Programmable dynamic over-current testing device

Abstract

The utility model relates to a programmable dynamic over-current testing device, which is characterized by comprising a sampling resistor, a channel switch, a DTC access switch, a short power switch, a short ground switch, an operational amplifier circuit, an AD sampling circuit, a port A and a port B. The port A is connected with the sampling resistor, the sampling resistor and the port B are connected with the channel switch, the DTC access switch is connected with the sampling resistor, and the sampling resistor is connected with the short power switch. One ends of the short power switch and the short ground switch are connected with the DTC access switch, the other end of the short power switch is connected with a power supply, the other end of the short ground switch is grounded, two ends of the sampling resistor are connected with the operational amplifier circuit, and the operational amplifier is connected with the AD sampling circuit. By adopting the technical scheme, the utility model provides the programmable dynamic over-current testing device which can sample channel current, is programmable in sampling rate, can quickly sample current change time, can programmably set channel protection characteristics and cut off output in specified time, and only needs to be connected in series with a driving channel, so that the testing efficiency is greatly improved. And other peripheral equipment does not need to be added and changed.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, in particular to a programmable dynamic overcurrent testing device. Background Art

[0002] Overcurrent protection is a protection method that activates the protection device when the current exceeds a predetermined maximum value. When the current flowing through the protected component exceeds a preset value, the protection device is activated and uses a time limit to ensure the selectivity of the action, causing the circuit breaker to trip or give an alarm signal. However, there is often another concept in product design, "overcurrent protection time"; when defining the product, it is generally stated that when the port current exceeds the rated current, the overcurrent protection will be performed within or outside a certain period of time to shut down the output.

[0003] Protection within the specified time: For components like vehicle body lights, immediate protection is generally required after overcurrent occurs to avoid short circuits and require immediate response.

[0004] For example, the headlight driver stipulates that protection must be performed 200ms after overcurrent. Then the following problems will occur:

[0005] Question 1: How to determine whether the overcurrent protection is within 200ms?

[0006] Question 2: How to test and obtain the fastest over-current protection time?

[0007] Protection outside the specified time: In addition to immediate overcurrent protection, there is also a type of overcurrent protection that starts protection only after a certain period of time has passed. For example, electric windows may encounter certain obstacles (dust, thermal expansion and contraction of rubber strips in winter) during the rise and fall process, which may cause the current to occasionally exceed the rated value. However, it is necessary to try to raise and lower the window. In this case, it is defined that the port will shut down the output after a certain period of time has passed the current, delaying the response.

[0008] For example, the electric window driver is required to shut down the output for protection 200ms after overcurrent. Then the following problems will occur:

[0009] Question 1: How to determine whether the overcurrent protection is after 200ms?

[0010] Question 2: If the overcurrent lasts for only 190ms, will the product report an overcurrent DTC? Summary of the invention

[0011] Purpose of the utility model: In order to overcome the defects of the prior art, the utility model provides a programmable dynamic overcurrent test device, which can sample channel current, has a programmable sampling rate, can quickly sample current change time, and can programmably set channel protection characteristics to shut down the output at a specified time. The device only needs to be connected in series on the drive channel without adding or changing other peripheral devices.

[0012] The technical solution of the utility model is a programmable dynamic overcurrent test device, comprising a sampling resistor, a channel switch, a DTC access switch, a short power switch, a short ground switch, an operational amplifier circuit, an AD sampling circuit, an A port and a B port, wherein the A port is connected to the sampling resistor, the sampling resistor and the B port are connected to the channel switch, the DTC access switch is connected to the sampling resistor, one end of the short power switch and the short ground switch is connected to the DTC access switch, the other end of the short power switch is connected to the power supply, the other end of the short ground switch is grounded, both ends of the sampling resistor are connected to the operational amplifier circuit, and the operational amplifier is connected to the AD sampling circuit.

