CN211509366U - LED drive circuit based on T-shaped lamp tube - Google Patents
LED drive circuit based on T-shaped lamp tube Download PDFInfo
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- CN211509366U CN211509366U CN201921885986.XU CN201921885986U CN211509366U CN 211509366 U CN211509366 U CN 211509366U CN 201921885986 U CN201921885986 U CN 201921885986U CN 211509366 U CN211509366 U CN 211509366U
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Abstract
The utility model discloses a LED drive circuit based on T type fluorescent tube, include: the input rectifier circuit, the Buck circuit, the IC power supply circuit, the PWM control integrated circuit, the compatible electronic ballast circuit and the output rectifier filter circuit are electrically connected with each other; the output end of the input rectifying circuit is respectively connected with the input end of the Buck circuit and the input end of the IC power supply circuit, the output end of the Buck circuit is connected with the input end of the output rectifying filter circuit, the output end of the IC power supply circuit is connected with the input end of the PWM control integrated circuit, and the output end of the PWM control integrated circuit is respectively connected with the input end of the Buck circuit and the input end of the output rectifying filter circuit; the output end of the compatible electronic ballast circuit is connected with the input end of the output rectifying and filtering circuit; the input end of the input rectifying circuit and the input end of the compatible electronic ballast circuit are connected with a power supply. Adopt the utility model discloses, can realize the compatibility of commercial power single-ended input, commercial power bi-polar input and electronic ballast bi-polar input, the circuit is simple, efficient, stable performance.
Description
Technical Field
The utility model relates to a circuit technical field especially relates to a LED drive circuit based on T type fluorescent tube.
Background
In recent decades, T-type fluorescent lamps have been widely popularized, and although fluorescent lamps have the advantage of energy saving, the service life of fluorescent lamps is short and the harm to the environment is large, so that many manufacturers are gradually stopping the production of fluorescent lamps.
With the progress of science and technology, more and more countries popularize LED lighting products, and compared with fluorescent lamps, LED lighting is more environment-friendly, energy-saving and efficient, and has more advantages in product performance. T-shaped lamps (mainly T5 and T8) are no exception.
However, in the european and american countries, the cost of line modification is very high, and in order to make the installation of LED lighting products more convenient and simple, there is an urgent need for an LED T-type product that can implement single-ended or double-ended AC mains input and is compatible with an electronic ballast (Instant Start Parallel) to replace the conventional fluorescent lamp.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that a LED drive circuit based on T type fluorescent tube is provided, can realize the compatibility of single-ended input of commercial power, commercial power bi-polar input and electronic ballast bi-polar input, the circuit is simple, the system is with low costs, small, efficient, stable performance.
In order to solve the technical problem, the utility model provides a LED drive circuit based on T type fluorescent tube, include: the input rectifier circuit, the Buck circuit, the IC power supply circuit, the PWM control integrated circuit, the compatible electronic ballast circuit and the output rectifier filter circuit are electrically connected with each other; the output end of the input rectifying circuit is respectively connected with the input end of the Buck circuit and the input end of the IC power supply circuit, the output end of the Buck circuit is connected with the input end of the output rectifying filter circuit, the output end of the IC power supply circuit is connected with the input end of the PWM control integrated circuit, and the output end of the PWM control integrated circuit is respectively connected with the input end of the Buck circuit and the input end of the output rectifying filter circuit; the output end of the compatible electronic ballast circuit is connected with the input end of the output rectifying and filtering circuit; the input end of the input rectifying circuit and the input end of the compatible electronic ballast circuit are connected with a power supply, when the input end of the input rectifying circuit and the input end of the compatible electronic ballast circuit are directly connected with the power supply, the input end of the compatible electronic ballast circuit does not work, and when the input end of the input rectifying circuit and the input end of the compatible electronic ballast circuit are connected with the power supply through the electronic ballast, the input end of the compatible electronic ballast circuit works.
As an improvement of the above scheme, the compatible electronic ballast circuit includes a detection capacitor and a ballast sub-circuit, one end of the detection capacitor is connected to the power supply, the other end of the detection capacitor is connected to the input end of the ballast sub-circuit, and the output end of the ballast sub-circuit is connected to the input end of the output rectifying and filtering circuit; when one end of the detection capacitor is directly connected with a power supply, the detection capacitor is disconnected, and the ballast sub-circuit does not work; when one end of the detection capacitor is connected with a power supply through the electronic ballast, the detection capacitor is connected with a circuit, and the ballast sub-circuit works.
