A 15-V Bidirectional Current Clamp Circuit for Integrated Patch Clamp Electrophysiology

This brief presents a high-voltage low-noise current clamp circuit for patch clamp electrophysiology systems. The circuit includes a novel programmable bidirectional current source spanning a pA to nA range, while supporting an 11.1-V input voltage range and being insensitive to opamp offset voltage. The measured output current noise floor is 8.0 fA/√(Hz) while sourcing 100 pA. For a measurement bandwidth of 1 kHz, the corresponding integrated noise current is 588 fARMS. The system occupies an area of 0.2 mm
²
in 180-nm CMOS and consumes 4 mA from a 15-V supply.