Multiplexing voltage drop test circuit

Abstract

The invention relates to the technical field of automobile wire harness testing, and is used for testing n sample monomers R1-Rn which are connected in series between a power supply and the ground. The input end of the sample monomer Ri is connected to the input end of a switch Sai through an ith voltage divider monomer, and the output end of the sample monomer Ri is connected to the input end of a switch Sbi through an (i+1)th voltage divider monomer. The output end of a multi-channel analog switch group a and the output end of a multi-channel analog switch group b are connected with an acquisition signal input end of an MCU through an amplifier, the control signal output end of the MCU is connected with the control signal input end of each switch in the multi-channel analog switch group a and the multi-channel analog switch group b, and i is an arbitrary value from 1 to n. There is no need t arrange a power supply in each channel, the cost is low, and meanwhile, higher sampling frequency is ensured.

Description

technical field [0001] The invention relates to the technical field of automobile wiring harness testing, in particular to a multiplexing voltage drop testing circuit. Background technique [0002] With the increasing progress of automobile testing standards, the requirements for durability testing of various wiring harnesses on automobiles are also becoming more and more stringent. More and more tests require passing a large current during the test, and at the same time, it is necessary to detect the voltage drop on the wiring harness during the test. However, if a programmable power supply is used to monitor the voltage and current of the wiring harness at the same time, a lot of power supplies are required. When the number of samples is particularly large, it is obviously unrealistic to use hundreds of power supplies, and a large number of tests Online on-site will bring great difficulties to the engineer's operation. [0003] Therefore, the best way is to connect the wi...

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Problems solved by technology

[0002] With the increasing progress of automobile testing standards, the requirements for durability testing of various wiring harnesses on automobiles are also becoming more and more stringent. More and more tests require passing a large current during the test, and at the same time, it is necessary to detect the voltage drop on the wiring harness during the test. However, if a programmable power supply is used to monitor the voltage and current of the wiring harness at the same time, a lot of power supplies are required. When the number of samples is particularly large, it is obviously unrealistic to use hundreds of power supplies, and a large number of tests Online on-site will bring great difficulties to the engineer's operation

[0003] Therefore, the best way is to connect the wiring harnesses with the same test current in series to supply power, and then measure the voltage drop on each wire. The usual method is: one is to use an instrument with inspection function. The relay matrix is ​​used to connect the measurement channels to different samples, but the use of relays brings another problem, the switching speed of the relays is not enough, resulting in insufficient sampling frequency

The second is to use a complex number of voltage sensors, so that the sampling frequency is improved, but a new problem arises. When measuring the voltage drop in the middle of the series wiring harness, each channel needs to use an isolated power supply, which will add hundreds of isolated The power supply module, and the sensor also needs to adopt the bus type, because the power supply of the signal also needs to be isolated by the optocoupler, so it is useless to achieve the purpose of reducing the cost

At the same time, the structure is low in integration and bulky

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