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CN108966403B - Conversion Constant Current LED Driver - Google Patents

Conversion Constant Current LED Driver Download PDF

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Publication number
CN108966403B
CN108966403B CN201710387184.5A CN201710387184A CN108966403B CN 108966403 B CN108966403 B CN 108966403B CN 201710387184 A CN201710387184 A CN 201710387184A CN 108966403 B CN108966403 B CN 108966403B
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current
inductor
duty cycle
constant current
voltage
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CN108966403A (en
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萧韦俊
江岳桦
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Taiwan Semiconductor Manufacturing Co TSMC Ltd
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

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Abstract

本发明公开了一种转换式定电流LED驱动器，具有一能量传输单元、一LED模块、一功率晶体管、一电阻以及一控制单元，该控制单元具有一驱动单元以产生一驱动电压信号，以及一责任周期决定单元以决定该驱动电压信号的一责任周期，其中，该责任周期决定单元根据该责任周期的一目前时间长度决定一参考电流对一外接电容的一充电时间及根据一电感放电时间决定一放电电流对该外接电容的一放电时间以产生一比较电压，并根据该比较电压和一锯齿电压的一比较运算产生该责任周期的下一个时间长度，且该放电电流和一电感充电状态信号的一平均值成正比。

Figure 201710387184

The present invention discloses a conversion type constant current LED driver, which has an energy transmission unit, an LED module, a power transistor, a resistor and a control unit. The control unit has a driving unit for generating a driving voltage signal, and a duty cycle determination unit for determining a duty cycle of the driving voltage signal. The duty cycle determination unit determines a charging time of an external capacitor by a reference current according to a current time length of the duty cycle and determines a discharge time of the external capacitor by a discharge current according to an inductor discharge time to generate a comparison voltage, and generates the next time length of the duty cycle according to a comparison operation of the comparison voltage and a sawtooth voltage, and the discharge current is proportional to an average value of an inductor charging state signal.

Figure 201710387184

Description

转换式定电流LED驱动器Conversion Constant Current LED Driver

技术领域technical field

本发明涉及一种转换式定电流LED驱动器。The invention relates to a conversion type constant current LED driver.

背景技术Background technique

请参照图1，图1所示为已知的现有技术中转换式定电流LED驱动器的方块图。如图1所示，该转换式定电流LED驱动器具有一电源转换控制单元10、一LED模块20及一电阻30。Please refer to FIG. 1 . FIG. 1 is a block diagram of a conversion type constant current LED driver in the prior art. As shown in FIG. 1 , the conversion type constant current LED driver has a power conversion control unit 10 , an LED module 20 and a resistor 30 .

电源转换控制单元10用于根据电阻30两端的一跨压VX调整一责任周期以将一输入直流电压VIN转成一输出定电流IO以驱动LED模块20。The power conversion control unit 10 is used to adjust a duty cycle according to a voltage V X across the resistor 30 to convert an input DC voltage V IN into an output constant current IO to drive the LED module 20 .

然而，该现有的转换式定电流LED驱动器的反应速度及稳定度仍有改善的空间。However, there is still room for improvement in the response speed and stability of the existing conversion type constant current LED driver.

为解决前述的问题，本领域需要一新颖的转换式定电流LED驱动器。To solve the aforementioned problems, there is a need in the art for a novel switching constant current LED driver.

发明内容SUMMARY OF THE INVENTION

本发明的一方面在于提供一种转换式定电流LED驱动器，其可通过以责任周期反馈方式产生一责任周期，以使输出电流快速稳定在一预定电流值，且该预定电流值可由一外部电阻设定。One aspect of the present invention is to provide a conversion type constant current LED driver, which can generate a duty cycle in a duty cycle feedback manner, so that the output current can be quickly stabilized at a predetermined current value, and the predetermined current value can be controlled by an external resistor set up.

本发明的另一方面在于提供一种转换式定电流LED驱动器，其可根据一电感充电状态信号、一责任周期的目前时间长度和一电感放电时间决定该责任周期的下一个时间长度。Another aspect of the present invention is to provide a switching constant current LED driver, which can determine the next time length of a duty cycle according to an inductor charge state signal, a current time length of a duty cycle, and an inductor discharge time.

