WO2015109977A1 - Led驱动电路 - Google Patents

Led驱动电路 Download PDF

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Publication number
WO2015109977A1
WO2015109977A1 PCT/CN2015/070992 CN2015070992W WO2015109977A1 WO 2015109977 A1 WO2015109977 A1 WO 2015109977A1 CN 2015070992 W CN2015070992 W CN 2015070992W WO 2015109977 A1 WO2015109977 A1 WO 2015109977A1
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WIPO (PCT)
Prior art keywords
voltage
signal
circuit
ripple
power supply
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PCT/CN2015/070992
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English (en)
French (fr)
Inventor
黄俊华
朱逸民
韩万华
欧阳昱宇
Original Assignee
通用电气公司
黄俊华
朱逸民
韩万华
欧阳昱宇
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Application filed by 通用电气公司, 黄俊华, 朱逸民, 韩万华, 欧阳昱宇 filed Critical 通用电气公司
Publication of WO2015109977A1 publication Critical patent/WO2015109977A1/zh

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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
    • H05B45/3725—Switched mode power supply [SMPS]
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • 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
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Definitions

  • the invention relates to a drive circuit for driving an LED light source.
  • LED As a new type of illumination source, LED has become a new generation of illumination source with its long life, high luminous efficiency, multi-light color and primary light distribution directional illumination function, which can work under safe voltage.
  • the conventional LED driving circuit usually receives an external AC power input (or DC power input) through a Switched-Mode Power Supply (SMPS) and adjusts the output provided to the LED module according to an adjustment signal such as a pulse width modulation (PWM) signal.
  • SMPS Switched-Mode Power Supply
  • PWM pulse width modulation
  • the simplest LED driver circuit only includes the first-stage switching power supply. Although the structure is simple, the output voltage provided by the primary switching power supply to the LED module is usually not very stable, which will affect the current on the LED module, thereby generating a pattern. Ripple Current, which in turn causes degradation in lighting quality and reduces the life of the LED module.
  • the more complicated LED driver circuit includes at least two stages of switching power supply or includes a dedicated constant current chip.
  • the adjustment of the two-stage and two-stage switching power supply or the constant current chip can make the final output voltage more stable because Two or more switching power supplies will adjust the external power supply by two or more stages, or a dedicated constant current chip will finely adjust the external power supply.
  • each additional switching power supply or each use of a dedicated constant current chip will greatly increase the cost and design complexity of the LED driving circuit, and is not suitable for general use.
  • the present invention is summarized in one or more aspects of the present invention, which is not intended to be a . Instead, the main purpose of the summary is to present some concepts of the invention in a simplified form.
  • the invention provides an LED driving circuit for driving an LED module.
  • the LED driving circuit includes:
  • a switching power supply for receiving an external power source and generating an adjusted output voltage according to the adjustment signal
  • a linear power circuit for receiving an output voltage of the switching power supply and converting it into a linear voltage for supplying to the LED module;
  • a ripple signal sampling circuit for collecting a ripple signal generated by the linear power circuit
  • ripple signal compensation circuit for receiving the collected ripple signal and converting it into a compensation voltage signal
  • An output voltage adjustment circuit configured to receive a voltage feedback signal of the linear power supply circuit and the compensation voltage signal, and generate the adjustment signal according to a difference between the voltage feedback signal and a reference voltage to adjust an output voltage of the switching power supply Wherein the reference voltage is equal to a sum of a predetermined first reference voltage source and the compensation voltage signal.
  • the output voltage regulating circuit provided in the LED driving circuit of the present invention enables comprehensive and accurate control of the switching power supply according to the integrated feedback and acquisition signals.
  • the output voltage regulation circuit receives a voltage feedback signal from the linear power supply circuit, and the voltage feedback signal can monitor the output voltage of the switching power supply in real time to meet a desired value, that is, compare with a first reference voltage source, and then generate a result based on the comparison result.
  • Corresponding adjustment signal is used to adjust the output voltage of the switching power supply; on the other hand, the output voltage adjustment circuit further collects a ripple signal from the linear power supply circuit through the ripple signal sampling circuit, and acquires the ripple signal through the ripple signal compensation circuit
  • the sampled ripple signal is in a signal energy having a ripple current period and converted into the compensation voltage signal to be combined with the first reference voltage source and at a voltage from the linear power supply circuit
  • the feedback signals are compared such that the resulting adjustment signal not only allows the switching power supply to meet the desired value, but also allows the LED module to operate normally at the lowest power, thereby reducing power loss.
  • the LED driving circuit of the present invention applies only the primary switching power supply, and does not apply the secondary or multi-stage switching power supply or the dedicated constant current chip, the cost is also greatly reduced.
  • FIG. 1 is a schematic block diagram of a preferred embodiment of an LED driving circuit of the present invention.
  • FIG. 2 is a circuit diagram showing a preferred embodiment of the rectifying filter circuit and the linear power supply circuit of FIG.
  • Figure 3 is a circuit diagram showing a preferred embodiment of the output voltage regulation circuit of Figure 1.
  • Figure 4 is a circuit diagram showing a preferred embodiment of the ripple signal sampling circuit of Figure 1.
  • Figure 5 illustrates the relationship between ripple current, ripple voltage, and shaping voltage.
  • Figure 6 is a circuit diagram showing a preferred embodiment of the ripple voltage shaping module of Figure 4.
  • Figure 7 is a circuit diagram showing a preferred embodiment of the ripple signal compensation circuit of Figure 1.
  • FIG. 1 is a schematic block diagram of a preferred embodiment of an LED driving circuit 100 of the present invention.
  • the LED driving circuit 100 includes an external power input interface 110, a rectifying and filtering circuit 120, a switched-mode power supply (SMPS) 130, a linear power supply circuit 140, an LED module 150, an output voltage adjusting circuit 160, and a ripple signal sampling. Circuit 170 and ripple signal compensation circuit 180.
  • the LED module 150 may be an integral part of the LED driving circuit 100, or may be independent parts thereof, and is included in the LED driving circuit portion for convenience of description.
  • the external power input interface 110 is configured to receive an external power signal (not shown), such as a 220V AC power source or a 24V DC power source.
  • an external power signal such as a 220V AC power source or a 24V DC power source.
  • the external power signal can be adjusted as needed.
  • the external power signal provides a stable and appropriate output voltage to the internal LED module 150 through a series of control of the subsequent circuit of the LED driving circuit 100.
  • the LED module 150 may include a single LED component, and may also include a plurality of LED component combinations, and the type of the LED component is not limited to one type, and may be adjusted according to actual needs.
  • the rectification and filtering circuit 120 is configured to rectify or/and filter the external power supply to obtain an input voltage required by the switching power supply 130. Since the rectifying and filtering circuit is a relatively mature technology, the present invention only shows the schematic rectification embodiment of Fig. 2 as an example. According to actual needs, the position of the rectifying and filtering circuit 120 can also be adjusted accordingly. For example, in addition to the example illustrated in FIG. 1, the rectifying and filtering circuit 120 can also be disposed at the rear end of the switching power supply 130 to the switching power supply 130. The output voltage signal is rectified or/and filtered.
  • the rectifying portion of the rectifying and filtering circuit 120 is disposed at a front end of the switching power supply 130, and the filtering portion of the rectifying and filtering circuit 120 is disposed at a rear end of the switching power supply 130.
  • the filtering portion of the rectifying and filtering circuit 120 is disposed at the front end of the switching power supply 130, and the rectifying portion of the rectifying and filtering circuit 120 is disposed at the rear end of the switching power supply 130.
