A Self-biased Current Source, using an Asymmetric Bulk-modified MOS Composite Transistor

In this work a new topology for a self-biased current reference, based on an asymmetric bulk-modified MOS (ABM) composite transistor is presented. Two current references based in this technique were designed: a 13.5nA current reference in a 1.5μm CMOS technology, and a 100nA current reference in a 0.18μm CMOS technology. The latter was designed to minimize the temperature dependence of the output current; the result was less than 5% from 0°C to 100°C, which is a very good result in comparison to other reported similar current references.Agencia Nacional de Investigación e Innovació

An asymmetrical bulk-modified composite MOS transistor with enhanced linearity

In this work, an asymmetrical bulk-linearized composite MOSFET is presented, with an enhanced linear range and an equivalent saturation voltage of up to several hundred mV even in weak inversion, allowing to implement large MOS resistors. Some preliminary measurements are presented, as well as 150MΩ and 200MΩ equivalent resistors simulations, with a linear range up to 1.5V. A low frequency, 40dB gain, fully integrated cardiac sensing channel filter/amplifier is also shown. Taking advantage of the proposed technique, the circuit consumes only 25nA of supply current.Agencia Nacional de Investigación e Innovació

Siwa: a RISC-V RV32I based micro-controller for implantable medical applications

The design of Siwa1, a compact low power custom system on chip (SoC), targeted for implantable/wearable applications, is reported in this paper. Siwa is based on a RISC-V RV32I architecture. It has a centrally controlled non-pipelined structure, and it includes a control interface for an integrated sensing and stimulation device for biological tissues as well as standard communication interfaces. Siwa was developed from scratch using System Verilog, and implemented in a 180nm CMOS technology; Siwa includes a latch based register file c apable to read and write in one clock cycle with an area 30% smaller and a power consumption 25% lower with respect to an equivalent flip flop implementation; also, it has an estimated average power consumption of 70μW (48pJ/cycle) which is comparable to other micro-controllers commonly used in IMD applications.Agencia Nacional de Investigación e Innovació

Siwa: A custom RISC-V based system on chip (SOC) for low power medical applications

This work introduces the development of Siwa, a RISC-V RV32I 32-bit based core, intended as a flexible control platform for highly integrated implantable biomedical applications, and implemented on a commercial 0.18 m high voltage (HV) CMOS technology. Simulations show that Siwa can outperform commercial micro-controllers commonly used in the medical industry as control units for implantable devices, with energy requirements below the 50 pJ per clock cycle.Agencia Nacional de Investigación e Innovació

Integrated programmable current source for implantable medical devices

In this work, the design and implementation of a 25mA (max), 8 bits integrated programmable current source for implantable medical devices is presented. The proposed circuit includes a six-bits trimming mechanism to balance sink/source outputs to a precision below 1%. The current source is powered by an external supply voltage of up to 10V. The circuit was fabricated in a 0.18um HV CMOS technology, some preliminary measurements are also presented showing a close agreement with previously simulated results.Agencia Nacional de Investigación e Innovació