CN211606882U - Drive circuit, LED circuit and lamp - Google Patents
Drive circuit, LED circuit and lamp Download PDFInfo
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- CN211606882U CN211606882U CN201922312856.3U CN201922312856U CN211606882U CN 211606882 U CN211606882 U CN 211606882U CN 201922312856 U CN201922312856 U CN 201922312856U CN 211606882 U CN211606882 U CN 211606882U
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Abstract
The utility model discloses a drive circuit, LED circuit and lamps and lanterns, this drive circuit includes: the charging and discharging 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 charge and 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; and forming a discharge loop with the energy storage device in the discharge process of the energy storage device. The embodiment of the utility model provides an above-mentioned drive circuit can eliminate the electric current ripple in the circuit, has guaranteed the stability of controlled load to alternating current input current is public symmetry axis relation with alternating current input voltage, thereby improves PF.
Description
Technical Field
The utility model relates to a drive circuit, LED circuit and lamps and lanterns.
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.
Currently, LED driving needs to meet certain performance requirements, for example, referring to the LED driving circuit shown in fig. 1, the LED driving circuit includes: the LED light source control circuit comprises a rectification module connected with an AC input power supply, an LED light source connected with the rectification module, a power control module connected with the LED light source and a capacitor connected with the LED light source in parallel. Referring to fig. 2, the LED driving circuit has good symmetry between the ac input voltage and the ac input current, and a high Power Factor (PF), and can reduce or eliminate harmonic pollution to the Power grid. However, the driving circuit with high PF cannot solve the problem of stroboflash, will cause damage to human eyes when in use, and cannot well meet the requirement of LED illumination.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a can realize high PF, do not have stroboscopic drive circuit, LED circuit and lamps and lanterns in order to satisfy the drive demand of actual controlled load.
As the utility model discloses a first aspect of the embodiment, the embodiment of the utility model provides a drive circuit is provided, include: the charging and discharging 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 charge and 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; 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 generating circuit includes a first controlled switching tube and a first switching control module connected to a control end of the first controlled switching tube, and the first switching control module is configured to control on/off of the first controlled switching tube.
In some optional embodiments, the driving circuit 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 unidirectional current path comprises:
a diode, or a parasitic body diode of the first controlled switching tube.
In some optional embodiments, the driving circuit further includes: and the at least one first resistor is connected with the first controlled switch tube.
In some optional embodiments, a circuit formed by connecting the at least one first resistor in series with the first controlled switching tube is connected in parallel with the unidirectional current path.
In some optional embodiments, the first controlled switching tube is connected to the at least one first resistor after being connected in parallel with the unidirectional current path.
In some optional embodiments, the first switch 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; 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 first controlled switching tube is an NMOS tube, and the current output end of the first controlled switching tube refers to a source electrode of the NMOS tube, or,
under the condition that the charging and discharging generating circuit is connected with the unidirectional current path in parallel, the first controlled switch tube is a bipolar transistor, and the current output end of the first controlled switch tube refers to an emitter of the bipolar transistor.
In some optional embodiments, the first switch control module further comprises: the current source, the second resistor, the third resistor, the second controlled switch tube and the third controlled switch tube;
the current source is connected in series with the second resistor and then connected in parallel with a charging loop formed by the energy storage device and the first controlled switch tube;
the positive input end of the first operational amplifier is connected between a current source and the second resistor;
the drain electrode of the third controlled switching tube is connected with the rectified bus voltage through the third resistor, or the drain electrode of the third controlled switching tube is used for being connected with the output end of the controlled load through the third resistor;
the second controlled switch tube and the third controlled switch tube are connected to form a current mirror.
In some optional embodiments, the driving circuit further includes: a unidirectional current path that conducts upon discharge of the energy storage device;
the charge and discharge generating circuit comprises at least one fourth resistor, and the unidirectional current path is connected with the at least one fourth resistor in parallel.
