; and a comparator is electrically connected to the switch unit, and compares a system current related voltage and a reference voltage to output a control The signal is used to control the switching unit, and the potential of the system current-related voltage is determined according to the current value of the system current, wherein the comparator outputs a switching signal having a first state when the current value of the system current is less than a threshold value to cause the switching unit Substantially short-circuited, and has an output when the current value of the system current is greater than a critical value Switch signal is the second state of the switching means substantial interruption.

In one embodiment, the power supply circuit includes a three-terminal bidirectional AC component having a first anode and a second anode, the first anode being electrically connected to the operating power source, and a rectifier having an output end and an input end. The output current path and the feedback current path are respectively electrically connected, and the rectifier further includes a first power terminal and a second power terminal, respectively electrically connecting the second anode end of the three-terminal bidirectional AC component and the working power source, wherein the threshold value The minimum holding current value of the three-terminal bidirectional AC component.

In an embodiment, the light emitting unit has a plurality of light emitting diodes, wherein the light emitting diodes are connected in series, wherein an anode end of the first light emitting diode is electrically connected to an output end of the power supply circuit for receiving System current.

In one embodiment, the switch unit and the comparator are disposed in an integrated circuit, and the integrated circuit has a first pin and a second pin electrically connected to the output current path and the feedback current path. And the switch unit is electrically connected to the first pin and the second pin respectively; a third pin is electrically connected to a negative pressure node on the feedback current path; and a fourth pin is electrically connected to the light The cathode end of the last LED of the diode is such that the system current flowing through the light-emitting unit flows from the fourth pin to the integrated circuit and from the second pin to the feedback current path.

In one embodiment, the illuminating device further includes a detecting resistor disposed on the feedback current path, the detecting resistor has a first end electrically connected to the second pin, and the detecting resistor has a second The end is electrically connected to the negative pressure node.

In an embodiment, the integrated circuit further includes: a reference voltage source electrically connected to a first input terminal of the comparator to provide a reference voltage; and a reference current source electrically connected to the first of the comparators a second input terminal, and providing a reference current: and an internal resistor having a first end and a second end respectively electrically connected to the third pin and the second input end of the comparator, wherein the reference current flows through the internal resistor And generating a system current related voltage at the second input of the comparator.

In an embodiment, the light emitting device further includes: a first circuit substrate, wherein the light emitting unit and the integrated circuit are disposed on the first circuit substrate; a second circuit substrate electrically connected to the first circuit substrate, and the power supply circuit The second circuit substrate is disposed on the second circuit substrate; and the heat dissipation module is disposed on the first circuit substrate.

In one embodiment, the light emitting device further includes: a protective diode having an anode end and a cathode end electrically connected to the power supply circuit and the anode end of the first LED of the LED.

In summary, the illuminating device and the illuminating driving circuit of the present invention determine whether to extract the supplementary current from the working power source according to the magnitude of the system current to actively adjust the system current. Therefore, the present invention has at least the following advantages: First, since the present invention can adjust the system current, thereby avoiding the phenomenon of flickering of the light-emitting diode during dimming, the present invention can be applied to a light-emitting device having a three-terminal bidirectional alternating current element. Secondly, since the light-emitting driving circuit and the power supply circuit are located on different circuit substrates, and the heat-dissipating module for adjusting the light-emitting unit is disposed on the substrate of the light-emitting driving circuit, the light-emitting driving circuit can also avoid overheating (when When the switching unit is turned on, due to the large amount of current, the entire integrated circuit may be overheated and damaged; 3. Since the above-mentioned switching unit and comparator are all disposed in the integrated circuit, the integrated circuit can be shared. The internal protection circuit not only protects the light-emitting drive circuit, but also reduces the circuit design cost.

