CN212064422U - LED constant current drive circuit and LED lighting device - Google Patents
LED constant current drive circuit and LED lighting device Download PDFInfo
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- CN212064422U CN212064422U CN202021259184.0U CN202021259184U CN212064422U CN 212064422 U CN212064422 U CN 212064422U CN 202021259184 U CN202021259184 U CN 202021259184U CN 212064422 U CN212064422 U CN 212064422U
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Abstract
The utility model provides a LED constant current drive circuit and LED lighting device, wherein, the LED constant current drive circuit comprises a power supply unit, a first constant current source control circuit and a charging and discharging adjusting circuit; the power supply unit, the first constant current source and the LED light-emitting unit are connected in series; the charging and discharging adjusting circuit is connected with the first constant current source and two ends of the LED light-emitting unit; the first constant current source control circuit is respectively connected with the LED light-emitting unit and the first constant current source; the power supply unit is used for supplying power to the LED light-emitting unit; the first constant current source is used for maintaining the current flowing through the LED light-emitting unit to be constant; the first constant current source control circuit is used for receiving the sampling voltage of the LED light-emitting unit and outputting the sampling voltage to the first constant current source so as to adjust the first constant current source to a preset current value; the charging and discharging adjusting circuit is used for charging and discharging to maintain the constant load current of the LED light-emitting unit, and the effects of constant power, high power factor and no stroboflash are achieved.
Description
Technical Field
The utility model relates to a LED lighting technology field especially relates to a LED constant current drive circuit and LED lighting device.
Background
With the continuous development of LED lighting technology, compared with energy-saving lamps and incandescent lamps, because LEDs are favored by people due to their low power consumption, environmental protection and low radiation, more and more lighting devices employ LED lamps.
The constant power function is gradually added to the existing LED constant current driving circuit in the current market, and the driving circuit used in the field of LED illumination can be self-adaptive to the input voltage of a wire network to adjust the output current. However, the LED constant-current driving circuit has obvious defects, and has stroboscopic phenomenon while meeting high power factor; or the power factor is lower while no stroboflash is met, and the high-power factor and no stroboflash cannot be realized.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a LED constant current drive circuit and LED lighting device to solve current LED constant current drive circuit and can't have constant power, high power factor and do not have the problem of stroboscopic function concurrently.
In order to achieve the above object, the present invention provides the following technical solutions:
the utility model provides a LED constant current drive circuit, which is used for driving an LED luminous unit and comprises a power supply unit, a first constant current source control circuit and a charging and discharging regulation circuit; wherein the content of the first and second substances,
the power supply unit, the first constant current source and the LED light-emitting unit are connected in series;
the charging and discharging adjusting circuit is connected to the first constant current source and two ends of the LED light-emitting unit;
the first constant current source control circuit is respectively connected with the LED light-emitting unit and the first constant current source;
the power supply unit is used for supplying power to the LED light-emitting unit; the first constant current source is used for maintaining the current flowing through the LED light-emitting unit to be constant; the first constant current source control circuit is used for receiving the sampling voltage of the LED light-emitting unit and outputting the sampling voltage to the first constant current source so as to adjust the first constant current source to a preset current value; the charging and discharging adjusting circuit is used for charging and discharging to maintain the load current of the LED light-emitting unit constant.
Further, the charge-discharge regulating circuit comprises a charge-discharge regulating unit, a second constant current source and a second constant current source control circuit which are connected in series;
the second constant current source control circuit is respectively connected with the charging and discharging regulation unit and a second constant current source;
the second constant current source control circuit is used for receiving the sampling voltage of the charging and discharging regulating unit and outputting the sampling voltage to the second constant current source so that the second constant current source is adjusted to a preset current value.
Optionally, the charging and discharging adjustment unit is configured to discharge the LED lighting unit to maintain a constant load current of the LED lighting unit when the output voltage of the power supply unit is less than or equal to the operating voltage of the LED lighting unit.