In some optional embodiments, the load current control circuit is a linear control circuit, a buck-type circuit, a fly-back-type circuit, or a boost-type circuit.
As a second aspect of the embodiments of the present invention, an embodiment of the present invention provides a LED circuit, including a LED load and any one of the above-mentioned driving circuits.
As the third aspect of the embodiment of the utility model provides a LED lamp, including foretell LED circuit.
The embodiment of the utility model provides an above-mentioned technical scheme's beneficial effect includes at least:
the embodiment of the utility model provides an above-mentioned drive circuit to the AC input power that rectifier module connects, this drive circuit utilizes busbar voltage to be the characteristics of sinusoidal wave change, carries out charge-discharge for an energy storage device. By controlling the charging current of the energy storage device, stable working voltage can be provided for the controlled load. When the bus voltage is greater than the voltage of the energy storage device, the bus voltage charges the energy storage device and provides load current at the same time, and when the bus voltage is less than the voltage of the energy storage device, the controlled load is powered through the energy storage device, so that the controlled load is powered stably, and ripples are eliminated. 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. In addition, the charging current of the energy storage device is used as a part of the alternating current input current, the alternating current input current and the alternating current input voltage can be in a common symmetry axis relation, the waveform consistency of the alternating current input current and the alternating current input voltage is improved, and the PF is improved.
Drawings
FIG. 1 is a schematic diagram of a prior art LED driving circuit;
FIG. 2 is a schematic diagram of the waveform variation of current with voltage in the LED driving circuit shown in FIG. 1;
fig. 3 is a first schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram three of a driving circuit according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram six of a driving circuit according to an embodiment of the present invention;
fig. 9 is a seventh schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram eight of a driving circuit according to an embodiment of the present invention;
fig. 11 is a schematic structural diagram nine of a driving circuit according to an embodiment of the present invention;
FIG. 12 is a schematic diagram of current and voltage waveforms in the driving circuit shown in FIG. 11;
fig. 13 is a schematic structural diagram ten of a driving circuit according to an embodiment of the present invention;
fig. 14 is an eleventh schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 15 is a twelfth schematic structural diagram of a driving circuit according to an embodiment of the present invention;
FIG. 16 is a schematic diagram of current and voltage waveforms in the driving circuit shown in FIG. 15;
fig. 17 is a twelfth schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 18 is a schematic structural diagram thirteen of a driving circuit according to an embodiment of the present invention;
fig. 19 is a fourteenth schematic structural diagram of a driving circuit according to an embodiment of the present invention;
fig. 20 is a schematic structural diagram fifteen of a driving circuit according to an embodiment of the present invention;
fig. 21 is a schematic structural diagram sixteen of a driving circuit 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 among the prior art LED drive circuit can not satisfy high PF and do not have stroboscopic problem, the embodiment of the utility model provides a drive circuit, it is shown with reference to fig. 3, this drive circuit, include: the device comprises a rectification module connected with an alternating current input power supply AC, a load current control circuit used for controlling connected controlled load current, an energy storage device and a charging and discharging generation circuit;
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 controlled load is connected between the rectifying module and the load current control circuit;
the charge and 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; 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. In some of the alternative embodiments, the first and second,
the embodiment of the utility model provides a drive circuit, produce the circuit control energy storage device through charging and discharging and charge, when the input voltage after the rectification is greater than the voltage of energy storage device, the energy storage device gets into the charging process, at this moment, rectifier module, energy storage device and charging and discharging produce the circuit and constitute the charging circuit, the charging and discharging produces the circuit and produces the electric current by Iin end to Iout end, this electric current can be constant current, also can be the electric current that changes along with the change of certain or some voltage or electric current in the drive circuit, produce the size that the circuit can control energy storage device charging current through charging and discharging; 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 embodiment of the utility model provides an above-mentioned drive circuit to the AC input power that rectifier module connects, this drive circuit utilizes busbar voltage to be the characteristics of sinusoidal wave change, carries out charge-discharge for an energy storage device. By controlling the charging current of the energy storage device, stable working voltage can be provided for the controlled load. When the bus voltage is greater than the voltage of the energy storage device, the bus voltage charges the energy storage device and provides load current at the same time, and when the bus voltage is less than the voltage of the energy storage device, the controlled load is powered through the energy storage device, so that the controlled load is powered stably, and ripples are eliminated. 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. In addition, the charging current of the energy storage device is used as a part of the alternating current input current, the alternating current input current and the alternating current input voltage can be in a common symmetry axis relation, the waveform consistency of the alternating current input current and the alternating current input voltage is improved, and the PF is improved.
