Design of multi - frequency constant current source based on intracellular and extracellular fluid capacity

Excitation current sources in multi-frequency detection systems for intracellular and extracellular fluid measurement, need to meet special requirements such as spectral width, waveform stability, phase synchronization and high output impedance. In this paper, the second generation of current transmitter AD844 as the core of the mirror image feedback current source was been designed, the theoretical analysis of the working principle and to improve and supplement, based on a current feedback operational amplifier and feedback loop technology, high precision low power voltage control Battery. Derive the transmission characteristics of the circuit, analyze the circuit output current and the equivalent output characteristic impedance. The load experiment shows that the load voltage waveform of the current source is consistent with the actual voltage waveform at 10kHz-1MHz frequency. The output current of the voltage control current source is constant and has a high output impedance, which meets the measurement experiment requirements, so this method can be regarded as an effective approach for ideal constant-current source.