Robert Greenwell

Flexible Electronics: Thin Silicon Die on Flexible Substrates

Silicon thinned to 50 mum and less is flexible allowing the fabrication of flexible and conformable electronics. Two techniques have been developed to achieve this goal using thinned die: die flip chip bonded onto flexible substrates [polyimide and liquid crystal polymer (LCP)] and die flip chip laminated onto LCP films. A key to achieving each of these techniques is the thinning of die to a thickness of 50 mum or thinner. Conventional grinding and polishing can be used to thin to 50 mum. At 50 mum, the active die becomes flexible and must be handled by temporarily bonding it to a holder die for assembly. Both reflow solder and thermocompression assembly methods are used. In the case of solder assembly, underfill is used to reinforce the solder joints. With thermocompression bonding of the die to an LCP substrate, the LCP adheres to the die surface, eliminating the need for underfill.

SOI-based integrated circuits for high-temperature power electronics applications

The growing demand for hybrid electric vehicles (HEVs) has increased the need for high-temperature electronics that can operate at the extreme temperatures that exist under the hood. This paper presents a high-voltage, high-temperature SOI-based gate driver for SiC FET switches. The gate driver is designed and implemented on a 0.8-micron BCD on SOI process. This gate driver chip is intended to drive SiC power FETs for DC-DC converters and traction drives in HEVs. To this end, the gate driver IC has been successfully tested up to 200ºC. Successful operation of the circuit at this temperature with minimal or no heat sink, and without liquid cooling, will help to achieve higher power-to-volume as well as power-to-weight ratios for the power electronics modules in HEVs.

A SiGe BiCMOS instrumentation channel for extreme environment applications

A instrumentation channel has been designed, implemented and tested in a 0.5-mum SiGe BiCMOS process. The circuit features a reconfigurable Wheatstone bridge network that interfaces a range of external sensors to signal processing circuits. Also, analog sampling has been implemented in the channel using a flying capacitor configuration. Measurement results show the instrumentation channel supports input signals up to 200 Hz.

High-temperature SOI-based gate driver IC for WBG power switches

High-temperature integrated circuits fill a need in applications where there are obvious benefits to reduced thermal management or where circuitry is placed away from temperature extremes. Examples of these applications include aerospace, automotive, power generation, and well-logging. This work focuses on automotive applications in which the growing demand for hybrid electric vehicles (HEVs), Plug-in-hybrids (PHEVs), and Fuel-cell vehicles (FCVs) has increased the need for high-temperature electronics that can operate at the extreme ambient temperatures that exist under the hood of these vehicles, which can be in excess of 150°C. Silicon carbide (SiC) and other wide-bandgap power switches that can function at these temperature extremes are now entering the market. To take full advantage of their potential, high-temperature capable circuits that can also operate in these environments are required.

PVT Compensation for Wilkinson Single-Slope Measurement Systems

A pulse-width locked loop (PWLL) circuit is reported that compensates for process, voltage, and temperature (PVT) variations of a linear ramp generator within a 12-bit multi-channel Wilkinson (single-slope integrating) Analog-to-Digital converter (ADC). This PWLL was designed and fabricated in a 0.5- μm Silicon Germanium (SiGe) BiCMOS process. Simulation and silicon measurement data are shown that demonstrate a large improvement in the accuracy of the PVT-compensated ADC over the uncompensated ADC.

A sige BiCMOS instrumentation channel for extreme environment applications

A instrumentation channel has been designed, implemented and tested in a 0.5-mum SiGe BiCMOS process. The circuit features a reconfigurable Wheatstone bridge network that interfaces a range of external sensors to signal processing circuits. Also, analog sampling has been implemented in the channel using a flying capacitor configuration. Measurement results show the instrumentation channel supports input signals up to 200 Hz.

SOI Based Voltage Regulator for High-Temperature Applications

Developments in automotive (particularly hybrid-electric vehicles), aerospace, and energy production industries have led to expanding research interest in integrated circuit (IC) design toward high-temperature applications. A high-voltage, high-temperature silicon-on-insulator (SOI) process allows for circuit design to expand into these extreme environment applications. Nearly all electronic devices require a reliable supply voltage capable of operating under various supply voltages and load currents. These supply voltages and load currents can be either DC or time-varying signals. In this work, a stable supply voltage for embedded circuits is generated on chip via a voltage regulator producing a stable 5-V output voltage. Although applications of this voltage regulator are not limited to gate driver circuits, this regulator has been developed to meet the demands of a gate driver IC. The voltage regulator must be able to provide reliable output voltage over an input range from 10 V to 30 V, a temperature ...

SOI-Based Integrated Gate Driver Circuit for High-Temperature Applications

The growing demand for hybrid electric vehicles (HEVs) has increased the need for high-temperature electronics that can operate at the temperatures that exist under the hood of these vehicles. In many cases this requires the use of thermal management systems to allow for the use of components not designed to operate at the ambient temperatures found in the engine compartment of an HEV. These systems add weight and complexity, which can increase the overall cost and reduce the efficiency of the vehicle. The alternative is to develop circuits and systems capable of operating with reduced or no thermal management. To this end, the latest version of our high-temperature gate driver integrated circuit (IC) has been developed. Designed and implemented on a 0.8-micron bipolar-CMOS-DMOS (BCD) on silicon-on-insulator (SOI) process, this gate driver chip is intended to drive silicon carbide (SiC) and other wide-bandgap (WBG) power field-effect transistors (FETs) for DC-DC converters and traction drives in HEVs. To ...

A UNIVERSAL SOI-BASED HIGH TEMPERATURE GATE DRIVER INTEGRATED CIRCUIT FOR SiC POWER SWITCHES WITH ON-CHIP SHORT CIRCUIT PROTECTION

In recent years, increasing demand for hybrid electric vehicles (HEVs) has generated the need for reliable and low-cost high-temperature electronics which can operate at the high temperatures under the hood of these vehicles. A high-voltage and high temperature gate-driver integrated circuit for SiC FET switches with short circuit protection has been designed and implemented in a 0.8-micron silicon-on-insulator (SOI) high-voltage process. The prototype chip has been successfully tested up to 200°C ambient temperature without any heat sink or cooling mechanism. This gate-driver chip can drive SiC power FETs of the DC-DC converters in a HEV, and future chip modifications will allow it to drive the SiC power FETs of the traction drive inverter. The converter modules along with the gate-driver chip will be placed very close to the engine where the temperature can reach up to 175ΰC. Successful operation of the chip at this temperature with or without minimal heat sink and without liquid cooling will help achieve greater power-to-volume as well as power-to-weight ratios for the power electronics module.

Design and Qualification Methodology for a Successful Technology Infusion for a Wide Temperature Op-Amp

In this paper, we present a methodology for design and qualification of microelectronics for low temperature applications, which has enabled the successful infusion of a custom designed Operational Amplifier into flight mission. The Op-Amp was designed to target a wide temperature range of -150degC to +125degC for at least 5 years operation for Mars Mission. The design and qualification methodology developed have provided the critical path for the technology infusion.