The following describes in detail a specific implementation of the present invention through several specific embodiments:
example one
In some optional embodiments, the charge and discharge generating circuit includes a first controlled switching tube and a first switching control module connected to a control end of the first controlled switching tube, and the first switching control module is configured to control on/off of the first controlled switching tube.
In some optional embodiments, the driving circuit 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.
The embodiment of the utility model provides an in, one-way current path includes the parasitic body diode of first controlled switch tube.
As a specific 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 is an NMOS tube M1. Referring to fig. 4, 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, wherein the drain of the NMOS transistor M1 is connected to the Iin terminal, the source is connected to the Iout terminal, the gate is connected to the first switch control module, the substrate SUB terminal is connected to the Iout terminal, and the LED load is connected to the load current control circuit and then forms a current loop with the rectifier module. In the driving circuit, when the rectified bus voltage Vin is greater than the voltage at two ends of the capacitor C1, the first switch control module controls the NMOS tube M1 to be turned on to generate a current in a direction from an Iin end to an Iout end, the rectifying module, the capacitor C1 and the NMOS tube M1 form a charging loop, and the bus voltage Vin supplies power to the LED load and the capacitor C1; when the rectified bus voltage Vin is smaller than the voltage at two ends of the capacitor C1, the first switch control module controls the NMOS transistor M1 to turn off, because the substrate SUB end of the non-isolated NMOS transistor is connected with the Iout end, a current in the direction from the Iout end to the Iin end is generated in a parasitic diode D1 'in the NMOS transistor M1, the capacitor C1, the LED load, the load current control circuit and the parasitic diode D1' of the NMOS transistor M1 form a discharge 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 the second reference voltage.
It should be noted that, in the embodiment of the present invention, load current control circuit specific implementation mode can refer to other structural modes of realizing controlled load current control in the prior art, its specific circuit implementation mode the embodiment of the present invention does not strictly limit here, as long as can realize the requirement of current control in the circuit can, in the embodiment of the present invention, no longer give details.
The embodiment of the utility model provides an among the above-mentioned embodiment, through parasitic body diode D1 'of NMOS pipe M1 who uses integrated circuit technology to make, circuit one-way when realizing electric capacity C1 and discharging does not need external other circuit device, when having reduced circuit cost, is favorable to reducing drive circuit's volume, the rational arrangement of each device in the drive circuit of being convenient for when manufacturing.
Example two
In a specific embodiment, referring to fig. 5, the driving circuit further comprises a unidirectional current path connected in parallel with the charge and discharge generating circuit, the unidirectional current path being conductive in case of discharge of the energy storage device.
As a specific embodiment of the utility model, this charge-discharge produces the circuit and includes first controlled switch tube and the first on-off control module who is connected with first controlled switch tube control end, and first on-off control module is used for controlling the break-make of first controlled switch tube. Specifically, the energy storage device may be a capacitor C1, and the first controlled switch tube of the charge-discharge generating circuit is an NMOS tube M1, in the second embodiment of the present invention, the unidirectional current path includes at least one diode D1. The first switch control module can realize the change of the current generated by the charge and discharge generating circuit by controlling the first controlled switch tube M1.
