Andre Luis Vilas Boas

Power management controller for automotive MCU applications in 90nm CMOS technology

This paper describes the design and test of a Power Management Controller (PMC) for microcontroller unit (MCU) automotive applications in 90nm CMOS technology. The requirements for the PMC include a small, robust architecture with low I/O pin count and flexible extended features, no power sequence dependence and real-time monitoring of critical analog signals. The PMC contains circuitry to generate an internal 3.3V regulated supply voltage and to control the regulation of 1.2V supply with external NPN ballast transistor. It also comprises Low Voltage Detector (LVD) and Power-on Reset (POR) circuits for the 1.2V, 3.3V, 3.3V/5V supply of the closest I/O segment, and the unregulated 5V supply. A three way switch circuit is used to bias the N-well of both voltage regulators. This is required to guarantee correct bias and functioning over all start-up conditions and effective power down for both regulators. The circuit has been fabricated in 90nm CMOS technology and silicon results are provided.

A very low power area efficient CMOS only bandgap reference

The design of a novel all-MOS low-power bandgap reference in an open loop topology is described. A forward biased p-n junction with complementary to absolute temperature coefficient (CTAT) is combined with a cascade of Self-Cascode MOSFET (SCM) structures providing a proportional to absolute temperature (PTAT) voltage to create the bandgap voltage reference. Using the Advanced Compact MOSFET (ACM) model the design of the cascade of SCMs is fairly straightforward. The design methodology is based on the concept of inversion level using current as the main variable. At room temperature, the nominal output reference voltage is 1.32V, and the total current consumption is 65nA (20nA for the current generator and 45nA for the bandgap reference itself). The circuit has been integrated in a 0.18μm standard CMOS process, and occupies an area of 0.01mm2. Power supply sensitivity is +/-0.7% from 1.55V (minimum operation voltage) to 3.3V After trimming, temperature compensation is attained with a total bandgap voltage variation of 0.6% from -40°C to 125°C, equivalent to 36ppm/°C.

A CMOS fast transient response low-dropout regulator with a compact NMOS output driver

We present a CMOS low-dropout voltage regulator with a high-speed NMOS compact driver suitable for supplying on-chip voltages for the digital core of a SoC. The LDO is part of a power management controller hardblock integrated within a microcontroller. The die area of the circuit implemented in a 90nm CMOS process is only 0.054mm^2. Experimental results show that the developed LDO can supply up to 15mA and it presents a very fast transient response, with a settling time of approximately 30ns and a voltage drop of 200mV when the load current changes from 100nA to 9mA.

A switched-capacitor Programmable Gain Amplifier optimized for motor control application using correlated double sampling technique

This paper describes the design of a 12-bit fully differential Switched-Capacitor (SC) Programmable Gain Amplifier (PGA) optimized for motor control application and implemented using Correlated Double Sampling (CDS) technique. The PGA performs differential to single-ended conversion and operates in concert with an Analog-to-Digital Converter (ADC). Fabricated in a standard 4-metal single-poly 0.25um CMOS process, it occupies an area of 0.18mm2 with a total dissipation of 450uA and operates from −40°C to 135°C. The circuit has been integrated on Freescales MC56F8006 family of Digital Signal Controllers (DSC) along with other on-chip peripherals designed to enhance the performance of motor control and power conversion applications.

Zero quiescent current startup circuit with automatic turning-off for low power current and voltage reference

A zero quiescent current startup circuit with automatic turning-off for low power current and voltage reference is presented. The proposed startup uses positive feedback to sense an internal bias voltage of the main current/voltage reference circuit and guarantees it properly achieves its desired steady state condition. After that, the start-up circuitry automatically turns off itself. Hence, there is no power consumption on start-up circuitry after start-up process. Also, its very robust architecture is compatible with standard CMOS processes and is able to operate down to sub-1V making it ideal for single battery applications. The circuit has been integrated in a 45nA current source implemented in TSMC 0.25um process. Transient response of the start-up circuitry has been measured as well as supply voltage variation has been evaluated to prove start-up operation.

Self-adaptable slew rate control output buffer for embedded microcontroller port applications

Design guidelines for output buffers with adaptive slew rate control are presented in this paper. By adapting the output driver strength against supply voltage variations it is possible to meet the slew rate requirements as well as to commit with Electromagnetic interference (EMI) compliance levels for an wide supply voltage range. An output buffer based on the proposed methodology was designed and fabricated using a 0.25um SMARTMOS process technology.