As an improvement of the above scheme, the ballast sub-circuit comprises a voltage stabilizing diode, an energy storage capacitor, a discharge resistor, a first rectifying diode, a second rectifying diode and a field effect transistor; the voltage stabilizing diode, the energy storage capacitor and the discharge resistor are connected in parallel, the negative electrode of the voltage stabilizing diode is connected with the grid electrode of the field effect transistor and is connected with the detection capacitor through the first rectifying diode, the positive electrode of the voltage stabilizing diode is connected with the source electrode of the field effect transistor and is connected with the detection capacitor through the second rectifying diode, and the drain electrode of the field effect transistor is connected with the output rectifying and filtering circuit.
As an improvement of the above scheme, the PWM control integrated circuit includes a PWM control chip, a compensation capacitor, a sampling resistor group, a sampling capacitor, and a detection resistor; the PWM control chip is provided with a chip power supply pin, a compensation pin, an output current sampling pin, a loop feedback pin, a driving pin and a grounding pin; the chip power supply pin is connected with the IC power supply circuit, the compensation pin is grounded through a compensation capacitor, the output current sampling pin is grounded through a sampling resistor group and connected with the output rectifying and filtering circuit through a sampling resistor group and a sampling capacitor, the loop feedback pin is connected with the IC power supply circuit and grounded through a detection resistor, the drive pin is connected with the Buck circuit, and the grounding pin is connected with the ground.
As an improvement of the above scheme, the Buck circuit comprises a voltage reduction resistor, a voltage reduction capacitor, a voltage reduction diode and a voltage reduction inductor; one end of the voltage reduction resistor is connected with the PWM control integrated circuit through the voltage reduction capacitor, and the other end of the voltage reduction resistor is connected with the input rectification circuit; the positive pole of the voltage reduction diode is connected with the PWM control integrated circuit, and the negative pole of the voltage reduction diode is connected with the input rectification circuit; one end of the voltage reduction inductor is connected with the PWM control integrated circuit, and the other end of the voltage reduction inductor is connected with the output rectifying and filtering circuit.
As an improvement of the above scheme, the IC power supply circuit includes a charging resistor group, a charging capacitor, a charging diode, a first charging resistor, a second charging resistor, and a charging inductor; one end of the charging resistor group is connected with the input rectifying circuit, and the other end of the charging resistor group is connected with the PWM control integrated circuit; one end of the charging capacitor is connected with the input rectifying circuit, and the other end of the charging capacitor is connected with the PWM control integrated circuit; one end of the charging inductor is grounded, and the other end of the charging inductor is connected with the PWM control integrated circuit through the first charging resistor and is connected with the PWM control integrated circuit through the charging diode and the second charging resistor in sequence.
As an improvement of the scheme, the LED driving circuit further comprises any one or a combination of a double-end contact protection circuit, an overvoltage and overcurrent protection circuit and an EMC filter circuit.
As an improvement of the above scheme, when the power supply is input to the LED load through a single end of the LED driving circuit, the double-end contact protection circuit is not turned on; when the power supply is input to the LED load through the two ends of the LED driving circuit, the two-end contact protection circuit is conducted.
As an improvement of the above scheme, the overvoltage and overcurrent protection circuit includes a first voltage dependent resistor and a second voltage dependent resistor, the first voltage dependent resistor is disposed at two ends of the input rectification circuit, and the second voltage dependent resistor is connected to the reverse output end of the input rectification circuit.
As an improvement of the above scheme, the EMC filter circuit includes a first common mode inductor set, a second common mode inductor set, a first filter capacitor, a second filter capacitor, a third filter capacitor, and a fourth filter capacitor; the first filter capacitor and the second filter capacitor are arranged at two ends of the input rectifying circuit; the first common-mode inductor group is connected with one output end of the input rectifying circuit, and the second common-mode inductor group is connected with the other output end of the input rectifying circuit; one end of the third filter capacitor is connected with one input end of the input rectification circuit, the other end of the third filter capacitor is connected with the compatible electronic ballast circuit, one end of the fourth filter capacitor is connected with the other input end of the input rectification circuit, and the other end of the fourth filter capacitor is connected with the compatible electronic ballast circuit.
