WO2021057851A1 - 一种高功率因数的控制电路以及ac/dc转换电路 - Google Patents

一种高功率因数的控制电路以及ac/dc转换电路 Download PDF

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WO2021057851A1
WO2021057851A1 PCT/CN2020/117483 CN2020117483W WO2021057851A1 WO 2021057851 A1 WO2021057851 A1 WO 2021057851A1 CN 2020117483 W CN2020117483 W CN 2020117483W WO 2021057851 A1 WO2021057851 A1 WO 2021057851A1
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signal
unit
module
current
control circuit
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PCT/CN2020/117483
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English (en)
French (fr)
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郜小茹
孙顺根
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上海晶丰明源半导体股份有限公司
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Publication of WO2021057851A1 publication Critical patent/WO2021057851A1/zh
Priority to US17/702,353 priority Critical patent/US12021449B2/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • H02M1/15—Arrangements for reducing ripples from dc input or output using active elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • 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]
    • H05B45/20—Controlling the colour of the light
    • 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
    • H05B45/355—Power factor correction [PFC]; Reactive power compensation
    • 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
    • H05B45/36—Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
    • 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]
    • 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]
    • H05B45/392—Switched mode power supply [SMPS] wherein the LEDs are placed as freewheeling diodes at the secondary side of an isolation transformer
    • 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]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • H05B45/59—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits for reducing or suppressing flicker or glow effects
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4258—Arrangements for improving power factor of AC input using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4291—Arrangements for improving power factor of AC input by using a Buck converter to switch the input current
    • 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]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology
    • 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]
    • H05B45/38—Switched mode power supply [SMPS] using boost topology
    • 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
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

  • the present invention relates to a control circuit and an AC/DC conversion circuit, in particular to a high power factor control circuit and an AC/DC conversion circuit.
  • Single-stage topology (Light-emitting diode, LED) controller with power factor correction has the following advantages: good power factor, harmonic current (Harmonic current) that meets the requirements, and circuit
  • the structure is simple and cost-effective.
  • this type of LED controller has a high power factor, a small bus capacitor (DC bus capacitor), and the bus uses a utility frequency voltage signal, so that the output current generates a large power frequency ripple.
  • FIG. 1 is a prior art LED control circuit 90, including a bridge rectifier 91, a bus capacitor 92, a buck converter 93, a high power factor controller 94, a load 95, and A switching element 96, an AC mains passing through the bridge rectifier 91, forms a DC current and passing through the bus capacitor 92 to generate a bus (Vbus).
  • the bus (Vbus) is a power frequency signal
  • the waveforms of the inductor current (IL) and the output current (IO) in the buck converter 93 are shown in Figure 2, and the output current (IO) is The average value of the inductor current (IL), and the output current (IO) has a power frequency ripple (ripple), and the amplitude of the ripple is positively correlated with the maximum peak current of the inductor current (IL).
  • the ripple can also cause the LED to flicker. Therefore, how to control the ripple of a single-stage topology light-emitting diode controller with power factor correction within a reasonable range is an important issue.
  • the main purpose of the present invention is to solve the problem of excessive power frequency ripple in the existing single-stage topology light-emitting diode controller with power factor correction.
  • the present invention provides a high power factor control circuit applied to an AC/DC conversion circuit.
  • the AC/DC conversion circuit includes a rectifier module, a conversion module coupled to the rectifier module, and a receiver.
  • the load driven by the conversion module, the rectification module receives an alternating current and rectifies it into a direct current
  • the conversion module converts the direct current into a driving power according to a load and provides the load to the load
  • the control circuit includes: a A peak limit unit that inputs a reference signal and generates at least one peak limit signal according to a sampling signal from the switch unit; and a drive unit is coupled to the switch unit and controls the switch unit to switch based on the peak limit signal, Therefore, when a voltage on the inductance element is higher than a threshold value
  • it is characterized in that it further includes a feedback unit, and the feedback unit samples a current on the switch unit to output the sampling signal.
  • the feedback unit is characterized in that the feedback unit includes a sampling unit coupled to the switch unit to sample the current on the switch unit to output a first sampling signal, and a sampling unit that outputs a first sampling signal based on the first sampling signal. Two sampling processors for sampling signals.
  • the peak limiting unit further includes a compensation module, and the compensation module generates a compensation signal according to the reference signal and the first sampling signal or the second sampling signal.
  • the compensation module is characterized in that the compensation module includes a differencer and a filter coupled to the differencer, the differencer inputs the reference signal, and the first sampling signal or the second sampling Signal and generate a difference to the filter to output the compensation signal.
  • the peak limit unit includes a current limit module that receives the compensation signal, and the current limit module generates the peak limit signal according to the compensation signal.
  • the driving unit further includes a minimum off-time regulator, and the minimum off-time regulator generates a shortest off-time signal according to the compensation signal.
  • the current limiting module includes an amplifier and a resistor string
  • the amplifier has an output terminal, a first input terminal for inputting the compensation signal, and a second input terminal coupled to the output terminal
  • the resistor string is coupled to the output terminal and outputs the peak limit signal.
  • the current limiting module includes an amplifier and a resistor string
  • the amplifier has an output terminal, a first input terminal for inputting the compensation signal, and a second input coupled to the resistor string Terminal, the peak limit signal is output between the output terminal of the amplifier and the resistor string.
  • the driving unit is characterized in that the driving unit includes a logic module and a driver connected to the logic module, and the logic module generates a switching signal to the driver to control the switching unit.
  • the driving unit further includes a delay, which receives a turn-on signal and generates a first control signal reflecting a maximum turn-on time of the switch unit.
  • the driving unit further includes a comparator, and the comparator generates a comparison result reflecting a current sampling signal and a limit threshold value according to the peak limit signal and the sampling signal.