为达上述目的，一种转换式定电流LED驱动器于是被提出，其具有：In order to achieve the above purpose, a conversion type constant current LED driver is proposed, which has:

一能量传输单元，具有一电感、一二极管以及一电容用于将一输入直流电压转成一输出定电流，其中该二极管通过释放该电感的一累积能量而提供一放电电流，该电容通过提供一辅助电流以和该放电电流合而提供该输出定电流，且该能量传输单元具有一感测电路以提供该电感的一电感放电状态信号；An energy transmission unit having an inductor, a diode and a capacitor for converting an input DC voltage into an output constant current, wherein the diode provides a discharge current by releasing an accumulated energy of the inductor, and the capacitor provides a discharge current by providing a The auxiliary current is combined with the discharge current to provide the output constant current, and the energy transmission unit has a sensing circuit to provide an inductance discharge state signal of the inductance;

一LED模块，与该能量传输单元连接以接收该输出定电流；an LED module, connected with the energy transmission unit to receive the output constant current;

一功率晶体管，具有一控制端、一通道输入端及一通道输出端，该控制端与一驱动电压信号连接，该通道输入端与该能量传输单元连接；a power transistor with a control end, a channel input end and a channel output end, the control end is connected with a driving voltage signal, and the channel input end is connected with the energy transmission unit;

一电阻，连接于该通道输出端与一参考地之间以产生一电感充电状态信号；以及a resistor connected between the channel output terminal and a reference ground to generate an inductor charging state signal; and

一控制单元，具有一责任周期决定单元及一驱动单元，该驱动单元用以产生该驱动电压信号，且该责任周期决定单元用以决定该驱动电压信号的一责任周期，其中，该责任周期决定单元根据该责任周期的一目前时间长度决定一第一电流对一外接电容的一充电时间及根据一电感放电时间决定一第二电流对该外接电容的一放电时间以产生一比较电压，并根据该比较电压和一锯齿电压的一比较运算产生该责任周期的下一个时间长度，该第一电流和一参考电压成正比，该第二电流和该电感充电状态信号的一平均值成正比，且该电感放电时间根据该电感放电状态信号决定。a control unit having a duty cycle determination unit and a drive unit, the drive unit is used for generating the driving voltage signal, and the duty cycle determination unit is used for determining a duty cycle of the driving voltage signal, wherein the duty cycle determines The unit determines a charging time of a first current to an external capacitor according to a current time length of the duty cycle and determines a discharge time of a second current to the external capacitor according to an inductor discharge time to generate a comparison voltage, and according to A comparison operation of the comparison voltage and a sawtooth voltage generates the next time length of the duty cycle, the first current is proportional to a reference voltage, the second current is proportional to an average value of the inductor state-of-charge signal, and The inductor discharge time is determined according to the inductor discharge state signal.

在一实施例中，该控制单元具有一第一转导放大器以根据该参考电压产生该第一电流，以及一第二转导放大器以根据该电感充电状态信号的所述平均值产生该第二电流。In one embodiment, the control unit has a first transconductance amplifier to generate the first current according to the reference voltage, and a second transconductance amplifier to generate the second current according to the average value of the inductor state-of-charge signal current.

在一实施例中，该第一转导放大器和/或该第二转导放大器具有一电流镜电路。In one embodiment, the first transconductance amplifier and/or the second transconductance amplifier has a current mirror circuit.

在一实施例中，该控制单元具有一比较器以根据该电感放电状态信号和一预定电压的一比较结果决定该电感放电时间。In one embodiment, the control unit has a comparator to determine the inductor discharge time according to a comparison result between the inductor discharge state signal and a predetermined voltage.

在一实施例中，该功率晶体管一N型MOSFET。In one embodiment, the power transistor is an N-type MOSFET.

附图说明Description of drawings

图1为现有技术中的转换式定电流LED驱动器的方块图。FIG. 1 is a block diagram of a conversion type constant current LED driver in the prior art.