Further, the charge and discharge adjusting unit comprises a charge capacitor, a first diode and a second diode; the anode of the charging capacitor is connected with the anode of the power supply unit, and the cathode of the charging capacitor is respectively connected with the anode of the first diode and the cathode of the second diode; the negative electrode of the first diode is connected with one end of the second constant current source, and the positive electrode of the second diode is connected with the other end of the second constant current source and the negative electrode of the power supply unit.
In one embodiment, any at least two of the first constant current source, the first constant current source control circuit, the second constant current source and the second constant current source control circuit are integrated on the same circuit module.
Optionally, one end of the LED light emitting unit is connected to the positive electrode of the power supply unit, the other end of the LED light emitting unit is connected to one end of the first constant current source, and the other end of the first constant current source is connected to the negative electrode of the power supply unit.
Optionally, one end of the first constant current source is connected to the anode of the power supply unit, the other end of the first constant current source is connected to one end of the LED light emitting unit, and the other end of the LED light emitting unit is connected to the cathode of the power supply unit.
Optionally, one end of the first constant current source control circuit is connected to the LED lighting unit through a resistor divider, and the other end of the first constant current source control circuit is connected to the first constant current source.
Optionally, the power supply unit includes a rectifier bridge and a protection circuit, one input end of the rectifier bridge is connected to a zero line interface of the power grid alternating current, another input end of the rectifier bridge is connected to one end of the protection circuit, and another end of the protection circuit is connected to a live line interface of the power grid alternating current.
Optionally, the first constant current source control circuit and/or the second constant current source control circuit include a first resistor, a second resistor, and a first field effect transistor, one end of the first resistor and one end of the second resistor are connected to the gate and the source of the first field effect transistor, the drain of the first field effect transistor and the other end of the second resistor are grounded, and the other end of the first resistor is connected to the LED lighting unit through resistor voltage division.
Furthermore, the first constant current source and/or the second constant current source comprise an operational amplifier and a second field effect transistor, a positive phase input end of the operational amplifier is connected with the reference voltage, a negative phase input end of the operational amplifier is connected with a source electrode of the second field effect transistor, and an output end of the operational amplifier is connected with a grid electrode of the second field effect transistor.
Correspondingly, the utility model also provides a LED lighting device, reach as above arbitrary one including the LED luminescence unit LED constant current drive circuit, LED constant current drive circuit with the LED luminescence unit electricity is connected.
Compared with the prior art, the utility model discloses a scheme has following advantage:
the utility model provides a LED constant current drive circuit, its power supply unit, first constant current source and LED luminescence unit series connection, the charge-discharge regulating circuit is connected at the both ends of first constant current source and LED luminescence unit, first constant current source control circuit connects LED luminescence unit and first constant current source respectively to supply power, utilize first constant current source to maintain the electric current that flows through LED luminescence unit invariable to LED luminescence unit through the power supply unit; and the first constant current source control circuit receives the sampling voltage of the LED light-emitting unit, outputs the sampling voltage to the first constant current source according to the sampling voltage, and adjusts the first constant current source to a preset current value, so that when the power supply voltage changes, the first constant current source adjusts the output current according to the sampling voltage, thereby obtaining a higher power factor and realizing constant power. Furthermore, the utility model discloses still carry out the invariant of charge-discharge in order to maintain LED luminescence unit load current through charge-discharge regulating circuit, make the circuit reduce the ripple current of LED load when reaching high power factor, reach and do not have stroboscopic purpose.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a block diagram of an LED constant current driving circuit according to an exemplary embodiment, wherein an LED light emitting unit is also shown for convenience of illustration;
fig. 2 is a circuit diagram illustrating an LED constant current drive circuit according to an exemplary embodiment;
fig. 3 is a circuit diagram illustrating yet another LED constant current drive circuit according to an exemplary embodiment;
FIG. 4 is a waveform diagram illustrating an LED constant current drive circuit according to an exemplary embodiment;
fig. 5 is a detailed circuit diagram of yet another LED constant current driving circuit according to an exemplary embodiment;
fig. 6 is a detailed circuit diagram of another LED constant current driving circuit according to an exemplary embodiment;
fig. 7 is a detailed circuit diagram of another LED constant current driving circuit according to an exemplary embodiment;
fig. 8 is a specific circuit diagram illustrating yet another LED constant current driving circuit according to an exemplary embodiment;
fig. 9 is a detailed circuit diagram of another LED constant current driving circuit according to an exemplary embodiment;
fig. 10 is a detailed circuit diagram of still another LED constant current driving circuit according to an exemplary embodiment;
fig. 11 is a circuit configuration diagram illustrating a constant current source control circuit according to an exemplary embodiment;
fig. 12 is a circuit configuration diagram illustrating a constant current source according to an exemplary embodiment.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention.