  • the second control signal is characterized in that the driving unit further includes a comparator, and the comparator generates a comparison result reflecting a current sampling signal and a limit threshold value according to the peak limit signal and the sampling signal. The second control signal.
  • the first control signal and the second control signal determine a turn-off control signal reflecting the turn-off time of the switch unit.
  • the driving unit further includes a demagnetization detection module, the demagnetization detection module has an input terminal coupled to the switch unit and an output terminal that outputs a demagnetization signal to the logic module.
  • it is characterized in that it further includes a dimming module that outputs the reference signal to the driving unit, and the load is an LED lamp adjusted by the reference signal.
  • the limit value changes with the change of at least one factor, and the factor is selected from the group consisting of the sampling signal, the reference signal, and the load.
  • the present invention also provides a high power factor AC/DC conversion circuit, which is characterized by comprising: a rectifier module, which receives an alternating current and rectifies it into a direct current; a conversion module, coupled to the rectifier module and According to a load, the direct current is converted into a driving power and provided to the load.
  • the conversion module includes a conversion unit having an inductance element and a conversion unit coupled to the conversion unit and switched between an on state and an off state
  • the switch unit a current passing through the inductance element forms a residual ripple based on the alternating current
  • a control module including: a peak limit unit that inputs a reference signal and generates at least A peak limit signal; and a drive unit, coupled to the switch unit and based on the peak limit signal to control the switching unit to switch, so that at least in half a power frequency cycle when a voltage on the inductive element is higher than a threshold At this time, the ripple of the current of the inductance element is not higher than a limit value.
  • the conversion module is selected from the group consisting of a floating buck converter, a boost converter, a flyback converter, and a buck-boost converter .
  • the load is an LED lamp.
  • the present invention provides the peak limit unit, which generates the peak limit signal according to the sampling signal. Since the peak limit signal is generated according to the sampling signal, it will change with the variation of the sampling signal. In other words, the peak limit signal will be adjusted according to different dimming brightness, bus voltage, output voltage or output current. Although the maximum inductor current peak value in the power frequency cycle is changing, the current peak limit reflected by the sampling signal The threshold is also changing, so as to achieve the effect of reducing the output current ripple, which not only extends the service life of the component, but also reduces the problem of LED flicker.
  • Figure 1 shows a prior art LED control circuit.
  • FIG. 2 is a schematic diagram of the waveforms of the inductor current (IL) and the output current (IO) of the LED control circuit in the prior art.
  • Fig. 3 is a schematic diagram of a high power factor control circuit according to the first embodiment of the present invention.
  • Fig. 4 is a schematic diagram of a high power factor control circuit according to a second embodiment of the present invention.
  • Fig. 5 is a schematic diagram of a high power factor control circuit according to a third embodiment of the present invention.
  • Fig. 6 is a schematic diagram of a high power factor control circuit according to a fourth embodiment of the present invention.
  • Fig. 7 is a schematic diagram of a high power factor control circuit according to a fifth embodiment of the present invention.
  • FIG. 8A is a schematic diagram of the configuration of the current limiting module in an embodiment of the present invention.
  • FIG. 8B is a schematic diagram of the configuration of the current limiting module in another embodiment of the present invention.
  • FIG. 9 is a schematic diagram of the waveforms of the inductor current (IL) and the output current (IO) of the control circuit of the present invention.
  • the present invention discloses a high power factor control circuit and an AC/DC conversion circuit.
  • the high power factor control circuit is applied to an AC/DC conversion circuit 10.
  • FIG. 3 shows the high power according to the first embodiment of the present invention.
  • the AC/DC conversion circuit 10 includes a rectification module 11, a conversion module 12, and a load 13.
  • the conversion module 12 is coupled to the rectification module 11 and drives the load 13, the rectification module 11 Receiving an alternating current AC and rectifying it into direct current DC, the rectifier module 11 includes a rectifier 111 and a capacitor 112.
  • the conversion module 12 converts the direct current DC into a driving power according to the load 13 and provides it to the load 13.
  • the module 12 includes a conversion unit 121 and a switch unit 122.
  • the conversion unit 121 includes an inductor 123, a capacitor 124, and a diode 125.
  • the switch unit 122 may be a power switch, such as a metal oxide semiconductor field effect transistor ( Metal Oxide Semiconductor Field-Effect Transistor, MOSFET), but not limited to this, the power switch can also be one or more transistors.
  • MOSFET Metal Oxide Semiconductor Field-Effect Transistor
  • the switch unit 122 switches between an on state and an off state, and the switch unit 122 includes a drain terminal D, a source terminal S, and a gate terminal G.
  • the load 13 is an LED lamp.
  • the control circuit includes a peak limiting unit 20 and a driving unit 30.
  • the peak limiting unit 20 receives a reference signal and generates at least one peak limiting signal according to a sampling signal from the switch unit 122.
  • the driving unit 30 is coupled to the gate terminal G of the switching unit 122, and the driving unit 30 controls the switching of the switching unit 122 according to the peak limit signal, so that at least within half a power frequency cycle, when When a voltage on the inductance element 123 is higher than a threshold value, the ripple of a current passing through the inductance element 123 is not higher than a limit value, and the limit value can vary with the change of at least one factor, which is selected from At least any one of the sampling signal, the reference signal, and the load 13.
  • the control circuit further includes a feedback unit 40 and a dimming module 50.
  • the feedback unit 40 samples the current on the switch unit 122 to output the sampling signal.
  • the feedback unit 40 may include a sampling resistor 41.
  • a sampling processor 42 the sampling resistor 41 is coupled to the switch unit 122, and samples the current on the switch unit 122 to output a first sampling signal, and the sampling processor 42 outputs according to the first sampling signal
  • a second sampling signal is provided to the peak limiting unit 20.
