Multipath current source magnet coil temperature monitoring circuit
By using pnp transistors and resistors to build a constant current source generation circuit in a multi-channel temperature measurement system, and using analog multiplexer to switch channels, the problem of high cost and complexity when acquiring multiple constant current sources is solved, and a low-cost, low-complexity, and high spatial efficiency is achieved, and the consistency of the current source is ensured.
Patent Information
- Application Number
- CN202421886109.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-06
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-08-06
AI Technical Summary
The prior art requires the use of multiple devices when acquiring multiple constant current sources in a multi-channel temperature measurement system, resulting in high cost and complexity, large space occupies in applications with limited space, and difficult to control the consistency of the current source.
The constant current source generation circuit is built by using a combination of pnp transistors and resistors, and the constant current source channel is switched by an analog multiplexer to achieve the acquisition of multiple constant current sources.
It realizes acquisition of multiple constant current sources with low cost, low complexity and small space. Due to the small leakage current of the analog multiplexer, the consistency of the current source is good, and it is suitable for multiple temperature measurement systems.
Smart Images
Figure CN222912928U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of temperature monitoring circuits, and particularly relates to a multi-channel current source magnet coil temperature monitoring circuit. Background Technique
[0002] Temperature measurement methods are roughly divided into the proportional method, the constant current method, and the bridge method. When using the proportional method and the constant current method for temperature measurement, a constant current source is often required. The methods for obtaining a constant current source generally include building a constant current circuit using an operational amplifier, using a dedicated constant current source chip, or building it using discrete transistors. For a multi-channel temperature measurement system, multiple current sources are often required to generate multiple constant current sources in the proportional method temperature measurement system. The existing solutions for obtaining multiple constant current sources usually involve building multiple current sources, which often require the use of multiple devices, increasing costs and complexity. For applications with limited space, it will also occupy space and is not conducive to layout. At the same time, it is difficult to control the consistency of the current sources. This patent mainly elaborates on the method for obtaining multiple constant current sources in the proportional method temperature measurement system. Content of the Utility Model
[0003] Aiming at the deficiencies of the prior art, the utility model provides a multi-channel current source magnet coil temperature monitoring circuit, which solves the problems raised by merchants.
[0004] To achieve the above objectives, the utility model is realized through the following technical solutions: A multi-channel current source magnet coil temperature monitoring circuit includes a power supply, a decoupling capacitor C3, a decoupling capacitor C4, a constant current source generation circuit, and a current source output channel selection circuit that are connected in sequence at the input end and the output end. The constant current source generation circuit is composed of a pnp transistor and resistors R2, R3, and R4.
[0005] The current source output channel selection circuit consists of an analog multiplexer. The analog multiplexer is a bidirectional analog switch, which is respectively connected to the digital signal channels of AGD708_A0, AGD708_A1, and AGD708_A2. And the three pins of AGD708_A0, AGD708_A1, and AGD708_A2 are connected to the mcu. The current source channel output ports of SA1, SA2, SA3, SA4, SA5, SA6, SA7, and SA8 are provided on the bidirectional analog switch.
[0006] As a further scheme of the utility model: The output current of the constant current source generation circuit is 8.55 μA.
[0007] As a further scheme of the utility model: AGD708_A0, AGD708_A1, and AGD708_A2 respectively correspond to the first, second, and third bits of the channel number in binary.
[0008] The utility model has the following beneficial effects compared with the prior art: In this solution, a current source can be obtained very simply by using a combination of a general triode and a resistor, with extremely low cost. An analog multiplexer is used to switch the constant current source channels. By using one chip plus a constant current source generation circuit, multiple constant current sources can be obtained, which can reduce the pcb area in design. At the same time, since the leakage current of the analog multiplexer is only about ±0.75 nA, after the current source selects the channel, the consistency is also good. In a multi-channel temperature measurement system, the current sources of each channel can maintain good consistency. Brief Description of the Drawings
[0009] Figure 1 It is the circuit schematic diagram of the utility model. Detailed Embodiment
[0010] To further elaborate on the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the following combines the drawings and preferred embodiments to detail the specific embodiments, structures, features and their effects of the utility model as follows.
[0011] Please refer to Figure 1 , the utility model provides a technical solution: A multi-channel current source magnet coil temperature monitoring circuit, including a power supply, a decoupling capacitor C3, a decoupling capacitor C4, a constant current source generation circuit and a current source output channel selection circuit connected in sequence at the input end and the output end. The constant current source generation circuit is composed of a pnp-type triode and resistors R2, R3 and R4;
[0012] The current source output channel selection circuit is composed of an analog multiplexer. The analog multiplexer is a bidirectional analog switch, which is respectively connected to the digital signal channels of AGD708_A0, AGD708_A1, and AGD708_A2, and the three pins of AGD708_A0, AGD708_A1, and AGD708_A2 are connected to the mcu. Current source channel output ports SA1, SA2, SA3, SA4, SA5, SA6, SA7 and SA8 are arranged on the bidirectional analog switch.
[0013] The output current of the constant current source generation circuit is 8.55 μA.
[0014] AGD708_A0, AGD708_A1, and AGD708_A2 respectively correspond to the first, second, and third bits of the channel number in binary.
[0015] The constant current source generation circuit is built by the combined use of a PNP transistor and a resistor, and its output current is set at around 8.55 μA. I out≈(3.3-(3.3v / (1 / 4.3)+0.5v) / 30kΩ=8.55 μA. The current source output channel selection circuit is built by an analog multiplexer. The analog multiplexer is a bidirectional analog switch that switches channels through the digital signals of AGD708_A0, AGD708_A1, and AGD708_A2. AGD708_A0, AGD708_A1, and AGD708_A2 correspond to the first, second, and third bits of the channel number in binary respectively. These three pins can be connected to the MCU for channel switching. SA1 to SA8 are the channel output ports of the current source.
[0016] In this solution, a combination of general-purpose transistors and resistors can be used to obtain a current source very simply, with extremely low cost. An analog multiplexer is used to switch the constant current source channels. By using one chip plus a constant current source generation circuit, multiple constant current sources can be obtained. This can reduce the PCB area in the design. At the same time, since the leakage current of the analog multiplexer is only about ±0.75 nA, after the current source selects the channel, the consistency is also good. In a multi-channel temperature measurement system, each channel current source can maintain good consistency.
[0017] The above description is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or equivalent changes and modifications within the scope of the technical solution of the present invention. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change, and modification made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A multi-channel current source magnet coil temperature monitoring circuit, characterized in that: It includes a power supply, a decoupling capacitor C3, a decoupling capacitor C4, a constant current source generating circuit and a current source output channel selection circuit, wherein the constant current source generating circuit is composed of a pnp transistor and resistors R2, R3 and R4; The current source output channel selection circuit is composed of an analog multiplexer, which is a bidirectional analog switch, which is connected to the digital signal channels of AGD708_A0, AGD708_A1, and AGD708_A2 respectively, and the three pins of AGD708_A0, AGD708_A1, and AGD708_A2 are connected to the MCU. The bidirectional analog switch is provided with current source channel output ports SA1, SA2, SA3, SA4, SA5, SA6, SA7, and SA8.
2. A multi-channel current source magnet coil temperature monitoring circuit according to claim 1, characterized in that: The constant current source generates a circuit output current of 8.55uA.
3. The multi-channel current source magnet coil temperature monitoring circuit according to claim 1, characterized in that: AGD708_A0, AGD708_A1, AGD708_A2 correspond to the first, second and third digits of the binary number of the channel number respectively.