CN217689875U - A high-precision shunt assembly - Google Patents

Abstract

The utility model discloses a high-precision shunt assembly, which comprises a shunt, a first printed circuit board, a second printed circuit board, at least one power resistor, at least one thermistor, a heat-conducting medium and a fixing external member; the shunt is arranged on the first printed circuit board, the power resistor and the thermistor are arranged on the second printed circuit board, the first printed circuit board and the second printed circuit board are assembled together by using a fixing sleeve, the power resistor, the thermistor and the shunt are close to but not in contact, and a gap is filled with a heat-conducting medium; the power resistor can effectively heat the shunt and control the temperature of the shunt, and the thermistor can effectively detect the actual temperature of the shunt.

Description

A high-precision shunt component

technical field

The utility model belongs to the field of constant temperature control, in particular to a method for assembling a shunt used for detecting large current and related components for constant temperature control of the shunt.

Background technique

A shunt used to detect large currents will cause a temperature rise due to self-heating when a large current flows through it, and the temperature rise will change its resistance value, which is the so-called temperature drift. The typical value is 50PPM (five parts per million) 10); Therefore, when using a shunt to measure large currents, stabilizing the temperature of the shunt body and reducing temperature drift is an effective way to improve detection accuracy. Putting shunts and other temperature-sensitive devices, such as operational amplifiers, ADCs, crystal oscillators, etc., together in a constant temperature box is a typical means of constant temperature, but the size of the constant temperature box is large, the control is complicated, and in the current When the change causes the self-heating power of the shunt to change relatively large, the temperature of the shunt cannot be quickly stabilized at a certain temperature value, resulting in a large hysteresis in temperature control.

SUMMARY OF THE INVENTION

The purpose of the utility model is to overcome the deficiencies in the prior art and invent a high-precision shunt assembly, which can quickly and directly control and detect the temperature of the shunt, thereby realizing high-precision current detection.

In the present invention, the shunt is installed on the first printed circuit board; the heating resistor and the temperature detection component are installed on the second printed circuit board, and the two sides of the temperature detection component on the second printed circuit board are slotted, and the temperature detection component can be positive Temperature coefficient thermistor PTC, temperature coefficient thermistor NTC, resistance temperature detector (RTD), IC temperature sensor, and also a thermocouple. Fill the middle of the first printed circuit board and the second printed circuit board with a heat-conducting medium, and then pass the screw and the screw column set; it can also be the pin header and its corresponding connector for transmitting electrical signals, and connect the first printed circuit board and the second printed circuit board. After the components of the second printed circuit board are assembled face-to-face and fixed together, remove the heat conduction medium on both sides of the temperature detection part from the groove opened by the second printed circuit board, and the power resistor and the temperature detection part are close to but not in contact with the shunt, so that the heating The resistance can directly heat the shunt, and the temperature detection component can also directly detect the temperature of the shunt body, so that the body temperature of the shunt can be directly and rapidly controlled and detected.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Figure 1 is a front view of the assembled diverter and its thermostatically controlled components.

Figure 2 is an exploded view showing the assembly details of the shunt.

Figure 3 is an exploded view showing details of the heating resistor and temperature sensing.

Figure 4 is a detailed view of the slots on both sides of the thermistor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

A high-precision shunt assembly, including a shunt 101, at least one power resistor 102, a thermistor 103, a first printed circuit board 104, a second printed circuit board 105, fixing screws 107 and corresponding screw rods 106, heat conduction Medium 108; the shunt 101 is patch-mounted on the first printed circuit board 104, the power resistor 102 and thermistor 103 are patch-mounted on the second printed circuit board 105, and the device faces of the two printed circuit boards are opposite , fixed by screws and threaded rods.

In this implementation case, the heating resistor 102 is a SMD power resistor packaged in 2512, and the thermistor is an NTC component of 0402. The height of both components is about 0.5mm, so the heating resistor and thermistor can be very flat Close to the shunt, due to the need for functional insulation, a heat-conducting medium, such as silicone grease or a heat-conducting gasket, can be filled in the middle.

The two printed circuit boards can be connected by screws and screw posts, or by pin headers and their corresponding connectors; in this implementation case, the screw and screw posts are preferably connected, and the screw posts are riveted on the first printed circuit board.

The shunt needs to transmit a large current, so the printed circuit board where the shunt is located is generally the main board, which can contain main control devices, such as MCU, op amp, analog-to-digital conversion chip, etc.; the printed circuit board where the thermal resistor and thermistor are located The circuit board can be regarded as a daughter board; because the connecting parts are metal, the fixing kit can also be used to directly transmit electrical signals between the two printed circuit boards, and the temperature detection signal on the daughter board is transmitted to the MCU of the main board through the fixing kit, while The power control-related signals sent by the MCU of the motherboard can also control the heating of the heating resistor through the fixed kit.

In order to allow the thermistor to accurately detect the temperature of the shunt without being affected by the adjacent heating resistors, as shown in Figure 4, grooves 109 with a width of more than 1 mm can be opened on the circuit boards on both sides of the thermistor; After the circuit board is installed, the heat conduction medium between the heating resistor and the thermistor can be removed through the opened slot 109 to reduce the influence of the thermistor on the heating resistor and detect the real temperature of the shunt.

Although the present disclosure has been disclosed above through the description of specific embodiments of the present disclosure, it should be understood that those skilled in the art can design various modifications, improvements or equivalents to the present disclosure within the spirit and scope of the appended claims thing. These modifications, improvements or equivalents should also be considered to be included in the protection scope of the present disclosure.

Claims (5)

1. A high-precision shunt assembly is characterized by comprising a shunt, a first printed circuit board, a second printed circuit board, at least one power resistor, at least one temperature detection component, a heat conducting medium and a fixing sleeve; the shunt is arranged on the first printed circuit board, the power resistor and the temperature detection component are arranged on the second printed circuit board, the first printed circuit board and the second printed circuit board are assembled together by utilizing the fixing sleeve, the power resistor, the temperature detection component and the shunt are close to but not in contact, and a gap is filled with a heat conduction medium.

2. The high precision shunt assembly of claim 1, wherein the temperature sensing member is formed with a groove on the second pcb on both sides of the temperature sensing member, and the heat transfer medium on both sides of the temperature sensing member is removed through the groove formed on the second pcb after the assembly.

3. The shunt assembly of claim 1, wherein said temperature sensing element is selected from the group consisting of a PTC thermistor, a NTC thermistor, a resistance temperature sensor, an IC temperature sensor, and a thermocouple.

4. The high precision shunt assembly of claim 1, wherein said fastening assembly is a screw and stud assembly; or a pin header and its corresponding connector.

5. The high precision shunt assembly of claim 4, wherein said first printed circuit board and said second printed circuit board transmit electrical signals through said mounting assembly.

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