A 100 ampere, 100 kHz transconductance amplifier

A high current, wide band transconductance amplifier is described that provides an unprecedented level of output current at high frequencies with exceptional stability. It is capable of converting a signal voltage applied to its input into a ground-referenced output current up to 100 amperes rms over a frequency range from dc to 100 kHz with a useable frequency extending to 1 MHz. The amplifier has a 1000 watt output capability, ±10 volts of compliance, and can deliver up to 400 amperes peak-to-peak of pulsed current. The amplifier design is based on the principle of paralleling a number of precision bipolar voltage-to-current converters. The design incorporates a unique ranging system controlled by opto-isolated switches, which permit a full-scale range from 5 to 100 amperes. The design considerations for maintaining wide bandwidth, high output impedance, and unconditional stability for all loads are discussed