IO level comparison test circuit

Abstract

The utility model relates to an IO level comparison test circuit, which comprises a comparator A, a comparator B, a triode Q6 and a triode Q8, a second pin of the comparator A and a sixth pin of the comparator B are respectively connected with an output end of a device to be tested, a first pin of the comparator A is connected with a light-emitting diode D10 through a resistor R44, a seventh pin of the comparator B is connected with a light-emitting diode D12 through a resistor R48, and a fourth pin of the comparator B is connected with a third pin of the triode Q8. The output ends of the light-emitting diode D10 and the light-emitting diode D12 are grounded, the third pin of the comparator A is grounded through a resistor R40, the sixth pin of the comparator B is grounded through a resistor R50, and the second pin of the comparator A and the sixth pin of the comparator B are further grounded through a resistor R140. The detection circuit provided by the scheme does not need a chip, considers the cost and the detection speed, and is better matched. At present, four working states of the to-be-detected equipment are distinguished through state changes of three LED lamps, the use mode is rapid, simple and convenient, and the cost is low.

Description

Technical Field

[0001] This utility model relates to the field of circuit testing technology, and in particular to a test circuit for comparing IO levels. Background Technology

[0002] Most existing circuit testing solutions use an AD sampling + MCU + digital display approach to achieve level detection. Through AD conversion sampling, the MCU calculates the current voltage level and then outputs the result via LEDs or an LCD screen using an algorithm.

[0003] This type of level detection is costly. Using AD sampling, or even an MCU's AD sampling, requires expensive chips. These chips need software code to function; they cannot run without it. Furthermore, the sampled output needs to be calculated and used independently, and the code may differ for different devices. Utility Model Content

[0004] The purpose of this invention is to provide a test circuit for comparing I / O levels to solve the problems encountered in the background art.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows:

[0006] A test circuit for comparing I / O levels includes comparator A, comparator B, transistor Q6, and transistor Q8. Pin 2 of comparator A and pin 6 of comparator B are respectively connected to the output terminal of the device under test. The base of transistor Q8 is connected to the output terminal of the device under test through diode D19. The emitter of transistor Q8 and the collector of transistor Q6 are connected through light-emitting diode D8. The collector of transistor Q8 is connected to the base of transistor Q6 through resistor R35. The base of transistor Q6 is also grounded through resistor R35.

[0007] In addition, pin 1 of comparator A is connected to LED D10 through resistor R44, pin 7 of comparator B is connected to LED D12 through resistor R48, the output terminals of LED D10 and LED D12 are grounded, pin 3 of comparator A is grounded through resistor R40, pin 6 of comparator B is grounded through resistor R50, and pin 2 of comparator A and pin 6 of comparator B are also grounded through resistor R140.

[0008] In the above scheme, the base of transistor Q8 is also connected to resistor R139, and the input terminal of resistor R139 is connected to the output terminal of the device under test through diode D19. The emitter of transistor Q8 is connected to the collector of transistor Q6 through resistor R32, and resistor R32 is connected in series with light-emitting diode D8.

[0009] In the above scheme, the output terminal of the device under test is connected to diode D19, pin 2 of comparator A, and pin 6 of comparator B via resistor R142. Pin 4 of comparator A is grounded, pin 8 of comparator A is connected to 24V voltage, and pin 3 of comparator A is also connected to 24V voltage via resistor R39.

[0010] In another embodiment of the above scheme, a capacitor C21 is also included. One side of the capacitor C21 is grounded, and the other side of the capacitor C21 is connected to resistor R44 and pin 1 of comparator A through resistor R41. The other side of the capacitor C21 is also connected to resistor R48 and pin 7 of comparator B through resistor R45.

