LED lamp circuit capable of increasing PF value

Abstract

The utility model discloses an LED lamp circuit capable of increasing a PF value. The LED lamp circuit comprises a power supply circuit, a control circuit and an LED lamp. The power supply circuit comprises an input circuit and a step-down rectifying circuit, the input end of the input circuit receives 220V voltage, the output end of the input circuit is connected to the step-down rectifying circuit, and the step-down rectifying circuit reduces the 220V voltage to safe voltage (such as 18V) to supply power to the LED lamp; the control circuit comprises a control chip U1, and the control chip U1 is used for providing a power factor PF value and restraining the charging current of a capacitor CE1 in the control circuit. In the actual design, U1 is a PFC boosting chip, the PF value of the boosting circuit is realized by changing the charging current of the suppression capacitor CE1, the charging electric quantity of the capacitor is the product of time * current, the charging time is prolonged by reducing the current value, and the phases of voltage and current are close to the PF value, so that the supply current of the LED lamp is effectively protected, and the stable work of the LED lamp is ensured.

Description

Technical Field

[0001] The utility model relates to the field of lamp control, in particular to an LED lamp circuit for improving PF value. Background Art

[0002] In lamp control, the general safety solution is to convert high voltage into safe voltage, and then drive the LED lamp to power on. The PF value is the key to the circuit. The power factor (PF) of the AC power supply is defined as the ratio of the actual power (watt) flowing into the load to the apparent power in the circuit. It is the product of current and voltage. It is expressed as PF = actual power (W) / apparent power (VA).

[0003] However, the existing control logic is relatively complex, the PF value stability is poor, and the LED lamp may occasionally be partially broken down, affecting the stability of use (for example, part of the light in the light strip is not on). Utility Model Content

[0004] The main purpose of the utility model is to provide an LED lamp circuit for improving the PF value, aiming to improve the control logic of the circuit, so that the PF value of the circuit tends to be stable, and ensure the stable power supply of the LED lamp.

[0005] To achieve the above object, the utility model provides an LED lamp circuit for improving the PF value, including a power supply circuit, a control circuit and an LED lamp;

[0006] The power supply circuit includes an input circuit and a step-down rectifier circuit, wherein the input end of the input circuit receives a 220V voltage and the output end is connected to the step-down rectifier circuit, and the step-down rectifier circuit reduces the 220V voltage to a safe voltage (e.g., 18V) to supply power to the LED lamp;

[0007] The control circuit includes a control chip U1, and the control chip U1 is used to provide a power factor PF value and suppress the charging current of the capacitor CE1 in the control circuit.

[0008] In the actual design, U1 is a PFC boost chip, which improves the circuit PF value by changing the charging current of the suppression capacitor CE1. The capacitor charging capacity is the product of time * current. By reducing the current value to lengthen the charging time, the phase of the voltage and current is close to improve the PF value, thereby effectively protecting the supply current of the LED lamp and ensuring the stable operation of the LED lamp. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a circuit diagram of the utility model.

[0010] In the figure, 101 is the first branch, 102 is the second branch, 103 is the third branch, 104 is the fourth branch, 105 is the fifth branch, 106 is the sixth branch, 107 is the seventh branch, and 108 is the power supply circuit. DETAILED DESCRIPTION

[0011] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0012] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial...), then the directional indication is only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0013] In addition, if there are descriptions involving "first" or "second" etc. in the embodiments of the utility model, the descriptions of "first" or "second" etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0014] like Figure 1 As shown, an LED lamp circuit for improving PF value includes a power supply circuit, a control circuit and an LED lamp;

[0015] The power supply circuit includes an input circuit and a step-down rectifier circuit, wherein the input end of the input circuit receives a 220V voltage and the output end is connected to the step-down rectifier circuit, and the step-down rectifier circuit reduces the 220V voltage to a safe voltage (e.g., 18V) to supply power to the LED lamp;

[0016] The control circuit includes a control chip U1, and the control chip U1 is used to provide a power factor PF value and suppress the charging current of the capacitor CE1 in the control circuit.

[0017] In the actual design, U1 is a PFC boost chip, which improves the circuit PF value by changing the charging current of the suppression capacitor CE1. The capacitor charging capacity is the product of time * current. By reducing the current value to lengthen the charging time, the phase of the voltage and current is close to improve the PF value, thereby effectively protecting the supply current of the LED lamp and ensuring the stable operation of the LED lamp.

[0018] Specifically, the input circuit includes a first branch and a second branch, the input end of the first branch is connected to the live wire, the input end of the first branch is connected to the neutral wire, the output end of the first branch and the output end of the second branch are connected to the upper end and the lower end of the bridge rectifier diode, thereby converting alternating current into direct current.

[0019] In the embodiment of the utility model, the potential end of the bridge rectifier diode is grounded, and the load end of the bridge rectifier diode is connected to the control circuit.