  • the switching power supply 130 is configured to receive the external power signal or the externally filtered power signal, and adjust the output voltage 132 according to the adjustment signal 162 from the output voltage adjustment circuit 160.
  • the adjustment signal 162 may be an amplitude.
  • a DC signal that changes up and down with the feedback signal.
  • the switching power supply 130 internally includes a PWM adjustment signal control integrated circuit and a transistor (not shown) as a switching element.
  • the PWM adjustment signal control integrated circuit generates a corresponding duty according to the adjustment signal 162.
  • the PWM signal is controlled to further control the on/off of the switching element, thereby correspondingly adjusting the output voltage 132 of the switching power supply 130.
  • the PWM adjustment signal control integrated circuit is typically coupled to the output voltage regulation circuit 160 by an external interface, such as an optically coupled input interface.
  • the output voltage adjustment circuit 160 inputs the adjustment signal 162 to the PWM adjustment signal control integrated circuit through the external interface described above. Since the specific structure inside the switching power supply 130 is not the gist of the invention, it will not be described in detail herein.
  • the linear source circuit 140 is configured to receive the output voltage 132 of the switching power supply 130 and convert it to a stable linear voltage 142 for the LED module 150 to operate normally. Since the linear power supply circuit 140 is a relatively mature technology, the present invention only gives an exemplary linear power supply implementation of FIG. 2 as an example. Other embodiments may also use other types of linear power supply circuits or linear power supply chips. The function of providing a stable linear voltage is not limited to the embodiment shown in FIG. 2, and will not be enumerated here.
  • the output voltage regulation circuit 160 is configured to receive the voltage feedback signal 144 of the linear power supply circuit 140.
  • the voltage feedback signal 144 indirectly (or directly) reflects the change of the output voltage 132 of the switching power supply 130. The change may be It is caused by a change in the external power source or the switching power supply 130 itself or the like.
  • the linear voltage 142 outputted by the linear power supply circuit 140 to the LED module 150 may also change, that is, a voltage instability condition occurs, which may cause the LED module 150 to work. Unstable.
  • the output voltage adjustment circuit 160 generates a corresponding adjustment signal (ie, a PWM adjustment signal according to a comparison result between the received voltage feedback signal 144 and a preset reference voltage (the reference reference voltage source V ref1 shown in FIG. 3 ). 162)
  • the switching power supply 130 is controlled to control the PWM adjustment signal in the switching power supply 130 to control the integrated circuit, and the PWM adjustment signal control integrated circuit adjusts the duty ratio of the PWM adjustment signal according to the adjustment signal 162, thereby adjusting the output voltage 132.
  • the linear voltage 142 output by the linear power supply circuit 140 is adjusted to meet the required range, thereby ensuring that the LED module 150 can work normally.
  • a specific preferred embodiment of the output voltage regulation circuit 160 will be described in conjunction with FIG. 3 to illustrate its specific operational principles.
  • the reference voltage referenced in the output voltage adjusting circuit 160 is fixed, so that the output voltage 132 may not be completely adjusted according to the preset reference voltage to reach the required optimal range.
  • the output voltage 132 adjusted only by the preset reference voltage V ref1 may cause the power loss to become higher because the ripple signal generated by the linear power supply circuit 140 is not compensated. Therefore, the LED driving circuit 100 of the present invention further provides a ripple signal sampling circuit 170 and a ripple signal compensation circuit 180.
  • the ripple signal sampling circuit 170 is configured to perform real-time sampling on the linear power circuit 142 when the ripple signal 146 is generated, and the sampled ripple signal 173 is output to the ripple signal compensation circuit 180.
  • the ripple signal compensation circuit 180 performs compensation control on the sampled ripple signal (or the shaped ripple signal), and outputs a compensation voltage signal 182 to the output voltage adjustment circuit 160.
  • the output voltage adjustment circuit 160 combines the preset reference voltage with the compensation voltage signal 182 to generate an adjustment signal 162.
  • the combined adjustment signal 162 adjusts the linear voltage 142 output by the linear power circuit 140. It is within the required range and consumes the least amount of power.
  • a specific preferred embodiment of the ripple signal sampling circuit 170 and the ripple signal compensation circuit 180 will be given in the following paragraphs in conjunction with FIGS. 4-7 to explain the specific working principle thereof in detail.
  • FIG. 2 a circuit diagram of a preferred embodiment of the rectifying and filtering circuit 120 and the linear power supply circuit 140 of FIG. 1 is illustrated. As described above, FIG. 2 only shows an exemplary implementation. In other embodiments, the rectification filter circuit 120 and the linear power supply circuit 140 can be designed into other circuit configurations according to different needs.
  • the rectifying and filtering circuit 120 includes a bridge rectifier circuit composed of four diodes D1-D4, that is, an anode of the diode D1 and a cathode of the diode D3 are connected to the external power input interface 110.
  • An output terminal, an anode of the diode D2 and a cathode of the diode D4 are connected to another output terminal of the external power input interface 110, a cathode of the diode D1 and an anode of the diode D3 are connected to an input terminal of the switching power supply 130
  • the diode The cathode of D2 and the anode of the diode D4 are connected to the other input terminal of the switching power supply 130.
  • the rectifying and filtering circuit 120 does not include a filtering circuit portion, which is because in some applications, filtering is not sufficient.
  • a suitable filter circuit such as a capacitor filter circuit, can be added as needed. Since the filter circuit is also a common technique in the prior art, corresponding examples and illustrations are not given here for simplicity of explanation.
  • the linear power supply circuit 140 includes a controllable precision voltage regulator device TL 1 (such as model TL431), three resistors R 1 -R 3 , a filter capacitor C 1 and an electronic switch (such as MOS tube) Q 1 .
  • the two ends of the resistor R 2 are respectively connected to the cathode and the anode of the controllable precision voltage stabilizing source device TL 1 , and the voltage distribution across the resistor R 2 satisfies the voltage across the cathode and the anode of the controllable precision voltage stabilizing source device TL 1 Requirements, specifically set according to actual parameters.
  • the capacitor C 1 is connected in series with the electronic switch Q 1 and the resistor R 3 and is connected in parallel with the series circuit composed of the resistors R 1 and R 2 .
  • the control terminal of the electronic switch Q 1 is connected to the node D between the resistors R 1 and R 2 , and the reference pole of the controllable precision voltage stabilization source device TL 1 is connected to the electronic switch Q 1 and the resistor R 3 Between nodes C.
  • the two ends A and B of the capacitor C 1 are respectively connected to the two power input ends of the LED module 150.
  • the switching power supply 130 provides the output voltage V A (i.e., 132 in FIG. 1 schematically) to a power supply circuit 140 to the linear, as 24V DC voltage.
  • V A i.e., 132 in FIG. 1 schematically
  • the reference pole supplies a fixed voltage to the node C, so that the voltage on the node C is clamped to the fixed voltage, such as clamped to 1.25. V.
  • both ends of the capacitor C 1 output an output linear voltage V AB (ie, 142 shown in FIG. 1) to the LED module 150.
  • V AB linear voltage
  • the linear power supply circuit of the other circuit structure can also be used to provide a linear voltage to the LED module 150, which is selected according to actual design requirements, and will not be exemplified herein.
  • the voltage V B at the point B is output to the output voltage adjustment circuit 160 as the voltage feedback signal 144.
  • the output voltage V A of the switching power supply may be directly output to the output voltage adjustment circuit 160 as the voltage feedback signal 144, or other associated voltage signals may be used as the voltage feedback signal 144. In a certain feedback method.
  • the output voltage adjustment circuit 160 includes a comparator U 1 , a reference voltage source V ref1 , and a capacitor C 2 .
  • the inverting input terminal of the comparator U 1 receives the voltage feedback signal 144 output by the linear power circuit 140.
