CN114126148A - Drive circuit for realizing line voltage compensation and LED circuit - Google Patents

Drive circuit for realizing line voltage compensation and LED circuit Download PDF

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Publication number
CN114126148A
CN114126148A CN202010900516.7A CN202010900516A CN114126148A CN 114126148 A CN114126148 A CN 114126148A CN 202010900516 A CN202010900516 A CN 202010900516A CN 114126148 A CN114126148 A CN 114126148A
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China
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circuit
current
resistor
charge
energy storage
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CN202010900516.7A
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Chinese (zh)
Inventor
周忠杰
张攀
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Meixinsheng Technology Beijing Co ltd
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Meixinsheng Technology Beijing Co ltd
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Priority to CN202010900516.7A priority Critical patent/CN114126148A/en
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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
    • H05B45/345—Current stabilisation; Maintaining constant 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
    • 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
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • H05B47/105—Controlling the light source in response to determined parameters
    • 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
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • H05B47/165—Controlling the light source following a pre-assigned programmed sequence; Logic control [LC]

Abstract

The invention discloses a drive circuit for realizing line voltage compensation and an LED circuit, wherein a charge-discharge generation circuit in the drive circuit is connected with an energy storage device and a load current control circuit; the energy storage device and the charge-discharge generating circuit are connected to two ends of the rectifying module; the line voltage compensation circuit is connected with the charge-discharge generation circuit and is used for sampling a voltage signal of a preset voltage detection point in the driving circuit and sending a voltage compensation signal to the charge-discharge generation circuit according to the sampled voltage signal; the charge-discharge generating circuit is used for forming a charge loop with the energy storage device in the process of charging the energy storage device and controlling the magnitude of the charge current of the energy storage device according to the received voltage compensation signal; and forming a discharge loop with the energy storage device in the discharge process of the energy storage device. The charging current of the energy storage device is adjusted through voltage compensation, so that current ripples are eliminated, and the stability of the circuit is guaranteed.

Description

Drive circuit for realizing line voltage compensation and LED circuit
Technical Field
The invention relates to a driving circuit for realizing line voltage compensation and an LED circuit.
Background
The LED light source is based on a light emitting diode and has the advantages of low-voltage power supply, low energy consumption, strong applicability, high stability, short response time, no environmental pollution, multicolor luminescence and the like. With the continuous development of LED technology, LED light sources are widely used, and scenes such as markets, factories, and houses use a large number of LED light sources as illumination or decoration, and adjust the brightness of the LED light sources as needed to provide comfortable illumination.
In order to ensure that the LED driving circuit supplies power to the LED load, an energy storage device, such as an energy storage capacitor, is generally required to be disposed in the driving circuit for supplying power to the LED load when the bus voltage is less than the driving voltage of the LED load. Because the energy storage device is generally charged by adopting constant current in the prior art, in the working process of the circuit, if the alternating current input voltage of the driving circuit changes, when the alternating current input voltage increases, the charging time of the energy storage device increases, and after the charge and discharge charge are rebalanced, the difference value between the charged voltage of the energy storage device and the load voltage is increased, so that the power efficiency is reduced. On the contrary, when the alternating current input voltage is reduced, the charging time of the energy storage device is reduced, and after the charge and discharge charge are rebalanced, the difference value between the charged voltage of the energy storage device and the load voltage is reduced, even lower than the load voltage, and the stroboscopic phenomenon is caused.
Disclosure of Invention
The embodiment of the invention aims to provide a driving circuit for realizing line voltage compensation and an LED circuit so as to meet the driving requirement of an actual controlled load.
As a first aspect of the embodiments of the present invention, an embodiment of the present invention provides a driving circuit for realizing line voltage compensation, including: the device comprises an energy storage device, a charging and discharging generation circuit, a line voltage compensation circuit, a load current control circuit and a rectification module;
the charge and discharge generating circuit is connected with the energy storage device and the load current control circuit; the energy storage device and the charge-discharge generating circuit are connected to two ends of the rectifying module;
the line voltage compensation circuit is connected with the charge and discharge generation circuit and is used for sampling a voltage signal of a preset voltage detection point in the driving circuit and sending a voltage compensation signal to the charge and discharge generation circuit according to the sampled voltage signal;
the charge and discharge generating circuit is used for forming a charge loop with the energy storage device in the charging process of the energy storage device and controlling the charging current of the energy storage device according to the received voltage compensation signal; and forming a discharge loop with the energy storage device in the discharge process of the energy storage device.
In some optional embodiments, the charge and discharge generation circuit includes a first controlled switch tube, at least one first resistor, and a charge current control module;
the at least one first resistor is connected with the first controlled switch tube;
the charging current control module is connected with the control end of the first controlled switch tube and used for controlling the on-off of the first controlled switch tube.
In some optional embodiments, the driving circuit for implementing line voltage compensation further includes: and the unidirectional current path is connected with the charge and discharge generating circuit in parallel and is conducted under the condition that the energy storage device discharges.