  • the sampling signal may be the first sampling signal or the second sampling signal as appropriate.
  • the dimming module 50 outputs the reference signal according to external or internal control, and the reference signal can be regarded as a dimming signal.
  • the peak limiting unit 20 includes a compensation module 21 and a current limiting module 22.
  • the compensation module 21 includes a differentiator 211 and a filter 212, and the filter 212 is coupled to the differentiator 211
  • the differencer 211 receives the reference signal and the first sampling signal (or the second sampling signal) from the dimming module 50 and generates a difference value to the filter 212.
  • the difference value The device 211 receives the reference signal and the second sampling signal.
  • the filter 212 outputs the compensation signal
  • the current limit module 22 is coupled to the compensation module 21 and receives the compensation signal
  • the current limit module 22 generates the peak limit signal according to the compensation signal
  • the peak limit signal reflects a Limit voltage.
  • the filter 212 can also be replaced by other forms of circuits (such as digital low-pass filters) or analog low-pass filters to achieve the result of filtering the difference to output a DC signal, for example, A combination of a transconductance amplifier and a capacitor.
  • the driving unit 30 includes a driver 31, a logic module 32, a demagnetization detection module 33, a first control module 34, and a second control module 35.
  • the first control module 34 is coupled to the peak limiting unit 20.
  • the first control module 34 includes a comparator 341, a delay 342 and an OR gate 343.
  • the driver 31 is coupled to the gate terminal G of the switch unit 122 and obtained from the logic module 32
  • a switching signal controls the closing and conducting of the switch unit 122.
  • the first control module 34 is used to generate a turn-off control signal, and the turn-off control signal controls the turn-off timing of the switch unit 122;
  • the second control module 35 is used to generate a shortest turn-off timing.
  • the shortest turn-off time signal controls the shortest turn-off duration of the switch unit 122.
  • the delay 342 inputs the switching signal to generate a first control signal, the first control signal reflects a maximum on time of the switch unit 122, and the first control signal is used to determine the off time of the switch unit 122 ( Turn-offtiming).
  • the comparator 341 has a first input terminal 341a, a second input terminal 341b, and an output terminal 341c.
  • the first input terminal 341a inputs the first sampling signal or the second sampling signal
  • the second input terminal 341b receives The current limit module 22 obtains the peak limit signal
  • the comparator 341 outputs a second control signal from the output terminal 341c to the logic module 32 according to the peak limit signal and the first sampling signal or the second sampling signal, In other words, after the comparator 341 compares the peak limit signal and the first sampling signal (or the second sampling signal), determines the second control signal and outputs it.
  • the second control signal reflects a current sampling signal (current A comparison result between the sampled voltage or the current sampled current) and a limit threshold (the limit voltage or the limit current), the second control signal is used to determine the turn-off timing of the switch unit 122.
  • the current sampling signal and the limit threshold are both voltages
  • the first input terminal 341a inputs the first sampling signal
  • the comparator 341 is based on the peak limit signal and the first sampling signal.
  • the second control signal is output.
  • the first control signal and the second control signal are then output to the OR gate 343, and the OR gate 343 then outputs the turn-off control signal to the logic module 32 according to the first control signal and the second control signal.
  • the turn-off control signal determines the turn-off timing of the switch unit 122.
  • the second control module 35 is coupled to the compensation module 21 of the peak limiting unit 20.
  • the second control module 35 can adopt a minimum off-time regulator, that is, generate according to the compensation signal output by the compensation module 21
  • a third control signal is sent to the logic module 32, and the third control signal reflects the shortest turn-off duration of the switch unit 122, that is, the third control signal is the shortest turn-off time signal, in other words, the first The three control signals are used to determine a turn-on timing of the switch unit 122.
  • the demagnetization detection module 33 is coupled between an output terminal of the driver 32 and the driver 31.
  • the demagnetization detection module 33 has an input terminal and an output terminal.
  • the demagnetization detection module 33 is coupled to the output terminal of the driver 31 According to the output of the driver 31, a demagnetization signal is output to the logic module 32.
  • the logic module 32 receives the turn-off control signal, the shortest turn-off time signal, and the demagnetization signal, and generates the switching signal to the driver 31 accordingly.
  • the function of the turn-off control signal is to control the turn-off of the switch unit 122 when one of the following two occurs (whichever is first): the switch unit 122 reaches the maximum on-time, or When the current sampling signal (current sampling voltage or current sampling current) rises to the limit threshold (limiting voltage or limiting current).
  • the function of the shortest off-time signal is that when the dimming brightness is low and the on-time is too short, the shortest off-time signal can control the switch unit 122 to be in a discontinuous conduction mode. )mode.
  • the conversion module 12 can be a floating buck converter, a boost converter, a flyback converter, or a buck-boost converter.
  • the specific circuit description part will be described below.
  • Configuration. Please refer to FIG. 4, which is a schematic diagram of a high power factor control circuit according to a second embodiment of the present invention.
  • This embodiment adopts a floating buck converter, and the driving unit 30 is coupled to the switching unit 122
  • the source terminal S of the converter unit 121 includes an inductor 123, a capacitor 124, a diode 125, and a resistor 126.
  • the capacitor 124, the diode 125 and the load 13 are connected in parallel, and the inductor 123 and the resistor 126 are connected in series.
  • FIG. 5 is a schematic diagram of a high power factor control circuit according to a third embodiment of the present invention.
  • This embodiment adopts a boost converter, and the driving unit 30 is coupled to the drain of the switching unit 122.
  • the conversion unit 121 includes an inductor 123, a capacitor 124, and a diode 125.
  • the capacitor 124 and the load 13 are connected in parallel, the inductor 123 and the diode 125 are connected in series between the capacitor 124 and the capacitor 112, and the switch
  • the drain terminal D of the unit 122 is coupled between the inductor 123 and the diode 125.