[0011] Compared with existing technologies, the advantages of this invention are: the proposed detection circuit eliminates the need for chips, balancing cost and detection speed for a more suitable solution. It distinguishes the four operating states of the device under test through three different LED states, offering quick and easy operation, low cost, a simple and easy-to-understand design, and convenient debugging. The circuit is implemented using a low-cost, pure hardware solution with a separate design. This pure hardware product requires no software intervention and features a simple and fast display. Attached Figure Description

[0012] The disclosure of this utility model is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this utility model. In the drawings, the same reference numerals are used to refer to the same parts. Wherein:

[0013] Figure 1 This is a schematic diagram of the circuit connection structure of this utility model. Detailed Implementation

[0014] To make the technical means, creative features, achieved objectives and effects of this utility model easier to understand, the utility model will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of this utility model, and therefore only show the relevant components of this utility model.

[0015] Based on the technical solution of this utility model, without changing the essential spirit of this utility model, those skilled in the art can propose various interchangeable structural methods and implementation methods. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative descriptions of the technical solution of this utility model, and should not be regarded as the entirety of this utility model or as a limitation or restriction of the technical solution of this utility model.

[0016] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0017] Example 1, such as Figure 1 As shown, a test circuit for comparing IO levels includes comparator A, comparator B, transistor Q6, and transistor Q8. Pin 2 of comparator A and pin 6 of comparator B are respectively connected to the output terminal of the device under test. The base of transistor Q8 is connected to the output terminal of the device under test through diode D19. In practice, the output terminal of the device under test is connected to diode D19, pin 2 of comparator A, and pin 6 of comparator B through resistor R142.

[0018] The emitter of transistor Q8 is connected to the collector of transistor Q6 via LED D8. The collector of transistor Q8 is connected to the base of transistor Q6 via resistor R35, and the base of transistor Q6 is also grounded via resistor R35. Resistor R139 is also connected to the base of transistor Q8, and the input of resistor R139 is connected to the output of the device under test via diode D19. The emitter of transistor Q8 is connected to the collector of transistor Q6 via resistor R32. Resistor R32 is connected in series with LED D8, and resistor R32 is connected in parallel with resistor R139 via resistor R31. R31, together with D19 and R140, forms a voltage divider to provide the initial floating voltage level.

[0019] Pin 1 of comparator A is connected to LED D10 via resistor R44. Pin 7 of comparator B is connected to LED D12 via resistor R48. The outputs of LEDs D10 and D12 are grounded. Pin 3 of comparator A is grounded via resistor R40. Pin 6 of comparator B is grounded via resistor R50. Pin 2 of comparator A and pin 6 of comparator B are also grounded via resistor R140.

[0020] Pin 4 of comparator A is grounded, pin 8 of comparator A is connected to 24V voltage, and pin 3 of comparator A is also connected to 24V voltage through resistor R39.

[0021] Example 2, based on Example 1, provides a test circuit for comparing I / O levels, including comparator A, comparator B, transistor Q6, transistor Q8, and capacitor C21. One side of capacitor C21 is grounded, and the other side is connected to resistor R44 and pin 1 of comparator A via resistor R41. The other side of capacitor C21 is also connected to resistor R48 and pin 7 of comparator B via resistor R45. Capacitor C21 serves as a filter, ensuring the circuit provides an accurate LED lighting response.

[0022] For the current product under test, three LEDs (D8, D10, and D12) are used as three sets of LEDs, which can display four operating states by turning them on and off. The four tooling states are: high configuration, 24V pull-up, 5V pull-up, and ground. When testing the status of the device under test using conventional voltage detection equipment, it is necessary to configure voltage detectors or multimeters according to the number of output terminals of the device. This is inefficient, has a slow refresh rate, and is not intuitive.

[0023] Based on the product's versatility, a dedicated output status detection circuit suitable for some products under test was designed. Using voltage comparators, the on / off states of three sets of LEDs are used to display four corresponding tooling states. The three sets of LEDs are implemented using LEDs of different colors, such as red, blue, and green. The grouping voltage is set by the comparator's resistor value, with comparator A's detection range set at 15V and comparator B's detection range set at 4V. Based on the output status and circuit characteristics of some products under test, there are four voltage values: floating state (3.3V), 24V pull-up (24V), 5V pull-up (5V), and 0V (0V). The two sets of comparators detect these four voltage values, and when different voltage values ​​are encountered, the comparators drive different LEDs to light up, indicating the corresponding status.