  • the non-inverting input terminal of the comparator U 1 receives the reference voltage source V ref1 , and the capacitor C 2 is connected to the comparison.
  • U is between the inverting input terminal and the output terminal 1, the output of the comparator U 1 162 generates the adjustment signal.
  • the reference voltage source V ref1 is set according to the actual needs of the output voltage generated by the switching power supply 130, i.e. the reference voltage V ref1 of the power source switch 130 should produce a desired output voltage, i.e. the direct voltage of the feedback signal should be 144 Expected value.
  • the adjustment signal 162 when the voltage feedback signal 144 is less than the reference voltage source V ref1 , it indicates that the output voltage 132 generated by the switching power supply 130 is smaller than a desired value, so the adjustment signal 162 will output a positive adjustment signal 162 to improve
  • the PWM adjusts the duty cycle of the signal in the switching power supply 130, thereby increasing the output voltage 132 of the switching power supply 130 to equal or approach the desired value.
  • the adjustment signal 162 will output a negative adjustment signal 162 to reduce the switch.
  • the PWM adjusts the duty cycle of the signal in power supply 130, which in turn reduces the output voltage 132 of the switching power supply 130 to be equal to or near the desired value. Therefore, by the feedback adjustment of the output voltage regulating circuit 160, the output voltage 132 generated by the switching power supply 130 can be always equal to or approaching a desired value.
  • the output voltage adjustment circuit 160 can also be designed in other structural forms, for example, by comparing the voltage feedback signal 144 with the reference voltage source V ref1 by using a comparison chip, and outputting a corresponding adjustment signal 162. Here is not an example.
  • the ripple signal sampling circuit 170 includes a ripple voltage shaping module 172 and a shaping voltage output module 174.
  • the ripple voltage shaping module 172 can also be applied only and the shaped voltage output module 174 can be omitted.
  • the ripple signal sampling circuit 170 is sampled according to the voltage V B at point B in FIG. 2 as the source of the ripple signal samples 146, i.e., the ripple of the signal samples with said source voltage 146
  • the feedback source of the feedback signal 144 is the same signal source.
  • other different sampling points may be selected for sampling or feedback collection, as long as the signal at the feedback source or the sampling source is directly or indirectly related to the feedback signal or sampling signal actually needed to be obtained, and is not limited to A kind of feedback or sampling method.
  • the ripple voltage shaping module 172 in the present embodiment, it includes a comparator U 2 and a reference voltage source V ref2 .
  • the ripple voltage shaping module 172 is configured to convert the ripple signal 146 into a square wave signal for subsequent processing of the signal, and other embodiments may be converted to other types of signals or not shaped. Conversion.
  • the inverting input of the comparator U 2 is for receiving the ripple signal 146
  • the non-inverting input of the comparator U 2 is for receiving the reference voltage source V ref2 .
  • the ripple current 52 is a partial waveform diagram of a current signal flowing through the LED module 150 when a ripple current is generated. It can be seen that there is no grain in the time period T1-T2, T3-T4, and T5-T6. The wave current is generated, and a ripple current is generated during the time period T2-T3, T4-T5, and T6-T7.
  • the present embodiment directly samples the ripple voltage signal 54 associated with it (ie, the voltage signal V B at point B in the linear power supply circuit 140).
  • the ripple voltage signal 54 associated with it (ie, the voltage signal V B at point B in the linear power supply circuit 140).
  • the amplitude of the ripple voltage 54 is positive, and the ripple current is generated.
  • the amplitude of the ripple voltage 54 is equal to zero. Therefore, by shaping the comparator U 2 , the amplitude of the ripple voltage 54 can be shaped to be equal to zero during a positive period, and the period of the ripple voltage 54 equal to zero is equal to a fixed period.
  • the voltage value i.e., the square wave signal of the shaped voltage 56 (corresponding to 1731 of Figure 4). Therefore, comparing the ripple current 52 with the shaping voltage 56, it can be seen that the ripple current 52 has a ripple period T2-T3, T4-T5, and T6-T7 correspond to a high amplitude period of the shaping voltage 56, but does not appear.
  • the time period T1-T2, T3-T4, and T5-T6 of the ripple correspond to the low amplitude period of the shaping voltage 56.
  • the ripple voltage shaping module 172 can also be implemented by other types of shaping circuits.
  • the ripple voltage shaping module 172 includes a resistor R 6 and an electronic switch Q 4 (eg, a triode).
  • the resistor R 6 is connected in series with the electronic switch Q 4 between a voltage source V cc and ground, and the control terminal of the electronic switch Q 4 is configured to receive the ripple signal 146, the node of the resistor R 6 and the electronic switch Q 4 Used as an output of the shaping voltage 1731 (similar to 56 in Figure 5). It is easy to know that when the ripple signal 146 (similar to 54 in FIG.
  • the ripple voltage shaping module 172 can also be implemented by other circuits, which are not illustrated here.
  • the ripple signal sampling circuit 170 further includes a shaped voltage output module 174.
  • the shaped voltage output module 174 is a mirrored current source circuit, which typically includes two resistors R 4 and R 5 , transistors Q 2 and Q 3 , resistor R 4 and transistor Q 2 form one side of the mirror current source circuit, and resistors R 5 and Q 3 form the other side of the mirror current source circuit, through which the mirror current source circuit 174
  • the output function enables the high-amplitude portion of the shaped square wave voltage 1731 generated by the ripple voltage shaping module 172 to generate a mirror current 1732 and then stably output the ripple signal compensation circuit 180. Since the mirror current source circuit is a common circuit in the prior art, it will not be specifically described here.
  • the shaped voltage output module 174 portion may be omitted, and the shaping voltage 1731 generated by the ripple voltage shaping module 172 may be directly output to the ripple signal compensation circuit 180.
  • the shaped voltage output module 174 can also be designed as other types of voltage output circuits to stably obtain the voltage output of the high amplitude portion of the shaped voltage 1731.
  • the signal ripple compensation circuit 180 includes a resistor R 7, resistors R 8, diode D 5 and the storage capacitor C 3.
  • the anode of the diode D 5 is coupled to the ripple signal sampling circuit 170 via a resistor R 7 to receive the sampled ripple signal 173 it produces (signal 1731 or 1732 as shown in FIG. 4).
  • the cathode of the diode D 5 is connected in series after the storage capacitor C 3 is grounded.
  • a node between the diode D 5 and the storage capacitor C 3 is coupled to the output voltage regulation circuit 160 via a resistor R 8 to provide a compensated voltage signal V add (refer to FIG. 3 together, ie, 182 in FIG. 1 ).
  • the resistors R 7 , R 8 and the diode D 5 in the ripple signal compensation circuit 180 are all for adjusting the performance of the tank circuit, for example, the resistor acts as a current limiting, and the diode functions to prevent current from flowing back.
  • the storage capacitor C 3 can be replaced by other energy storage components having energy storage functions
  • the resistors R 7 , R 8 and the diode D 5 can be replaced by other similar functional electronic components, and the circuit structure is also Adjustment can be made as needed, and is not limited to the example given in the embodiment.
  • the ripple signal sampling circuit 170 will correspondingly generate the shaped signal 173, as shown in the figure.
  • the ripple signal to the sampling circuit 170 3 ripple compensation circuit 180 in the signal storage capacitor C Charge it so that the voltage across it increases.
  • the increased voltage V dd will compensate the voltage reference value V ref1 of the non- inverting input of the comparator U 1 in the output voltage regulating circuit 160 shown in FIG.
  • the feedback voltage signal 142 with the linear power supply circuit 140 can be increased.
  • a range of reference voltages (buffer voltages) to be compared is performed to effectively cancel the ripple current in the linear power supply circuit 140.
  • the increased voltage V add can eliminate the linear power supply circuit 140.
  • the ripple current allows the LED module 150 to operate normally at the lowest power, thereby reducing power loss.
  • the LED driving circuit 100 of the present invention can normally control the LED module 150 to operate at the lowest power.
  • the LED driving circuit 100 of the present invention applies only the primary switching power supply, and does not apply the secondary or multi-stage switching power supply or the dedicated constant current chip, the cost is also greatly reduced.

