A tungsten lamp constant current control circuit system

Abstract

This invention provides a constant current control circuit system for a tungsten lamp, relating to the field of scientific instrument technology. The system includes a microcontroller unit (MCU) and a DC-DC converter. The MCU activates the DC-DC converter via an enable signal (EN). The DC-DC converter supplies power to the tungsten lamp through an LC circuit and generates a feedback signal through a feedback loop, which is input to the DC-DC converter for constant current control and overvoltage protection. The MCU acquires voltage and current signals in real time for fault diagnosis and indication. This constant current control circuit system enables constant current control of the tungsten lamp during use, resulting in more stable lamp brightness, reduced current surges, and a decreased impact on the lamp's lifespan.

Description

Technical Field

[0001] This invention relates to the field of scientific instrument technology, specifically to a tungsten lamp constant current control circuit system. Background Technology

[0002] The ultraviolet-visible spectrophotometer is an optical instrument that analyzes the absorption characteristics of substances in the ultraviolet-visible region. It is widely used in fields such as chemistry, biology, medicine, and environment. One of its main components is the light source, which is divided into deuterium lamps (ultraviolet region, 190-400nm) and tungsten lamps (visible region, 350-900nm).

[0003] Tungsten lamps, usually halogen tungsten lamps, are the core light source of visible spectrophotometers. Different driving methods for tungsten lamps will directly affect their stability, lifespan, and spectral output quality. Existing products use a constant voltage driving method, which means directly applying a fixed voltage. The disadvantage is that the resistance of the tungsten lamp changes with temperature. If the voltage is kept constant, the current will fluctuate. Current fluctuations will lead to unstable brightness. When the filament is cold-started, the initial resistance is very small and the current is very large. The large current surge will affect the lifespan. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a tungsten lamp constant current control circuit system, which solves the problem that it is inconvenient to control the constant current of tungsten lamps during use, resulting in unstable lamp brightness, large current surges, and reduced lifespan of the tungsten lamps.

[0006] (II) Technical Solution

[0007] To facilitate constant current control of the tungsten lamp during use, thereby ensuring more stable lamp brightness, reducing current surges, and minimizing the impact on the lamp's lifespan, this invention achieves this through the following technical solution: A tungsten lamp constant current control circuit system, comprising a microcontroller unit (MCU) and a DC-DC converter. The MCU activates the DC-DC converter via an enable signal (EN). The DC-DC converter provides power to the tungsten lamp through an LC circuit and generates a feedback signal through a feedback loop, which is input to the DC-DC converter for constant current control and overvoltage protection control. The MCU acquires voltage and current signals in real time for fault diagnosis and indication.

[0008] Preferably, the microcontroller unit (MCU) controls the DC-DC converter to start or stop via an enable signal (EN).

[0009] Preferably, the DC-DC converter is a DC-DC converter.

[0010] Preferably, the voltage sampling circuit acquires the voltage across the tungsten lamp via a voltage divider resistor.

[0011] Preferably, the current sampling circuit uses the current flowing through the sampling resistor.

[0012] Preferably, the voltage sampling circuit and the current sampling circuit generate feedback signals through a feedback loop.

[0013] Preferably, the microcontroller unit (MCU) acquires voltage and current signals in real time.

[0014] Preferably, the microcontroller unit (MCU) is shown as U1 in the circuit.

[0015] (III) Beneficial Effects

[0016] This invention provides a tungsten lamp constant current control circuit system. It has the following beneficial effects:

[0017] 1. The DC-DC step-down converter is a DC-DC step-down converter that provides power to the tungsten lamp through an LC circuit. It can control the constant current, making the lamp brightness more stable, reducing current surges, and reducing the impact on the life of the tungsten lamp.

[0018] 2. The voltage sampling circuit collects the voltage across the tungsten lamp through the voltage divider resistor, and the current sampling circuit generates a feedback signal through the feedback loop by the current flowing through the sampling resistor, which is then input to the DC-DC converter for constant current control and overvoltage protection control.

[0019] 3. The microcontroller unit (MCU) can acquire voltage and current signals in real time, perform fault diagnosis and fault indication, thereby enabling timely and accurate identification of line fault points, facilitating timely troubleshooting and repair by staff. Attached Figure Description

[0020] Figure 1 This is a structural functional diagram of the present invention;

[0021] Figure 2 This is a schematic diagram of the circuit structure of the present invention;

[0022] Figure 3 This is a flowchart of the structure and program of the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0024] Please see Figures 1-3 The present invention provides a technical solution: a tungsten lamp constant current control circuit system, including a microcontroller unit (MCU) and a DC-DC converter. The microcontroller unit (MCU) starts the DC-DC converter through an enable signal (EN). The DC-DC converter provides power to the tungsten lamp through an LC circuit and generates a feedback signal through a feedback loop, which is input to the DC-DC converter for constant current control and overvoltage protection control. The microcontroller unit (MCU) collects voltage and current signals in real time to perform fault judgment and fault indication.

[0025] In this embodiment, the microcontroller unit (MCU) controls the DC-DC converter to start or stop via the enable signal (EN);

[0026] Specifically, this enables the microcontroller unit (MCU) to control the DC-DC converter to start or stop.