[0024] This solution uses a two-way comparator for voltage division and comparison. The default circuit has a 3.3V pull-up and uses diodes for reverse connection protection. The OUT terminal states correspond to four different fixture states: high, 24V pull-up, 5V pull-up, and 0V. The comparator compares the OUT terminal voltage value with the preset value for each of these four states, obtaining different output results. These four states are represented by the on / off state of three sets of LEDs. The corresponding states are shown in the table below:

[0025] state red light Blue light Green light Suspended 0 1 0 24V pull-up 1 1 0 5V pull-up 1 0 0 0V state 1 0 1

[0026] The indicator light colors change to correspond to the four operating states of our product, offering fast response and low latency. This circuit design can also be adapted for different voltage levels by adjusting the voltage divider resistor values.

[0027] In existing technologies, the sampling speed of an analog-to-digital converter (AD) depends on the speed of the chip. High-speed chips are generally more expensive and are more suitable for high-precision and high-speed detection circuits. However, for detection equipment, the cost is high and the suitability is poor. If an MCU is used for sampling, analysis, and display, dedicated code needs to be written.

[0028] Therefore, for the general output settings of self-developed products, this solution proposes a detection circuit that requires no chips, balancing cost and detection speed for a more suitable solution. It now uses three LED state changes to distinguish the four working states of the device under test, offering quick and easy operation, low cost, a simple and easy-to-understand design, and convenient debugging. The circuit in this solution is implemented using a low-cost, pure hardware design. This pure hardware product requires no software intervention and features a simple and fast display.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. These undisclosed elements are all prior art known to those skilled in the art.

[0030] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A test circuit for IO level comparison, characterized by: The comparator A, the comparator B, the triode Q6, the triode Q8, the pin 2 of the comparator A, the pin 6 of the comparator B are connected to the output of the device under test respectively, the base of the triode Q8 is connected to the output of the device under test through the diode D19, the emitter of the triode Q8 and the collector of the triode Q6 are connected through the light emitting diode D8, the collector of the triode Q8 is connected to the base of the triode Q6 through the resistor R35, the base of the triode Q6 is also grounded through the resistor R35; The pin 1 of the comparator A is connected with the light emitting diode D10 through the resistor R44, the pin 7 of the comparator B is connected with the light emitting diode D12 through the resistor R48, the output of the light emitting diode D10 and the light emitting diode D12 is grounded, the pin 3 of the comparator A is grounded through the resistor R40, the pin 6 of the comparator B is grounded through the resistor R50, the pin 2 of the comparator A and the pin 6 of the comparator B are also grounded through the resistor R140 respectively.

2. The test circuit for IO level comparison according to claim 1, characterized in that: The base of the triode Q8 is also connected with the resistor R139, the input of the resistor R139 is connected to the output of the device under test through the diode D19.

3. The test circuit for IO level comparison of claim 2, wherein: The emitter of the triode Q8 is connected to the collector of the triode Q6 through the resistor R32, the resistor R32 is connected in series with the light emitting diode D8.

4. The test circuit for IO level comparison of claim 1, wherein: The output of the device under test is connected to the diode D19, the pin 2 of the comparator A and the pin 6 of the comparator B through the resistor R142 respectively.

5. The test circuit for IO level comparison of claim 1, wherein: The pin 4 of the comparator A is grounded, the pin 8 of the comparator A is connected to the 24V voltage, the pin 3 of the comparator A is also connected to the 24V voltage through the resistor R39.

6. The test circuit for IO level comparison of claim 1, wherein: It also includes the capacitor C21, one side of the capacitor C21 is grounded, the other side of the capacitor C21 is connected to the resistor R44 and the pin 1 of the comparator A through the resistor R41 respectively, the other side of the capacitor C21 is also connected to the resistor R48 and the pin 7 of the comparator B through the resistor R45 respectively.

Images