Implement the utility model discloses, following beneficial effect has:
the utility model is suitable for a T type fluorescent tube can realize that AC commercial power single-ended input, AC commercial power bi-polar input and electronic ballast bi-polar input are compatible, has advantages such as the circuit is simple, the system is with low costs, small, efficient and stable performance. Specifically, when the T-shaped lamp tube is connected with the single-end or double-end input of the AC commercial power, the compatible electronic ballast circuit does not work, and the PWM control integrated circuit drives the LED load. When the T-shaped lamp tube is connected with the input end of the two ends of the electronic ballast, the output of the PWM control integrated circuit is zero, and the electronic ballast is compatible with the operation of the electronic ballast circuit to drive the LED load.
Drawings
FIG. 1 is a schematic structural diagram of a T-shaped lamp tube connected to a single-ended input of commercial power;
FIG. 2 is a schematic structural diagram of a T-shaped lamp tube connected to a double-end input of commercial power;
FIG. 3 is a schematic diagram of a T-tube configuration when connected to a dual input of an electronic ballast;
fig. 4 is a schematic structural diagram of a first embodiment of the LED driving circuit based on the T-shaped lamp tube of the present invention;
fig. 5 is a circuit diagram of a first embodiment of the LED driving circuit based on the T-shaped lamp tube of the present invention;
fig. 6 is a schematic structural diagram of a second embodiment of the LED driving circuit based on the T-shaped lamp tube of the present invention;
fig. 7 is a circuit diagram of a second embodiment of the LED driving circuit based on the T-shaped lamp tube of the present invention;
fig. 8 is a schematic structural diagram of a third embodiment of the LED driving circuit based on the T-shaped lamp tube of the present invention;
fig. 9 is a circuit diagram of a third embodiment of the LED driving circuit based on the T-shaped lamp tube.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings.
The utility model discloses LED drive circuit based on T type fluorescent tube is applicable to T type fluorescent tube, can realize single-ended commercial power, bi-polar commercial power and north american electronic ballast (Instant Start Parallel) input compatibility, has advantages such as circuit is simple, the system is with low costs, small, efficient and stable performance.
Referring to fig. 4, fig. 4 shows a first embodiment of the LED driving circuit based on T-shaped lamp tube of the present invention, which includes an input rectifying circuit 1, a Buck circuit 2, an IC power supply circuit 3, a PWM control integrated circuit 4, a compatible electronic ballast circuit 5 and an output rectifying and filtering circuit 6, which are electrically connected to each other. The input rectifying circuit 1 is used for rectifying an input power supply into direct current; the Buck circuit 2 is used for reducing voltage; the IC power supply circuit 3 is used for supplying power to the PWM control integrated circuit 4; the PWM control integrated circuit 4 is configured to provide a control PWM (Pulse Width Modulation) signal to the Buck circuit 2; the compatible electronic ballast circuit 5 is used for compatible electronic ballast; the output rectifying and filtering circuit 6 is used for rectifying and filtering the output current. Specifically, the method comprises the following steps:
the output end of the input rectification circuit 1 is respectively connected with the input end of the Buck circuit 2 and the input end of the IC power supply circuit 3, the output end of the Buck circuit 2 is connected with the input end of the output rectification filter circuit 6, the output end of the IC power supply circuit 3 is connected with the input end of the PWM control integrated circuit 4, the output end of the PWM control integrated circuit 4 is respectively connected with the input end of the Buck circuit 2 and the input end of the output rectification filter circuit 6, and the output end of the output rectification filter circuit 6 is connected with the LED load. The LED load is preferably an LED T-shaped lamp tube.
The output end of the compatible electronic ballast circuit 5 is connected with the input end of the output rectifying and filtering circuit 6.
The input end of the input rectifying circuit 1 and the input end of the compatible electronic ballast circuit 5 are connected with a power supply, when the input end of the input rectifying circuit 1 and the input end of the compatible electronic ballast circuit 5 are directly connected with the power supply, the input end of the compatible electronic ballast circuit 5 does not work, and when the input end of the input rectifying circuit 1 and the input end of the compatible electronic ballast circuit 5 are connected with the power supply through the electronic ballast, the input end of the compatible electronic ballast circuit 5 works.