[0020] Specifically, a thermistor is connected in parallel between the first branch and the second branch, thereby achieving automatic power-off in case of a short circuit.

[0021] In an embodiment of the utility model, the control circuit includes a third branch connected to the load end of the bridge rectifier diode, the third branch is connected to a fourth branch, the fourth branch is provided with the LED lamp, the fourth branch is connected to a power supply circuit, and the fourth branch is a power supply output circuit. Thus, it is ensured that the input current can minimize the damage to the LED lamp while ensuring stability. When the voltage is reduced to 5V, the current of the first LED lamp and the second LED lamp is increased by increasing the current, thereby improving the stability and safety of the LED lamp.

[0022] Specifically, the third branch is connected in parallel with the fifth branch, and pins 6, 7 and 8 of the U1 chip are connected to the fifth branch. The fifth branch is located at the upper and lower ends of pins 6, 7 and 8, and resistors R1 and R2 are respectively provided. Pins 1, 2, 3 and 4 of the U1 chip are connected to the lower end of the fifth branch and a sixth branch connected to the fifth branch is provided, and the end of the sixth branch is connected to the third branch.

[0023] In the embodiment of the utility model, the end of the sixth branch away from the third branch is connected to a ground terminal, and the sixth branch is provided with a voltage stabilizing diode D2 and a resistor R3.

[0024] Specifically, the 4th pin is connected in series with a resistor RS1.

[0025] In the embodiment of the utility model, the first leg 5 is connected to the third branch and is provided with a capacitor CE1, and the seventh branch led out from the leg 5 is connected to the sixth branch.

[0026] Specifically, the U1 is a SR1555 chip. Of course, other chips can also be used. The SR1555 is a multi-channel linear constant current LED driver chip that achieves high power factor (PFC) and low THD by dividing the series-connected LEDs into up to four segments. The chip integrates an over-temperature compensation function. When the internal temperature of the chip exceeds the compensation starting temperature, the output current is linearly reduced to ensure application reliability and avoid flickering. The solution requires only a few components, effectively reducing costs. The SR1555 uses an ESOP8 package, and the chip chassis has a heat sink to reduce the internal temperature of the chip and help maintain a stable output current.

[0027] The above description is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. A LED lamp circuit for improving PF value, characterized in that: Including power supply circuit, control circuit and LED lamp; The power supply circuit includes an input circuit and a step-down rectifier circuit, wherein the input end of the input circuit receives a 220V voltage and the output end is connected to the step-down rectifier circuit, and the step-down rectifier circuit reduces the 220V voltage to a safe voltage to supply power to the LED lamp; The control circuit includes a control chip U1, and the control chip U1 is used to provide a power factor PF value and suppress the charging current of the capacitor CE1 in the control circuit.

2. The LED lamp circuit for improving PF value as claimed in claim 1, characterized in that: The input circuit includes a first branch and a second branch, the input end of the first branch is connected to the live wire, the input end of the first branch is connected to the neutral wire, and the output end of the first branch and the output end of the second branch are connected to the upper end and the lower end of the bridge rectifier diode.

3. The LED lamp circuit for improving PF value as claimed in claim 2, characterized in that: The potential end of the bridge rectifier diode is grounded, and the load end of the bridge rectifier diode is connected to the control circuit.

4. The LED lamp circuit for improving PF value as claimed in claim 2, characterized in that: A thermistor is connected in parallel between the first branch and the second branch.

5. The LED lamp circuit for improving PF value as claimed in claim 3, characterized in that: The control circuit includes a third branch connected to the load end of the bridge rectifier diode, the third branch is connected to a fourth branch, the fourth branch is provided with the LED lamp, the fourth branch is connected to a power supply circuit, and the fourth branch is a power supply output circuit.

6. The LED lamp circuit for improving PF value as claimed in claim 5, characterized in that: The third branch is connected in parallel with a fifth branch, and pins 6, 7 and 8 of the control chip U1 are connected to the fifth branch. The fifth branch is located at the upper and lower ends of pins 6, 7 and 8 and is respectively provided with resistors R1 and R2. Pins 1, 2, 3 and 4 of the control chip U1 are connected to the lower end of the fifth branch and are provided with a sixth branch connected to the fifth branch, and the end of the sixth branch is connected to the third branch.

7. The LED lamp circuit for improving PF value as claimed in claim 6, characterized in that: The end of the sixth branch away from the third branch is connected to a ground terminal, and the sixth branch is provided with a voltage stabilizing diode D2 and a resistor R3.

8. The LED lamp circuit for improving PF value as claimed in claim 7, characterized in that: The 4th pin is connected in series with a resistor RS1.

9. The LED lamp circuit for improving PF value as claimed in claim 7, characterized in that: The U1 is a SR1555 chip.

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