1‧‧‧Lighting device

11‧‧‧Working power supply

12‧‧‧Power supply circuit

13‧‧‧Lighting drive circuit

15‧‧‧Lighting unit

121‧‧‧Three-terminal bidirectional AC components

122‧‧‧Rectifier

121A‧‧‧First anode end

121B‧‧‧second anode end

122A‧‧‧First power terminal

122B‧‧‧second power terminal

122C, 423‧‧‧ output

122D, 421, 422‧‧‧ input

132‧‧‧ integrated circuit

21‧‧‧Main system path

22‧‧‧Output current path

23‧‧‧Responding to the current path

32‧‧‧Protection diode

322‧‧‧First circuit board

324‧‧‧Second circuit substrate

326‧‧‧ Thermal Module

33‧‧‧ Capacitance

34‧‧‧Detection resistance

41‧‧‧Switch unit

42‧‧‧ comparator

43‧‧‧Reference current source

44‧‧‧reference voltage source

45‧‧‧Internal resistance

51, 52, 53‧‧‧Lighting diodes

N‧‧‧ node

P1, P2, P3, P4, P5‧‧‧ pins

V _led ‧‧‧Lighting control signal

V _det ‧‧‧ system current related voltage

V-‧‧‧negative voltage

V _ref ‧‧‧reference voltage

V _c ‧‧‧ control signal

I _ref ‧‧‧reference current

I _a ‧‧‧Supply current

I _sys ‧‧‧ system current

1 is a circuit diagram of a light emitting device in accordance with a preferred embodiment of the present invention.

FIG. 2 is an internal circuit diagram of the integrated circuit of FIG. 1. FIG.

FIG. 3 is a schematic diagram showing the system configuration of a light emitting device according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a light-emitting device according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals.

1 is a circuit diagram of a light emitting device in accordance with a preferred embodiment of the present invention. Referring to FIG. 1, the light emitting device 1 includes a power supply circuit 12, an illumination driving circuit 13, and at least one light emitting unit 15. The power supply circuit 12 is electrically connected to a working power source 11 and electrically connected to the light-emitting driving circuit 13 and the light-emitting unit 15.

In the present embodiment, the light emitting unit 15 has a plurality of light emitting diodes such as the light emitting diodes 51, 52, and 53. Additionally, in some embodiments, the operating power source 11 is an alternating current.

Referring to FIG. 1 , the power supply circuit 12 has an output end 122C electrically connected to the light emitting unit 15 through the main system path 21 . In this way, the power supply circuit 12 can output a system current I _sys from the output terminal 122C, and the system current I _sys is transmitted to and drives the light emitting unit 15 through the main system path 21. In the present embodiment, a protection diode 32 is disposed on the main system path 21. The anode end of the protection diode 32 is electrically connected to the output end 122C of the power supply circuit 12, and the cathode end of the protection diode 32 is electrically connected to the illumination unit 15 through the main system path 21. In this way, when the system current is too low, the protection diode 32 can block the reverse current from the light emitting unit 15. In addition, the power supply circuit 12 is also electrically connected to the light-emitting drive circuit 13 through the output current path 22 and the feedback current path 23. In particular, the output current path 22 does not pass through the illumination unit 15.

The power supply circuit 12 includes a three-terminal bidirectional AC element 121 and a rectifier 122. The three-terminal bidirectional AC element 121 has a first anode end 121A and a second anode end 121B, wherein the first anode end 121A is electrically connected to the working power source 11. In addition, in the present embodiment, the rectifier 122 can be implemented using a bridge rectifier circuit. The rectifier 122 has an output (ie It is an output terminal 122C and an input terminal 122D) of the power supply circuit 12, wherein the input terminal 122D is electrically connected to the feedback current path 23. In addition, the rectifier 122 further includes a first power terminal 122A and a second power terminal 122B electrically connected to the second anode terminal 121B and the working power source 11 of the three-terminal bidirectional AC component 121, respectively.

Referring to FIG. 1, the light-emitting drive circuit 13 includes a control unit, such as an integrated circuit 132 (hereinafter referred to as integrated circuit 132). The integrated circuit 132 includes pins P1, P2, P3, P4, and P5. The pin P1 is electrically connected to the output current path 22; the pin P4 is electrically connected to the light emitting unit 15; the pins P2 and P3 are electrically connected to the node N, and the node N is electrically connected to the feedback current path 23 to The power supply circuit 12 is electrically connected to the light-emitting unit 15 so that the integrated circuit 132 transmits the light-emission control signal V _led to the light-emitting unit 15 through the pin P5 to control the state of the light-emitting unit 15.