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Abstract

本发明涉及一种LED驱动电路，其包括：开关电源，用于接收外部电源并根据调整信号产生调整后的输出电压；线性电源电路，用于接收该开关电源的输出电压，并将其转换为线性电压提供给LED模组；纹波信号采样电路，用于采集该线性电源电路产生的纹波信号；纹波信号补偿电路，用于接收该采集到的纹波信号，并将其转换为补偿电压信号；及输出电压调节电路，用于接收该线性电源电路的电压反馈信号及该补偿电压信号，并根据该电压反馈信号与参考电压之间的差值产生该调整信号来对该开关电源的输出电压进行调节，其中该参考电压等于一个预设的第一参考电压源与该补偿电压信号之和。

Description

LED驱动电路 技术领域
本发明涉及用于驱动LED光源的驱动电路。
背景技术
LED作为一种新型照明光源，以其长寿命、高光效、多光色及一次配光定向照射功能，可在安全电压下工作等诸多优势，成为新一代照明光源的发展趋势。
传统的LED驱动电路通常通过开关电源(Switched-Mode Power Supply，SMPS)接收外部交流电源输入(或直流电源输入)并根据调整信号如脉宽调制(PWM)信号来调整提供至LED模组的输出电压信号，以使其满足供电的需要。
最简单的LED驱动电路只包括一级开关电源，虽然此结构结构简单，但一级开关电源提供给LED模组的输出电压通常不是非常稳定的，会影响LED模组上的电流，从而产生纹波电流(Ripple Current)，进而造成照明品质下降且会降低LED模组的使用寿命。
而较复杂的LED驱动电路则包括至少两级开关电源或包括专用的恒流芯片，通过两级及两级以上开关电源或恒流芯片的调整，可使最终的输出电压变得更加稳定，因为两级或两级以上开关电源会对外部电源进行两级或两级以上的调整，或专用的恒流芯片也会对外部电源进行精密的调整。但是，每增加一个开关电源或每使用一个专用的恒流芯片，都将会大幅增加LED驱动电路的成本及设计复杂度，不适合应用在普通场合中。
所以，需要提供一种新的LED驱动电路来解决上述问题。
发明内容
现在归纳本发明的一个或多个方面以便于本发明的基本理解，其中该归纳并不是本发明的扩展性纵览，且并非旨在标识本发明的某些要素，也并非旨在划出其范围。相反，该归纳的主要目的是在下文呈现更详细的描述之前用简化形式呈现本发明的一些概念。
本发明在于提供一种LED驱动电路，用于驱动LED模组。该LED驱动电路包括：
开关电源，用于接收外部电源并根据调整信号产生调整后的输出电压；
线性电源电路，用于接收该开关电源的输出电压，并将其转换为线性电压提供给该LED模组；
纹波信号采样电路，用于采集该线性电源电路产生的纹波信号；
纹波信号补偿电路，用于接收该采集到的纹波信号，并将其转换为补偿电压信号；及
输出电压调节电路，用于接收该线性电源电路的电压反馈信号及该补偿电压信号，并根据该电压反馈信号与参考电压之间的差值产生该调整信号来对该开关电源的输出电压进行调节，其中该参考电压等于一个预设的第一参考电压源与该补偿电压信号之和。
相较于现有技术，本发明的LED驱动电路中提供的输出电压调节电路使根据综合的反馈及采集信号来对开关电源进行全面且精确的控制。一方面，该输出电压调节电路接收来自线性电源电路的电压反馈信号，通过该电压反馈信号可以实时监控该开关电源的输出电压符合期望值，即与第一参考电压源进行比较，然后基于比较结果产生对应的调整信号来调整该开关电源的输出电压；另一方面，该输出电压调节电路还进一步通过该纹波信号采样电路采集来自线性电源电路的纹波信号，并通过该纹波信号补偿电路获取该采样的纹波信号中处于具有纹波电流的时间段内的信号能量，并将其转化为该补偿电压信号，使其与该第一参考电压源进行结合后在与来自线性电源电路的电压反馈信号进行比较，如此使产生的调整信号不但使该开关电源符合期望值，并且可使该LED模组在最低功率下正常工作，进而降低了功率的损耗。另外，由于本发明的LED驱动电路仅应用了一级开关电源，而未应用二级或多级开关电源或专用的恒流芯片，因此也大大降低了成本。
附图说明
通过结合附图对于本发明的实施方式进行描述，可以更好地理解本发明，在附图中：
图1为本发明LED驱动电路的一种较佳实施方式的示意框图。
图2示意了图1中的整流滤波电路及线性电源电路的一种较佳施方式的电路图。
图3示意了图1中的输出电压调节电路的一种较佳施方式的电路图。
图4示意了图1中的纹波信号采样电路的一种较佳施方式的电路图。
图5示意了纹波电流、纹波电压及整形电压之间的关系图。
图6示意了图4中的纹波电压整形模块的一种较佳施方式的电路图。
图7示意了图1中的纹波信号补偿电路的一种较佳施方式的电路图。
具体实施方式
以下将描述本发明的具体实施方式，需要指出的是，在这些实施方式的具体描述过程中，为了进行简明扼要的描述，本说明书不可能对实际的实施方式的所有特征均作详尽的描述。应当可以理解的是，在任意一种实施方式的实际实施过程中，正如在任意一个工程项目或者设计项目的过程中，为了实现开发者的具体目标，为了满足系统相关的或者商业相关的限制，常常会做出各种各样的具体决策，而这也会从一种实施方式到另一种实施方式之间发生改变。此外，还可以理解的是，虽然这种开发过程中所作出的努力可能是复杂并且冗长的，然而对于与本发明公开的内容相关的本领域的普通技术人员而言，在本公开揭露的技术内容的基础上进行的一些设计，制造或者生产等变更只是常规的技术手段，不应当理解为本公开的内容不充分。
除非另作定义，权利要求书和说明书中使用的技术术语或者科学术语应当为本发明所属技术领域内具有一般技能的人士所理解的通常意义。本发明专利申请说明书以及权利要求书中使用的“第一”、“第二”以及类似的词语并不表示任何顺序、数量或者重要性，而只是用来区分不同的组成部分。“一个”或者“一”等类似词语并不表示数量限制，而是表示存在至少一个。“包括”或者“包含”等类似的词语意指出现在“包括”或者“包含”前面的元件或者物件涵盖出现在“包括”或者“包含”后面列举的元件或者物件及其 等同元件，并不排除其他元件或者物件。“连接”或者“相连”等类似的词语并非限定于物理的或者机械的连接，而是可以包括电气的连接，不管是直接的还是间接的。