  • FIG. 6 is a schematic diagram of a high power factor control circuit according to a fourth embodiment of the present invention.
  • a flyback converter is used, and the driving unit 30 is coupled to the drain of the switching unit 122.
  • the conversion unit 121 includes an inductor 123, a capacitor 124, and a diode 125.
  • the capacitor 124 and the load 13 are connected in parallel.
  • the inductor 123 is a transformer having a first side and a second side. The first side is coupled to the capacitor 112 and the drain terminal D of the switch unit 122, the second side is connected in parallel with the capacitor 124, and the diode 125 is coupled between the capacitor 124 and the second side.
  • FIG. 6 is a schematic diagram of a high power factor control circuit according to a fourth embodiment of the present invention.
  • a flyback converter is used, and the driving unit 30 is coupled to the drain of the switching unit 122.
  • the conversion unit 121 includes an inductor 123, a capacitor 124, and
  • FIG. 7 is a schematic diagram of a high power factor control circuit according to a fifth embodiment of the present invention.
  • This embodiment adopts a buck-boost converter, and the driving unit 30 is coupled to the switch
  • the drain terminal D of the unit 122, the conversion unit 121 includes an inductor 123, a capacitor 124, and a diode 125.
  • the inductor 123, the capacitor 124 and the load 13 are connected in parallel, and the diode 125 is coupled to the inductor 123 and the capacitor 124 between.
  • the above are only examples. In other embodiments of the present invention, converters with other configurations may also be used.
  • the current limiting module 22 may be configured as shown in FIG. 8A, including an amplifier 221, a first resistor 222, and a second resistor 223.
  • the amplifier 221 includes a first input terminal 221a and a second input terminal 221a. Terminal 221b and an output terminal 221c.
  • the first input terminal 221a inputs the compensation signal, and the second input terminal 221b is coupled to the output terminal 221c.
  • One end of the first resistor 222 is coupled to the output terminal 221c of the amplifier 221, and the other end is coupled to the second resistor 223.
  • the second resistor 223 is grounded.
  • the peak limit signal (CS_limit) is transmitted from the first resistor 222 and the second resistor 223 output.
  • the configuration of the current limit module 22 may also be as shown in FIG. 8B.
  • a node formed between the first resistor 222 and the second resistor 223 is input to the second input terminal 221b, and the peak limit signal (CS_limit) is output from the The output is between the terminal 221c and the first resistor 222.
  • CS_limit peak limit signal
  • FIG. 9 is a schematic diagram of the waveforms of the inductor current (IL) and the output current (IO) of the control circuit of the present invention.