It should be noted that the utility model discloses can connect to exchange single-ended input of commercial power, bi-polar input or electronic ballast bi-polar input. When the LED load is connected with AC commercial power single-end input, the compatible electronic ballast circuit 5 does not work, and the input rectifying circuit 1, the Buck circuit 2, the IC power supply circuit 3, the PWM control integrated circuit 4 and the output rectifying filter circuit 6 work to drive the LED load to emit light; when the LED load is connected with AC commercial power double-end input, the compatible electronic ballast circuit 5 does not work, and the input rectifying circuit 1, the Buck circuit 2, the IC power supply circuit 3, the PWM control integrated circuit 4 and the output rectifying filter circuit 6 work to drive the LED load to emit light; when the LED load is connected with the input of the two ends of the electronic ballast, the output of the PWM control integrated circuit 4 is '0', and the input rectifying circuit 1, the compatible electronic ballast circuit 5 and the output rectifying filter circuit 6 work to drive the LED load to emit light.
Therefore, the utility model discloses a compatible electronic ballast circuit 5's operating condition realizes exchanging single-ended input of commercial power, bi-polar input or electronic ballast bi-polar input, and the flexibility is strong.
As shown in fig. 5, the compatible electronic ballast circuit 5 includes a detection capacitor C1 and a ballast sub-circuit 51, one end of the detection capacitor C1 is connected to the power supply, the other end of the detection capacitor C1 is connected to the input end of the ballast sub-circuit 51, and the output end of the ballast sub-circuit 51 is connected to the input end of the output rectifying and filtering circuit 6; when one end of the detection capacitor C1 is directly connected with a power supply, the detection capacitor C1 is disconnected, and the ballast sub-circuit 51 does not work; when one end of the detection capacitor C1 is connected to the power supply through the electronic ballast, the detection capacitor C1 is turned on, and the ballast sub-circuit 51 operates.
It should be noted that the detection capacitor C1 has the characteristic of high frequency passing and low frequency blocking, when the LED load is connected to the single-ended/double-ended input of the AC mains supply, the current is cut off midway due to the low current frequency of the AC mains supply, the detection capacitor C1 is open, and the ballast sub-circuit 51 does not work; when the LED load is connected to the two-terminal input of the electronic ballast, the current flows all the time due to the high frequency of the current output by the electronic ballast, the sensing capacitor C1 is turned on, and the ballast sub-circuit 51 operates. Therefore, the utility model discloses a detecting capacitance C1's break-make state confirms compatible electronic ballast circuit 5's operating condition, thereby make the utility model discloses three kinds of circumstances such as alternating current commercial power single-ended input, bi-polar input or electronic ballast bi-polar input, the system is with low costs, small, the flexibility is strong.
Further, the ballast sub-circuit 51 includes a zener diode Z1, an energy storage capacitor C2, a discharge resistor R1, a first rectifier diode D1, a second rectifier diode D2, and a field effect transistor Q1; the voltage stabilizing diode Z1, the energy storage capacitor C2 and the discharge resistor R1 are connected in parallel, the negative electrode of the voltage stabilizing diode Z1 is connected with the grid electrode of the field effect transistor Q1 and is connected with the detection capacitor C1 through the first rectifier diode D1, the positive electrode of the voltage stabilizing diode Z1 is connected with the source electrode of the field effect transistor Q1 and is connected with the detection capacitor C1 through the second rectifier diode D2, and the drain electrode of the field effect transistor Q1 is connected with the output rectifying and filtering circuit 6.
The input rectifying circuit 1 is a rectifying bridge, and the output rectifying filter circuit 6 is an RC oscillating circuit.
The Buck circuit 2 comprises a voltage reduction resistor R2, a voltage reduction capacitor C3, a voltage reduction diode D3 and a voltage reduction inductor TIB; one end of the voltage reduction resistor R2 is connected with the PWM control integrated circuit 4 through a voltage reduction capacitor C3, and the other end of the voltage reduction resistor R2 is connected with the input rectification circuit 1; the anode of the voltage reduction diode D3 is connected with the PWM control integrated circuit 4, and the cathode of the voltage reduction diode D3 is connected with the input rectification circuit 1; one end of the voltage reduction inductor TIB is connected with the PWM control integrated circuit 4, and the other end of the voltage reduction inductor TIB is connected with the output rectifying and filtering circuit 6.