FIG. 2 is an internal circuit diagram of the integrated circuit 132 of FIG. 1. Referring to FIG. 1 and FIG. 2 together, the integrated circuit 132 includes a switching unit 41 and a comparator 42. The switching unit 41 is disposed between the output current path 22 and the feedback current path 23. In the present embodiment, the switching unit 41 can be implemented using a MOS transistor. In addition, the output terminal 423 of the comparator 42 is electrically connected to the switch unit 41, and the input terminals 421 and 422 of the comparator are electrically connected to a reference voltage source 44 and a system current related voltage V _{det , respectively} . Thereby, the comparator 42 can compare a reference voltage V _ref with the system current related voltage V _det , and output a control signal V _c according to the comparison result to control the switching unit 41. In the present embodiment, the potential of the system current related voltage V _det is determined according to the magnitude of the current value of the system current I _sys .

In addition, in the embodiment, the pin P4 is substantially electrically connected to the pin P2. Here, the term "substantially electrically connected" means that the current flowing into the pin P4 also flows to the pin P2, but between the pins P2 and P4, other components are also disposed. I will not repeat them one by one.

In more detail, the integrated circuit 132 further includes a reference current source 43 and an internal impedance element, such as an internal resistor 45, and the reference current source 43 and the internal resistor 45 are electrically coupled to the input terminal 422 of the comparator 42, respectively.

In addition, the light-emitting drive circuit 13 includes a detection resistor 34 and a capacitor 33 in addition to the integrated circuit 132. The detecting resistor 34 is disposed between the pin P2 and the node N, and the two ends of the capacitor 33 are electrically connected to the pin P3 and the cathode end of the protective diode 32, respectively. When the system current I _sys flows from the light emitting unit 15 , it flows from the pin P4 into the integrated circuit 132 and flows from the pin P2 to the detecting resistor 34. When the system current I _sys flows through the sense resistor 34, the node N generates a negative voltage V-. On the other hand, when the reference current I _ref in the integrated circuit 132 flows through the internal resistor 45, the voltage across the internal resistor 45 is also generated. At this time, the voltage across the negative voltage V- plus the internal resistance 45 is equal to the system current related voltage V _det .

When the power supply circuit 12 outputs the system current I _sys from the output terminal 122C, the system current I _sys flows to the light emitting unit 15 following the main system path 21. In addition, the system current I _sys also charges the capacitor 33. When the current value of the system current I _sys is higher than a critical value (that is, the lowest holding current value of the three-terminal bidirectional AC element 121), the system current related voltage V _det is a low voltage value. At this time, the comparator 42 outputs a control signal V _c having a first state to the switching unit 41 according to the comparison result of the system current related voltage V _det and the reference voltage V _ref , so that the switching unit 41 assumes a substantially open state. Since the system current I _sys is above the critical value, the three-terminal bidirectional AC element 121 will remain in an on state.

In contrast, when the light-emitting unit 15 is dimmed, the current value of the system current I _sys may be lower than the above-mentioned critical value. Therefore, the above system current related voltage V _det will be a high voltage value, and the comparator 42 outputs the control signal V _c having the second state to the switching unit 41, so that the switching unit 41 is turned on. At this time, a substantial short circuit occurs between the pins P1 and P2, which causes the integrated circuit 132 to extract the supplementary current I _a from the operating power source 11. The supplemental current I _a flows from the pin P1 into the integrated circuit 132 along the output current path 22, and the supplemental current I _a flows back to the power supply from the pin P2 along the feedback current path 23 together with the system current I _{sys .} Supply circuit 12. Since the current flowing back to the power supply circuit 12 is the system current I _sys plus the supplementary current I _a , the current flowing back to the power supply circuit 12 is still maintained above the critical value, so that the three-terminal bidirectional AC element 121 is continuously turned on. As a result, the light-emitting unit 15 does not have a flicker phenomenon.