  • the peak limit unit is provided in the present invention, and the peak limit unit generates the peak limit signal according to the sampling signal. It can be seen from Figure 9 that the current flowing through the inductor is limited to a current peak limit threshold (IL_limit), thereby reducing the current ripple. Since the second control module is provided, the shortest off-time signal can be generated, so although the current is limited to the current peak limit threshold (IL_limit), at low brightness, the problem of too short on-time will not occur.
  • IL_limit current peak limit threshold
  • the peak limit signal since the peak limit signal is generated based on the sampling signal, it changes with the variation of the sampling signal. In other words, the peak limit signal will be adjusted according to different dimming brightness, bus voltage, output voltage or output current.
  • the maximum inductor current peak value in the power frequency cycle is changing, the current peak limit reflected by the sampling signal
  • the threshold is also changing, so as to reduce the output current ripple effect, which not only prolongs the service life of the components, but also reduces the problem of LED flicker. In addition, you can choose a smaller output capacitor to achieve the same output current. Ripple reduces the cost.

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Abstract

一种高功率因数的控制电路，应用于一AC/DC转换电路，该转换电路包括一整流模块、一转换模块以及一负载，该整流模块接收一交流电而整流为一直流电，该转换模块根据一负载将该直流电转换为一驱动电力给该负载，且包括一具有一电感元件的转换单元及一在一导通状态和一关闭状态之间切换的开关单元，通过该电感元件的一电流形成一基于该交流电而残余的波纹，该控制电路包括一峰值限制单元及一驱动单元，该峰值限制单元输入一参考信号并根据一采样信号而产生至少一峰值限制信号，该驱动单元耦接至该开关单元并基于该峰值限制信号控制该开关单元切换，使得至少在半个工频周期内当该电感元件上的一电压高于一门槛值时，该电感元件的该电流的该波纹不高于一限制值。

Description

一种高功率因数的控制电路以及AC/DC转换电路 技术领域
本发明涉及一种控制电路以及AC/DC转换电路，尤其涉及一种高功率因数的控制电路以及AC/DC转换电路。
背景技术
具功率因数校正的单级拓扑(Single stage topology)发光二极管(Light-emitting diode，LED)控制器，拥有以下优点：良好的功率因数、符合需求的谐波电流(Harmonic current)可满足需求、电路架构简洁以及高性价比。然而，该类型的LED控制器具有高功率因数，母线电容(DC bus capacitor)较小，又母线为工频(Utility frequency)电压信号，使得输出的电流产生较大的工频纹波。
请参阅图1，为现有技术的LED控制电路90，包括一桥式整流器91、一母线电容92、一降压变换器(Buck converter)93、一高功率因数控制器94、一负载95以及一开关元件96，一交流市电经过该桥式整流器91后形成一直流电通过该母线电容92，产生一母线(Vbus)。如前所述，该母线(Vbus)为一工频信号，而该降压变换器93中的电感电流(IL)和输出电流(IO)的波形如图2所示，输出电流(IO)为电感电流(IL)的平均值，且输出电流(IO)存在工频纹波(ripple)，纹波的幅度跟电感电流(IL)的最大峰值电流呈正相关。
纹波除了会降低元件的寿命外，也会使得LED发生闪烁的问题。因此，如何将具功率因数校正的单级拓扑发光二极管控制器的纹波控制在合理的范围，为一重要课题。
发明公开
本发明的主要目的在于解决现有具功率因数校正的单级拓扑发光二极管控制器，存在工频纹波过大的问题。
为达上述目的，本发明提供一种高功率因数的控制电路，应用于一AC/DC转换电路，该AC/DC转换电路包括一整流模块、一耦接至该整流模块的转换模块以及一受该转换模块驱动的负载，该整流模块接收一交流电而整流为一直 流电，该转换模块根据一负载将该直流电转换为一驱动电力而提供给该负载，且包括一具有一电感元件的转换单元以及一耦接至该转换单元并在一导通状态和一关闭状态之间切换的开关单元，通过该电感元件的一电流形成有一基于该交流电而残余的波纹，其特征在于该控制电路包括：一峰值限制单元，输入一参考信号并根据来自于该开关单元的一采样信号而产生至少一峰值限制信号；以及一驱动单元，耦接至该开关单元并基于该峰值限制信号控制该开关单元切换，使得至少在半个工频周期内当该电感元件上的一电压高于一门槛值时，该电感元件的该电流的该波纹不高于一限制值。
于一实施例中，其特征在于还包括一反馈单元，该反馈单元采样该开关单元上的一电流而输出该采样信号。
于一实施例中，其特征在于该反馈单元包括一耦接该开关单元以采样该开关单元上的该电流而输出一第一采样信号的采样单元以及一基于该第一采样信号而输出一第二采样信号的采样处理器。