The IC power supply circuit 3 comprises a charging resistor group (R3, R4), a charging capacitor C4, a charging diode D4, a first charging resistor R5, a second charging resistor R6 and a charging inductor TIA; one end of the charging resistor group (R3, R4) is connected with the input rectification circuit 1, and the other end is connected with the PWM control integrated circuit 4; one end of the charging capacitor C4 is connected with the input rectification circuit 1, and the other end is connected with the PWM control integrated circuit 4; one end of the charging inductor TIA is grounded, and the other end of the charging inductor TIA is connected with the PWM control integrated circuit 4 through the first charging resistor R5 and is connected with the PWM control integrated circuit 4 through the charging diode D4 and the second charging resistor R6 in sequence. Preferably, the charging resistor group (R3, R4) comprises at least two resistors connected in series with each other.
The PWM control integrated circuit 4 comprises a PWM control chip U1, a compensation capacitor C5, a sampling resistor group (R7 and R8), a sampling capacitor C6 and a detection resistor R9; the PWM control chip U1 is provided with a chip power supply pin VCC, a compensation pin COMP, an output current sampling pin SNP, a loop feedback pin FB, a driving pin DRAIN and a grounding pin GND; the chip power supply pin VCC is connected with the IC power supply circuit 3, the compensation pin COMP is grounded through a compensation capacitor C5, the output current sampling pin SNP is grounded through a sampling resistor group (R7, R8) and is connected with the output rectifying and filtering circuit 6 through a sampling resistor group (R7, R8) and a sampling capacitor C6, the loop feedback pin FB is connected with the IC power supply circuit 3 and is grounded through a detection resistor R9, the drive pin DRAIN is connected with the Buck circuit 2, and the ground pin GND is connected with the ground. Preferably, the sampling resistor group (R7, R8) at least comprises two resistors which are connected in parallel with each other.
Specifically, the PWM controller U1 may be, but is not limited to, a JW1602D chip, and the PWM controller U1 is packaged with an SO8-8 package, and pins thereof are defined as follows:
it should be noted that JW1602D is a chip specially made for LED, and can be applied to a non-isolated buck LED system with a source illumination design for constant current driving PFC control. The JW1602D can achieve excellent constant current characteristics with few peripheral devices, and has low system cost and high efficiency.
The present invention will be described in further detail with reference to specific circuits.
(1) When the LED load is connected with the single-end/double-end input of AC commercial power, the compatible electronic ballast circuit 5 does not work, and the input rectifying circuit 1, the Buck circuit 2, the IC power supply circuit 3, the PWM control integrated circuit 4 and the output rectifying filter circuit 6 work to drive the LED load to emit light.
Starting:
after the system is powered on, the VCC of the PWM control chip U1 is charged by the bus voltage through the charging resistor groups (R3, R4), when the VCC voltage of the PWM control chip U1 reaches 22V, the gate driving signal starts to switch, the PWM control chip U1 enters a stable working state, and at the moment, the output voltage supplies power to the PWM control chip. The PWM control chip U1 is internally provided with a VCC voltage protection function, when VCC exceeds 35V, the 6mA current in the PWM control chip U1 pulls down VCC, and once VCC voltage is lower than 7V, the PWM control chip U1 stops working.
Loop compensation:
the integrating element is introduced into the input current loop by connecting a compensation capacitor C5 to a compensation pin COMP of the PWM control chip U1. In off-line application, the crossing frequency is far greater than the secondary power frequency of 120Hz or 100 Hz. In order to achieve better PFC (power factor correction) effect, the compensation pin COMP needs to be connected with an appropriate compensation capacitor C5.
Constant current control:
the PWM control chip U1 controls the output current of the system according to the voltage signal on the sampling resistor. The calculation formula of the average value of the output current of the system is as follows: ILED ═ 300/Rcs (ma), where Rcs is the resistance of the sampling resistor group (R7, R8) between the output current sampling pin SNP and the ground pin GND.
Critical conduction mode:
the PWM control chip U1 operates in the inductor current continuous conduction mode. When the PWM control chip U1 controls the external MOSFET to be conducted, the current flowing through the inductor starts to rise from zero; when the PWM control chip U1 controls the external MOSFET to be turned off, the current flowing through the inductor starts to drop from the peak value, and when the current of the inductor drops to zero, the PWM control chip U1 controls the MOSFET to be turned on again.
(2) When the LED load is connected with the input of the double-end of the electronic ballast, the PWM control chip U1 is not needed to work, and the input rectifying circuit 1, the output rectifying and filtering circuit 6 and the compatible electronic ballast circuit 5 drive the LED load to emit light.