Referring to fig. 6, the ac input power is connected to a rectifying module, the rectifying module is connected to a capacitor C1, the capacitor C1 is connected to an Iin terminal of the charge and discharge generating circuit, an Iout terminal of the charge and discharge generating circuit is grounded, an NMOS transistor M1 in the charge and discharge generating circuit is an isolated MOS transistor, wherein a drain of the NMOS transistor M1 is connected to the Iin terminal, a source of the NMOS transistor M1 is connected to the Iout terminal, a gate of the NMOS transistor M1 is connected to the first switch control module, a diode D1 is connected in parallel between the drain and the source of the NMOS transistor M1, and an LED load and a load current control circuit are connected to form. In the driving circuit, when the rectified bus voltage Vin is greater than the voltage at two ends of the capacitor C1, the first switch control module controls the NMOS transistor M1 to be turned on to generate a current in a direction from an Iin end to an Iout end, the rectifying module, the capacitor C1 and the NMOS transistor M1 form a charging loop, and the bus voltage Vin supplies power to the LED load and the capacitor C1; when the rectified bus voltage Vin is smaller than the voltage at two ends of the capacitor C1, the first switch control module controls the NMOS transistor M1 to turn off, a current in the direction from the Iout end to the Iin end is generated in the diode D1, the capacitor C1, the LED load, the load current control circuit and the diode D1 form a discharge loop, and the capacitor C1 supplies power to the LED load.
It should be noted that, in the driving circuit shown in fig. 6, the first controlled switch transistor is an NMOS transistor only as a specific implementation manner of the embodiment of the present invention, and the first controlled switch transistor may also be another current control switch transistor, for example, a bipolar transistor BJT (not shown in the figure), as long as the current can be controlled, so that a charging loop is formed when the capacitor C1 is charged.
EXAMPLE III
In some alternative embodiments, the driving circuit shown in fig. 7 to 10 further includes at least one first resistor connected to the first controlled switching tube.
In a specific embodiment, referring to fig. 7 or fig. 8, the at least one first resistor is connected in series with the first controlled switching tube to form a circuit, and the circuit is connected in parallel with the unidirectional current path.
In the driving circuit shown in fig. 7, based on the driving circuit described in the second embodiment, the first resistor R1 is connected between the NMOS transistor M1 and the terminal Iout, when the capacitor C1 needs to be charged, after the NMOS transistor M1 is turned on, a current from the terminal Iin to the terminal Iout can be generated, and the terminal Iout current flows through the first resistor R1, so as to flow into or out of the power circuit. The current regulation is realized through the first resistor R1, and the current control when the energy storage device is charged is realized.
Similarly, the driving circuit shown in fig. 8 is based on the driving circuit described in the first embodiment, and the first resistor R1 is connected between the NMOS transistor M1 and the Iout terminal, so that current regulation can be realized through the first resistor R1, and current control when the energy storage device is charged is realized. In this embodiment, the same NMOS transistor M1 as in the first embodiment is used to achieve the same or similar technical effects.
The specific circuit implementation and the specific implementation manner of fig. 7 or fig. 8 have been described in detail in the first embodiment and the second embodiment, and will not be described in detail here.
In a specific embodiment, referring to fig. 9 or fig. 10, the first controlled switch tube is connected to the at least one first resistor after being connected in parallel with the unidirectional current path.
In the driving circuit shown in fig. 9, on the basis of the driving circuit described in the second embodiment, the first resistor R1 is connected between the Iout terminal and the ground terminal, so that current regulation can be realized through the first resistor R1, and current control during charging of the energy storage device is realized.
Similarly, the driving circuit shown in fig. 10 is based on the driving circuit described in the first embodiment, and the first resistor R1 is connected between the Iout terminal and the ground terminal, so that current regulation can be realized through the first resistor R1, and current control when the energy storage device is charged is realized. In this driving circuit, the substrate SUB terminal (not shown) of the NOMS transistor M1 is connected to the source, and the diode D1 described in fig. 9 is replaced by its parasitic body diode D1'. Similar to the NMOS transistor M1 in the first embodiment, in this embodiment, 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.