图2为本发明转换式定电流LED驱动器一具体实施例的方块图。FIG. 2 is a block diagram of a specific embodiment of a conversion type constant current LED driver according to the present invention.

图3a为图2的一能量传输单元的一实施例电路图。FIG. 3a is a circuit diagram of an embodiment of an energy transmission unit of FIG. 2 .

图3b为图2的一能量传输单元的另一实施例电路图。FIG. 3b is a circuit diagram of another embodiment of an energy transmission unit of FIG. 2 .

图4为图2的一控制单元的一实施例电路图。FIG. 4 is a circuit diagram of an embodiment of a control unit of FIG. 2 .

具体实施方式Detailed ways

为使本发明的目的、技术方案和优点更加清楚明白，以下结合具体实施例，并参照附图，对本发明作进一步的详细说明。In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

请参照图2，图2为本发明转换式定电流LED驱动器一具体实施例的方块图。如图2所示，该转换式定电流LED驱动器包括一能量传输单元100、一LED模块110、一功率晶体管120、一电阻130、一控制单元140以及一电容150。Please refer to FIG. 2 . FIG. 2 is a block diagram of a specific embodiment of a conversion type constant current LED driver according to the present invention. As shown in FIG. 2 , the conversion type constant current LED driver includes an energy transmission unit 100 , an LED module 110 , a power transistor 120 , a resistor 130 , a control unit 140 and a capacitor 150 .

能量传输单元100具有一电感、一二极管以及一电容以将一输入直流电压VIN转成一输出定电流IO，其中该二极管通过释放该电感的一累积能量而提供一放电电流，该电容通过提供一辅助电流以和该放电电流合而提供该输出定电流，且该能量传输单元具有一感测电路以提供该电感的一电感放电状态信号Vdis。The energy transmission unit 100 has an inductor, a diode and a capacitor to convert an input DC voltage V IN into an output constant current IO , wherein the diode provides a discharge current by releasing an accumulated energy of the inductor, and the capacitor passes through An auxiliary current is provided to provide the output constant current in combination with the discharge current, and the energy transfer unit has a sensing circuit to provide an inductance discharge state signal V dis of the inductance.

LED模块110与能量传输单元100连接以接收输出定电流IO。The LED module 110 is connected to the energy transmission unit 100 to receive the output constant current I O .

功率晶体管120，可为一N型MOSFET(metal-oxide-semiconductor field effecttransistor；金属氧化物半导体场效晶体管)，具有一控制端、一通道输入端及一通道输出端，该控制端与一驱动电压信号VG连接，该通道输入端与该能量传输单元100连接。The power transistor 120 can be an N-type MOSFET (metal-oxide-semiconductor field effect transistor; metal oxide semiconductor field effect transistor), and has a control terminal, a channel input terminal and a channel output terminal, the control terminal and a driving voltage The signal V G is connected, and the channel input end is connected with the energy transmission unit 100 .

电阻130具有一电阻值RCS且连接于该通道输出端与一参考地之间以产生一电感充电状态信号VCS。The resistor 130 has a resistance value R CS and is connected between the channel output terminal and a reference ground to generate an inductor charging state signal V CS .

请参照图3a，图3a为图2的能量传输单元100的一实施例电路图。如图3a所示，能量传输单元100具有一电感101、一二极管102以及一电容103，其中，电感101的一端与直流电压VIN连接，另一端则与二极管102的阳极以及功率晶体管120的通道连接，而二极管102的阴极则与电容103及LED模块110连接。Please refer to FIG. 3 a , which is a circuit diagram of an embodiment of the energy transmission unit 100 of FIG. 2 . As shown in FIG. 3 a , the energy transmission unit 100 has an inductor 101 , a diode 102 and a capacitor 103 . One end of the inductor 101 is connected to the DC voltage V IN , and the other end is connected to the anode of the diode 102 and the channel of the power transistor 120 . The cathode of the diode 102 is connected to the capacitor 103 and the LED module 110 .

