CMOS level shifters from 0 to 18 V output

A design methodology for level shifters voltage translators, where the output voltage ranges from 0 to 18 V, and the input voltage ranges from 2 to 5.5 V in a 0.6 lm CMOS-HV technology, is presented. This family of circuits have a special interest in the case of implantable medical devices where is common to handle previously unknown voltages either positive or negative, above or below the control logic supply VDD. Two application examples are presented: a composite switch to control negative stimuli voltage pulses, and a multi-channel programmable charge-pump voltage multiplier, aimed at charging the output capacitors of an IMD.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

A RISC-V based medical implantable SOC for high voltage a current tissue stimulus

A RISC-V based System on Chip (SoC) for high voltage and current tissue stimulus, targeting implantable medical devices, is presented. The circuit is designed in a 0.18μm HV-CMOS process, including the RISC-V 32RVI based microcontroller core, called Siwa —which includes SPI, UART and GPIO interfaces, a packet-based bus and memory controller, and 8kB SRAM—, combined with several biological tissue stimulus and sensing circuits. The complete test chip (analog+RISC-V) occupies a 5mm2 area but only 0.82mm2 correspond to the RISCV micro-controller, which operates up to 20MHz, with average energy needs of less than 48 pJ/cycle (3pJ STD), and for which several reliability and safety issues were considered.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

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

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