The utility model provides a LED constant current drive circuit, which is used for driving an LED light-emitting unit so as to solve the problem that the current LED constant current drive circuit has stroboscopic phenomenon while meeting the high power factor; or the problems of no stroboflash, low power factor, incapability of realizing high power factor and no stroboflash are met. In an exemplary embodiment, as shown in fig. 1, the LED constant current driving circuit includes a power supply unit 1, a first constant current source 3, a first constant current source control circuit 5, and a charge and discharge adjusting circuit 4; the power supply unit 1, the first constant current source 3 and the LED light emitting unit 2 are connected in series. Specifically, as shown in fig. 2, the anode of the LED lighting unit 2 may be connected to the anode of the power supply unit 1, the cathode of the LED lighting unit 2 is connected to the input end of the first constant current source 3, and the output end of the first constant current source 3 is connected to the cathode of the power supply unit 1. Of course, in another connection mode, as shown in fig. 3, the input end of the first constant current source 3 is connected to the positive electrode of the power supply unit 1, the output end of the first constant current source 3 is connected to the positive electrode of the LED lighting unit 2, and the negative electrode of the LED lighting unit 2 is electrically connected to the negative electrode of the power supply unit 1. Wherein, the negative pole of the power supply unit 1 can form a loop through grounding. It should be noted that the two connection modes only differ in the positions of the LED lighting unit 2 and the first constant current source 3, and do not affect the working principle of the entire LED constant current driving circuit, and therefore, the description is omitted here.
Optionally, the charge and discharge adjusting circuit 4 is connected to the first constant current source 3 and two ends of the LED lighting unit 2; namely, after the first constant current source 3 is connected in series with the LED lighting unit 2, both ends of the first constant current source are connected in parallel with the charge-discharge regulating circuit 4 and are connected to the positive and negative electrodes of the power supply unit 1. In addition, the first constant current source control circuit 5 is respectively connected with the LED light emitting unit 2 and the first constant current source 3; the LED light emitting unit 2 may be a light string composed of a plurality of light beads from LED1 to LEDn, or may further be composed of a plurality of LED light strings connected in parallel.
The power supply unit 1 is used for supplying power to the LED lighting unit 2, so that the LED lighting unit 2 emits light for illumination; the first constant current source 3 is used for maintaining the current flowing through the LED light-emitting unit 2 constant, so that the LED light-emitting unit 2 works at the constant current and stroboflash is reduced; the first constant current source control circuit 5 is configured to receive the sampling voltage of the LED lighting unit 2, and output the sampling voltage to the first constant current source 3, so that the first constant current source 3 adjusts the output current to a preset current value based on the sampling voltage; the charge and discharge regulating circuit 4 is used for charging and discharging to maintain the load current of the LED light-emitting unit 2 constant.
The utility model provides a LED constant current drive circuit, its power supply unit 1, first constant current source 3 and LED luminescence unit 2 series connection, charge-discharge regulating circuit 4 is connected at the both ends of first constant current source 3 and LED luminescence unit 2, and first constant current source control circuit 5 connects LED luminescence unit 2 and first constant current source 3 respectively to supply power to LED luminescence unit 2 through power supply unit 1, utilize first constant current source 3 to maintain the electric current that flows through LED luminescence unit 2 invariable; the first constant current source control circuit 5 receives the sampling voltage of the LED lighting unit 2, outputs the sampling voltage to the first constant current source 3 according to the sampling voltage, and adjusts the first constant current source 3 to a preset current value, so that when the power supply voltage changes, the first constant current source 3 adjusts the output current according to the sampling voltage, thereby obtaining a higher power factor and realizing constant power. Furthermore, the utility model discloses still carry out the invariant of charge-discharge in order to maintain 2 load current of LED luminescence unit through charge-discharge regulating circuit 4, make the circuit reduce the ripple current of LED load when reaching high power factor, reach no stroboscopic purpose.