在功率晶体管120的一导通期间TON，电感101两端的跨压约等于VIN；而在功率晶体管120断开时，电感101在一放电期间Tdis所承受的跨压约等于(VIN-VD-VLED)，其中VD为二极管102的偏置电压，VLED为LED模块110的偏置电压。由于电感101在导通期间TON所累积的能量等于在放电期间Tdis所释出的能量，而输出定电流IO等于电感101在放电期间Tdis所提供的电流的平均值，因此，输出定电流IO可推导如下：During a turn-on period T ON of the power transistor 120 , the voltage across the inductor 101 is approximately equal to V IN ; and when the power transistor 120 is turned off, the voltage across the inductor 101 during a discharge period T dis is approximately equal to (V IN ) -V D -V LED ), where V D is the bias voltage of the diode 102 and V LED is the bias voltage of the LED module 110 . Since the energy accumulated by the inductor 101 during the conduction period T ON is equal to the energy released during the discharge period T dis , and the output constant current IO is equal to the average value of the current provided by the inductor 101 during the discharge period T dis , the output The constant current I O can be derived as follows:

VIN×TON+(VIN-VD-VLED)×Tdis＝0 (1)V IN ×T ON +(V IN -V D -V LED )×T dis =0 (1)

Figure BDA0001306201430000041
Figure BDA0001306201430000041

Figure BDA0001306201430000042
Figure BDA0001306201430000042

Figure BDA0001306201430000043
Figure BDA0001306201430000043

Figure BDA0001306201430000044
Figure BDA0001306201430000044

Figure BDA0001306201430000045
Figure BDA0001306201430000045

其中，EIN代表在一转换周期TS内电感101所累积的能量，EOUT代表在该转换周期TS内电感101所释出的能量，I1代表电感101的充电电流，I2代表电感101的放电电流，VCS，AVG代表电感充电状态信号VCS的平均值。Among them, E IN represents the energy accumulated by the inductor 101 in a conversion period T S , E OUT represents the energy released by the inductor 101 in the conversion period T S , I 1 represents the charging current of the inductor 101, and I 2 represents the inductance The discharge current of 101, V CS, AVG represents the average value of the inductor charge state signal V CS .

若在控制单元140内部设计一充电电流源(其电流值＝VREF×gm1)以在导通期间TON对电容150充电，及设计一放电电流源(其电流值＝VCS，AVG×gm2)以在放电期间Tdis对电容150放电，则在稳态时，If a charging current source (its current value=V REF ×g m1 ) is designed inside the control unit 140 to charge the capacitor 150 during the conduction period T ON , and a discharge current source (its current value=V CS, AVG × g m2 ) to discharge the capacitor 150 during the discharge period Tdis , then in steady state,

VCS，AVG×gm2×Tdis＝VREF×gm1×TON (7)V CS, AVG ×g m2 ×T dis =V REF ×g m1 ×T ON (7)

Figure BDA0001306201430000046
Figure BDA0001306201430000046

即，本发明可让设计者只需改变电阻130的电阻值即可获得所要的输出定电流IO。That is, the present invention allows the designer to obtain the desired output constant current IO only by changing the resistance value of the resistor 130 .

请参照图3b，图3b为图2的能量传输单元100的另一实施例电路图。如图3b所示，能量传输单元100具有一电感101、一二极管102以及一电容103，其中，电感101的一端与直流电压VIN连接，另一端则与二极管102的阳极以及功率晶体管120的通道连接，而二极管102的阴极则与电容103及LED模块110连接。Please refer to FIG. 3b , which is a circuit diagram of another embodiment of the energy transmission unit 100 of FIG. 2 . As shown in FIG. 3 b , the energy transmission unit 100 has an inductor 101 , a diode 102 and a capacitor 103 . One end of the inductor 101 is connected to the DC voltage V IN , and the other end is connected to the anode of the diode 102 and the channel of the power transistor 120 . The cathode of the diode 102 is connected to the capacitor 103 and the LED module 110 .