The specific circuit implementation and the specific implementation manner of fig. 9 or fig. 10 have been described in detail in the first and second embodiments, and will not be described in detail here.
Example four
Based on the driving circuit described in the first to third embodiments, further, the first switch 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; 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 tube is an NMOS tube, the current output end of the first controlled switch tube refers to the source electrode of the NMOS tube.
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.
As will be described in detail below by a specific embodiment, referring to the driving circuit shown in fig. 11, the ac input power source is connected to the rectifying module, the rectifying module is connected to the LED load, the LED load is connected to the load current control circuit, the load current control circuit includes a power control module and a load-controlled switching tube, the power control module may be a second operational amplifier, the load-controlled switching tube may be an NMOS tube M0, wherein a drain of the NMOS tube M0 is connected to the LED load, an output end of the second operational amplifier AMP2 is connected to a gate of the NMOS tube M0, a source of the NMOS tube M0 is connected to a resistor Rcs, and is also connected to a negative-phase input end of the second operational amplifier AMP2, and a positive-phase input end of the second operational amplifier AMP2 is connected to the second reference voltage VREF 2. 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. The cathode of the diode D1 of the unidirectional current path is connected with the Iin end of the charge and discharge generating circuit and is connected with one end of the capacitor C1; the anode of the diode is connected with the Iout end of the charge and discharge generation circuit. The drain electrode of an NMOS tube M1 of the charge and discharge generating circuit is connected with an Iin end, the source electrode of an NMOS tube M1 is connected with one end of a first resistor R1 and is also connected with the negative phase input end of a first operational amplifier AMP1, and the other end of the first resistor R1 is connected with 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, the first reference voltage VREF1 may be a constant value, and the current Ichg generated by the charge and discharge generating circuit is a constant value VREF 1/R1. If the second reference voltage VREF2 may be a constant value, the load current Iload is also a constant value VREF 2/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 FIGS. 11 and 12, VC1The voltage across the capacitor C1, VD1 is the forward conduction voltage of the diode D1, Vac is the ac input voltage, | Vac | is the ac rectified input voltage. In general VC1The voltage is much greater than the diode forward conduction voltage VD1, and for simplicity of analysis, the effect of VD1 is ignored in the following description. When | Vac | is greater than VC1Hour, charge and dischargeThe current Ichg generated by the generating circuit charges the capacitor C1; when | Vac | is less than VC1When the charging process is finished, the D1 is conducted in the forward direction, the capacitor C1 discharges the LED load until the value of Vac is larger than V againC1And the process is circulated. Referring to FIG. 12, T1 shows the capacitor C1 in a charging phase, where Vac is greater than VC1Capacitor C1 is in a charged state, and since Ichg is a constant current, voltage V isC1Is linearly increased, the voltage V of the capacitor C1 in the charging phaseC1Has a variation of Δ VC1(Ichg × T1)/C1; t2 shows that capacitor C1 is in the discharging phase, and since load current Iload is a constant value, voltage VC1Is in a linear descending state, and the voltage V of the capacitor C1 in a discharging stageC1Has a variation of Δ VC1(Iload T2)/C1. When the charging and discharging states of the capacitor C1 are stable, the voltage V of the charging stateC1The variation and the voltage V of the discharge stateC1The amount of change is equal, i.e. conservation of charge is achieved, when: (Ichg × T1)/C1 ═ Iload × T2)/C1, i.e., Ichg × T1 ═ Iload × T2, i.e., Ichg ═ Iload × T2/T1. Since the ac rectified input voltage | Vac | is periodically varied and has a period Tvac, if the voltage period of the ac rectified input voltage | Vac | is stable, the charging time T1 and the discharging time T2 of the capacitor C1 are also periodic, and the sum of the charging time and the discharging time is equal to the period Tvac of the ac input voltage, i.e., T1+ T2. From the above analysis, it can be easily found that the load voltage V is dependent onLEDAnd a load current Iload, which can be set by Δ VC1V can be realized by adjusting the sizes of the capacitor C1 and the charging current IchgC1≥VLED. It can be seen that the post-bridge input current Imain is characterized by: when Vac is less than VC1When Imain is zero, when Vac is greater than VC1Then Imain ═ Ichg + Iload. For the controlled load, due to VC1≥VLEDIload is always a constant value and is VREF2/RCSEspecially for the LED load, no ripple current in the LED load is ensured, and no stroboflash is realized. Since the periods of charging and discharging the capacitor are stable, it is easy to find that the post-bridge input current Imain and the ac input voltage Vac exhibit a common voltage in one period of the ac input voltage VacThe symmetry axis relation, that is, the waveform consistency of the alternating input current and the alternating input voltage is good, and the PF of the alternating input power supply is high.
