Brightness-adjustable optical fiber amplifier constant current circuit

Abstract

The utility model relates to the field of optical fiber amplifiers, and provides an optical fiber amplifier constant-current circuit capable of adjusting brightness, which comprises a main control module, an adjusting voltage generating circuit, a constant-current circuit and a transmitting tube, one end of the transmitting tube is connected with a power supply, and the other end of the transmitting tube is grounded under the control of the constant-current circuit. The input end of the regulation voltage generation circuit is connected with the main control module, the output end of the regulation voltage generation circuit is connected with the input end of the constant current circuit, and the regulation voltage generation circuit sends different regulation voltages to the constant current circuit according to the control of the main control module, so that the constant current circuit regulates the current passing through the transmitting tube to realize constant current regulation; the light quantity adjusting range of the transmitting part of the optical fiber amplifier is wide.

Description

Technical Field

[0001] The utility model relates to the field of fiber optic amplifiers, and more specifically, to a constant current circuit for a fiber optic amplifier with adjustable brightness. Background Art

[0002] A fiber optic amplifier is a new type of all-optical amplifier that can amplify signals. According to its position and function in the fiber optic line, it can generally be divided into three types: relay amplification, preamplification, and power amplification. It can directly perform all-optical amplification on signals and has good "transparency", especially suitable for relay amplification in long-distance optical communication. The working voltage of the fiber optic amplifier is 12 - 24V. During use, in order to prevent the degradation of the product's working performance, the emitting part of the fiber optic amplifier requires a constant current design to avoid performance degradation at low voltages, which may affect customer use. At the same time, due to the diverse working environments of fiber optic amplifier products, corresponding product parameters need to be adjusted according to different customer scenario requirements, such as adjusting the luminous intensity or gain. During actual research, it was found that the adjustment range of domestic fiber optic amplifiers is generally divided into three gears, with a small adjustment range and no linear adjustment, and in some special environments, it cannot meet customer use requirements.

[0003] For example, Figure 2 As shown, it is a regulation of a mainstream fiber optic amplifier on the market. It directly uses a voltage regulator diode LDO. The voltage regulator diode outputs the input voltage of 12 - 24V as 8V. Regardless of how the power supply voltage of the fiber optic amplifier changes between 12 - 24V, the power supply voltage of the emitting part of the fiber optic amplifier is always 8V to achieve constant current. The emitting part includes an emitting tube, and the emitting tube is respectively connected to three regulating resistors with different resistances through three switches. During the use of the fiber optic amplifier, when it is necessary to adjust the luminous intensity, different switch adjustment gears are used to connect resistors with different resistances to adjust the brightness, realizing three-gear adjustment with a small adjustment range.

[0004] Therefore, it is necessary to design a constant current circuit for a fiber optic amplifier with a wide light quantity adjustment range. Summary of the Utility Model

[0005] The problem solved by the utility model is how to provide a constant current circuit for a fiber optic amplifier with a wide light quantity adjustment range.

[0006] To solve the above problems, the utility model provides a constant current circuit for a fiber optic amplifier with adjustable brightness, including: a main control module, an adjustable voltage generation circuit, a constant current circuit, and an emitting tube. One end of the emitting tube is connected to the power supply, and the other end is controlled by the constant current circuit to be grounded. The input end of the adjustable voltage generation circuit is connected to the main control module, and the output end is connected to the input end of the constant current circuit. The adjustable voltage generation circuit issues different adjustable voltages to the constant current circuit according to the control of the main control module, thereby enabling the constant current circuit to adjust the current passing through the emitting tube to achieve constant current regulation.

[0007] Further, the constant current circuit includes a switch tube control circuit, a first MOS tube, and a first resistor. The first resistor is a sampling resistor. The input end of the switch tube control circuit is connected to the output end of the regulation voltage generation circuit, and the output end is connected to the gate of the first MOS tube. The drain of the first MOS tube is connected to the power supply through the emitting tube, the source is connected to the first end of the first resistor, the second end of the first resistor is grounded, and the first end of the first resistor is connected to the feedback end of the switch tube control circuit.

[0008] Further, the switch tube control circuit includes a first operational amplifier, a second resistor, and a third resistor. The positive input end of the first operational amplifier is connected to the output end of the regulation voltage generation circuit, the negative input end is connected to the first end of the first resistor through the second resistor, and the output end of the first operational amplifier is connected to the gate of the first MOS tube through the third resistor.

[0009] Further, the constant current circuit further includes a fourth resistor, and the fourth resistor is connected in series between the emitting tube and the power supply.

