An LED dimming circuit for aircraft lighting

Abstract

The present invention discloses an LED dimming circuit for aircraft lighting, comprising an anti-reverse surge suppression unit, a voltage reference unit, a dimming signal unit and a DC / DC conversion unit, wherein the DC / DC conversion unit has a DC / DC power supply module N1, and the dimming signal unit is composed of a capacitor C10, a capacitor C11, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a potentiometer RP and a reference source U3. The present invention has the advantages that the circuit is flexible to adjust, the circuit parameters can be appropriately changed, and the adjustable voltage range is 0V to Vm to meet different output current requirements.

Description

Technical Field

[0001] The invention relates to the field of aircraft lighting, in particular to an LED dimming circuit for aircraft lighting. Background Art

[0002] LED dimming drive modes include voltage dimming and PWM dimming. Voltage dimming has low efficiency and small dimming range, and is suitable for low-power products with low dimming accuracy requirements. PWM dimming has high dimming accuracy and high efficiency, and is usually implemented by combining software and hardware, and the circuit is relatively complex. At present, the commonly used aircraft lighting voltage dimming circuit can use an output adjustable monolithic integrated regulator, such as the LM117 series, which can achieve dimming control, but the LM117 series has limited load capacity, high heat generation, and a narrow dimming range.

[0003] After the above investigation and data collection, it is particularly important to design a circuit that can adapt to higher power and does not require high dimming accuracy. Summary of the invention

[0004] The purpose of the present invention is to solve the problem of limited load capacity of the LM117 series of LED dimming in the prior art, and to provide a novel LED dimming circuit for aircraft lighting.

[0005] In order to achieve this purpose, the technical solution of the present invention is as follows: an LED dimming circuit for aircraft lighting, comprising an anti-reverse surge suppression unit, a voltage reference unit, a dimming signal unit and a DC / DC conversion unit, wherein the DC / DC conversion unit has a DC / DC power supply module N1, the dimming signal unit is composed of a capacitor C10, a capacitor C11, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a potentiometer RP and a reference source U3, the output end of the voltage reference unit is respectively connected to the first end of the resistor R4 and the first end of the capacitor C10, ... The second end of the resistor R4 is connected to the cathode of the reference source U3, the first end of the resistor R5, the adjustment end and the first end of the potentiometer RP, the first end of the capacitor C11 and the TRIM end of the DC / DC power supply module N1, the second end of the resistor R5 is respectively connected to the second end of the potentiometer RP and the first end of the resistor R6, the second end of the resistor R6 is respectively connected to the first end of the resistor R7 and the reference level of the reference source U3, the second end of the capacitor C10, the second end of the capacitor C11, the anode of the reference source U3 and the resistor R7 are all grounded.

[0006] As a preferred solution for an LED dimming circuit for aircraft lighting, the reference source U3 adopts TL431D.

[0007] As a preferred solution for an LED dimming circuit for aircraft lighting, the DC / DC power supply module is an integrated circuit JZF5B75-24S28A.

[0008] As a preferred solution of the LED dimming circuit for aircraft lighting, the DC / DC conversion unit further comprises a resistor R1, a resistor R2, a resistor R3, a resistor RG, a capacitor CY1, a capacitor CY2, a capacitor CY3, a capacitor CY4, a capacitor C8, a capacitor C9, a switch BK, a transistor Q1 and an optical coupler U2, the output end of the voltage reference unit is respectively connected to the first end of the resistor R1 and the first end of the switch BK, the second end of the resistor R1 is respectively connected to the collector of the transistor Q1 and the first end of the primary of the optical coupler U2, the second end of the switch BK is respectively connected to the first end of the resistor R2, the second end of the resistor R2 is respectively connected to the base of the transistor Q1 and the first end of the resistor R3, the first end of the secondary of the optical coupler U2 is respectively connected to the CNT end of the DC / DC power module N1, and the second end of the secondary of the optical coupler U2 is respectively connected to the -Vin end of the DC / DC power module N1 and the The first end of the capacitor CY2 and the +Vin terminal of the DC / DC power module N1 are connected to the second end of the capacitor CY1 and the voltage source, the second end of the capacitor CY3 is connected to the +Vout and +S terminals of the DC / DC power module N1, the first end of the capacitor C8, the first end of the capacitor C9 and the L+ terminal, the first end of the resistor RG is grounded GND, the second end of the resistor RG is grounded DGND, the second end of the capacitor CY2, the first end of the capacitor CY1, the first end of the capacitor CY3 and the second end of the capacitor CY4 are all grounded EARTH, the second end of the resistor R3, the emitter of the transistor Q1 and the second end of the primary of the optocoupler U2 are all grounded DGND, the first end of the capacitor CY4 is respectively connected to the -S and -Vout terminals of the DC / DC power module N1, the second end of the capacitor C8, and the second end of the capacitor C9 are all grounded GND.