[0013] It is further configured that the operational amplifier circuit includes a chip, a resistor R120, capacitors C116, C119, C125 and C137, the two ends of the resistor R120 are respectively connected to the first pin and the eighth pin of the chip, one end of the capacitor C116 is connected to the positive pole of the power supply, and the other end is grounded, the seventh pin of the chip is connected to the capacitor C116, the capacitor C119 and the capacitor C125 are connected in parallel, and one end is connected to the sixth pin of the chip and the other end is grounded, the fifth pin of the chip is grounded, one end of the capacitor C137 is connected to the negative pole of the power supply, and the other end is grounded, the fourth pin of the chip is connected to the capacitor C137, and the second pin and the third pin of the chip are connected to the two ends of the sampling resistor through the filtering circuit.

[0014] It is further configured that the filtering circuit includes a resistor R2, a resistor R3, a resistor R4, a resistor R32 and a capacitor C85, wherein the resistor R2 and the resistor R3 are connected in parallel, the resistor R3 is connected to the second pin of the chip, the resistor R2 is connected to one end of the sampling resistor, the resistor R4 and the resistor R32 are connected in parallel, the resistor R32 is connected to the third pin of the chip, the resistor R4 is connected to the other end of the sampling resistor, one end of the capacitor C85 is connected between the resistor R2 and the resistor R3, and the other end is connected between the resistor R4 and the resistor R32.

[0015] The beneficial effects of the utility model are that it is intelligent, can realize automated testing, and improves testing efficiency; it is flexible, and during testing, it only needs to be connected in series to the measurement channel without changing too many devices and routes; and it is low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the structural principle diagram of the utility model;

[0017] Figure 2 is a schematic diagram of the operational amplifier circuit;

[0018] Figure 3 is a connection diagram of each switch;

[0019] Figure 4 It is the schematic diagram of AD sampling circuit;

[0020] Figure 5 This is a schematic diagram of the filter circuit. DETAILED DESCRIPTION

[0021] The technical scheme in this embodiment will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] It should be noted that in the description of the present invention, all directional indications (such as up, down, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. In the description of the present invention, the meaning of "several" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0024] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that technical personnel in this field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] like Figure 1-5 As shown, a programmable dynamic overcurrent test device includes a sampling resistor, a channel switch, a DTC access switch, a short power switch, a short ground switch, an operational amplifier circuit, an AD sampling circuit, an A port, and a B port. The A port is connected to the sampling resistor, the sampling resistor and the B port are connected to the channel switch, the DTC access switch is connected to the sampling resistor, one end of the short power switch and the short ground switch is connected to the DTC access switch, the other end of the short power switch is connected to the power supply, the other end of the short ground switch is grounded, both ends of the sampling resistor are connected to the operational amplifier circuit, the operational amplifier is connected to the AD sampling circuit, and the above switches can use relays or MOS tubes.

[0026] It is further configured that the operational amplifier circuit includes a chip, a resistor R120, capacitors C116, C119, C125 and C137, the two ends of the resistor R120 are respectively connected to the first pin and the eighth pin of the chip, one end of the capacitor C116 is connected to the positive pole of the power supply, and the other end is grounded, the seventh pin of the chip is connected to the capacitor C116, the capacitor C119 and the capacitor C125 are connected in parallel, and one end is connected to the sixth pin of the chip and the other end is grounded, the fifth pin of the chip is grounded, one end of the capacitor C137 is connected to the negative pole of the power supply, and the other end is grounded, the fourth pin of the chip is connected to the capacitor C137, and the second pin and the third pin of the chip are connected to the two ends of the sampling resistor through the filtering circuit.

[0027] The filtering circuit includes a resistor R2, a resistor R3, a resistor R4, a resistor R32 and a capacitor C85, wherein the resistor R2 and the resistor R3 are connected in parallel, the resistor R3 is connected to the second pin of the chip, the resistor R2 is connected to one end of the sampling resistor, the resistor R4 and the resistor R32 are connected in parallel, the resistor R32 is connected to the third pin of the chip, the resistor R4 is connected to the other end of the sampling resistor, one end of the capacitor C85 is connected between the resistor R2 and the resistor R3, and the other end is connected between the resistor R4 and the resistor R32.