In some optional embodiments, the charge and discharge generation circuit further comprises a unidirectional current path, the unidirectional current path being conductive in case the energy storage device is discharged;
the unidirectional current path includes: a parasitic body diode of the first controlled switching tube.
In some optional embodiments, the line voltage compensation circuit includes a line voltage compensation module, and one end of the line voltage compensation module is connected to the preset voltage detection point, and the other end of the line voltage compensation module is connected to the charging current control module.
In some optional embodiments, the line voltage compensation circuit further comprises: the second resistor and the third resistor are connected in series;
one end of the line voltage compensation module is connected between the second resistor and a third resistor, the line voltage compensation module is connected with the preset voltage detection point through the second resistor, and the third resistor is grounded;
the preset voltage detection point is positioned on the driving circuit bus or at the output end of a controlled load connected with the driving circuit.
In some optional embodiments, the charging current control module comprises a first operational amplifier;
the positive phase input end of the first operational amplifier is used for being connected with a first reference voltage, and the negative phase input end of the first operational amplifier is connected with the current output end of the first controlled switching tube through a fourth resistor; the output end of the first operational amplifier is connected with the control end of the first controlled switch tube.
In some optional embodiments, the line voltage compensation module comprises: the second operational amplifier, the third operational amplifier, the second controlled switching tube, the third controlled switching tube, the first current source circuit, the second current source circuit, the fifth resistor and the sixth resistor;
the positive phase input end of the second operational amplifier is connected between the second resistor and the third resistor, the negative phase input end of the second operational amplifier is connected with the current output end of the second controlled switch tube, and the output end of the second operational amplifier is connected with the control end of the second controlled switch tube;
the current output end of the second controlled switching tube is grounded through the fifth resistor; the current input end of the second controlled switching tube is connected to the negative phase input end of the first operational amplifier through the first current source circuit;
the positive phase input end of the third operational amplifier is used for being connected with a third reference voltage, the negative phase input end of the third operational amplifier is connected with the current output end of the third controlled switching tube, and the output end of the third operational amplifier is connected with the control end of the third controlled switching tube;
the current output end of the third controlled switching tube is grounded through the sixth resistor; and the current input end of the third controlled switch tube is connected with the current output end of the second controlled switch tube through the second current source circuit.
In some optional embodiments, the first current source circuit includes a fourth controlled switching tube and a fifth controlled switching tube; the current output ends of the fourth controlled switch tube and the fifth controlled switch tube are respectively connected with a bus of the driving circuit, and the current input end of the fourth controlled switch tube is connected with the negative phase input end of the first operational amplifier; the current input end of the fifth controlled switch tube is connected with the current input end of the second controlled switch tube;
the second current source circuit comprises a sixth controlled switch tube and a seventh controlled switch tube; the current output ends of the sixth controlled switch tube and the seventh controlled switch tube are respectively connected with a bus of the driving circuit, and the current input end of the sixth controlled switch tube is connected with the current output end of the second controlled switch tube; and the current input end of the seventh controlled switch tube is connected with the current input end of the third controlled switch tube.
As a second aspect of the embodiments of the present invention, the embodiments of the present invention provide an LED circuit, including an LED load and any one of the above-mentioned driving circuits for line voltage compensation.
As a third aspect of the embodiments of the present invention, an LED lamp is provided, including the LED circuit described above.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
the driving circuit for realizing line voltage compensation provided by the embodiment of the invention has the advantages that for an alternating current input power supply connected with a rectifying module, the drive circuit utilizes the characteristic that the bus voltage is changed in a sine wave manner, realizes the charging and discharging of the energy storage device by controlling the on-off of the charging and discharging generating circuit, and the current generated by the charge-discharge generating circuit changes along with the change of the bus voltage according to the voltage compensation signal of the line voltage compensation circuit, namely, when the alternating current input voltage is increased, the current generated by the charging and discharging generation circuit is reduced, so that the charged voltage of the energy storage device still keeps close to the load voltage, so that the working efficiency of the driving circuit is always kept at a higher level, and when the AC input voltage is reduced, the current generated by the charging and discharging generating circuit is increased, the charged voltage of the energy storage device is always slightly larger than the load voltage, and the ripple cannot be generated in the circuit. Particularly for the LED load, the voltage of the energy storage device is always slightly larger than the load voltage of the LED load, and no stroboflash can be realized.
Drawings
Fig. 1 is a first schematic structural diagram of a driving circuit for implementing line voltage compensation according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a driving circuit for implementing line voltage compensation according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram three of a driving circuit for implementing line voltage compensation according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of current and voltage waveforms in the driving circuit for line voltage compensation shown in FIG. 3;
fig. 5 is a schematic structural diagram of a driving circuit for implementing line voltage compensation according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
In order to solve the above problems of the LED driving circuit in the prior art, an embodiment of the present invention provides a driving circuit for line voltage compensation, which is shown in fig. 1 or fig. 2 and includes: the energy storage device, a charging and discharging generation circuit, a line voltage compensation circuit, a load current control circuit and a rectification module;
the charge and discharge generating circuit is connected with the energy storage device and the load current control circuit; the energy storage device and the charge-discharge generating circuit are connected to two ends of the rectifying module;
the line voltage compensation circuit is connected with the charge and discharge generation circuit and is used for sampling a voltage signal of a preset voltage detection point in the driving circuit and sending a voltage compensation signal to the charge and discharge generation circuit according to the sampled voltage signal;
the charge and discharge generating circuit is used for forming a charge loop with the energy storage device in the charging process of the energy storage device and controlling the charging current of the energy storage device according to the received voltage compensation signal; and forming a discharge loop with the energy storage device in the discharge process of the energy storage device.