[0009] Compared with the prior art, the beneficial effects of the present invention are at least as follows: the DC / DC conversion unit is based on a 75W DC / DC power module as a core component, and the input of its TRIM terminal is an adjustable voltage signal to change the output voltage of the DC / DC power module to achieve the purpose of LED brightness adjustment; the circuit adjustment is flexible, and the circuit parameters can be appropriately changed to meet different output current requirements. The adjustable voltage range is 0V~Vm (the maximum load is determined by the DC / DC power module and can reach 75W). BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The figure is a block diagram of the working principle of an embodiment of the present invention.

[0011] Figure 2FIG. 4 is a circuit diagram of a dimming signal unit according to an embodiment of the present invention.

[0012] Figure 3 FIG. 4 is a circuit diagram of a DC / DC conversion unit in one embodiment of the present invention.

[0013] Figure 4 FIG. 4 is a dimming curve diagram after correction according to an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The present invention is further described in detail below by means of specific embodiments connected with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0015] See also Figures 1 to 3 The figure shows an LED dimming circuit for aircraft lighting, which includes an anti-reverse surge suppression unit, a voltage reference unit, a dimming signal unit and a DC / DC conversion unit. The DC / DC conversion unit has a DC / DC power supply module N1, and the dimming signal unit consists of a capacitor C10, a capacitor C11, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a potentiometer RP and a reference source U3. The output end of the voltage reference unit is respectively connected to the first end of the resistor R4 and the first end of the capacitor C10, the second end of the resistor R4 is connected to the cathode of the reference source U3, the first end of the resistor R5, the adjustment end and the first end of the potentiometer RP, the first end of the capacitor C11 and the TRIM end of the DC / DC power supply module N1, the second end of the resistor R5 is respectively connected to the second end of the potentiometer RP and the first end of the resistor R6, the second end of the resistor R6 is respectively connected to the first end of the resistor R7 and the reference level of the reference source U3, the second end of the capacitor C10, the second end of the capacitor C11, the anode of the reference source U3 and the resistor R7 are all grounded.

[0016] The reference source U3 adopts TL431D.

[0017] The DC / DC power supply module is an integrated circuit JZF5B75-24S28A.

[0018] The DC / DC conversion unit also includes a resistor R1, a resistor R2, a resistor R3, a resistor RG, a capacitor CY1, a capacitor CY2, a capacitor CY3, a capacitor CY4, a capacitor C8, a capacitor C9, a switch BK, a transistor Q1 and an optical coupler U2. The output end of the voltage reference unit is respectively connected to the first end of the resistor R1 and the first end of the switch BK, the second end of the resistor R1 is respectively connected to the collector of the transistor Q1 and the first end of the primary of the optical coupler U2, the second end of the switch BK is respectively connected to the first end of the resistor R2, the second end of the resistor R2 is respectively connected to the base of the transistor Q1 and the first end of the resistor R3, the first end of the secondary of the optical coupler U2 is connected to the CNT end of the DC / DC power module N1, the second end of the secondary of the optical coupler U2 is respectively connected to the -Vin end of the DC / DC power module N1 and the first end of the capacitor CY2, The +Vin terminal of the DC / DC power module N1 is connected to the second end of the capacitor CY1 and the voltage source, the second end of the capacitor CY3 is connected to the +Vout and +S terminals of the DC / DC power module N1, the first end of the capacitor C8, the first end of the capacitor C9 and the L+ terminal, the first end of the resistor RG is grounded GND, the second end of the resistor RG is grounded DGND, the second end of the capacitor CY2, the first end of the capacitor CY1, the first end of the capacitor CY3 and the second end of the capacitor CY4 are all grounded EARTH, the second end of the resistor R3, the emitter of the transistor Q1 and the second end of the primary of the optocoupler U2 are all grounded DGND, and the first end of the capacitor CY4 is respectively connected to the -S and -Vout terminals of the DC / DC power module N1, the second end of the capacitor C8, and the second end of the capacitor C9 are all grounded GND.