Further, with continued reference to fig. 2 or fig. 3, the charge and discharge adjusting circuit 4 includes a charge and discharge adjusting unit 41, a second constant current source 42, and a second constant current source control circuit 43 connected in series; the second constant current source control circuit 43 is connected to the charge/discharge adjusting unit 41 and the second constant current source 42, respectively; that is, one end of the second constant current source control circuit 43 is connected to the input terminal or the output terminal of the charge/discharge adjusting unit 41, and one end of the second constant current source control circuit 43 is connected to the input terminal of the second constant current source 42.
The charging and discharging adjusting unit 41 is configured to perform charging and discharging to maintain a load current of the LED lighting unit 2 constant, and the second constant current source 42 is configured to maintain a current of the charging and discharging adjusting unit 41 constant during charging and discharging, so as to implement constant current charging or discharging. The second constant current source control circuit 43 is configured to receive the sampling voltage of the charge/discharge adjustment unit 41, and output the sampling voltage to the second constant current source 42, so that the second constant current source 42 adjusts to a preset current value.
Specifically, the charging and discharging adjustment unit 41 is configured to discharge the LED lighting unit 2 to maintain a constant load current of the LED lighting unit 2 when the output voltage of the power supply unit 1 is less than or equal to the operating voltage of the LED lighting unit 2.
Further, the charging and discharging adjustment unit 41 includes a charging capacitor E1, a first diode D1 and a second diode D2, the charging capacitor E1 is an electrolytic capacitor, an anode thereof is connected to an anode of the power supply unit 1, a cathode thereof is connected to an anode of the first diode D1 and a cathode of the second diode D2, a cathode of the first diode D1 is connected to one end of the second constant current source 42, and an anode of the second diode D2 is connected to the other end of the second constant current source 42 and the cathode of the power supply unit 1. Namely, the first diode D1, the charging capacitor E1 and the second constant current source 42 form a series mode, and the second diode D2 is connected in parallel with two ends of the first diode D1 and the second constant current source 42 which are connected in series.
In implementation, when the input line network voltage reaches the operating voltage of the LED lighting unit 2, the voltage sampling signal sampled by the first constant current source control circuit 5 is input to the first constant current source 3 along with the increase of the line network voltage, and the first constant current source 3 adjusts the magnitude of the output current according to the voltage sampling signal.
When the rectified voltage of the input net voltage is greater than the starting voltage of the second constant current source 42, the current passes through the charge/discharge adjusting unit 41 composed of the charging capacitor E1, the first diode D1 and the second diode D2, and the charging capacitor E1 is charged with a constant current. When the rectified voltage is less than or equal to the charging capacitor E1 or the operating voltage of the LED lighting unit 2, the input current stops flowing, and when the voltage of the LED lighting unit 2 is equal to the loop voltage of the charging capacitor E1, the charging capacitor E1 discharges the loop of the LED lighting unit 2 to maintain the load current of the LED lighting unit 2 constant. For example, as shown in fig. 4, the higher the input net voltage is, the smaller the current output by the first constant current source 3 is; when the voltage of the input line network is reduced, the current output by the first constant current source 3 is increased, the voltage waveform of the alternating current input line network and the input current waveform are concave, and the output current waveform is a smooth straight line, so that constant current output is realized. Wherein the phase cycle time of the ac input current from no current to peak current in one net cycle is less than 65 °.