在功率晶体管120的一导通期间TON，电感101两端的跨压约等于VIN；而在功率晶体管120断开时，电感101在一放电期间Tdis所承受的跨压约等于(-VD-VLED)，其中VD为二极管102的偏置电压，VLED为LED模块110的偏置电压。由于电感101在导通期间TON所累积的能量等于在放电期间Tdis所释出的能量，而输出定电流IO等于电感101在放电期间Tdis所提供的电流的平均值，因此，输出定电流IO可推导如下：During a turn-on period T ON of the power transistor 120 , the voltage across the inductor 101 is approximately equal to V IN ; and when the power transistor 120 is turned off, the voltage across the inductor 101 during a discharge period T dis is approximately equal to (-V D - V LED ), where V D is the bias voltage of the diode 102 and V LED is the bias voltage of the LED module 110 . Since the energy accumulated by the inductor 101 during the conduction period T ON is equal to the energy released during the discharge period T dis , and the output constant current IO is equal to the average value of the current provided by the inductor 101 during the discharge period T dis , the output The constant current I O can be derived as follows:

VIN×TON+(-VD-VLED)×Tdis＝0 (1)V IN ×T ON +(-V D -V LED )×T dis =0 (1)

Figure BDA0001306201430000051
Figure BDA0001306201430000051

Figure BDA0001306201430000052
Figure BDA0001306201430000052

Figure BDA0001306201430000053
Figure BDA0001306201430000053

Figure BDA0001306201430000054
Figure BDA0001306201430000054

Figure BDA0001306201430000055
Figure BDA0001306201430000055

其中，EIN代表在一转换周期TS内电感101所累积的能量，EOUT代表在该转换周期TS内电感101所释出的能量，I1代表电感101的充电电流，12代表电感101的放电电流，VCS，AVG代表电感充电状态信号VCS的平均值。Among them, E IN represents the energy accumulated by the inductor 101 in a conversion period T S , E OUT represents the energy released by the inductor 101 in the conversion period T S , I 1 represents the charging current of the inductor 101, and 1 2 represents the inductance The discharge current of 101, V CS, AVG represents the average value of the inductor charge state signal V CS .

若在控制单元140内部设计一充电电流源(其电流值＝VREF×gm1)以在导通期间TON对电容150充电，及设计一放电电流源(其电流值＝VCS，AVG×gm2)以在放电期间Tdis对电容150放电，则在稳态时，If a charging current source (its current value=V REF ×g m1 ) is designed inside the control unit 140 to charge the capacitor 150 during the conduction period T ON , and a discharge current source (its current value=V CS, AVG × g m2 ) to discharge the capacitor 150 during the discharge period Tdis , then in steady state,

VCS，AVG×gm2×Tdis＝VREF×gm1×TON (7)V CS, AVG ×g m2 ×T dis =V REF ×g m1 ×T ON (7)

Figure BDA0001306201430000056
Figure BDA0001306201430000056

即，本发明可让设计者只需改变电阻130的电阻值即可获得所要的输出定电流IO。That is, the present invention allows the designer to obtain the desired output constant current IO only by changing the resistance value of the resistor 130 .