于一实施例中，其特征在于该峰值限制单元还包括一补偿模块，该补偿模块根据该参考信号，以及该第一采样信号或该第二采样信号产生一补偿信号。
于一实施例中，其特征在于该补偿模块包括一差值器以及一耦接至该差值器的滤波器，该差值器输入该参考信号，以及该第一采样信号或该第二采样信号并产生一差值给该滤波器而输出该补偿信号。
于一实施例中，其特征在于该峰值限制单元包括一接收该补偿信号的电流限制模块，该电流限制模块根据该补偿信号产生该峰值限制信号。
于一实施例中，其特征在于该驱动单元还包括一最小关断时间调节器，该最小关断时间调节器根据该补偿信号产生一最短关断时间信号。
于一实施例中，其特征在于该电流限制模块包括一放大器以及一电阻串，该放大器具有一输出端、一输入该补偿信号的第一输入端以及一耦接至该输出端的第二输入端，该电阻串耦接至该输出端并输出该峰值限制信号。
于一实施例中，其特征在于该电流限制模块包括一放大器以及一电阻串，该放大器具有一输出端、一输入该补偿信号的第一输入端以及一耦接至该电阻串的第二输入端，该放大器的输出端和该电阻串之间输出该峰值限制信号。
于一实施例中，其特征在于该驱动单元包括一逻辑模块以及一和该逻辑模块连接的驱动器，该逻辑模块产生一切换信号给该驱动器，以控制该开关单元。
于一实施例中，其特征在于该驱动单元还包括一延迟器，该延迟器接受一导通信号而产生一反映该开关单元的一最大导通时间的第一控制信号。
于一实施例中，其特征在于该驱动单元还包括一比较器，该比较器根据该峰值限制信号以及该采样信号，产生一反映一当前采样信号以及一限制阀值之间的一比较结果的第二控制信号。
于一实施例中，其特征在于该第一控制信号和该第二控制信号决定一反映该开关单元的关断时刻的关断控制信号。
于一实施例中，其特征在于该驱动单元还包括一退磁检测模块，该退磁检测模块具有一和该开关单元耦接的输入端以及一输出一退磁信号至该逻辑模块的输出端。
于一实施例中，其特征在于还包括一输出该参考信号给该驱动单元的调光模块，该负载为一受该参考信号调整的LED灯。
于一实施例中，其特征在于该限制值随至少一因子的变化而变化，该因子择自于该采样信号、该参考信号以及该负载所组成的群组。
为达上述目的，本发明还提供一种高功率因数的AC/DC转换电路，其特征在于包括：一整流模块，接收一交流电而整流为一直流电；一转换模块，耦接至该整流模块并根据一负载将该直流电转换为一驱动电力而提供给该负载，该转换模块包括一具有一电感元件的转换单元以及一耦接至该转换单元并在一导通状态和一关闭状态之间切换的开关单元，通过该电感元件的一电流形成有一基于该交流电而残余的波纹；以及一控制模块，包括：一峰值限制单元，输入一参考信号并根据反应该开关单元的一采样信号而产生至少一峰值限制信号；以及一驱动单元，耦接至该开关单元并基于该峰值限制信号控制该开关单元切换，使得至少在半个工频周期内当该电感元件上的一电压高于一门槛值时，该电感元件的该电流的该波纹不高于一限制值。
于一实施例中，其特征在于该转换模块择自于一浮动式降压转换器、一升压转换器、一返驰式转换器以及一降压-升压式转换器所组成的群组。
于一实施例中，其特征在于该负载为一LED灯。
本发明设置了该峰值限制单元，该峰值限制单元根据该采样信号而产生该峰值限制信号，由于该峰值限制信号的生成为根据该采样信号，故会随该采样信号的变动而改变。换句话说，该峰值限制信号会根据不同的调光亮度、母线 电压、输出电压或输出电流而调整，尽管工频周期内的最大电感电流峰值在变化，但该采样信号所反映的电流峰值限制阈值也在变化，从而达到减小输出电流纹波的效果，不仅延长的元件的使用寿命，也减轻了LED闪烁的问题。
附图简要说明
图1，为现有技术的LED控制电路。
图2，为现有技术的LED控制电路的电感电流(IL)和输出电流(IO)的波形示意图。
图3，为本发明第一实施例的高功率因数的控制电路的示意图。
图4，为本发明第二实施例的高功率因数的控制电路的示意图。
图5，为本发明第三实施例的高功率因数的控制电路的示意图。
图6，为本发明第四实施例的高功率因数的控制电路的示意图。
图7，为本发明第五实施例的高功率因数的控制电路的示意图。
图8A，为本发明一实施例中，该电流限制模块的配置示意图。
图8B，为本发明另一实施例中，该电流限制模块的配置示意图。
图9，为本发明控制电路的电感电流(IL)和输出电流(IO)的波形示意图。
实现本发明的最佳方式
有关本发明的详细说明及技术内容，现就配合附图说明如下：
本发明揭露一种高功率因数的控制电路以及AC/DC转换电路，该高功率因数的控制电路应用于一AC/DC转换电路10，请参阅图3，为本发明第一实施例的高功率因数的控制电路的示意图，该AC/DC转换电路10包括一整流模块11、一转换模块12以及一负载13，该转换模块12耦接至该整流模块11且驱动该负载13，该整流模块11接收一交流电AC而整流为一直流电DC，该整流模块11包括一整流器111以及一电容112，该转换模块12根据该负载13将该直流电DC转换为一驱动电力而提供给该负载13，该转换模块12包括一转换单元121以及一开关单元122，该转换单元121包括一电感123、一电容124以及一二极管125，该开关单元122可为一功率开关，例如一金属氧化物半导体场效晶体管(Metal Oxide Semiconductor Field-Effect Transistor，MOSFET)，但不以此为限，该功率开关亦可为一个或多个的三极管。该开关 单元122在一导通状态和一关闭状态之间切换，且该开关单元122包括一漏极端D、一源极端S以及一栅极端G。本实施例中，该负载13为一LED灯。
该控制电路包括一峰值限制单元20以及一驱动单元30，其中，该峰值限制单元20接受一参考信号并根据来自于该开关单元122的一采样信号而产生至少一峰值限制信号。本实施例中，该驱动单元30耦接至该开关单元122的该栅极端G，该驱动单元30根据该峰值限制信号控制该开关单元122的切换，使得至少在半个工频周期内，当该电感元件123上的一电压高于一门槛值时，通过该电感元件123的一电流的波纹不高于一限制值，该限制值可随至少一因子的变化而变化，该因子择自于该采样信号、该参考信号以及该负载13的至少任一。在本实施例中，该控制电路还包括一反馈单元40以及一调光模块50，该反馈单元40采样该开关单元122上的电流而输出该采样信号，该反馈单元40可包括一采样电阻41以及一采样处理器42，该采样电阻41耦接至该开关单元122，并采样该开关单元122上的该电流而输出一第一采样信号，该采样处理器42根据该第一采样信号而输出一第二采样信号给该峰值限制单元20，本发明中，该采样信号视情况可为该第一采样信号或该第二采样信号。另外，该调光模块50根据外部或内部控制而输出该参考信号，该参考信号可视为一调光信号。