The connection of the first constant current source control circuit 5 and the first constant current source 3 and the connection of the second constant current source control circuit 43 and the second constant current source 42 can be varied. Alternatively, as shown in fig. 5, one end of the first constant current source control circuit 5 is connected to the anode of the LED lighting unit 2 after being divided by resistors R3 and R4, and the other end is connected to the input end of the first constant current source 3, so as to input the sampling voltage after being divided by the resistors to the first constant current source 3. Similarly, one end of the second constant current source control circuit 43 may also be connected to the positive electrode of the LED lighting unit 2 after being divided by the resistors R5 and R6, and the other end of the second constant current source control circuit is connected to the input end of the second constant current source 42, so as to input the sampling voltage obtained after the voltage division into the second constant current source 42, and adjust the output current according to the sampling voltage.
In an embodiment, as shown in fig. 6, the first constant current source control circuit 5 may also be implemented by only a resistor R3, one end of the resistor R3 is connected to the anode of the LED lighting unit 2, and the other end is connected to the input end of the first constant current source 3. At this time, the second constant current source control circuit 43 is connected to the anode of the LED lighting unit 2 through one end of the resistor R5, and the other end is connected to the input end of the second constant current source 42.
In another embodiment, as shown in fig. 7, one end of the R3 may be connected to the cathode of the LED lighting unit 2, and the other end of the R3 is connected to the input terminal of the first constant current source 3. At this time, the second constant current source control circuit 43 is connected to the negative electrode of the charging capacitor E1 through one end of the resistor R5, and the other end is connected to the input end of the second constant current source 42.
Optionally, the power supply unit includes a rectifier bridge DB1 and a protection circuit FR1, the rectifier bridge DB1 may be composed of four rectifier diodes, one input end of the rectifier bridge DB1 is connected to a neutral line interface N of the grid alternating current, another input end of the rectifier bridge DB1 is connected to one end of the protection circuit FR1, and another end of the protection circuit FR1 is connected to a live line interface L of the grid alternating current. The protection circuit FR1 may be a thermal relay, for example, for overload protection of electrical devices. And the positive electrode output end of the rectifier bridge DB1 is connected with the LED light-emitting unit 2, and the negative electrode output end is grounded.
In one embodiment, at least two of the first constant current source 3, the first constant current source control circuit 5, the second constant current source 42, and the second constant current source control circuit 43 are integrated on the same circuit module. For example, as shown in fig. 8, the first constant current source 3 and the first constant current source control circuit 5 may be combined to operate in an integrated circuit mode, and the required peripheral devices are integrated in the same basic circuit, for example, on the same chip U1. Similarly, the second constant current source 42 and the second constant current source control circuit 43 may be combined to operate in an integrated circuit mode, and the required peripheral devices are integrated in the same basic circuit, for example, integrated on the same chip U2. In addition, as shown in fig. 9 and 10, the first constant current source 3, the first constant current source control circuit 5, the second constant current source 42, and the second constant current source control circuit 43 may be integrated on the same chip U1, thereby reducing the use of pins and simplifying the circuit.
Alternatively, as shown in fig. 11, fig. 11 is a circuit structure diagram of a constant current source control circuit provided by the present invention, and at least one of the first constant current source control circuit 5 and the second constant current source control circuit 43 may adopt such a circuit structure. Specifically, the constant current source control circuit includes a first resistor R11, a second resistor R12 and a first field effect transistor Q1, one end of the first resistor R11 and one end of the second resistor R12 are connected to a gate G1 and a drain D1 of the first field effect transistor Q1, the other end of a source S1 and the other end of the second resistor R12 of the first field effect transistor are grounded, and the other end of the first resistor R11 is connected to the LED lighting unit 2 by dividing voltage through a resistor R3.
Alternatively, as shown in fig. 12, fig. 12 is a circuit structure diagram of a constant current source provided by the present invention, and at least one of the first constant current source 3 and the second constant current source 42 may adopt this circuit structure. Specifically, the constant current source comprises an operational amplifier INV1 and a second field effect transistor Q2, a reference voltage Uref is connected to a positive phase input end of the operational amplifier INV1, and a negative phase input end of the operational amplifier INV1 is connected to a source S2 of the second field effect transistor Q2; the output end of the operational amplifier INV1 is connected to the gate G2 of the second field effect transistor Q2, and the drain D2 of the second field effect transistor Q2 is connected to the cathode of the LED lighting unit 2 or the cathode of the first diode D1.