In a specific embodiment, the energy storage device may be a capacitor, and the controlled load may be an LED load.
According to the driving circuit for realizing line voltage compensation, the energy storage device is controlled to be charged and discharged through the charging and discharging generation circuit, when the rectified input voltage is larger than the voltage of the energy storage device, the energy storage device enters a charging process, at the moment, the rectifying module, the energy storage device and the charging and discharging generation circuit form a charging loop, the charging and discharging generation circuit generates current from an Iin end to an Iout end, a voltage signal of a preset voltage detection point in the driving circuit is sampled through the line voltage compensation circuit, a voltage compensation signal is sent to the charging and discharging generation circuit according to the sampled voltage signal, the current from the Iin end to the Iout end generated by the charging and discharging generation circuit is controlled to change along with the change of the voltage of the preset voltage detection point in the driving circuit, and then the charging and discharging generation circuit can control the magnitude of the charging current of the energy storage device; when the rectified input voltage is smaller than the charging voltage of the energy storage device, the energy storage device enters a discharging process, at the moment, the energy storage device, the LED load, the load current control circuit and the charging and discharging generating circuit form a discharging loop, and current in the charging and discharging generating circuit flows from the Iout end to the Iin end.
The driving circuit for realizing line voltage compensation provided by the embodiment of the invention has the advantages that for an alternating current input power supply connected with a rectifying module, the drive circuit utilizes the characteristic that the bus voltage is changed in a sine wave manner, realizes the charging and discharging of the energy storage device by controlling the on-off of the charging and discharging generating circuit, and the current generated by the charge-discharge generating circuit changes along with the change of the bus voltage according to the voltage compensation signal of the line voltage compensation circuit, namely, when the alternating current input voltage is increased, the current generated by the charging and discharging generation circuit is reduced, so that the charged voltage of the energy storage device still keeps close to the load voltage, so that the working efficiency of the driving circuit is always kept at a higher level, and when the AC input voltage is reduced, the current generated by the charging and discharging generating circuit is increased, the charged voltage of the energy storage device is always slightly larger than the load voltage, and the ripple cannot be generated in the circuit. Particularly for the LED load, the voltage of the energy storage device is always slightly larger than the load voltage of the LED load, and no stroboflash can be realized.
The following describes in detail specific implementations of the present invention through several specific embodiments:
example one
In some optional embodiments, referring to fig. 1, the charge and discharge generating circuit of the driving circuit for realizing line voltage compensation includes a first controlled switching tube, a first resistor, and a charging current control module, where the first resistor is connected to the first controlled switching tube, and the charging current control module is connected to a control end of the first controlled switching tube, and is used to control on/off of the first controlled switching tube; the line voltage compensation circuit of the driving circuit comprises a line voltage compensation module, one end of the line voltage compensation module is connected with a preset voltage detection point, and the other end of the line voltage compensation module is connected with a charging current control module.
In some optional embodiments, referring to fig. 1, the line voltage compensation circuit further includes: the second resistor and the third resistor are connected in series;
one end of a line voltage compensation module of the line voltage compensation circuit is connected between the second resistor and the third resistor, the line voltage compensation module is connected with a preset voltage detection point on a driving circuit bus through the second resistor, and the third resistor is grounded.
In some optional embodiments, the driving circuit for realizing line voltage compensation further comprises: and the unidirectional current path is connected with the charge and discharge generating circuit in parallel, is conducted under the condition that the energy storage device discharges, and at the moment, can comprise a diode.
In the first embodiment of the present invention, the charge and discharge generating circuit further includes a unidirectional current path, and the unidirectional current path is turned on when the energy storage device is discharged, and at this time, the unidirectional current path may include a parasitic body diode D1 of the first controlled switching tube.
As an embodiment of the present invention, the energy storage device may be a capacitor C1, and the first controlled switch tube of the charge and discharge generating circuit may be an NMOS tube M1.
