Method for detecting line insulation of circuit board

Abstract

The invention relates a method for detecting line insulation of a circuit board. According to the method, the insulating resistance of the circuit board is detected by adopting an insulating resistance testing circuit of the circuit board. The detection method comprises the following steps of: providing a compensating circuit which is connected with the compensating end of a front end circuit; and generating compensating voltage or current by using the compensating circuit to eliminate the error of output total voltage Uo of the front end circuit, wherein the error only refers to an error generated by the base current IB of a triode which is in a conducted state in a triode array flowing into a sampling resistor. According to the method, an amplifying circuit consists of multiple stages, and the amplifying time is adjustable and high; an error output quantity caused by the base current of the triode in the measuring circuit is compensated through the compensating circuit, and an error caused by the base current of the triode in the triode array is eliminated; and double-end differential mode input is adopted at the first stage of the amplifying circuit, and single-end output is adopted at the tail stage of the amplifying circuit, so that the amplifying circuit has the characteristics of high common-mode rejection capability, low null drift, high input impedance, low output impedance and the like.

Description

technical field [0001] The invention relates to a detection method of a circuit board, in particular to a method for detecting circuit board circuit insulation. Background technique [0002] In the modern electronics industry, printed circuit boards have been widely used, and various methods for detecting the quality of circuit boards have emerged due to the urgent needs of the industry. The contact detection of the circuit board can be understood as the computer-controlled automatic online detection ICT (In-CircuitTester). The tested circuit board is fixed on the test platform fixture through a pneumatic mechanism, and n tested The number of measuring points (usually the number of n is determined by the number of pads or vias on the circuit board), through the probes connected to the test nodes in the triode switch array and the pads or vias fully contacted, respectively measured each The relationship between the current and voltage between the nodes, so as to obtain the c...

AI Technical Summary

Problems solved by technology

[0003] In the prior art, only the conduction resistance of the line segment is often detected, and the insulation resistance is not detected, resulting in inaccurate test data and misjudgment, and because the test part uses an array circuit composed of triodes, the above-mentioned The base current of the triode in the array circuit is sent to the subsequent circuit for processing together with the test current, causing the final test data to deviate from the standard data, resulting in misjudgment

Images