请参考图1，为本发明LED驱动电路100的一种较佳实施方式的示意框图。该LED驱动电路100包括外部电源输入接口110、整流滤波电路120、开关电源(Switched-Mode Power Supply，SMPS)130、线性电源电路140、LED模组150、输出电压调节电路160、纹波信号采样电路170及纹波信号补偿电路180。其中，该LED模组150可以为该LED驱动电路100的组成部分，也可以为各自独立的部分，这里仅是为了说明方便将其纳入了该LED驱动电路部分。
该外部电源输入接口110用于接收外部电源信号(未示出)，如220V交流电源或24V直流电源等。这里仅是举例说明，实际上外部电源信号可以根据需要进行调整，该外部电源信号通过该LED驱动电路100后续电路的一系列控制后提供稳定合适的输出电压给其内部的LED模组150。该LED模组150可能包括单一的LED元件，也可能包括若干个LED元件组合，且LED元件的类型也不限于某一种，均可根据实际需要进行调整。
该整流滤波电路120用于对外部电源进行整流或/及滤波处理，以获得开关电源130所需要的输入电压。由于整流滤波电路为较成熟的技术，故本发明仅给出了图2示意性的整流实施方式作为一个例子加以说明。根据实际需要，该整流滤波电路120的位置也可进行相应的调整，例如除了图1示意的例子外，该整流滤波电路120还可以设置在该开关电源130的后端，以对开关电源130的输出电压信号进行整流或/及滤波处理。又或者，将该整流滤波电路120的整流部分设置于该开关电源130的前端，而该整流滤波电路120的滤波部分则设置于该开关电源130的后端。再或者，将该整流滤波电路120的滤波部分设置于该开关电源130的前端，而该整流滤波电路120的整流部分则设置于该开关电源130的后端。上述举例了一些实施方式，具体还可根据实际需要进行其他类型的调整，不局限于上述给出的例子。除了整理或滤波处理之外，根据实际电路的需要还可对电路中的信号进行其他合适的处理，例如放大处理等，由于这些信号处理并非本发明的设计要点，故这里不具体说明，且图中也未示意出来，但根据本领域人员的理解，可以作相应的信号处理。
该开关电源130用于接收该外部电源信号或经过整理滤波后的外部电源信号，并根据来自输出电压调节电路160的调整信号162调整其输出电压132，例如，该调整信号162可以是一个幅值随反馈信号而上下变化的直流信号。可以知道的是，作为一个例子，该开关电源130内部通常包括PWM调整信号控制集成电路和作为开关元件的晶体管(未示出)，该PWM调整信号控制集成电路根据该调整信号162产生对应占空比的PWM信号，进而控制该开关元件的通断，从而对应调整该开关电源130的输出电压132。该PWM调整信号控制集成电路通常由外部接口与该输出电压调节电路160连接，如光耦合输入接口。该输出电压调节电路160通过上述的外部接口输入该调整信号162到该PWM调整信号控制集成电路。由于该开关电源130内部的具体结构不是本发明的发明要点，故这里不作详细说明。
该线性电源(Linear Source)电路140用于接收该开关电源130的输出电压132并转换为稳定的线性电压142提供给该LED模组150，以使其正常工作。由于该线性电源电路140为较成熟的技术，故本发明仅给出图2示意性的一个线性电源实施方式作为例子加以说明，其他实施方式中也可选用其他类型的线性电源电路或线性电源芯片实现提供稳定线性电压的功能，不局限于图2给出的实施方式，这里不再一一列举。
该输出电压调节电路160用于接收该线性电源电路140的电压反馈信号144，该电压反馈信号144间接地(或直接地)反映了该开关电源130的输出电压132的变化，这种变化可能是由外部电源的变化或者开关电源130自身等原因引起的。当该开关电源130的输出电压132发生变化时，该线性电源电路140输出至LED模组150的线性电压142可能也随之变化，即出现电压不稳定状况，这可能会导致LED模组150工作的不稳定。为此，该输出电压调节电路160根据接收到的电压反馈信号144与预设的基准电压(如图3所示的基准参考电压源Vref1)的比较结果产生相应的调整信号(即PWM调整信号162)给到该开关电源130，以控制该开关电源130内的PWM调整信号控制集成电路，该PWM调整信号控制集成电路根据该调整信号162调整PWM调整信号的占空比，进而调整输出电压132，以使该线性电源电路140输出的线性电压142调整至符合要求的范围内，从而保证该LED模组150可以正常工作。后续段落将结合图3给出该输出电压调节电路160的一个具体的较佳实施方式，以详细说明其具体的工作原理。
但是，上述输出电压调节电路160中参考的基准电压是固定不变的，故有时仅仅根据该预设的基准电压不能完全调整输出电压132达到符合要求的最佳范围。例如，为了有效消除流经LED模组150上电流的纹波，需要将线性电源电路140中线性电源的压降设定有较大的余量，以应对外部电源输入端的能量波动或输出电压132的误差。因此，仅通过该预设的基准电压Vref1调整后的输出电压132可能会使电能损耗变得较高，因为没有对线性电源电路140产生的纹波信号进行补偿。故，本发明LED驱动电路100进一步还提供了纹波信号采样电路170及纹波信号补偿电路180。
该纹波信号采样电路170用于在该线性电源电路142产生纹波信号146时对其进行实时采样，该采样后的纹波信号173输出给该纹波信号补偿电路180。该纹波信号补偿电路180对该采样后的纹波信号(或整形后的纹波信号)进行补偿控制，并输出补偿电压信号182给到该输出电压调节电路160。该输出电压调节电路160根据其内的预设基准电压与该补偿电压信号182结合后再对应产生调整信号162，该结合调整后的调整信号162将使该线性电源电路140输出的线性电压142调整至符合要求的范围内且消耗的功率最小。后续段落将结合图4-图7给出该纹波信号采样电路170及纹波信号补偿电路180的具体的较佳实施方式，以详细说明其具体的工作原理。