Referring to fig. 1, the ac input power is connected to the rectifier module, the rectifier module is connected to the capacitor C1, the capacitor C1 is connected to the Iin terminal of the charge and discharge generating circuit, the Iout terminal of the charge and discharge generating circuit is grounded, the NMOS transistor M1 in the charge and discharge generating circuit is a non-isolated MOS transistor, the drain of the NMOS transistor M1 is connected to the Iin terminal, the source is connected to the Iout terminal through the first resistor R1, the gate is connected to the charging current control module, the parasitic diode D1 of the NMOS transistor M1 is connected to the Iout terminal, the LED load is connected to the load current control circuit and then forms a current loop with the rectifier module, the second resistor R2 is connected to the third resistor R3 in series, one end of the second resistor R2 is connected to a preset voltage detection point on the bus of the driving circuit, the third resistor R3 is grounded, one end of the line voltage compensation module is connected between the second resistor R2 and the third resistor R3, and the other end of the line voltage compensation module is connected to the charging current control module. In the driving circuit, when the rectified bus voltage Vin is greater than the voltage at two ends of a capacitor C1, a charging current control module controls an NMOS tube M1 to be conducted to generate current in the direction from an Iin end to an Iout end, the rectifying module, the capacitor C1, the NMOS tube M1 and a first resistor R1 form a charging loop, the bus voltage Vin supplies power to an LED load and a capacitor C1, in the charging process, a bus voltage signal is sampled by a line voltage compensation module through a second resistor R2 and a third resistor R3, a voltage compensation signal is generated according to the sampled bus voltage signal and is sent to the charging current control module, and the current in the direction from the Iin end to the Iout end, generated by a charge and discharge generation circuit, is controlled to be reduced along with the increase of the bus voltage or increased along with the reduction of the bus voltage; when the rectified bus voltage Vin is smaller than the voltage at two ends of the capacitor C1, the charging current control module controls the NMOS transistor M1 to turn off, because the parasitic body diode D1 of the non-isolated NMOS transistor is connected with the terminal Iout, the parasitic body diode D1 in the NMOS transistor M1 generates a current in a direction from the terminal Iout to the terminal Iin, the capacitor C1, the LED load, the load current control circuit, the first resistor R1 and the parasitic body diode D1 of the NMOS transistor M1 form a discharging circuit, and the capacitor C1 supplies power to the LED load.
In a specific embodiment, the load current control circuit includes a power control module, which may be an operational amplifier, and a load-controlled switch, which may be an NMOS transistor M0, wherein a drain of the NMOS transistor M0 is connected to a controlled load, an output terminal of the operational amplifier is connected to a gate of the NMOS transistor M0, a source of the NMOS transistor M0 is connected to a resistor Rcs and is also connected to a negative input terminal of the operational amplifier, and a positive input terminal of the operational amplifier is connected to a fourth reference voltage VREF 4.
It should be noted that, in the embodiment of the present invention, the specific implementation manner of the load current control circuit may refer to other structural manners for implementing controlled load current control in the prior art, and the specific circuit implementation manner in the embodiment of the present invention is not strictly limited herein, as long as the requirement of current control in the circuit can be implemented, and details are not described in the embodiment of the present invention.
In the above embodiment provided by the embodiment of the present invention, the parasitic body diode D1 of the NMOS transistor M1 manufactured by using an integrated circuit process realizes unidirectional circuit conduction when the capacitor C1 discharges, and does not need to be externally connected with other circuit devices, so that the circuit cost is reduced, the size of the driving circuit is reduced, and the reasonable arrangement of each device in the driving circuit is facilitated during production and manufacturing.
Example two
In some optional embodiments, referring to fig. 2, in an embodiment of the present invention, the second resistor R2 of the line voltage compensation circuit may be further connected to a preset voltage collecting point at the output end of the LED load, and is configured to sample a voltage signal of a difference between the bus voltage and the load voltage, so that during the charging process of the energy storage device, i.e., the capacitor C1, the line voltage compensation module samples the voltage signal of the difference between the bus voltage and the load voltage through the second resistor R2 and the third resistor R3, and generates a voltage compensation signal according to the sampled voltage signal of the difference between the bus voltage and the load voltage, and sends the voltage compensation signal to the charging current control module, so as to control the current generated by the charge and discharge generation circuit from the Iin end to the Iout end to decrease with the increase of the difference between the bus voltage and the load voltage or increase with the decrease of the bus voltage.
In the embodiment of the present invention, a specific circuit implementation scheme and a specific implementation manner of the driving circuit for implementing line voltage compensation shown in fig. 2 are similar to those of the driving circuit for implementing line voltage compensation shown in fig. 1, and a specific implementation process may refer to the detailed description about fig. 1 in the above embodiment, which will not be described in detail herein.
In the foregoing embodiments provided in the embodiments of the present invention, the parasitic body diode D1 of the NMOS transistor M1 in the unidirectional current path may also be replaced by a diode in the prior art. At the moment, the diode of the unidirectional current path is connected in parallel between the drain electrode and the source electrode of the NMOS tube M1; or, the cathode of the diode of the unidirectional current path is connected with the Iin end of the charge and discharge generating circuit and is connected to one end of the capacitor C1; the anode of the diode is connected with the Iout end of the charge and discharge generation circuit.
It should be noted that, in the driving circuit for realizing line voltage compensation shown in fig. 1 or fig. 2, the first controlled switching transistor is an NMOS transistor, which is only a specific implementation manner of the embodiment of the present invention, and the first controlled switching transistor may also be another current controlled switching transistor, for example, a bipolar transistor BJT (not shown in the figure), as long as it can realize control of current so as to form a charging loop when the capacitor C1 is charged.