FIG. 3 is a schematic diagram showing the system configuration of a light emitting device according to a preferred embodiment of the present invention. Referring to FIG. 3 , in a preferred embodiment, the power supply circuit 12 is disposed on the first circuit substrate 322 , and the light-emitting drive circuit 13 is disposed on the second circuit substrate 324 together with the light-emitting unit 15 . In addition, the second circuit substrate 324 is further provided with a heat dissipation module 326, such as a heat sink of the aluminum substrate, so that the light-emitting drive circuit 13 is not damaged by overheating.

In summary, the illuminating device and the illuminating driving circuit of the present invention determine whether to extract the supplementary current from the working power source according to the magnitude of the system current to actively adjust the system current. Therefore, the present invention has at least the following advantages: First, since the present invention can adjust the system current, thereby avoiding the phenomenon of flickering of the light-emitting diode during dimming, the present invention can be applied to a light-emitting device having a three-terminal bidirectional alternating current element. Secondly, since the light-emitting driving circuit and the power supply circuit are located on different circuit substrates, and the heat-dissipating module for adjusting the light-emitting unit is disposed on the substrate of the light-emitting driving circuit, the light-emitting driving circuit can also avoid overheating (when When the switching unit is turned on, due to the large amount of current, the entire integrated circuit may be overheated and damaged; 3. Since the above-mentioned switching unit and comparator are all disposed in the integrated circuit, the integrated circuit can be shared. The internal protection circuit not only protects the light-emitting drive circuit, but also reduces the circuit design cost.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1‧‧‧Lighting device

11‧‧‧Working power supply

12‧‧‧Power supply circuit

13‧‧‧Lighting drive circuit

15‧‧‧Lighting unit

21‧‧‧Main system path

22‧‧‧Output current path

23‧‧‧Responding to the current path

32‧‧‧Protection diode

33‧‧‧ Capacitance

34‧‧‧Detection resistance

51, 52, 53‧‧‧Lighting diodes

121‧‧‧Three-terminal bidirectional AC components

122‧‧‧Rectifier

121A‧‧‧First anode end

121B‧‧‧second anode end

122A‧‧‧First power terminal

122B‧‧‧second power terminal

122C‧‧‧ Output

122D‧‧‧ input

132‧‧‧ integrated circuit

N‧‧‧ node

P1, P2, P3, P4, P5‧‧‧ pins

V _led ‧‧‧Lighting control signal

V-‧‧‧negative voltage

I _sys ‧‧‧ system current

Claims (13)