上述段落讲述了本发明LED驱动电路100整体的工作原理，下面将结合图2-图7及具体实施方式分别介绍各个部分示例的电路结构及工作原理。需要说明的是，这些实施方式仅仅是为了方便说明各自电路的工作原理而举出的一些实施方式，而这些实施方式可以根据本领域一般技术人员的知识进行常规性的调整设计，不拘泥于这里给出的例子。
请参考图2，示意了图1中整流滤波电路120及线性电源电路140的一种较佳施方式的电路图。正如之前所述，图2仅仅给出了一个示意性的实施方式，其他实施方式中，该整流滤波电路120及线性电源电路140可根据不同需要设计成其他的电路结构。
在图2的实施方式中，该整流滤波电路120包括一个由四个二极管D1-D4组成的桥式整流电路，即该二极管D1的阳极与该二极管D3的阴极连接至该外部电源输入接口110的一个输出端子，该二极管D2的阳极与该二极管D4的阴极连接至该外部电源输入接口110的另一个输出端子，该二极管D1的阴极与该二极管D3的阳极连接至该开关电源130的一个输入端子，该二极管 D2的阴极与该二极管D4的阳极连接至该开关电源130的另一个输入端子。由于该桥式整流电路为现有常见技术，故这里不再详细说明其工作原理。本实施方式中，该整流滤波电路120中并未包括滤波电路部分，这是由于有些应用中，无需滤波即可满足需要。在其他实施方式中，可根据需要相应的增加合适的滤波电路，如电容滤波电路。由于滤波电路也为现有常见技术，故这里为了简化说明，并未给出相应的例子及图示。
在图2的实施方式中，该线性电源电路140包括一个可控精密稳压源器件TL1(如型号为TL431)、三个电阻R1-R3、一个滤波电容C1及一个电子开关(如MOS管)Q1。
该开关电源130的两个电压输出端与该两电阻R1及R2串联，以对该开关电源130的输出电压进行分压处理。该电阻R2的两端分别与该可控精密稳压源器件TL1的阴极与阳极连接，该电阻R2两端的电压分配满足该可控精密稳压源器件TL1阴极与阳极两端的电压要求，具体根据实际参数进行设定。该电容C1与该电子开关Q1及该电阻R3组成串联电路后与该电阻R1及R2组成的串联电路并联在一起。该电子开关Q1的控制端连接至该电阻R1与R2之间的节点D上，该可控精密稳压源器件TL1的参考极连接在该电子开关Q1与该电阻R3之间的节点C上。该电容C1的两端点A及B分别连接至该LED模组150的两个电源输入端。
工作时，该开关电源130提供该输出电压VA(即图1示意的132)给到该线性电源电路140，如24V直流电压。根据该可控精密稳压源器件TL1的器件功能，其参考极将输出固定的电压给到该节点C上，以使该节点C上的电压钳位于该固定的电压，如钳位至1.25V。当C点电压VC＞1.25V时，由于该电子开关Q1工作在放大区，D点的电压VD会下降，进而B点与C点之间的电压VBC会上升。由于VC＝VA-VAB-VBC，故VBC上升后，C点的电压VC会下降直至该钳位电压如1.25V。经过上述一系列控制，该电容C1的两端将输出线性电压VAB(即图1示意的142)给到该LED模组150。其他实施方式中，也可通过其他电路结构的线性电源电路提供线性电压给到该LED模组150，具体根据实际设计要求进行选择，这里不再一一举例说明。
同时，本实施方式中，该B点的电压VB作为该电压反馈信号144输出给该输出电压调节电路160。之所以该电压反馈信号144可以作为反映该开关电源130的输出电压VA，是由于VB＝VA-VAB，故VB间接地反映该开关电源130 的输出电压VA。其他实施方式中，也可以直接将该开关电源的输出电压VA作为该电压反馈信号144输出给该输出电压调节电路160，或者将其他相关联的电压信号作为该电压反馈信号144，而不拘泥于某一种反馈方式。
请继续参考图3，示意了图1中的输出电压调节电路160的一种较佳施方式的电路图。本实施方式中，该输出电压调节电路160包括一个比较器U1、一个参考电压源Vref1及一个电容C2。
该比较器U1的反相输入端接收该线性电源电路140输出的该电压反馈信号144，该比较器U1的正相输入端接收该参考电压源Vref1，该电容C2连接在该比较器U1的反相输入端与输出端之间，该比较器U1的输出端产生该调整信号162。该参考电压源Vref1根据该开关电源130实际需要产生的输出电压而设定，即该参考电压源Vref1的值对应该开关电源130期望产生的输出电压，即直接对应该电压反馈信号144的期望值。
工作时，当该电压反馈信号144小于该参考电压源Vref1时，表明该开关电源130产生的输出电压132比期望值要小，故此时该调整信号162将输出一个正值的调整信号162来提高开关电源130中PWM调整信号的占空比，进而提高该开关电源130的输出电压132以使其等于或趋近于期望值。反之，当该电压反馈信号144大于该参考电压源Vref1时，表明该开关电源130产生的输出电压132比期望值要大，故此时该调整信号162将输出一个负值的调整信号162来降低开关电源130中PWM调整信号的占空比，进而降低该开关电源130的输出电压132以使其等于或趋近于期望值。因此，通过该输出电压调节电路160的反馈调整，可使该开关电源130产生的输出电压132始终等于或趋近于期望值。在其他实施方式中，该输出电压调节电路160也可以设计成其他结构的电路形式，例如通过应用比较芯片实现该电压反馈信号144与该参考电压源Vref1的比较，并输出相应的调整信号162，这里不一一举例说明。
请继续参考图4，示意了图1中的纹波信号采样电路170的一种较佳施方式的电路图。本实施方式中，该纹波信号采样电路170包括纹波电压整形模块172及整形电压输出模块174。在一些实施方式中，也可仅应用该纹波电压整形模块172而省略该整形电压输出模块174。