EXAMPLE III
Based on the driving circuit for realizing line voltage compensation described in the first and second embodiments, further, referring to fig. 3, the charging current control module in the embodiment of the present invention may include a first operational amplifier;
the positive phase input end of the first operational amplifier is used for being connected with a first reference voltage, and the negative phase input end of the first operational amplifier is connected with the current output end of the first controlled switching tube through a fourth resistor R4; the output end of the first operational amplifier is connected with the control end of the first controlled switch tube.
When the first controlled switch transistor is an NMOS transistor M1, the current output terminal of the first controlled switch transistor M1 is the source of the NMOS transistor.
When the charging and discharging generating circuit is connected in parallel with the unidirectional current path, the first controlled switching tube may also be a bipolar transistor, and at this time, the current output end of the first controlled switching tube refers to an emitter of the bipolar transistor.
Referring to fig. 3, the line voltage compensation module according to an embodiment of the present invention may include: the second operational amplifier, the third operational amplifier, the second controlled switching tube, the third controlled switching tube, the first current source circuit, the second current source circuit, the fifth resistor and the sixth resistor; the positive phase input end of the second operational amplifier is connected between the second resistor and the third resistor, the negative phase input end of the second operational amplifier is connected with the current output end of the second controlled switching tube, and the output end of the second operational amplifier is connected with the control end of the second controlled switching tube;
the current output end of the second controlled switching tube is grounded through a fifth resistor; the current input end of the second controlled switching tube is connected to the negative phase input end of the first operational amplifier through the first current source circuit;
the positive phase input end of the third operational amplifier is used for being connected with a third reference voltage, the negative phase input end of the third operational amplifier is connected with the current output end of the third controlled switching tube, and the output end of the third operational amplifier is connected with the control end of the third controlled switching tube;
the current output end of the third controlled switching tube is grounded through a sixth resistor; the current input end of the third controlled switch tube is connected with the current output end of the second controlled switch tube through the second current source circuit.
In an embodiment of the present invention, the second controlled switch tube and the third controlled switch tube may be NMOS tubes M2 and M3 with the same specification.
In a specific embodiment, referring to fig. 3, the first current source circuit may be a mirror current source circuit, and the mirror current source circuit includes: a fourth controlled switching tube and a fifth controlled switching tube; the current output ends of the fourth controlled switch tube and the fifth controlled switch tube are respectively connected with a bus of the driving circuit, and the current input end of the fourth controlled switch tube is connected with the negative phase input end of the first operational amplifier; the current input end of the fifth controlled switch tube is connected with the current input end of the second controlled switch tube;
the second current source circuit may be a mirror current source circuit, and the mirror current source circuit includes: a sixth controlled switching tube and a seventh controlled switching tube; the current output ends of the sixth controlled switch tube and the seventh controlled switch tube are respectively connected with a bus of the driving circuit, and the current input end of the sixth controlled switch tube is connected with the current output end of the second controlled switch tube; and the current input end of the seventh controlled switch tube is connected with the current input end of the third controlled switch tube.
In an embodiment of the present invention, the fourth to seventh controlled switch transistors may be NMOS transistors M4, M5, M6 and M7 with the same specification.
In an embodiment, based on the description about the first current source circuit shown in fig. 3, the mirror current source circuit in the embodiment of the present invention may be replaced by a proportional current source circuit, that is, a proportional resistor (not shown in the figure) is respectively connected between the source of the fourth controlled switch transistor NMOS 4 and the bus of the driving circuit, and between the source of the fifth controlled switch transistor NMOS 5 and the bus of the driving circuit, so as to adjust the resistance of the two proportional resistors, thereby adjusting the current of the drain of the NMOS transistor M4;
based on the same principle, the mirror current source circuit in the second current source circuit in the embodiment of the present invention may also be replaced with a proportional current source circuit, that is, a proportional resistor (not shown in the figure) is respectively connected between the source of the sixth controlled switch transistor NMOS 6 of the mirror current source circuit and the bus of the driving circuit, and between the source of the seventh controlled switch transistor NMOS 7 and the bus of the driving circuit, so as to adjust the resistance of the two proportional resistors, thereby adjusting the current of the drain of the NMOS transistor M6.
In the following, a detailed description is given by using a specific embodiment, referring to the driving circuit for realizing line voltage compensation shown in fig. 3, an ac input power is connected to a rectifying module, the rectifying module is connected to an LED load, the LED load is connected to a load current control circuit, a charge-discharge generating circuit is connected to an energy storage device and the load current control circuit, the energy storage device and the charge-discharge generating circuit are connected to two ends of the rectifying module, one end of the line voltage compensation circuit is connected to the charge-discharge generating circuit, and the other end is connected to a preset voltage detection point.
In the embodiment of the present invention, the diode D1 of the unidirectional current path shown in fig. 3 may be a single diode, or may be a parasitic body diode of the NMOS transistor M1 of the charge and discharge generating circuit.