For the sake of understanding, the following explains the principle of the LED constant current driving circuit of the present application:
when the voltage of the input line network rectified by the power supply unit 1 is higher than the sum of the minimum starting voltages of the LED lighting unit 2 and the first constant current source 3, the LED lighting unit 2 and the first constant current source 3 start to work, and the constant current generated by the first constant current source 3 passes through the LED lighting unit 2.
When the input net voltage reaches the operating voltage of the LED lighting unit 2, the voltage sampling signal sampled by the first constant current source control circuit 5 is input to the first constant current source 3 along with the rise of the net voltage, and the first constant current source 3 adjusts the magnitude of the output current according to the voltage sampling signal. For example, the higher the input net voltage, the smaller the current output by the first constant current source 3. Meanwhile, when the rectified voltage of the input line network voltage is greater than the starting voltage of the second constant current source 42, the current passes through the charge and discharge adjusting unit 41 composed of the charging capacitor E1, the first diode D1 and the second diode D2, and the charging capacitor E1 is charged with a constant current.
When the rectified voltage is less than or equal to the charging capacitor E1 or the operating voltage of the LED lighting unit 2, the input current stops flowing, and when the voltage of the LED lighting unit 2 is equal to the loop voltage of the charging capacitor E1, the charging capacitor E1 discharges the loop of the LED lighting unit 2 to maintain the load current of the LED lighting unit 2 constant.
Therefore, the charging capacitor E1 of the present application is always charged with a constant current during the charging process, when the first constant current source 3 works, the current flowing through the LED lighting unit 2 is also in a constant current mode, the total current input by the wire network follows the input voltage of the wire network, and the whole LED constant current driving circuit can obtain a higher power factor. When the input current becomes 0, the charging capacitor E1 can continuously discharge the LED lighting unit 2, the current of the LED lighting unit 2 is still controlled by the first constant current source 3, reasonable parameters can be set, and the LED lighting unit 2 can achieve a constant working current when the online network has input current or no input current, so as to achieve no stroboflash.
Correspondingly, the utility model also provides a LED lighting device, including LED luminescence unit 2 and be used for driving LED luminescence unit 2 LED constant current drive circuit, LED constant current drive circuit with LED luminescence unit 2 electricity is connected, LED constant current drive circuit's power supply unit 1, first constant current source 3 and LED luminescence unit 2 series connection, charge-discharge regulating circuit 4 is connected at the both ends of first constant current source 3 and LED luminescence unit 2, and first constant current source control circuit 5 connects LED luminescence unit 2 and first constant current source 3 respectively to supply power, utilize first constant current source 3 to maintain the electric current that flows through LED luminescence unit 2 invariable to LED luminescence unit 2 through power supply unit 1; the first constant current source control circuit 5 receives the sampling voltage of the LED lighting unit 2, outputs the sampling voltage to the first constant current source 3 according to the sampling voltage, and adjusts the first constant current source 3 to a preset current value, so that when the power supply voltage changes, the first constant current source 3 adjusts the output current according to the sampling voltage, thereby obtaining a higher power factor and realizing constant power. Furthermore, the utility model discloses still carry out the invariant of charge-discharge in order to maintain 2 load current of LED luminescence unit through charge-discharge regulating circuit 4, make the circuit reduce the ripple current of LED load when reaching high power factor, reach no stroboscopic purpose. The LED lamp driven by the LED lamp has a better lighting effect.