Of course, the above-mentioned embodiment shown in fig. 11 is only a specific implementation manner of the embodiment of the present invention, and in the embodiment of the present invention, as shown in fig. 13, a non-isolated MOS transistor is adopted as the NMOS transistor M1 in the first controlled switch transistor, and the parasitic body diode D1' is used to replace the diode D1 shown in fig. 11. Alternatively, referring to fig. 14, the NMOS transistor M1 in the first controlled switching transistor is an isolated MOS transistor, that is, the substrate SUB terminal of the NMOS transistor is connected to the source, and the parasitic body diode D1' is used to replace the diode D1 shown in fig. 11.
EXAMPLE five
In the driving circuit according to the fifth embodiment, the first reference voltage VREF1 may be changed according to a change in a control amount in the circuit, so that a current generated in the charge/discharge generating circuit may be changed accordingly.
As an embodiment of the present invention, on the basis of the driving circuit shown in fig. 11, referring to fig. 15, the first reference voltage is a variable voltage, specifically, the first switch control module may further include: the current source IREF1, the second resistor R2, the third resistor R3, the second controlled switch tube and the third controlled switch tube; for example, the second controlled switch tube and the third controlled switch tube may be NMOS tubes M2 and M3 of the same specification, wherein:
the current source IREF1 is connected in series with the second resistor R2 and then connected in parallel with a charging circuit consisting of a capacitor C1, an NMOS transistor M1 and a first operational amplifier AMP 1;
a non-inverting input terminal of the first operational amplifier AMP1 is connected between the current source and the second resistor R2;
the drain of the NMOS transistor M3 is connected to the rectified bus voltage Vin via a third resistor R3, and the gates of the NMOS transistor M2 and the NMOS transistor M3 are connected to form a current mirror.
Referring to fig. 15 and 16, the current Ichg generated by the charge and discharge generating circuit in this embodiment varies with the bus voltage. Specifically, in fig. 15 and 16, the current source IREF1 may be connected to the second resistor R2, and the first reference voltage VREF1 may be generated at the second resistor R2. When the ac input voltage Vac is low, the NMOS transistor M3 is not turned on, the current Icomp flowing through the current mirror is zero, the first reference voltage VERF1 is IREF1 × R2, and the current Ichg generated by the charge and discharge generating circuit is VERF 1/R1. When the input voltage | Vac | after the ac rectification rises, the NMOS transistors M2 and M3 are turned on, and the current Icomp increases, where the first reference voltage VERF1 is (IREF1-Icomp) × R2, and the current Ichg generated by the charge and discharge generation circuit is (IREF1-Icomp) × R2/R1. The higher the ac input voltage Vac, the higher Icomp, and the lower the first reference voltage VERF 1.
Referring to fig. 16, 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 shown in fig. 15, the current Ichg generated by the charge/discharge generating circuit changes with the change of 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 can be set to VC1Still 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 shown in fig. 15 is only one specific embodiment in which the first reference voltage VREF1 changes with the change of the rectified bus voltage in the circuit, and in other embodiments, the first reference voltage VREF1 may also change with the change of other control quantities in the circuit, for example, referring to fig. 17, the drain of the NMOS transistor M3 shown in fig. 15 is connected to the output end of the controlled load through the third resistor R3, and under the condition that the connection mode of other circuits is not changed, the first reference voltage VREF1 can change with the change of the difference value between the rectified bus voltage and the load voltage in the circuit, so as to achieve the same technical effect as the driving circuit shown in fig. 15.