An illuminating driving circuit is applicable to an illuminating device having at least one illuminating unit and a power supply circuit, wherein the power supply circuit sends a system current from an output terminal to drive the illuminating unit, and the illuminating driving circuit comprises a switching unit disposed between an output current path and a feedback current path, the output current path being electrically connected to the output end of the power supply circuit, and the current on the feedback current path is fed back to the power supply Supplying a circuit, and the output current path does not pass through the light emitting unit; and a comparator electrically connecting the switch unit, and comparing a system current related voltage and a reference voltage to output a control signal to control the switch unit, the system The potential of the current-dependent voltage is determined according to the current value of the current of the system, wherein the comparator outputs a switching signal having a first state when the current value of the current of the system is less than a threshold, so that the switching unit is substantially short-circuited. And outputting a second state when the current value of the current of the system is greater than the threshold The signal switching unit breaking the substance. The illuminating drive circuit of claim 1, wherein the switch unit and the comparator are disposed in an integrated circuit, the integrated circuit having: a first pin and a second pin, respectively The output current path and the feedback current path are electrically connected, and the switch unit is electrically connected to the first pin and the second pin respectively; a third pin is electrically connected to the feedback current path a negative voltage node; and a fourth pin electrically connected to the light emitting unit, and the system current flowing through the light emitting unit flows from the fourth pin into the integrated circuit, and from the second pin Flow to the feedback current path. The illuminating driving circuit of claim 2, further comprising: a detecting resistor disposed on the feedback current path, the detecting resistor having a first end electrically connected to the second pin And the detecting resistor has a second end electrically connected to the negative pressure node. The illuminating drive circuit of claim 2, wherein the integrated circuit further comprises: a reference voltage source electrically connected to a first input end of the comparator to provide the reference voltage; a reference current source electrically connected to a second input of the comparator and providing a reference current: and an internal resistor having a first end and a second end electrically connected to the third pin And the second input of the comparator, wherein the reference current flows through the internal resistor, and the system current related voltage is generated at the second input of the comparator. The illuminating driving circuit of claim 1, further comprising: a protective diode having an anode end and a cathode end electrically connected to the power supply circuit and the illuminating unit, wherein the current of the system passes through The protective diode flows to the light emitting unit. A lighting device includes: a power supply circuit electrically connected to a working power source and providing a system current from an output terminal; an illumination unit electrically connected to the power supply circuit to receive the system current, and according to the The system current is driven, and the system current is fed back to the power supply circuit through a feedback current path through the illumination unit; a switch unit is disposed between an output current path and the feedback current path, and the switch unit is disposed between the output current path and the feedback current path. An output current path is electrically connected to an output end of the power supply circuit, and the output current path does not pass through the light emitting unit; and a comparator electrically connected to the switch unit and compares a system current related voltage and a reference voltage Outputting a control signal to control the switch unit, the potential of the current-dependent voltage of the system is determined according to the current value of the current of the system, wherein the comparator outputs a first when the current value of the current of the system is less than a threshold value A state of the switching signal causes the switching unit to be substantially shorted, and the current value of the current in the system is greater than the current Outputting a switch signal having a second state when the value of the switching unit so that the substantial open circuit. The light-emitting device of claim 6, wherein the power supply circuit comprises: a three-terminal bidirectional AC component having a first anode and a second anode, the first anode being electrically connected to the working power source; a rectifier having an output terminal and an input terminal electrically connected to the output current path and the feedback current path, respectively, and the rectifier further includes a first power terminal and a second power terminal, respectively electrically connected to the three The second anode terminal of the bidirectional AC component and the operating power source, wherein the threshold is a minimum holding current value of the triac. The illuminating device of claim 6, wherein the illuminating unit has a plurality of illuminating diodes, wherein the illuminating diodes are connected in series, wherein an anode end of the first illuminating diode is electrically connected The output of the power supply circuit receives the system current. The illuminating device of claim 8, wherein the switch unit and the comparator are disposed in an integrated circuit, the integrated circuit having: a first pin and a second pin, respectively The output current path and the feedback current path are connected, and the switch unit is electrically connected to the first pin and the second pin respectively; and a third pin is electrically connected to the feedback current path a negative voltage node; and a fourth pin electrically connected to the cathode end of the last light emitting diode of the light emitting diodes, so that the system current flowing through the light emitting unit is from the fourth connection The foot flows into the integrated circuit and flows from the second pin to the feedback current path. The illuminating device of claim 9, further comprising: a detecting resistor disposed on the feedback current path, the detecting resistor having a first end electrically connected to the second pin, The detecting resistor has a second end electrically connected to the negative pressure node. The illuminating device of claim 9, wherein the integrated circuit further comprises: a reference voltage source electrically connected to a first input end of the comparator to provide the reference voltage; a reference current The source is electrically connected to a second input end of the comparator and provides a reference current: and an internal resistor having a first end and a second end electrically connected to the third pin and the comparison The second input of the device, wherein the reference current flows through the internal resistor, and the system current related voltage is generated at the second input of the comparator. The illuminating device of claim 9, further comprising: a first circuit substrate, wherein the light emitting unit and the integrated circuit are disposed on the first circuit substrate; a second circuit substrate electrically connected to the first circuit substrate, and the power supply circuit is disposed on the second circuit a substrate; and a heat dissipation module disposed on the first circuit substrate. The illuminating device of claim 9, further comprising: a protective diode having an anode end and a cathode end electrically connected to the power supply circuit and the first illuminating of the illuminating diodes The anode end of the diode.