[0019] The 28VDC on-board DC power supply passes through the anti-reverse surge suppression unit and enters the voltage reference unit and the DC / DC conversion unit. The voltage reference unit generates a 15.5VDC power supply and provides it to the dimming signal unit. The dimming control voltage after passing through the dimming signal unit is provided to the DC / DC conversion unit. By adjusting the resistance value of the potentiometer RP and combining the output voltage calculation method of the reference source U3, the output adjustable voltage is corrected. The adjustable voltage output to the TRIM terminal is 8.8VDC~3.6VDC. The corrected output voltage is as follows Figure 4 As shown, the dimming effect basically meets the requirements of ergonomics of in-machine lighting fixtures.

[0020] The above only expresses the implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. An LED dimming circuit for aircraft lighting, characterized in that: The invention comprises an anti-surge suppression unit, a voltage reference unit, a dimming signal unit and a DC / DC conversion unit, wherein the DC / DC conversion unit has a DC / DC power supply module N1, the dimming signal unit is composed of a capacitor C10, a capacitor C11, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a potentiometer RP and a reference source U3, the output end of the voltage reference unit is respectively connected to the first end of the resistor R4 and the first end of the capacitor C10, the second end of the resistor R4 is connected to the cathode of the reference source U3, the first end of the resistor R5, the adjustment end and the first end of the potentiometer RP, the first end of the capacitor C11 and the TRIM end of the DC / DC power supply module N1, and the The second end of the resistor R5 is respectively connected to the second end of the potentiometer RP and the first end of the resistor R6, the second end of the resistor R6 is respectively connected to the first end of the resistor R7 and the reference level of the reference source U3, the second end of the capacitor C10, the second end of the capacitor C11, the anode of the reference source U3 and the resistor R7 are all grounded; the DC / DC conversion unit also has a resistor R1, a resistor R2, a resistor R3, a resistor RG, a capacitor CY1, a capacitor CY2, a capacitor CY3, a capacitor CY4, a capacitor C8, a capacitor C9, a switch BK, a transistor Q1 and an optical coupler U2, the output end of the voltage reference unit is respectively connected to the first end of the resistor R1 and the first end of the switch BK The second end of the resistor R1 is respectively connected to the collector of the transistor Q1 and the first end of the primary of the optocoupler U2, the second end of the switch BK is connected to the first end of the resistor R2, the second end of the resistor R2 is respectively connected to the base of the transistor Q1 and the first end of the resistor R3, the first end of the secondary of the optocoupler U2 is connected to the CNT end of the DC / DC power module N1, the second end of the secondary of the optocoupler U2 is respectively connected to the -Vin end of the DC / DC power module N1 and the first end of the capacitor CY2, the +Vin end of the DC / DC power module N1 is connected to the second end of the capacitor CY1 and the voltage source, the second end of the capacitor CY3 is connected to the DC / DC power module N1 The +Vout and +S ends, the first end of the capacitor C8, the first end of the capacitor C9 and the L+ end, the first end of the resistor RG is grounded GND, the second end of the resistor RG is grounded DGND, the second end of the capacitor CY2, the first end of the capacitor CY1, the first end of the capacitor CY3 and the second end of the capacitor CY4 are all grounded EARTH, the second end of the resistor R3, the emitter of the transistor Q1 and the second end of the primary of the optocoupler U2 are all grounded DGND, the first end of the capacitor CY4 is respectively connected to the -S and -Vout ends of the DC / DC power supply module N1, the second end of the capacitor C8, and the second end of the capacitor C9 are all grounded GND.

2. The LED dimming circuit for aircraft lighting according to claim 1, characterized in that: The reference source U3 adopts TL431D.

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