[0027] In this embodiment, the DC-DC converter is a DC-DC converter;

[0028] Specifically, it facilitates the conversion of DC power into different voltage values.

[0029] In this embodiment, the voltage sampling circuit collects the voltage across the tungsten lamp through a voltage divider resistor;

[0030] Specifically, it facilitates the real-time acquisition of the voltage across the tungsten lamp.

[0031] In this embodiment, the current sampling circuit uses the current flowing through the sampling resistor;

[0032] Specifically, this allows for real-time acquisition of the current from the resistor.

[0033] In this embodiment, the voltage sampling circuit and the current sampling circuit generate a feedback signal through a feedback loop;

[0034] Specifically, this allows the input to a DC-DC converter for constant current control and overvoltage protection.

[0035] In this embodiment, the microcontroller unit (MCU) acquires voltage and current signals in real time;

[0036] Specifically, this is to facilitate fault diagnosis and fault indication.

[0037] In this embodiment, the microcontroller unit (MCU) is shown as U1 in the circuit;

[0038] Specifically, such as Figure 2 As shown, U1 is a DC-DC converter, IN is the power input, EN is the enable signal, BST is a boost circuit (R1 and C4 form a charge pump for driving the internal MOS gate), SW is a switch signal, FB is a feedback signal, L1 and C5 are an LC circuit for driving the tungsten lamp, H1 is the tungsten lamp interface, R6 and R8 are a resistor voltage divider circuit, U2.1 and D1 form a voltage sampling circuit, R7 is a current sampling resistor, R4, R5, U3.1, R9, and R10 form an operational amplifier circuit to amplify the current signal, U5.1 and D2 form a current signal sampling circuit, U4.1 and R11 are voltage followers that input the feedback signal to the DC-DC converter, U6.1, R13, and C7 are voltage acquisition circuits that input the voltage to the analog-to-digital converter in the MCU, and U7.1, R14, and C8 are current acquisition circuits that input the voltage to the analog-to-digital converter in the MCU.

[0039] Overvoltage protection:

[0040] The preset output voltage upper limit is V UP The upper limit voltage V of R8 can be calculated based on R8 and R6. R8 When V R8 Greater than V FB When the (DC-DC converter feedback voltage) is reached, the DC-DC converter will stop outputting to achieve overvoltage protection;

[0041] Constant current control:

[0042] above V o For U3.1 output (pin 6), I is the set constant current value, when V o <VFB The DC-DC converter outputs when V o >V FB When the DC-DC converter stops outputting, the current I remains constant, achieving constant current control. U1 is a high-frequency, synchronous, adjustable, step-down converter (MP9943) with a built-in MOSFET (85mΩ / 55mΩ), wide input voltage (4V~36V), peak current up to 3A, 410kHz switching frequency, internal soft start, power chip status indication, overcurrent protection, and thermal protection. U2.1, U5.1, U6.1, and U7.1 are LMV344 operational amplifiers with a gain-bandwidth product of 1MHz, a slew rate of 1V / µs, and an input bias current of 20fA. U3.1 and U4.1 are OPA2377 high-bandwidth CMOS operational amplifiers with low noise, low input bias current, and low offset voltage.

[0043] The working principle and usage process of this invention are as follows: The microcontroller unit (MCU) starts the DC-DC converter output through the enable signal (EN), and provides power to the tungsten lamp through the LC circuit. The voltage sampling circuit collects the voltage across the tungsten lamp through the voltage divider resistor. The current sampling circuit generates a feedback signal through the feedback loop by the current flowing through the sampling resistor, and inputs it to the DC-DC converter for constant current control and overvoltage protection control. The microcontroller unit (MCU) collects the voltage and current signals in real time to perform fault judgment and fault indication.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tungsten lamp constant current control circuit system comprising a microcontroller unit (MCU) and a direct current step-down converter (DC-DC), characterized in that: The microcontroller unit (MCU) starts the DC-DC converter via the enable signal (EN). The DC-DC converter supplies power to the tungsten lamp through the LC circuit and generates a feedback signal through the feedback loop, which is input to the DC-DC converter for constant current control and overvoltage protection control. The microcontroller unit (MCU) collects voltage and current signals in real time to perform fault diagnosis and fault indication.

2. A tungsten lamp constant current control circuit system according to claim 1, characterized in that: The microcontroller unit (MCU) controls the DC-DC converter to start or stop via an enable signal (EN).

3. The tungsten lamp constant current control circuit system according to claim 1, wherein: The DC-DC converter is a DC-DC converter.

4. The tungsten lamp constant current control circuit system according to claim 1, wherein: The voltage sampling circuit collects the voltage across the tungsten lamp through a voltage divider resistor.

5. The tungsten lamp constant current control circuit system according to claim 1, wherein: The current sampling circuit uses the current flowing through the sampling resistor.

6. A tungsten lamp constant current control circuit system according to claim 1, characterized in that: The voltage sampling circuit and the current sampling circuit generate feedback signals through a feedback loop.

7. The tungsten lamp constant current control circuit system according to claim 1, wherein: The microcontroller unit (MCU) acquires voltage and current signals in real time.

8. The tungsten lamp constant current control circuit system according to claim 1, wherein: The microcontroller unit (MCU) is shown as U1 in the circuit.

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