[0028] The beneficial effects of the utility model are that it is intelligent, can realize automated testing, and improves testing efficiency; it is flexible, and during testing, it only needs to be connected in series to the measurement channel without changing too many devices and routes; and it is low cost.

[0029] The main functions are as follows:

[0030] 1. The channel current can be sampled, and the current sampling range is 0~45A, with a wide range;

[0031] 2. The sampling rate can be set programmably to quickly sample the current change time;

[0032] 3. The channel protection characteristics can be programmed to shut down the output at a specified time.

[0033] Current measurement / current duration measurement

[0034] The channel switch is closed and the DTC access switch is opened. At this time, the current flows through the sampling resistor while passing through the AB port. The operational amplifier circuit processes the voltage across the sampling resistor and transmits it to the AD sampling circuit after processing. The AD sampling circuit converts the analog quantity into a digital quantity for reading, and converts the digital quantity into the actual current value through an algorithm. At this time, the current size and duration can be measured.

[0035] Overcurrent time test

[0036] First set the test parameters, such as overcurrent and overcurrent protection response time;

[0037] The A port is connected to the sample ICD output terminal, and the B port is connected to the load to put it in an overcurrent state;

[0038] The channel switch is closed and the current on the channel switch is collected in real time. When the current is ≥ the preset current, the timing starts. When the timing is ≥ the preset corresponding time, the channel is closed to put it in a short-circuit state.

[0039] Short circuit protection time test

[0040] Port A is connected to the output port of the ICD under test;

[0041] Turn on the DIC access switch. If the ICD access switch output is high, turn on the short ground switch. If the output is low, turn on the short power switch.

[0042] The current is collected in real time, and the time when there is current is the corresponding time of the short circuit of the ICD under test.

Claims

1. A programmable dynamic overcurrent test device, characterized in that: The invention comprises a sampling resistor, a channel switch, a DTC access switch, a short power switch, a short ground switch, an operational amplifier circuit, an AD sampling circuit, an A port and a B port. The A port is connected to the sampling resistor, the sampling resistor and the B port are connected to the channel switch, the DTC access switch is connected to the sampling resistor, one end of the short power switch and the short ground switch is connected to the DTC access switch, the other end of the short power switch is connected to the power supply, the other end of the short ground switch is grounded, both ends of the sampling resistor are connected to the operational amplifier circuit, and the operational amplifier is connected to the AD sampling circuit.

2. The programmable dynamic overcurrent test device according to claim 1, characterized in that: The operational amplifier circuit includes a chip, a resistor R120, capacitors C116, C119, C125 and C137, the two ends of the resistor R120 are respectively connected to the first pin and the eighth pin of the chip, one end of the capacitor C116 is connected to the positive pole of the power supply, and the other end is grounded, the seventh pin of the chip is connected to the capacitor C116, the capacitor C119 and the capacitor C125 are connected in parallel, and one end is connected to the sixth pin of the chip and the other end is grounded, the fifth pin of the chip is grounded, one end of the capacitor C137 is connected to the negative pole of the power supply, and the other end is grounded, the fourth pin of the chip is connected to the capacitor C137, and the second pin and the third pin of the chip are connected to the two ends of the sampling resistor through the filtering circuit.

3. The programmable dynamic overcurrent test device according to claim 2, characterized in that: The filtering circuit includes a resistor R2, a resistor R3, a resistor R4, a resistor R32 and a capacitor C85, wherein the resistor R2 and the resistor R3 are connected in parallel, the resistor R3 is connected to the second pin of the chip, the resistor R2 is connected to one end of the sampling resistor, the resistor R4 and the resistor R32 are connected in parallel, the resistor R32 is connected to the third pin of the chip, the resistor R4 is connected to the other end of the sampling resistor, one end of the capacitor C85 is connected between the resistor R2 and the resistor R3, and the other end is connected between the resistor R4 and the resistor R32.

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