In the embodiment of the present invention, referring to fig. 3, the drain of the NMOS transistor M1 of the charge and discharge generating circuit is connected to the Iin terminal, the source of the NMOS transistor M1 is connected to one terminal of the first resistor R1 and is also connected to the negative input terminal of the first operational amplifier AMP1, and the other terminal of the first resistor R1 is connected to Iout; the grid electrode of the NMOS tube M1 is connected with the output end of the first operational amplifier AMP 1; the non-inverting input terminal of the first operational amplifier AMP1 is connected to a first reference voltage VREF 1.
In the embodiment of the present invention, referring to fig. 3, in the second resistor R2 and the third resistor R3 connected in series in the line voltage compensation circuit, the second resistor R2 is connected to a preset voltage detection point on the bus, the third resistor R3 is grounded, the positive phase input terminal (i.e., the second reference voltage VREF2) of the second operational amplifier AMP2 is connected between the second resistor R2 and the third resistor R3, the negative phase input terminal of the second operational amplifier AMP2 is connected to the source of the NMOS transistor M2, and the output terminal of the second operational amplifier AMP2 is connected to the gate of the NMOS transistor M2;
the gate of the NMOS transistor M2 is grounded through a fifth resistor R5; the drain electrode of the NMOS tube M2 is connected to the negative phase input end of the first operational amplifier AMP1 through a first current source circuit;
the positive phase input end of the third operational amplifier AMP3 is used for being connected with a third reference voltage VREF3, the negative phase input end of the third operational amplifier AMP3 is connected with the source electrode of the NMOS tube M3, and the output end of the third operational amplifier AMP3 is connected with the grid electrode of the NMOS tube M3;
the gate of the NMOS transistor M3 is grounded through a sixth resistor R6; the drain of the NMOS transistor M3 is connected to the source of the NMOS transistor M2 via a second current source circuit.
The load current control circuit comprises a fourth operational amplifier AMP4 and a load controlled switching tube, wherein the load controlled switching tube can be an NMOS tube M0, the drain electrode of the NMOS tube M0 is connected with an LED load, the output end of the fourth operational amplifier AMP4 is connected to the grid electrode of the NMOS tube M0, the source electrode of the NMOS tube M0 is connected with a resistor Rcs and is simultaneously connected to the negative phase input end of the fourth operational amplifier AMP4, and the positive phase input end of the fourth operational amplifier AMP4 is connected with a fourth reference voltage VREF 4. The capacitor C1 is connected with the rectified bus voltage Vin, and the diode D1 is connected with the charge-discharge generating circuit in parallel.
In the embodiment of the present invention, the first reference voltage VREF1 may be a constant value, and the line voltage compensation circuit sends a voltage compensation signal to the negative phase input terminal of the first operational amplifier AMP1 in the charge and discharge generation circuit according to the sampled bus voltage signal, so that the current Ichg generated by the charge and discharge generation circuit varies with the bus voltage. If the fourth reference voltage VREF4 may be a constant value, the load current Iload is also a constant value VREF 4/Rcs. The rectifier module is a full-bridge rectifier bridge, and the relation between the rectified AC input current and the rectified AC input current is as follows: i Iac | ═ Imain, and Imain ═ Ichg + Iload.
Referring to fig. 3 and 4, the reference voltage VREF3 is input to the non-inverting input terminal of the third operational amplifier AMP3, and the negative input terminal of the third operational amplifier AMP3 is connected between the NMOS transistor M3 and the sixth resistor R6, so that a constant current is supplied from the reference voltage VREF3 to the sixth resistor R6, so that a constant current source is formed by the third operational amplifier AMP3, the NMOS transistor M3, the sixth resistor R6, and the second current source circuit, and a constant voltage is supplied to the second operational amplifier AMP 2. When the ac input voltage Vac rises, the ac rectified input voltage | Vac | rises, the bus voltage Vin rises, the voltage sampled by the second resistor R2 and the third resistor R3 at the positive phase input terminal of the second operational amplifier AMP2 rises, and at this time, the current at the NMOS transistor M2 increases, the voltage applied to the negative phase input terminal of the first operational amplifier AMP1 increases through the first current source circuit connected thereto, and the voltage at the output terminal of the first operational amplifier AMP1 decreases, which causes the current at the NMOS transistor M1 to decrease, that is, the current Ichg generated by the charge and discharge generation circuit decreases. On the contrary, when the ac input voltage Vac decreases, the ac rectified input voltage | Vac | decreases, the bus voltage Vin decreases, the voltage sampled by the second resistor R2 and the third resistor R3 at the positive input terminal of the second operational amplifier AMP2 decreases, and at this time, the current at the NMOS transistor M2 decreases, and through the first current source circuit connected thereto, the voltage at the negative input terminal of the first operational amplifier AMP1 decreases, and the voltage at the output terminal of the first operational amplifier AMP1 increases, which causes the current at the NMOS transistor M1 to increase, that is, the current Ichg generated by the charge and discharge generating circuit increases.