本实施例中，该峰值限制单元20包括一补偿模块21以及一电流限制模块22，该补偿模块21包括一差值器211以及一滤波器212，该滤波器212耦接至该差值器211，该差值器211从该调光模块50接收该参考信号以及该第一采样信号(或该第二采样信号)并产生一差值给该滤波器212，在本实施例中，该差值器211接收该参考信号以及该第二采样信号。该滤波器212输出该补偿信号，该电流限制模块22耦接至该补偿模块21，并接收该补偿信号，该电流限制模块22根据该补偿信号产生该峰值限制信号，该峰值限制信号反映了一限制电压。本发明中，该滤波器212也可以用其他形式的电路(例如数字低通滤波器)或模拟低通滤波器取代，而达到将该差值进行滤波而输出一直流电信号的结果，例如可以采用一跨导放大器和一电容的组合。
该驱动单元30包括一驱动器31、一逻辑模块32、一退磁检测模块33、一第一控制模块34以及一第二控制模块35，该第一控制模块34耦接至该峰值限制单元20的该电流限制模块22，该第一控制模块34包括一比较器341、 一延迟器342及一或闸343，该驱动器31耦接至该开关单元122的该栅极端G，并从该逻辑模块32取得一切换信号而控制该开关单元122的关闭和导通。其中，该第一控制模块34用来产生一关断控制信号，该关断控制信号控制该开关单元122的关断时刻(Turn-off timing)；该第二控制模块35用来产生一最短关断时间信号，该最短关断时间信号控制该开关单元122的最短的关断时间(Turn-off duration)。
该延迟器342输入该切换信号而产生一第一控制信号，该第一控制信号反映该开关单元122的一最大导通时间，该第一控制信号用以决定该开关单元122的关断时刻(Turn-offtiming)。该比较器341具有一第一输入端341a、一第二输入端341b以及一输出端341c，该第一输入端341a输入该第一采样信号或该第二采样信号，该第二输入端341b从该电流限制模块22取得该峰值限制信号，该比较器341根据该峰值限制信号以及该第一采样信号或该第二采样信号而从该输出端341c输出一第二控制信号至该逻辑模块32，换言之，该比较器341对该峰值限制信号以及该第一采样信号(或该第二采样信号)进行比较后，决定该第二控制信号并输出，该第二控制信号反映一当前采样信号(当前采样电压或当前采样电流)以及一限制阀值(限制电压或限制电流)之间的一比较结果，该第二控制信号用以决定该开关单元122的关断时刻(Turn-offtiming)。在本实施例中，该当前采样信号以及该限制阀值均采用电压，且该第一输入端341a输入该第一采样信号，故该比较器341根据该峰值限制信号以及该第一采样信号而输出该第二控制信号。该第一控制信号和该第二控制信号再输出给该或闸343，该或闸343再根据该第一控制信号和该第二控制信号输出该关断控制信号给该逻辑模块32。该关断控制信号决定该开关单元122的关断时刻(Turn-offtiming)。
该第二控制模块35耦接至该峰值限制单元20的该补偿模块21，该第二控制模块35可采用一最小关断时间调节器，即根据该补偿模块21输出的该补偿信号，而产生一第三控制信号至该逻辑模块32，该第三控制信号反映该开关单元122最短的关断时间(Turn-offduration)，即该第三控制信号为该最短关断时间信号，换言之，该第三控制信号用以决定该开关单元122的一导通时间(Turn-on timing)。该退磁检测模块33耦接于该驱动器32的一输出端以及该驱动器31之间，该退磁检测模块33具有一输入端以及一输出端，该退磁检测模 块33耦接至该驱动器31的输出端并根据该驱动器31的输出而输出一退磁信号至该逻辑模块32。
该逻辑模块32接收该关断控制信号、该最短关断时间信号以及该退磁信号，而据此产生该切换信号给该驱动器31。根据以上所述，该关断控制信号的功能为当以下两者之一发生时(视何者为先)，控制该开关单元122的关断：该开关单元122到达该最大导通时间，或是当该当前采样信号(当前采样电压或当前采样电流)上升至该限制阀值(限制电压或限制电流)时。另一方面，该最短关断时间信号的功能为，当调光亮度低，而导通时间太短时，该最短关断时间信号可控制该开关单元122处于一非连续导通(Discontinuous Conduction Mode)模式。
本发明中，该转换模块12可以为一浮动式降压转换器、一升压转换器、一返驰式转换器或一降压-升压式转换器，以下将以具体的电路说明部分的配置。请参阅图4，为本发明第二实施例的高功率因数的控制电路的示意图，本实施例采用一浮动式降压转换器(Floating buck converter)，该驱动单元30耦接至该开关单元122的该源极端S，该转换单元121包括一电感123、一电容124、一二极管125以及一电阻126，该电容124、该二极管125和该负载13并联，该电感123和该电阻126则串联在该电容124的一端和该二极管125的一端之间，该电容124的另一端连接到接地。请参阅图5，为本发明第三实施例的高功率因数的控制电路的示意图，本实施例采用一升压转换器(Boost converter)，该驱动单元30耦接至该开关单元122的该漏极端D，该转换单元121包括一电感123、一电容124、一二极管125，该电容124和该负载13并联，该电感123和该二极管125串联至该电容124和该电容112之间，该开关单元122的该漏极端D耦接至该电感123和该二极管125之间。
请参阅图6，为本发明第四实施例的高功率因数的控制电路的示意图，本实施例采用一返驰式转换器(Flybackconverter)，该驱动单元30耦接至该开关单元122的该漏极端D，该转换单元121包括一电感123、一电容124以及一二极管125，该电容124和该负载13并联，该电感123为一变压器，该变压器具有一第一侧以及一第二侧，该第一侧耦接至该电容112以及该开关单元122的该漏极端D，该第二侧则和该电容124并联，该二极管125耦接于该电容124和该第二侧之间。请参阅图7，为本发明第五实施例的高功率因数的控 制电路的示意图，本实施例采用一降压-升压式转换器(Buck-boostconverter)，该驱动单元30耦接至该开关单元122的该漏极端D，该转换单元121包括一电感123、一电容124以及一二极管125，该电感123、该电容124和该负载13并联，该二极管125耦接于该电感123和该电容124之间。以上仅为举例说明，本发明的其他实施例中，亦可以采用其他配置的转换器。
本发明中，该电流限制模块22的配置可以如图8A所示，包括一放大器221、一第一电阻222以及一第二电阻223，该放大器221包括一第一输入端221a、一第二输入端221b以及一输出端221c，该第一输入端221a输入该补偿信号，该第二输入端221b耦接至该输出端221c。该第一电阻222的一端耦接至该放大器221的该输出端221c，另一端耦接至该第二电阻223，该第二电阻223则接地，该峰值限制信号(CS_limit)从该第一电阻222和该第二电阻223之间输出。该电流限制模块22的配置也可以如图8B所示，该第一电阻222和该第二电阻223之间形成一节点输入至该第二输入端221b，该峰值限制信号(CS_limit)从该输出端221c和该第一电阻222之间输出。以上仅为举例说明，本发明的其他实施例中，亦可以采用其他配置的电流限制模块。