请参照图4，图4为图2的控制单元140的一实施例电路图。如图4所示，控制单元140具有一第一转导放大器141、一开关142、一积分电路143、一第二转导放大器144、一开关145、一比较器146、一放电时间侦测电路147及一驱动单元148，其中第一转导放大器141、开关142、积分电路143、第二转导放大器144、开关145、比较器146及放电时间侦测电路147组成一责任周期决定单元。驱动单元148用以产生该驱动电压信号VG，且该责任周期决定单元用以决定该驱动电压信号VG的一责任周期(即TON)，其中，该责任周期决定单元根据该责任周期(即TON)的一目前时间长度决定开关142的导通时间以决定一第一电流IC1对外接电容150的一充电时间，及根据一电感放电时间(即Tdis)决定开关145的导通时间以决定一第二电流IC2对该外接电容150的一放电时间，从而产生一比较电压VCMP；该第一电流IC1和一参考电压VREF成正比且由第一转导放大器141对该参考电压VREF进行一第一转导放大运算而产生，该第二电流IC2和该电感充电状态信号VCS的一平均值VCS，AVG成正比且由第二转导放大器144对该平均值VCS，AVG进行一第二转导放大运算而产生，且积分电路143用以对该电感充电状态信号VCS进行一平均运算以产生该平均值VCS，AVG；以及比较器146用以对该比较电压VCMP和一锯齿电压VSAW进行一比较运算以产生该责任周期(即TON)的下一个时间长度。另外，放电时间侦测电路147用以根据该电感放电状态信号Vdis和一预定电压的一比较结果决定该电感放电时间(即Tdis)。另外，第一转导放大器141及/或第二转导放大器144可具有一电流镜电路。Please refer to FIG. 4 , which is a circuit diagram of an embodiment of the control unit 140 of FIG. 2 . As shown in FIG. 4 , the control unit 140 has a first transconductance amplifier 141 , a switch 142 , an integrating circuit 143 , a second transconductance amplifier 144 , a switch 145 , a comparator 146 , and a discharge time detection circuit 147 and a driving unit 148, wherein the first transconductance amplifier 141, the switch 142, the integrating circuit 143, the second transconductance amplifier 144, the switch 145, the comparator 146 and the discharge time detection circuit 147 constitute a duty cycle determination unit. The driving unit 148 is used for generating the driving voltage signal V G , and the duty cycle determining unit is used for determining a duty cycle (ie, T ON ) of the driving voltage signal V G , wherein the duty cycle determining unit is based on the duty cycle ( That is, a current time length of T ON ) determines the conduction time of the switch 142 to determine a charging time for the external capacitor 150 by a first current I C1 , and determines the conduction time of the switch 145 according to an inductor discharge time (ie T dis ) time to determine a discharge time of a second current I C2 to the external capacitor 150 to generate a comparison voltage V CMP ; the first current I C1 is proportional to a reference voltage V REF and is paired by the first transconductance amplifier 141 The reference voltage V REF is generated by a first transconductance amplifying operation, the second current I C2 is proportional to an average value V CS, AVG of the inductor charge state signal V CS , and is proportional to the second transconductance amplifier 144 . The average values V CS, AVG are generated by performing a second transconductance amplification operation, and the integrating circuit 143 is used for performing an averaging operation on the inductor charging state signal V CS to generate the average values V CS, AVG ; and the comparator 146 uses A comparison operation is performed between the comparison voltage V CMP and a sawtooth voltage V SAW to generate the next time length of the duty cycle (ie, T ON ). In addition, the discharge time detection circuit 147 is used for determining the inductor discharge time (ie, T dis ) according to a comparison result between the inductor discharge state signal V dis and a predetermined voltage. In addition, the first transconductance amplifier 141 and/or the second transconductance amplifier 144 may have a current mirror circuit.

通过前述所公开的设计，本发明具有以下的优点：Through the design disclosed above, the present invention has the following advantages:

1.本发明的转换式定电流LED驱动器可通过以责任周期反馈方式产生一责任周期，以使输出电流快速稳定在一预定电流值，且该预定电流值可由一外部电阻设定。1. The conversion type constant current LED driver of the present invention can generate a duty cycle by means of duty cycle feedback, so that the output current can be quickly stabilized at a predetermined current value, and the predetermined current value can be set by an external resistor.

2.本发明的转换式定电流LED驱动器可根据一电感充电状态信号、一责任周期的目前时间长度和一电感放电时间决定该责任周期的下一个时间长度。2. The switching constant current LED driver of the present invention can determine the next time length of the duty cycle according to an inductor charging state signal, the current time length of a duty cycle and an inductor discharge time.

以上所述的具体实施例，对本发明的目的、技术方案和有益效果进行了进一步详细说明，应理解的是，以上所述仅为本发明的具体实施例而已，并不用于限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned specific embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principle of the present invention, any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention.