Referring to fig. 4, if the current Ichg generated by the charge/discharge generating circuit is constant, the ac input voltage changes during the circuit operation, for example, when the ac input voltage Vac increases, the charging time of the capacitor C1 increases, and is based on Δ VC1(Ichg × T1)/C1, charging time T1 increases, Δ VC1Inevitably increased, when the charge and discharge are rebalanced, V will be causedC1And a load voltage VLEDIncrease in the difference (V)C1Greater than VLED) Causing a reduction in power supply efficiency. Conversely, when the ac input voltage Vac decreases, the charging time of the capacitor C1 decreases according to Δ VC1(Ichg T1)/C1, when charging time T1 decreases, Δ VC1Is necessarily reduced, with the result that VC1And VLEDIs reduced, even VC1Less than VLEDCausing stroboflash. With the driving circuit for line voltage compensation shown in fig. 3, the current Ichg generated by the charge/discharge generating circuit varies with the bus voltage, and when the ac input voltage Vac increases, the current Ichg generated by the charge/discharge generating circuit decreases, so that V is obtainedC1Still remains close to the load VLEDThereby keeping the power supply efficiency at a high level at all times. When the ac input voltage Vac decreases, the current Ichg generated by the charge/discharge generating circuit increases, so that V is increasedC1Is always slightly larger than VLEDAnd no ripple waves exist in the circuit, so that stroboflash is avoided, and the power supply efficiency is always kept at a higher level.
Of course, the driving circuit for compensating the line voltage shown in fig. 3 is only a specific embodiment in which the current Ichg generated by the charge and discharge generating circuit varies with the variation of the rectified bus voltage in the circuit, and in other embodiments, the current Ichg generated by the charge and discharge generating circuit may also vary with the variation of other control quantities in the circuit, for example, referring to fig. 5, when the second resistor R2 shown in fig. 3 is connected to the output end of the controlled load, and the connection mode of other circuits is not changed, the current Ichg generated by the charge and discharge generating circuit may vary with the variation of the difference between the rectified bus voltage and the load voltage in the circuit, so as to achieve the same technical effect as the driving circuit for compensating the line voltage shown in fig. 3.
In the driving circuits for line voltage compensation in the first to third embodiments, the load current control circuit may be a linear control circuit, or may be a switch-type control circuit, such as a buck-type circuit, a fly-back-type circuit, or a boost-type circuit. As the circuit implementation manners of other parts of the driving circuit including the switch-type control circuit for implementing the line voltage compensation are similar to those in the above embodiments, the specific implementation manners may refer to the detailed descriptions in the first to third embodiments, and it should be noted that, in the embodiment of the present invention, the specific implementation manner of the constant current control module may refer to other structural manners for implementing the constant current control of the controlled load in the prior art, and the specific circuit implementation manners in the embodiment of the present invention are not strictly limited herein, as long as the requirements of the constant current control in the circuit can be implemented, and no further description is given in the embodiment of the present invention.
Based on the same inventive concept, the embodiment of the invention also provides an LED circuit, which includes an LED load and the driving circuit for realizing line voltage compensation described in the above embodiment.
With regard to the LED circuit in the above embodiments, the specific manner of implementing the operation and implementation of the driving circuit for implementing the line voltage compensation has been described in detail in the above embodiments one to three, and will not be elaborated herein.
Based on the same inventive concept, the embodiment of the invention also provides an LED lamp which comprises the LED circuit.
With regard to the LED lamp in the above embodiments, the specific manner of implementing the operation and implementation of the driving circuit of the LED circuit for implementing the line voltage compensation has been described in detail in the first to third embodiments, and will not be elaborated herein.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (10)

1. A driving circuit for compensating a line voltage, comprising: the device comprises an energy storage device, a charging and discharging generation circuit, a line voltage compensation circuit, a load current control circuit and a rectification module;
the charge and discharge generating circuit is connected with the energy storage device and the load current control circuit; the energy storage device and the charge-discharge generating circuit are connected to two ends of the rectifying module;
the line voltage compensation circuit is connected with the charge and discharge generation circuit and is used for sampling a voltage signal of a preset voltage detection point in the driving circuit and sending a voltage compensation signal to the charge and discharge generation circuit according to the sampled voltage signal;
the charge and discharge generating circuit is used for forming a charge loop with the energy storage device in the charging process of the energy storage device and controlling the charging current of the energy storage device according to the received voltage compensation signal; and forming a discharge loop with the energy storage device in the discharge process of the energy storage device.
2. The circuit of claim 1, wherein the charge and discharge generating circuit comprises a first controlled switching tube, at least one first resistor, and a charge current control module;
the at least one first resistor is connected with the first controlled switch tube;
the charging current control module is connected with the control end of the first controlled switch tube and used for controlling the on-off of the first controlled switch tube.
3. The circuit of claim 2, further comprising: and the unidirectional current path is connected with the charge and discharge generating circuit in parallel and is conducted under the condition that the energy storage device discharges.