When the compatible electronic ballast circuit 5 is turned on, the potential of the position point a of the compatible electronic ballast circuit 5 becomes zero potential, so that the output of the PWM control chip U1 is zero, the operation of the PWM control chip U1 is responsible for the LED not to work, and thus the LED load compatible electronic ballast can also work normally.
Therefore, the utility model is suitable for a T type fluorescent tube can realize single-ended commercial power, bi-polar commercial power and electronic ballast bi-polar input compatibility, has advantages such as circuit is simple, system cost is low, small, efficient and stable performance.
Referring to fig. 6 and 7, fig. 6 and 7 show a second embodiment of the LED driving circuit based on T-shaped lamp tube of the present invention, which is different from the first embodiment shown in fig. 4 and 5, and the present embodiment further includes a double-end contact protection circuit 7. A protection chip U2 is arranged in the double-end contact protection circuit 7, and when a power supply is input into an LED load through a single end of the LED drive circuit, the double-end contact protection circuit 7 is not conducted; when power is input to the LED load through the two ends of the LED driving circuit, the two-end contact protection circuit 7 is turned on. The protection chip is preferably LT2600, but not limited thereto.
After the system is powered on, if only one pin at one end of the T-shaped lamp tube is connected, the double-end contact protection circuit 7 is not conducted, and the circuit cannot work; when pin pins at two ends of the T-shaped lamp tube are simultaneously connected, the double-end contact protection circuit 7 is conducted. Therefore, the double-end contact protection circuit 7 can ensure that when only one pin of the T-shaped lamp tube is connected, the other pin does not work, so that electric shock accidents are avoided when a user contacts the pin at the other end.
Referring to fig. 8 and 9, fig. 8 and 9 show a second embodiment of the LED driving circuit based on T-shaped lamp tube of the present invention, which is different from the first embodiment shown in fig. 4 and 5, the present embodiment further includes a double-end contact protection circuit 7, an overvoltage and overcurrent protection circuit 8, and an EMC filter circuit 9.
The overvoltage and overcurrent protection circuit 8 comprises a first voltage dependent resistor VR1 and a second voltage dependent resistor VR2, the first voltage dependent resistor VR1 is arranged at two ends of the input rectification circuit 1, and the second voltage dependent resistor VR2 is connected with the reverse output end of the input rectification circuit 1.
The EMC filter circuit 9 comprises a first common mode inductance group (L1, R10), a second common mode inductance group (L2, R11), a first filter capacitor C7, a second filter capacitor C8, a third filter capacitor C9 and a fourth filter capacitor C10; the first filter capacitor C7 and the second filter capacitor C8 are arranged at two ends of the input rectifying circuit 1; the first common mode inductor group (L1, R10) is connected with one output end of the input rectification circuit 1, and the second common mode inductor group (L2, R11) is connected with the other output end of the input rectification circuit 1; one end of the third filter capacitor C9 is connected with one input end of the input rectification circuit 1, the other end of the third filter capacitor C9 is connected with the compatible electronic ballast circuit 5, one end of the fourth filter capacitor C10 is connected with the other input end of the input rectification circuit 1, and the other end of the fourth filter capacitor C10 is connected with the compatible electronic ballast circuit 5. The first common mode inductor group (L1, R10) and the second common mode inductor group (L2, R11) both comprise an air core inductor and a resistor which are connected in parallel, and can effectively filter ElectroMagnetic Interference (EMI) signals.
When the LED load is connected with AC commercial power single-end input, the compatible electronic ballast circuit 5 and the double-end contact protection circuit 7 do not work, and the input rectifying circuit 1, the overvoltage and overcurrent protection circuit 8, the EMC filter circuit 9, the Buck circuit 2, the IC power supply circuit 3, the PWM control integrated circuit 4 and the output rectifying filter circuit 6 work to drive the LED load to emit light; when the LED load is connected with AC commercial power double-end input, the compatible electronic ballast circuit 5 does not work, and the input rectifying circuit 1, the overvoltage and overcurrent protection circuit 8, the EMC filter circuit 9, the double-end contact protection circuit 7, the Buck circuit 2, the IC power supply circuit 3, the PWM control integrated circuit 4 and the output rectifying filter circuit 6 work to drive the LED load to emit light; when the LED load is connected with the input of the two ends of the electronic ballast, the output of the PWM control integrated circuit 4 is '0', and the input rectifying circuit 1, the overvoltage and overcurrent protection circuit 8, the EMC filter circuit 9, the two-end contact protection circuit 7, the compatible electronic ballast circuit 5 and the output rectifying filter circuit 6 work to drive the LED load to emit light.