EXAMPLE six
In one embodiment, the charge and discharge generating circuit in the driving circuit may include at least one fourth resistor and a unidirectional current path connected in parallel with the fourth resistor, and the unidirectional current path includes at least one diode D1.
Referring to fig. 18, the charge and discharge generating circuit includes a fourth resistor R4 and a diode D1, and the diode D1 is connected in parallel with the fourth resistor R4.
As a specific implementation manner of the embodiment of the present invention, this energy storage device can be the electric capacity C1, and the rectifier module connects the ac input power before, and electric capacity C1 behind the rectifier module, the fourth resistance R4 of charging and discharging production circuit is connected to electric capacity C1's the other end, utilizes ac input voltage to be the characteristics of sinusoidal wave, realizes carrying out the charging of specific time to electric capacity C1. The charge/discharge generation circuit can make the voltage across the capacitor C1 reach a certain value VC1Then automatically stopping charging; after the charging is stopped, the capacitor C1 discharges the controlled load, which is especially the LED load, through the diode D1, so as to provide a substantially stable voltage for the controlled load, for the LED load, it is ensured that no ripple exists in the circuit, and no stroboflash can be achieved, and at the same time, the sum of the charging current and the load current of the capacitor C1 and the ac input voltage have a common symmetry axis relationship in a single cycle, so that the PF of the driving circuit is high. In some alternative embodiments, the fourth resistor R4 may be a variable resistor.
In the driving circuits in the first to sixth embodiments, the load current control circuit may be a linear control circuit or a switching control circuit, such as a buck-type circuit shown in fig. 19, a fly-back-type circuit shown in fig. 20, or a boost-type circuit shown in fig. 21. Because the circuit implementation mode of other parts of drive circuit including above-mentioned switch type control circuit is similar with above-mentioned embodiment, specific implementation mode can refer to the detailed description in embodiment one to embodiment six, and, it is to be explained, the utility model discloses in the embodiment, constant current control module's specific implementation mode can refer to other structural modes that realize the constant current control of controlled load among the prior art, its specific circuit implementation mode the utility model discloses do not do strictly limit here in the embodiment, as long as can realize the requirement of constant current control in the circuit can, the embodiment of the utility model provides an, no longer describe repeatedly.
Based on the same utility model concept, the embodiment of the utility model provides a still provides a LED circuit, including LED load and the drive circuit that describes in the above-mentioned embodiment.
With regard to the LED circuit in the above embodiments, the specific manner of performing operation and implementation of the driving circuit therein has been described in detail in the above embodiments one to six, and will not be elaborated herein.
Based on the same utility model concept, the embodiment of the utility model provides a still provide a LED lamp, including foretell 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 has been described in detail in the above embodiments one to six, and will not be elaborated herein.
It will be apparent to those skilled in the art that various changes and modifications may be made 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 and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (15)
1. A drive circuit, comprising: load current control circuit and rectifier module, its characterized in that still includes: the charging and discharging 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 charge and 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; and forming a discharge loop with the energy storage device in the discharge process of the energy storage device.
2. The driving circuit according to claim 1, wherein the charge and discharge generating circuit comprises a first controlled switching tube and a first switching control module connected to a control end of the first controlled switching tube, and the first switching control module is configured to control on/off of the first controlled switching tube.
3. The drive 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 drive circuit of claim 3, wherein the unidirectional current path comprises: a diode, or a parasitic body diode of the first controlled switching tube.
5. The drive circuit of claim 2, further comprising: and the at least one first resistor is connected with the first controlled switch tube.
6. The drive circuit of claim 3, further comprising: and the at least one first resistor is connected with the first controlled switch tube.