[0010] Further, the constant current circuit further includes a fifth resistor, the first end of the fifth resistor is connected to the positive input end of the first operational amplifier, and the second end is grounded.

[0011] Further, the regulation voltage generation circuit includes a first analog switch. The input end of the first analog switch is connected to the main control module, and the output end is connected to the positive input end of the first operational amplifier, and is used to output a corresponding voltage signal to the first operational amplifier according to the signal input by the main control module. The control end of the first analog switch is connected to the main control module to control the on / off of the first analog switch by the main control module.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] By sending different digital signals from the main control module, the regulation voltage generation circuit outputs corresponding voltage signals to the input end of the constant current circuit, and then the output end of the constant current circuit adjusts the current passing through the emitting tube, realizing linear regulation with a wide regulation range. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the overall principle structure of an embodiment of the present invention;

[0015] Figure 2 is a schematic diagram of the principle structure of the existing optical fiber amplifier of the present invention;

[0016] Figure 3 is a schematic diagram of the circuit principle structure of an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] In order to make the above objects, features, and advantages of the present utility model more obvious and understandable, the following will describe in detail the specific embodiments of the present utility model with reference to the accompanying drawings.

[0018] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0019] In the description of this specification, the descriptions with reference to terms such as "embodiment", "one embodiment", and "one implementation manner" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or implementation manner are included in at least one embodiment or implementation manner of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or implementation manner. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or implementation manners in a suitable manner.

[0020] As Figure 1 shown, the present utility model provides a constant current circuit for an optical fiber amplifier with adjustable brightness, including: a main control module, an adjustable voltage generation circuit, a constant current circuit, and a transmitting tube. One end of the transmitting tube is connected to the power supply, and the other end is grounded under the control of the constant current circuit. The input end of the adjustable voltage generation circuit is connected to the main control module, and the output end is connected to the input end of the constant current circuit. The adjustable voltage generation circuit issues different adjustable voltages to the constant current circuit according to the control of the main control module, thereby enabling the constant current circuit to adjust the current passing through the transmitting tube to achieve constant current regulation.

[0021] It should be noted that by issuing different digital signals through the main control module, the adjustable voltage generation circuit outputs corresponding voltage signals to the input end of the constant current circuit. Then, the output end of the constant current circuit adjusts the current passing through the transmitting tube, achieving linear regulation with a wide regulation range.

[0022] In an embodiment of the present utility model, the constant current circuit includes a switch tube control circuit, a first MOS tube, and a first resistor. The first resistor is a sampling resistor. The input end of the switch tube control circuit is connected to the output end of the regulated voltage generating circuit, and the output end is connected to the gate of the first MOS tube. The drain of the first MOS tube is connected to the power supply through the emitting tube, the source is connected to the first end of the first resistor, the second end of the first resistor is grounded, and the first end of the first resistor is connected to the feedback end of the switch tube control circuit.

[0023] It should be noted that by adjusting the comparison between the control signal of the switch tube control circuit and the feedback signal of the sampling resistor, the switch tube control circuit can adjust the conduction angle of Q1, thereby realizing the adjustment of the current of the first MOS tube LED1.

[0024] In an embodiment of the present utility model, the switch tube control circuit includes a first operational amplifier, a second resistor, and a third resistor. The positive input end of the first operational amplifier is connected to the output end of the regulated voltage generating circuit, the negative input end is connected to the first end of the first resistor through the second resistor, and the output end of the first operational amplifier is connected to the gate of the first MOS tube through the third resistor.

[0025] It should be noted that as Figure 3 shown, according to the virtual short and virtual open of the operational amplifier, Vin+ = Vin- of the operational amplifier. The current passing through the emitting tube LED1 is real-time feedback by the first resistor R5. When the load current increases, the voltage at the inverting input end of the operational amplifier is higher than the voltage at the non-inverting input end. The first operational amplifier U2 outputs a low level, causing the first MOS tube Q1 to turn off and reducing the current of the emitting tube LED1. When the current of the emitting tube LED1 decreases, the voltage at the inverting input end of the operational amplifier is lower than the voltage at the non-inverting input end. The operational amplifier outputs a high level, causing the triode to conduct and increasing the current of the emitting tube LED1. Therefore, the current of the emitting tube LED1 finally reaches a constant stable current under the real-time feedback of the first resistor R5.

[0026] In an embodiment of the present utility model, the constant current circuit further includes a fourth resistor, and the fourth resistor is connected in series between the emitting tube and the power supply.