It should be noted that the double-end contact protection circuit 7, the overvoltage and overcurrent protection circuit 8 and the EMC filter circuit 9 are independent from each other, and an engineer can add or delete the double-end contact protection circuit 7, the overvoltage and overcurrent protection circuit 8 or the EMC filter circuit 9 in the LED driving circuit according to actual conditions. For example, the double-end contact protection circuit 7, the overvoltage and overcurrent protection circuit 8 or the EMC filter circuit 9 may be separately provided, the double-end contact protection circuit 7 and the overvoltage and overcurrent protection circuit 8, the overvoltage and overcurrent protection circuit 8 and the EMC filter circuit 9, the double-end contact protection circuit 7 and the EMC filter circuit 9 may be provided at the same time, the double-end contact protection circuit 7, the overvoltage and overcurrent protection circuit 8 and the EMC filter circuit 9 may be provided at the same time, and flexibility is high.
By the above, the utility model is suitable for a T type fluorescent tube can realize that AC commercial power single-ended input, AC commercial power bi-polar input and electronic ballast bi-polar input are compatible, have advantages such as the circuit is simple, the system is with low costs, small, efficient and stable performance. Specifically, when the T-type lamp tube is connected with the single-ended or double-ended input of the AC mains, the compatible electronic ballast circuit 5 does not operate, and the PWM control integrated circuit 4 drives the LED load. When the T-shaped lamp tube is connected with the input end of the two ends of the electronic ballast, the output of the PWM control integrated circuit 4 is zero, and the compatible electronic ballast circuit 5 works to drive the LED load.
The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations are also considered as the protection scope of the present invention.
Claims (10)
1. An LED drive circuit based on a T-shaped lamp tube is characterized by comprising an input rectification circuit, a Buck circuit, an IC power supply circuit, a PWM control integrated circuit, a compatible electronic ballast circuit and an output rectification filter circuit which are electrically connected with each other;
the output end of the input rectifying circuit is respectively connected with the input end of the Buck circuit and the input end of the IC power supply circuit, the output end of the Buck circuit is connected with the input end of the output rectifying filter circuit, the output end of the IC power supply circuit is connected with the input end of the PWM control integrated circuit, and the output end of the PWM control integrated circuit is respectively connected with the input end of the Buck circuit and the input end of the output rectifying filter circuit;
the output end of the compatible electronic ballast circuit is connected with the input end of the output rectifying and filtering circuit;
the input end of the input rectifying circuit and the input end of the compatible electronic ballast circuit are connected with a power supply, when the input end of the input rectifying circuit and the input end of the compatible electronic ballast circuit are directly connected with the power supply, the input end of the compatible electronic ballast circuit does not work, and when the input end of the input rectifying circuit and the input end of the compatible electronic ballast circuit are connected with the power supply through the electronic ballast, the input end of the compatible electronic ballast circuit works.
2. The LED driving circuit according to claim 1, wherein the compatible electronic ballast circuit comprises a detection capacitor and a ballast sub-circuit, one end of the detection capacitor is connected to the power supply, the other end of the detection capacitor is connected to an input terminal of the ballast sub-circuit, and an output terminal of the ballast sub-circuit is connected to an input terminal of the output rectifying and filtering circuit;
when one end of the detection capacitor is directly connected with a power supply, the detection capacitor is disconnected, and the ballast sub-circuit does not work;
when one end of the detection capacitor is connected with a power supply through the electronic ballast, the detection capacitor is connected with a circuit, and the ballast sub-circuit works.
3. The LED driver circuit of claim 2, wherein the ballast subcircuit includes a zener diode, an energy storage capacitor, a discharge resistor, a first rectifying diode, a second rectifying diode, and a field effect transistor;
the voltage stabilizing diode, the energy storage capacitor and the discharge resistor are connected in parallel, the negative electrode of the voltage stabilizing diode is connected with the grid electrode of the field effect transistor and is connected with the detection capacitor through the first rectifying diode, the positive electrode of the voltage stabilizing diode is connected with the source electrode of the field effect transistor and is connected with the detection capacitor through the second rectifying diode, and the drain electrode of the field effect transistor is connected with the output rectifying and filtering circuit.