7. The driving circuit as recited in claim 6 wherein said at least one first resistor is connected in series with said first controlled switching tube to form a circuit in parallel with said unidirectional current path.
8. The driving circuit as recited in claim 6 wherein said first controlled switching transistor is connected to said at least one first resistor after being connected in parallel with said unidirectional current path.
9. The driving circuit of claim 6, wherein the first switch 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; the output end of the first operational amplifier is connected with the control end of the first controlled switch tube.
10. The driving circuit as claimed in claim 9, wherein the first controlled switch transistor is an NMOS transistor, the current output terminal of the first controlled switch transistor is a source of the NMOS transistor, or,
under the condition that the charging and discharging generating circuit is connected with the unidirectional current path in parallel, the first controlled switch tube is a bipolar transistor, and the current output end of the first controlled switch tube refers to an emitter of the bipolar transistor.
11. The drive circuit of claim 9, wherein the first switch control module further comprises: the current source, the second resistor, the third resistor, the second controlled switch tube and the third controlled switch tube;
the current source is connected in series with the second resistor and then connected in parallel with a charging loop formed by the energy storage device and the first controlled switch tube;
the positive input end of the first operational amplifier is connected between a current source and the second resistor;
the drain electrode of the third controlled switching tube is connected with the rectified bus voltage through the third resistor, or the drain electrode of the third controlled switching tube is used for being connected with the output end of the controlled load through the third resistor;
the second controlled switch tube and the third controlled switch tube are connected to form a current mirror.
12. The drive circuit of claim 1, further comprising: a unidirectional current path that conducts upon discharge of the energy storage device;
the charge and discharge generating circuit comprises at least one fourth resistor, and the unidirectional current path is connected with the at least one fourth resistor in parallel.
13. The drive circuit according to claim 9 or 12, wherein the load current control circuit is a linear control circuit, a buck-type circuit, a fly-back-type circuit, or a boost-type circuit.
14. An LED circuit comprising an LED load and a driver circuit as claimed in any one of claims 1 to 13.
15. An LED lamp comprising the LED circuit of claim 14.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922312856.3U CN211606882U (en) | 2019-12-20 | 2019-12-20 | Drive circuit, LED circuit and lamp |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922312856.3U CN211606882U (en) | 2019-12-20 | 2019-12-20 | Drive circuit, LED circuit and lamp |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112105123A (en) * | 2020-10-19 | 2020-12-18 | 美芯晟科技（北京）有限公司 | Low-power-consumption constant-current control circuit and method |
| CN113015287A (en) * | 2019-12-20 | 2021-06-22 | 美芯晟科技（北京）有限公司 | Drive circuit, related circuit and device |
| WO2022142857A1 (en) * | 2020-12-30 | 2022-07-07 | 华润微集成电路(无锡)有限公司 | Led driving system and closed-loop control method for led driving |
-
2019
- 2019-12-20 CN CN201922312856.3U patent/CN211606882U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113015287A (en) * | 2019-12-20 | 2021-06-22 | 美芯晟科技（北京）有限公司 | Drive circuit, related circuit and device |
| CN113015287B (en) * | 2019-12-20 | 2024-02-06 | 美芯晟科技(北京)股份有限公司 | Driving circuit, related circuit and device |
| CN112105123A (en) * | 2020-10-19 | 2020-12-18 | 美芯晟科技（北京）有限公司 | Low-power-consumption constant-current control circuit and method |
| CN112105123B (en) * | 2020-10-19 | 2024-01-23 | 美芯晟科技(北京)股份有限公司 | Low-power-consumption constant-current control circuit and method |
| WO2022142857A1 (en) * | 2020-12-30 | 2022-07-07 | 华润微集成电路(无锡)有限公司 | Led driving system and closed-loop control method for led driving |
| US11917735B2 (en) | 2020-12-30 | 2024-02-27 | CRM ICBG (Wuxi) Co., Ltd. | LED driving system and closed-loop control method for LED driving |
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