The voltage logic value of integrated circuit output

Due to the fact that the voltage logic value output by integrated circuits may not necessarily be related to all nodes in the circuit, voltage testing cannot detect non functional failure faults in integrated circuits. So, in the early 1980s, diagnostic techniques based on integrated circuit power supply currents were proposed. The power current is usually directly or indirectly related to all nodes in the circuit, so current based diagnostic methods can cover more circuit faults. However, the introduction of current diagnosis technology is not intended to replace voltage testing, but to supplement it in order to improve the detection rate and coverage of fault diagnosis.