4. The LED driving circuit according to claim 1, wherein the PWM control integrated circuit includes a PWM control chip, a compensation capacitor, a sampling resistor group, a sampling capacitor, and a detection resistor;
the PWM control chip is provided with a chip power supply pin, a compensation pin, an output current sampling pin, a loop feedback pin, a driving pin and a grounding pin;
the chip power supply pin is connected with the IC power supply circuit, the compensation pin is grounded through a compensation capacitor, the output current sampling pin is grounded through a sampling resistor group and connected with the output rectifying and filtering circuit through a sampling resistor group and a sampling capacitor, the loop feedback pin is connected with the IC power supply circuit and grounded through a detection resistor, the drive pin is connected with the Buck circuit, and the grounding pin is connected with the ground.
5. The LED driving circuit according to claim 1, wherein the Buck circuit includes a Buck resistor, a Buck capacitor, a Buck diode, and a Buck inductor;
one end of the voltage reduction resistor is connected with the PWM control integrated circuit through the voltage reduction capacitor, and the other end of the voltage reduction resistor is connected with the input rectification circuit;
the positive pole of the voltage reduction diode is connected with the PWM control integrated circuit, and the negative pole of the voltage reduction diode is connected with the input rectification circuit;
one end of the voltage reduction inductor is connected with the PWM control integrated circuit, and the other end of the voltage reduction inductor is connected with the output rectifying and filtering circuit.
6. The LED driving circuit according to claim 1, wherein the IC power supply circuit comprises a charging resistor group, a charging capacitor, a charging diode, a first charging resistor, a second charging resistor and a charging inductor;
one end of the charging resistor group is connected with the input rectifying circuit, and the other end of the charging resistor group is connected with the PWM control integrated circuit;
one end of the charging capacitor is connected with the input rectifying circuit, and the other end of the charging capacitor is connected with the PWM control integrated circuit;
one end of the charging inductor is grounded, and the other end of the charging inductor is connected with the PWM control integrated circuit through the first charging resistor and is connected with the PWM control integrated circuit through the charging diode and the second charging resistor in sequence.
7. The LED driving circuit as claimed in claim 1, wherein the LED driving circuit further comprises any one or a combination of a two-terminal contact protection circuit, an over-voltage and over-current protection circuit and an EMC filter circuit.
8. The LED driver circuit according to claim 7,
when the power supply is input into the LED load through the single end of the LED driving circuit, the double-end contact protection circuit is not conducted;
when the power supply is input to the LED load through the two ends of the LED driving circuit, the two-end contact protection circuit is conducted.
9. The LED driving circuit according to claim 7, wherein the over-voltage and over-current protection circuit comprises a first voltage dependent resistor and a second voltage dependent resistor, the first voltage dependent resistor is disposed at two ends of the input rectification circuit, and the second voltage dependent resistor is connected to the inverted output end of the input rectification circuit.
10. The LED driver circuit of claim 7, wherein the EMC filter circuit includes a first common mode inductance set, a second common mode inductance set, a first filter capacitance, a second filter capacitance, a third filter capacitance, and a fourth filter capacitance;
the first filter capacitor and the second filter capacitor are arranged at two ends of the input rectifying circuit;
the first common-mode inductor group is connected with one output end of the input rectifying circuit, and the second common-mode inductor group is connected with the other output end of the input rectifying circuit;
one end of the third filter capacitor is connected with one input end of the input rectifying circuit, the other end of the third filter capacitor is connected with the compatible electronic ballast circuit,
one end of the fourth filter capacitor is connected with the other input end of the input rectifying circuit, and the other end of the fourth filter capacitor is connected with the compatible electronic ballast circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921885986.XU CN211509366U (en) | 2019-11-04 | 2019-11-04 | LED drive circuit based on T-shaped lamp tube |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921885986.XU CN211509366U (en) | 2019-11-04 | 2019-11-04 | LED drive circuit based on T-shaped lamp tube |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110798927A (en) * | 2019-11-04 | 2020-02-14 | 佛山电器照明股份有限公司 | LED drive circuit based on T-shaped lamp tube |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110798927A (en) * | 2019-11-04 | 2020-02-14 | 佛山电器照明股份有限公司 | LED drive circuit based on T-shaped lamp tube |
| CN110798927B (en) * | 2019-11-04 | 2024-07-02 | 佛山电器照明股份有限公司 | LED drive circuit based on T-shaped lamp tube |
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