The foregoing is only a partial embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (11)
1. An LED constant current driving circuit is used for driving an LED light-emitting unit and is characterized by comprising a power supply unit, a first constant current source control circuit and a charging and discharging adjusting circuit; wherein the content of the first and second substances,
the power supply unit, the first constant current source and the LED light-emitting unit are connected in series;
the charging and discharging adjusting circuit is connected to the first constant current source and two ends of the LED light-emitting unit;
the first constant current source control circuit is respectively connected with the LED light-emitting unit and the first constant current source;
the power supply unit is used for supplying power to the LED light-emitting unit; the first constant current source is used for maintaining the current flowing through the LED light-emitting unit to be constant; the first constant current source control circuit is used for receiving the sampling voltage of the LED light-emitting unit and outputting the sampling voltage to the first constant current source so as to adjust the first constant current source to a preset current value; the charging and discharging adjusting circuit is used for charging and discharging to maintain the load current of the LED light-emitting unit constant.
2. The LED constant current driving circuit according to claim 1, wherein the charge-discharge regulating circuit comprises a charge-discharge regulating unit, a second constant current source and a second constant current source control circuit which are connected in series;
the second constant current source control circuit is respectively connected with the charging and discharging regulation unit and a second constant current source;
the second constant current source control circuit is used for receiving the sampling voltage of the charging and discharging regulating unit and outputting the sampling voltage to the second constant current source so that the second constant current source is adjusted to a preset current value.
3. The LED constant-current driving circuit according to claim 2, wherein the charge-discharge regulating unit is configured to discharge the LED light-emitting unit to maintain a constant load current of the LED light-emitting unit when the output voltage of the power supply unit is less than or equal to the operating voltage of the LED light-emitting unit.
4. The LED constant current driving circuit according to claim 2 or 3, wherein the charge and discharge adjusting unit comprises a charge capacitor, a first diode and a second diode;
the anode of the charging capacitor is connected with the anode of the power supply unit, and the cathode of the charging capacitor is respectively connected with the anode of the first diode and the cathode of the second diode;
the negative electrode of the first diode is connected with one end of the second constant current source, and the positive electrode of the second diode is connected with the other end of the second constant current source and the negative electrode of the power supply unit.
5. The LED constant current driving circuit according to claim 2, wherein at least any two of the first constant current source, the first constant current source control circuit, the second constant current source, and the second constant current source control circuit are integrated on the same circuit module.
6. The LED constant current driving circuit according to claim 1, wherein one end of the LED light emitting unit is connected to a positive electrode of a power supply unit, the other end of the LED light emitting unit is connected to one end of the first constant current source, and the other end of the first constant current source is connected to a negative electrode of the power supply unit.
7. The LED constant current driving circuit according to claim 1, wherein one end of the first constant current source is connected to an anode of a power supply unit, the other end of the first constant current source is connected to one end of the LED light emitting unit, and the other end of the LED light emitting unit is connected to a cathode of the power supply unit.
8. The LED constant current driving circuit according to claim 1, wherein one end of the first constant current source control circuit is connected to the LED light emitting unit through a resistor divider, and the other end is connected to the first constant current source.
9. The LED constant current driving circuit according to claim 1, wherein the first constant current source control circuit and/or the second constant current source control circuit comprises a first resistor, a second resistor and a first field-effect transistor, one end of the first resistor and one end of the second resistor are connected with a gate and a source of the first field-effect transistor, the other end of the drain of the first field-effect transistor and the other end of the second resistor are grounded, and the other end of the first resistor is connected with the LED light-emitting unit through resistor voltage division.
10. The LED constant current driving circuit according to claim 1, wherein the first constant current source and/or the second constant current source comprises an operational amplifier and a second field effect transistor, a positive input terminal of the operational amplifier is connected to a reference voltage, a negative input terminal of the operational amplifier is connected to a source of the second field effect transistor, and an output terminal of the operational amplifier is connected to a gate of the second field effect transistor.
11. An LED lighting device, comprising an LED light emitting unit and the LED constant current driving circuit as claimed in any one of claims 1 to 10, wherein the LED constant current driving circuit is electrically connected to the LED light emitting unit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021259184.0U CN212064422U (en) | 2020-06-30 | 2020-06-30 | LED constant current drive circuit and LED lighting device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021259184.0U CN212064422U (en) | 2020-06-30 | 2020-06-30 | LED constant current drive circuit and LED lighting device |
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| CN212064422U true CN212064422U (en) | 2020-12-01 |
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