4. The circuit of claim 2, wherein the charge and discharge generating circuit further comprises a unidirectional current path that conducts upon discharge of the energy storage device;
the unidirectional current path includes: a parasitic body diode of the first controlled switching tube.
5. The circuit of any one of claims 2-4, wherein the line voltage compensation circuit comprises a line voltage compensation module, one end of the line voltage compensation module is connected to the preset voltage detection point, and the other end of the line voltage compensation module is connected to the charging current control module.
6. The circuit of claim 5, wherein the line voltage compensation circuit further comprises: the second resistor and the third resistor are connected in series;
one end of the line voltage compensation module is connected between the second resistor and a third resistor, the line voltage compensation module is connected with the preset voltage detection point through the second resistor, and the third resistor is grounded;
the preset voltage detection point is positioned on the driving circuit bus or at the output end of a controlled load connected with the driving circuit.
7. The circuit of claim 6, wherein the charge current control module comprises a first operational amplifier;
the positive phase input end of the first operational amplifier is used for being connected with a first reference voltage, and the negative phase input end of the first operational amplifier is connected with the current output end of the first controlled switching tube through a fourth resistor; the output end of the first operational amplifier is connected with the control end of the first controlled switch tube.
8. The drive circuit of claim 7, wherein the line voltage compensation module comprises: the second operational amplifier, the third operational amplifier, the second controlled switching tube, the third controlled switching tube, the first current source circuit, the second current source circuit, the fifth resistor and the sixth resistor;
the positive phase input end of the second operational amplifier is connected between the second resistor and the third resistor, the negative phase input end of the second operational amplifier is connected with the current output end of the second controlled switch tube, and the output end of the second operational amplifier is connected with the control end of the second controlled switch tube;
the current output end of the second controlled switching tube is grounded through the fifth resistor; the current input end of the second controlled switching tube is connected to the negative phase input end of the first operational amplifier through the first current source circuit;
the positive phase input end of the third operational amplifier is used for being connected with a third reference voltage, the negative phase input end of the third operational amplifier is connected with the current output end of the third controlled switching tube, and the output end of the third operational amplifier is connected with the control end of the third controlled switching tube;
the current output end of the third controlled switching tube is grounded through the sixth resistor; and the current input end of the third controlled switch tube is connected with the current output end of the second controlled switch tube through the second current source circuit.
9. The drive circuit of claim 8, wherein the first current source circuit comprises: a fourth controlled switching tube and a fifth controlled switching tube; the current output ends of the fourth controlled switch tube and the fifth controlled switch tube are respectively connected with a bus of the driving circuit, and the current input end of the fourth controlled switch tube is connected with the negative phase input end of the first operational amplifier; the current input end of the fifth controlled switch tube is connected with the current input end of the second controlled switch tube;
the second current source circuit includes: a sixth controlled switching tube and a seventh controlled switching tube; the current output ends of the sixth controlled switch tube and the seventh controlled switch tube are respectively connected with a bus of the driving circuit, and the current input end of the sixth controlled switch tube is connected with the current output end of the second controlled switch tube; and the current input end of the seventh controlled switch tube is connected with the current input end of the third controlled switch tube.
10. An LED circuit comprising an LED load and a driver circuit according to any one of claims 1 to 9 for line voltage compensation.
CN202010900516.7A 2020-08-31 2020-08-31 Drive circuit for realizing line voltage compensation and LED circuit Pending CN114126148A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103841730A (en) * 2014-03-21 2014-06-04 深圳市梓晶微科技有限公司 Line voltage compensation circuit used for LED drive
US20170034882A1 (en) * 2013-12-30 2017-02-02 Shenzhen Sendis Green Power Integrations Technology Corporation Line voltage compensation ac led driving device
CN106658868A (en) * 2017-02-16 2017-05-10 深圳市晟碟半导体有限公司 LED driving apparatus, and line voltage compensation circuit and compensation method thereof
WO2019184668A1 (en) * 2018-03-27 2019-10-03 深圳市晟碟半导体有限公司 Led driving device, delayed compensation driving circuit, and driving method
CN212413485U (en) * 2020-08-31 2021-01-26 美芯晟科技（北京）有限公司 Drive circuit for realizing line voltage compensation and LED circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170034882A1 (en) * 2013-12-30 2017-02-02 Shenzhen Sendis Green Power Integrations Technology Corporation Line voltage compensation ac led driving device
CN103841730A (en) * 2014-03-21 2014-06-04 深圳市梓晶微科技有限公司 Line voltage compensation circuit used for LED drive
CN106658868A (en) * 2017-02-16 2017-05-10 深圳市晟碟半导体有限公司 LED driving apparatus, and line voltage compensation circuit and compensation method thereof
WO2019184668A1 (en) * 2018-03-27 2019-10-03 深圳市晟碟半导体有限公司 Led driving device, delayed compensation driving circuit, and driving method
CN212413485U (en) * 2020-08-31 2021-01-26 美芯晟科技（北京）有限公司 Drive circuit for realizing line voltage compensation and LED circuit

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