Abstract: In order to meet the demand for a wide input common-mode range (ICMR) required by high-side current-sensing amplifiers,input stages whose ICMR can exceed the supply rail were researched and analyzed.Combining the advantages of different circuit structures,a wide ICMR input stage having low input bias current was proposed.With the input stage,a current-sensing amplifier was designed and implemented in a 1.5μm BCD process.It can work at both high and low common mode voltages.The test results show that its ICMR is from 0 to 30V at a 5V supply voltage.Its total output error is below 1.67%.

Key words: wide input common-mode range, input stage, high-side current-sensing, BCD technology