Claims (4)

1. A switched constant current LED driver, having:
an energy transmission unit having an inductor, a diode and a capacitor for converting an input dc voltage into an output constant current, wherein the diode provides a discharge current by discharging an accumulated energy of the inductor, the capacitor provides the output constant current by providing an auxiliary current for combining with the discharge current, and the energy transmission unit has a sensing circuit for providing an inductor discharge state signal of the inductor;
the LED module is connected with the energy transmission unit to receive the output constant current;
the power transistor is provided with a control end, a channel input end and a channel output end, the control end is connected with a driving voltage signal, and the channel input end is connected with the energy transmission unit;
a resistor connected between the channel output end and a reference ground to generate an inductance charging state signal; and
a control unit having a duty cycle determining unit and a driving unit, the driving unit being configured to generate the driving voltage signal, and the duty cycle determining unit being configured to determine a duty cycle of the driving voltage signal, wherein the duty cycle determining unit determines a charging time of a first current to an external capacitor according to a current time duration of the duty cycle and a discharging time of a second current to the external capacitor according to an inductor discharging time to generate a comparison voltage, and generates a next time duration of the duty cycle according to a comparison operation of the comparison voltage and a sawtooth voltage, the first current being directly proportional to a reference voltage, the second current being directly proportional to an average value of the inductor charging status signal, and the inductor discharging time being determined according to the inductor discharging status signal;
the control unit has a first transconductance amplifier for generating the first current according to the reference voltage, and a second transconductance amplifier for generating the second current according to the average value of the inductor charging state signal.
2. The switched constant current LED driver of claim 1, wherein the first transconductance amplifier and/or the second transconductance amplifier has a current mirror circuit.
3. The converted constant current LED driver of claim 1, wherein the control unit comprises a comparator for determining the inductor discharge time according to a comparison of the inductor discharge state signal and a predetermined voltage.
4. The switched mode constant current LED driver of claim 1, wherein said power transistor is an N-type MOSFET.
CN201710387184.5A 2017-05-26 2017-05-26 Conversion Constant Current LED Driver Expired - Fee Related CN108966403B (en)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201349353Y (en) * 2009-01-19 2009-11-18 冠捷投资有限公司 Double-dimming backlight source driving device
CN103108437A (en) * 2011-11-15 2013-05-15 昂宝电子（上海）有限公司 Light-emitting diode (LED) illuminating system and method for constant-current control in various operation modes
CN103858328A (en) * 2011-09-30 2014-06-11 皇家飞利浦有限公司 Active capacitor circuit
TWM496905U (en) * 2014-11-21 2015-03-01 Anwell Semiconductor Corp LED driving circuit with improved performance and utilization rate
TW201526699A (en) * 2013-12-18 2015-07-01 Univ Lunghwa Sci & Technology Single-stage SEPIC LED driver with PFC function
TW201531149A (en) * 2014-01-17 2015-08-01 Immense Advance Technology Corp PWM controller capable of adjusting output current ripple by resistor and LED driving circuit
TW201603633A (en) * 2014-07-02 2016-01-16 盛群半導體股份有限公司 LED backlight driving device
TWM518453U (en) * 2014-08-01 2016-03-01 Anwell Semiconductor Corp LED dimming circuit of front-end power factor correction

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201349353Y (en) * 2009-01-19 2009-11-18 冠捷投资有限公司 Double-dimming backlight source driving device
CN103858328A (en) * 2011-09-30 2014-06-11 皇家飞利浦有限公司 Active capacitor circuit
CN103108437A (en) * 2011-11-15 2013-05-15 昂宝电子（上海）有限公司 Light-emitting diode (LED) illuminating system and method for constant-current control in various operation modes
TW201526699A (en) * 2013-12-18 2015-07-01 Univ Lunghwa Sci & Technology Single-stage SEPIC LED driver with PFC function
TW201531149A (en) * 2014-01-17 2015-08-01 Immense Advance Technology Corp PWM controller capable of adjusting output current ripple by resistor and LED driving circuit
TW201603633A (en) * 2014-07-02 2016-01-16 盛群半導體股份有限公司 LED backlight driving device
TWM518453U (en) * 2014-08-01 2016-03-01 Anwell Semiconductor Corp LED dimming circuit of front-end power factor correction
TWM496905U (en) * 2014-11-21 2015-03-01 Anwell Semiconductor Corp LED driving circuit with improved performance and utilization rate

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