[0027] It should be noted that the fourth resistor R7 is connected in series with the emitting tube LED1 and is used for current limiting in the loop of the emitting tube LED1.

[0028] In an embodiment of the present utility model, the constant current circuit further includes a fifth resistor. The first end of the fifth resistor is connected to the positive input end of the first operational amplifier, and the second end is grounded.

[0029] It should be noted that the fifth resistor R2 is arranged at the positive input end of the first operational amplifier U2 and functions as buffering and current limiting.

[0030] In an embodiment of the present utility model, the regulated voltage generating circuit includes a first analog switch. The input end of the first analog switch is connected to the main control module, and the output end is connected to the positive input end of the first operational amplifier, for outputting a corresponding voltage signal to the first operational amplifier according to the signal input by the main control module. The control end of the first analog switch is connected to the main control module to control the switching of the first analog switch by the main control module.

[0031] It should be noted that, in order to make the adjustable range of the emission tube's light emission wider, an analog switch is externally added to the positive input end of the first operational amplifier U2. As Figure 3 shown, the SEL end of the first analog switch U1 is the control end, which is controlled by the main control module. The S end of the first analog switch U1 inputs a variable voltage from the main control module (the maximum voltage range is 0 - 5V, and the actual emission power consumption needs to be calculated for limitation according to the design parameter requirements; the main control module can use a single-chip microcomputer chip, and the variable voltage is output by the built-in DAC of the main control module, or an external digital-to-analog conversion chip can be used to perform DAC conversion on the output of the main control module to provide the variable voltage). The D end of the first analog switch U1 is the output end, outputting a corresponding voltage to the positive input end of the first operational amplifier U2, changing the voltage at the positive input end of the first operational amplifier U2, and further changing the current when the load emission tube LED1 is in constant current, which can effectively adjust the brightness of the emission tube LED1. Since the voltage signal output by the first analog switch U1 is linearly variable, the current adjustment of the emission tube LED1 is a linear adjustment method, and the adjustment range is wider.

[0032] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Without departing from the spirit and scope of the present disclosure, those skilled in the art can make various changes and modifications, and these changes and modifications will all fall within the protection scope of the present utility model.

Claims

1. A constant current circuit for an optical fiber amplifier with adjustable brightness, characterized in that: include: A main control module, a regulating voltage generating circuit, a constant current circuit and a transmitting tube, wherein one end of the transmitting tube is connected to a power supply, and the other end is grounded by the constant current circuit; the input end of the regulating voltage generating circuit is connected to the main control module, and the output end is connected to the input end of the constant current circuit; the regulating voltage generating circuit sends different regulating voltages to the constant current circuit according to the control of the main control module, so that the constant current circuit regulates the current passing through the transmitting tube to achieve constant current regulation; the constant current circuit comprises a switch tube control circuit, a first MOS tube and a first resistor, wherein the first resistor is a sampling resistor, the input end of the switch tube control circuit is connected to the output end of the regulating voltage generating circuit, the output end is connected to the gate of the first MOS tube, the drain of the first MOS tube is connected to the power supply via the transmitting tube, the source is connected to the first end of the first resistor, the second end of the first resistor is grounded, and the first end of the first resistor is connected to the feedback end of the switch tube control circuit.

2. The constant current circuit of the optical fiber amplifier with adjustable brightness according to claim 1, characterized in that: The switch tube control circuit includes a first operational amplifier, a second resistor, and a third resistor. The positive input terminal of the first operational amplifier is connected to the output terminal of the regulating voltage generating circuit, and the negative input terminal is connected to the first end of the first resistor via the second resistor. The output terminal of the first operational amplifier is connected to the gate of the first MOS tube via the third resistor.

3. The constant current circuit of the optical fiber amplifier with adjustable brightness according to claim 2, characterized in that: The constant current circuit further includes a fourth resistor, which is connected in series between the transmitting tube and the power supply.

4. The constant current circuit of the optical fiber amplifier with adjustable brightness according to claim 3, characterized in that: The constant current circuit further includes a fifth resistor, a first end of the fifth resistor is connected to the positive input end of the first operational amplifier, and a second end of the fifth resistor is grounded.

5. The constant current circuit of the optical fiber amplifier with adjustable brightness according to claim 4, characterized in that: The regulating voltage generating circuit includes a first analog switch, wherein the input end of the first analog switch is connected to the main control module, and the output end is connected to the positive input end of the first operational amplifier, and is used to output a corresponding voltage signal to the first operational amplifier according to the signal input by the main control module. The control end of the first analog switch is connected to the main control module so that the main control module controls the switching of the first analog switch.

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