在该实施方式中，该纹波信号采样电路170是依据图2中B点的电压VB作为该纹波信号146的采样源进行采样的，即该纹波信号146的采样源与上 述的电压反馈信号144的反馈源为同一个信号源。其他实施方式中，也可选用其他不同的采样点进行采样或反馈收集，只要满足反馈源或采样源处的信号与实际需要获得的反馈信号或采样信号直接或间接相关联即可，不局限于某一种反馈或采样方式。
针对本实施方式中的纹波电压整形模块172，其包括一个比较器U2及一个参考电压源Vref2。在该实施方式中，该纹波电压整形模块172用于将该纹波信号146转换成方波信号，以便于后续对信号的处理，其它实施方式也可转换成其他类型的信号或不进行整形转换。
在该实施方式中，该比较器U2的反相输入端用于接收该纹波信号146，该比较器U2的正相输入端用于接收该参考电压源Vref2。参考图5，示意了纹波电流52、纹波电压54及整形电压56之间的关系图。其中，该纹波电流52为流经该LED模组150的电流信号在产生纹波电流时的局部波形图，可以看出，在时间段T1-T2，T3-T4，T5-T6时无纹波电流产生，而在时间段T2-T3，T4-T5，T6-T7时产生了纹波电流。由于直接采样电流信号52可能会有能量损耗的问题，故本实施方式直接采样的是与其相关联的纹波电压信号54(即线性电源电路140中的B点处电压信号VB)。从图5中可以看出，在无纹波电流产生的时间段T1-T2，T3-T4，T5-T6内，该纹波电压54的幅值均为正值，而在产生纹波电流的时间段T2-T3，T4-T5，T6-T7内，该纹波电压54的幅值均等于零。因此，通过该比较器U2的整形，可将该纹波电压54的幅值在正值的时间段均整形等于零，而将该纹波电压54的幅值等于零的时间段均整形等于一固定电压值，即如整形电压56的方波信号(对应图4的1731)。因此，比较纹波电流52与整形电压56，可知该纹波电流52出现纹波的时间段T2-T3，T4-T5，T6-T7对应该整形电压56的高幅值时间段，而未出现纹波的时间段T1-T2，T3-T4，T5-T6对应该整形电压56的低幅值时间段。
在其他实施方式中，该纹波电压整形模块172也可通过其他类型的整形电路实现。例如图6示意的另一种实施方式。该实施方式中，该纹波电压整形模块172包括电阻R6及电子开关Q4(如三极管)。该电阻R6与该电子开关Q4串联于一个电压源Vcc及地之间，该电子开关Q4的控制端用于接收该纹波信号146，该电阻R6与电子开关Q4的节点用于作为整形电压1731(类似于图5中的56)的输出。易知，当该纹波信号146(类似于图5中的54)为正值时，该电子开关Q4导通，故该整形电压1731等于零，当该纹波信号146为零时， 该电子开关Q4截止，故该整形电压1731等于一固定电压值。该纹波电压整形模块172还可通过其他电路实现，这里不一一举例说明。
返回至图4，该纹波信号采样电路170进一步包括一个整形电压输出模块174，在该实施方式中，该整形电压输出模块174为一个镜像电流源电路，其典型地包括两个电阻R4及R5、三极管Q2及Q3，电阻R4与三极管Q2组成镜像电流源电路的一侧，电阻R5与Q3组成镜像电流源电路的另一侧，通过该镜像电流源电路174的输出功能，可使该纹波电压整形模块172产生的整形方波电压1731的高幅值部分产生镜像电流1732后再稳定的输出给该纹波信号补偿电路180。由于镜像电流源电路为现有常见电路，故这里不作具体说明。如之前所述，在其他实施方式中，也可省略该整形电压输出模块174部分，而直接将该纹波电压整形模块172产生的整形电压1731输出给该纹波信号补偿电路180。其他实施方式中，该整形电压输出模块174也可以设计成其他类型的电压输出电路来稳定的获取该整形电压1731高幅值部分的电压输出。
请继续参考图7，示意了图1中的纹波信号补偿电路180的一种较佳施方式的电路图。在该实施方式中，该纹波信号补偿电路180包括电阻R7、电阻R8、二极管D5及储能电容C3。
该二极管D5的阳极通过电阻R7连接至该纹波信号采样电路170，以接收其产生的采样后的纹波信号173(如图4所示的信号1731或1732)。该二极管D5的阴极串联该储能电容C3后接地。该二极管D5与该储能电容C3之间的节点通过电阻R8连接至该输出电压调节电路160，以向其提供补偿的电压信号Vadd(共同参考图3，即图1中的182)。该纹波信号补偿电路180中的该电阻R7、R8及二极管D5均是为了调节储能电路的性能，如电阻起到限流的作用，二极管起到防止电流回流的作用。其他实施方式中，该储能电容C3可以由其他具有储能功能的储能元件替换，而该电阻R7、R8及二极管D5均可由其他类似功能的电子元件进行替换，电路结构也可根据需要进行调整，不局限于本实施方式给出的例子。
工作时，当线性电源电路140产生纹波电流时，例如图5所示的时间段T2-T3，T4-T5，T6-T7，该纹波信号采样电路170将对应产生整形信号173，如图5所示的方波信号56。对应地，在该方波信号56的正向时间段T2-T3，T4-T5，T6-T7内，该纹波信号采样电路170将对该纹波信号补偿电路180中的储能电容C3进行充电，使其两端电压增加。进而该增加的电压Vdd将 会补偿图3所示的输出电压调节电路160中的比较器U1正相输入端的电压参考值Vref1，如此可提高与该线性电源电路140的反馈电压信号142进行比较的参考电压(缓冲电压)的范围，以有效地消除该线性电源电路140中的纹波电流。另外，又由于该纹波信号补偿电路180中储能电容C3的电能增量对应于该线性电源电路140中的纹波电流，因此该增加的电压Vadd刚好可以消除线性电源电路140中的纹波电流，即可使该LED模组150在最低功率下正常工作，因而降低了功率的损耗。如此，通过上述电路的控制，本发明LED驱动电路100可在最低功率下正常控制LED模组150进行工作。另外，由于本发明的LED驱动电路100仅应用了一级开关电源，而未应用二级或多级开关电源或专用的恒流芯片，因此也大大降低了成本。
虽然结合特定的实施方式对本发明进行了说明，但本领域的技术人员可以理解，对本发明可以作出许多修改和变型。因此，要认识到，权利要求书的意图在于覆盖在本发明真正构思和范围内的所有这些修改和变型。