请参阅图9，为本发明控制电路的电感电流(IL)和输出电流(IO)的波形示意图，本发明设置了该峰值限制单元，该峰值限制单元根据该采样信号而产生该峰值限制信号，由图9可以看出，流经该电感的电流被限制在一电流峰值限制阈值(IL_limit)，因而降低了电流纹波。由于设置了该第二控制模块，可以产生该最短关断时间信号，故虽然该电流被限制在该电流峰值限制阈值(IL_limit)，在低亮度时，不至于发生导通时间过短的问题。
此外，由于该峰值限制信号的生成为根据该采样信号，故会随该采样信号的变动而改变。换句话说，该峰值限制信号会根据不同的调光亮度、母线电压、输出电压或输出电流而调整，尽管工频周期内的最大电感电流峰值在变化，但该采样信号所反映的电流峰值限制阈值也在变化，从而达到减小输出电流纹波的效果，不仅延长的元件的使用寿命，也减轻了LED闪烁的问题，此外，更可以选择更小电容值的输出电容来达到相同的输出电流纹波，降低了成本。
当然，本发明还可有其它多种实施例，在不背离本发明精神及其实质的情况下，熟悉本领域的技术人员当可根据本发明作出各种相应的改变和变形，但这些相应的改变和变形都应属于本发明所附的权利要求的保护范围。

Claims (19)

  1. 一种高功率因数的控制电路，应用于一AC/DC转换电路，该AC/DC转换电路包括一整流模块、一耦接至该整流模块的转换模块以及一受该转换模块驱动的负载，该整流模块接收一交流电而整流为一直流电，该转换模块根据一负载将该直流电转换为一驱动电力而提供给该负载，且包括一具有一电感元件的转换单元以及一耦接至该转换单元并在一导通状态和一关闭状态之间切换的开关单元，通过该电感元件的一电流形成有一基于该交流电而残余的波纹，其特征在于，该控制电路包括：
    一峰值限制单元，输入一参考信号并根据来自于该开关单元的一采样信号而产生至少一峰值限制信号；以及
    一驱动单元，耦接至该开关单元并基于该峰值限制信号控制该开关单元切换，使得至少在半个工频周期内当该电感元件上的一电压高于一门槛值时，该电感元件的该电流的该波纹不高于一限制值。
  2. 根据权利要求1所述的控制电路，其特征在于，还包括一反馈单元，该反馈单元采样该开关单元上的一电流而输出该采样信号。
  3. 根据权利要求2所述的控制电路，其特征在于，该反馈单元包括一耦接该开关单元以采样该开关单元上的该电流而输出一第一采样信号的采样单元以及一基于该第一采样信号而输出一第二采样信号的采样处理器。
  4. 根据权利要求3所述的控制电路，其特征在于，该峰值限制单元还包括一补偿模块，该补偿模块根据该参考信号，以及该第一采样信号或该第二采样信号产生一补偿信号。
  5. 根据权利要求4所述的控制电路，其特征在于，该补偿模块包括一差值器以及一耦接至该差值器的滤波器，该差值器输入该参考信号，以及该第一采样信号或该第二采样信号并产生一差值给该滤波器而输出该补偿信号。
  6. 根据权利要求4所述的控制电路，其特征在于，该峰值限制单元包括一接收该补偿信号的电流限制模块，该电流限制模块根据该补偿信号产生该峰值限制信号。
  7. 根据权利要求4所述的控制电路，其特征在于，该驱动单元还包括一最小关断时间调节器，该最小关断时间调节器根据该补偿信号产生一最短关断时 间信号。
  8. 根据权利要求6所述的控制电路，其特征在于，该电流限制模块包括一放大器以及一电阻串，该放大器具有一输出端、一输入该补偿信号的第一输入端以及一耦接至该输出端的第二输入端，该电阻串耦接至该输出端并输出该峰值限制信号。
  9. 根据权利要求6所述的控制电路，其特征在于，该电流限制模块包括一放大器以及一电阻串，该放大器具有一输出端、一输入该补偿信号的第一输入端以及一耦接至该电阻串的第二输入端，该放大器的输出端和该电阻串之间输出该峰值限制信号。
  10. 根据权利要求1所述的控制电路，其特征在于，该驱动单元包括一逻辑模块以及一和该逻辑模块连接的驱动器，该逻辑模块产生一切换信号给该驱动器，以控制该开关单元。
  11. 根据权利要求10所述的控制电路，其特征在于，该驱动单元还包括一延迟器，该延迟器接受一导通信号而产生一反映该开关单元的一最大导通时间的第一控制信号。
  12. 根据权利要求11所述的控制电路，其特征在于，该驱动单元还包括一比较器，该比较器根据该峰值限制信号以及该采样信号，产生一反映一当前采样信号以及一限制阀值之间的一比较结果的第二控制信号。
  13. 根据权利要求12所述的控制电路，其特征在于，该第一控制信号和该第二控制信号决定一反映该开关单元的关断时刻的关断控制信号。
  14. 根据权利要求10所述的控制电路，其特征在于，该驱动单元还包括一退磁检测模块，该退磁检测模块具有一和该开关单元耦接的输入端以及一输出一退磁信号至该逻辑模块的输出端。
  15. 根据权利要求1至14任一项所述的控制电路，其特征在于，还包括一输出该参考信号给该驱动单元的调光模块，该负载为一受该参考信号调整的LED灯。
  16. 根据权利要求1至14任一项所述的控制电路，其特征在于，该限制值随至少一因子的变化而变化，该因子择自于该采样信号、该参考信号以及该负载所组成的群组。
  17. 一种高功率因数的AC/DC转换电路，其特征在于，包括：
    一整流模块，接收一交流电而整流为一直流电；
    一转换模块，耦接至该整流模块并根据一负载将该直流电转换为一驱动电力而提供给该负载，该转换模块包括一具有一电感元件的转换单元以及一耦接至该转换单元并在一导通状态和一关闭状态之间切换的开关单元，通过该电感元件的一电流形成有一基于该交流电而残余的波纹；以及
    一控制模块，包括：
    一峰值限制单元，输入一参考信号并根据反应该开关单元的一采样信号而产生至少一峰值限制信号；及
    一驱动单元，耦接至该开关单元并基于该峰值限制信号控制该开关单元切换，使得至少在半个工频周期内当该电感元件上的一电压高于一门槛值时，该电感元件的该电流的该波纹不高于一限制值。
  18. 根据权利要求17所述的转换电路，其特征在于，该转换模块择自于一浮动式降压转换器、一升压转换器、一返驰式转换器以及一降压-升压式转换器所组成的群组。
  19. 根据权利要求17所述的转换电路，其特征在于，该负载为一LED灯。
PCT/CN2020/117483 2019-09-24 2020-09-24 一种高功率因数的控制电路以及ac/dc转换电路 WO2021057851A1 (zh)

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