Claims (10)

  1. 一种LED驱动电路，用于驱动LED模组，其特征在于：该LED驱动电路包括：
    开关电源，用于接收外部电源并根据调整信号产生调整后的输出电压；
    线性电源电路，用于接收该开关电源的输出电压，并将其转换为线性电压提供给该LED模组；
    纹波信号采样电路，用于采集该线性电源电路产生的纹波信号；
    纹波信号补偿电路，用于接收该采集到的纹波信号，并将其转换为补偿电压信号；及
    输出电压调节电路，用于接收该线性电源电路的电压反馈信号及该补偿电压信号，并根据该电压反馈信号与参考电压之间的差值产生该调整信号来对该开关电源的输出电压进行调节，其中该参考电压等于一个预设的第一参考电压源与该补偿电压信号之和。
  2. 如权利要求1所述的LED驱动电路，其中该纹波信号采样电路采集的纹波信号是与纹波电流相对应的纹波电压信号。
  3. 如权利要求2所述的LED驱动电路，其中该纹波信号采样电路包括一个比较器及一个预设的第二参考电压源，该比较器的反相输入端接收该纹波电压信号，该比较器的正相输入端接收该第二参考电压源，该比较器的输出端输出整形后的纹波信号，该整形后的纹波信号为方波信号且该方波信号的高幅值部分对应出现纹波电流的时间段。
  4. 如权利要求2所述的LED驱动电路，其中该纹波信号采样电路包括一个电阻及一个开关元件，该电阻与该开关元件串联在一个电压源与地之间，该开关元件的控制端接收该纹波电压信号，该电阻与该开关元件之间的节点输出整形后的纹波信号，该整形后的纹波信号为方波信号且该方波信号的高幅值部分对应出现纹波电流的时间段。
  5. 如权利要求3或4所述的LED驱动电路，其中该纹波信号采样电路进一步包括一个镜像电流源电路，用于将该方波信号的高幅值部分的能量以电流的形式输出。
  6. 如权利要求1-4中任意一项所述的LED驱动电路，其中该纹波信号补偿电路包括一个储能元件，该储能元件基于该采集到的纹波信号在对应具有纹波电流的时间段内的电压信号进行储能，并将该存储的能量转化为该补偿电压信号。
  7. 如权利要求6所述的LED驱动电路，其中该储能元件包括电容。
  8. 如权利要求7所述的LED驱动电路，其中该纹波信号补偿电路还包括第一电阻、第二电阻及二极管，该二极管的阳极通过该第一电阻接收该采集到的纹波信号，该二极管的阴极通过该电容接地，该二极管与电容的节点通过该第二电阻提供该补偿电压信号。
  9. 如权利要求1所述的LED驱动电路，其中该输出电压调节电路包括一个比较器及一个电容，该比较器的反相输入端接收该线性电源电路输出的电压反馈信号，该比较器的正相输入端接收该参考电压，该电容连接在该比较器的反相输入端与输出端之间，该比较器的输出端产生该调整信号。
  10. 如权利要求1所述的LED驱动电路，其中该线性电源电路包括一个可控精密稳压源器件、第一至第三电阻、一个电容及一个电子开关，该开关电源的两个电压输出端与该第一及第二电阻串联，该第二电阻的两端分别与该可控精密稳压源器件的阴极与阳极连接，该电容与该电子开关及该第三电阻组成串联电路后与该第一及第二电阻组成的串联电路并联连接，该电子开关的控制端连接至该第一电阻与第二电阻之间的节点上，该可控精密稳压源器件的参考极连接在该电子开关与该第三电阻之间的节点上，该电容的两端分别连接至该LED模组的两个电源输入端。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112953220A (zh) * 2021-02-03 2021-06-11 电子科技大学 带有电流检测和控制的dc-dc转换器

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105188201B (zh) * 2015-08-25 2018-07-17 北京极澈远技术有限公司 一种应用于led照明的高速调光电路
CN106793322B (zh) * 2016-12-30 2020-05-19 深圳Tcl数字技术有限公司 Led驱动电路
CN106527561B (zh) * 2017-01-04 2018-07-17 西南应用磁学研究所 一种带电压跟踪的高效率磁调谐器件驱动电路
CN108811225A (zh) * 2017-05-04 2018-11-13 深圳市帝莱特照明有限公司 一种中小功率智能照明的无频闪调光变色led驱动电源
JP7295881B2 (ja) 2018-10-31 2023-06-21 ローム株式会社 リニア電源回路
CN112423434B (zh) * 2020-11-13 2021-10-08 浙江大学 基于电源纹波的多路led灯亮度旁路检测装置和方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101404846A (zh) * 2008-11-17 2009-04-08 南京源之峰科技有限公司 功率led驱动系统中对输入电压波动的实时补偿装置
CN101754540A (zh) * 2010-02-09 2010-06-23 四川锦明光电股份有限公司 Led光源的驱动器
CN103259437A (zh) * 2012-02-15 2013-08-21 欧司朗股份有限公司 负载驱动器和用于减小负载驱动器的输出纹波电流的方法
CN103298218A (zh) * 2013-06-27 2013-09-11 苏州智浦芯联电子科技有限公司 用于减小led纹波电流的电路

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100446395C (zh) * 2007-04-28 2008-12-24 电子科技大学 具有电压纹波检测电路的稳压开关电源

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101404846A (zh) * 2008-11-17 2009-04-08 南京源之峰科技有限公司 功率led驱动系统中对输入电压波动的实时补偿装置
CN101754540A (zh) * 2010-02-09 2010-06-23 四川锦明光电股份有限公司 Led光源的驱动器
CN103259437A (zh) * 2012-02-15 2013-08-21 欧司朗股份有限公司 负载驱动器和用于减小负载驱动器的输出纹波电流的方法
CN103298218A (zh) * 2013-06-27 2013-09-11 苏州智浦芯联电子科技有限公司 用于减小led纹波电流的电路

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112953220A (zh) * 2021-02-03 2021-06-11 电子科技大学 带有电流检测和控制的dc-dc转换器
CN112953220B (zh) * 2021-02-03 2022-12-30 电子科技大学 带有电流检测和控制的dc-dc转换器

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