Integration of Low Power, High-Frequency Digitally Controlled SMPS-Power Management for Portable Applications (AC122-101-0)

SynopsisThis short course provides a systematic approach to the design and integration of digitally controlled switch-mode power supplies (SMPS) for DC-DC converters operating at high switching frequencies, ranging from a fraction of MHz to 20 MHz. It is expected that the audience attending this course has knowledge about basic switching converter topologies and understands fundamentals of conventional feedback control theory. We expect that the audience will obtain a useful insight into problems related to monolithic integration of digital controlled SMPS and gain understanding of basic design principles used in their practical realization.

The first part of the seminar, will show basic digital control structures (PWM and current mode) and address problems of their high-power consumption, quantization effects, and large on-chip area. Specifically, difficulties in the design of basic functional blocks, such as, analog-to-digital converter (ADC), compensator, digital pulse-width modulator (DPWM), and current sensing circuits will be addressed. We will then introduce different architectures for each of these blocks with low current consumption, fast processing time, and small on-chip area. A survey of ADC architectures will include flash converters, delay-line and ring oscillator-based structures, as well as programmable ADCs. Compensators will be presented through conventional PID and nonlinear multi-mode structures. Delay line, hybrid, segmented, and segmented-ring DPWM architectures will also be described and their characteristics assessed. For current mode control, full-digital and mixed-signal architectures will be explained. We will describe operation and design of current-sense, i.e. current mirror, senseFETs and corresponding wide-bandwidth amplifier and show methods for their optimization.

The second part begins with a review of smart power integrated circuit technology. This includes a survey of current power devices, fabrication processes, integration issues and existing applications. Problems related to the realization of power transistors and gate drivers in latest deep submicron technologies will be addressed. Accordingly, guidelines for effective power MOSFETs design in deep submicron technologies will be given. Special attention will be given to design challenges such as device layout, isolation techniques, limitations on power and thermal dissipation, gate drive circuits and output stage segmentation. We will also talk about effective IC packaging and integration with micro-inductors and capacitors.

We will also demonstrate design principles and showcase potential advantages of digital control. We will show a step-by-step implementation of two digitally controlled SMPS. First is a current-mode controlled 10 MHz converter with a segmented power stage. The second example will show a multi-mode digital power management IC consisting of dual-mode controller and high frequency power stage. At heavy loads the dual-mode controller operates as PWM regulator, while, when the load is light it performs digital pulse-frequency modulation. In addition, the concept of using digital spread spectrum to suppress EMI will also be demonstrated.

What previous participants say about this course
Answers to the question 'what did you like most about the course'

• "A lot of examples" - 16 Aug 07
• "Auto segment mode control of power management" - 16 Aug 07
• "DSP application in the power saving" - 16 Aug 07
• "Power management for portaple application" - 16 Aug 07
• "Practical examples included" - 16 Aug 07
• "The knowledge about handling panier in IC" - 16 Aug 07
• "Theory supported by lots of lab experiment case study" - 16 Aug 07
• "Theory comparing to practical result" - 16 Aug 07

What You Will LearnThis is a two days intensive course that covers the design and implementation of a complete integrated digitally controlled DC-DC converter, including detailed explanation of digital controller, power stage, and gate drivers. The format will include approximately five lecture hours each day followed by hands-on simulation exercises.

Who Should AttendTechnicians, engineers, circuit designers, and managers involved in design, testing or reliability of monolithic integration of digital-controlled SMPS including:

• Reliability engineering
• Yield analysis engineering
• Product engineering
• FA engineering
• Application engineering

PrerequisitePreferrably with knowledge of basic switching converter topologies and fundamentals of conventional feedback control theory.

Course MethodologyThis course is presented classroom style, with case studies to illustrate the concepts taught.

Course Duration2 days, 9am-5pm

Course Structure1.1 Review of basic digital control architectures

• Digital PWM controller and its analog equivalent
• Current program mode controllers
• All-digital implementation
• Mixed-signal digital controllers

• High-frequency high-resolution requirements and sources of power losses
• Quantization effects
• Design optimization of digital pulse-width modulated converters
• Minimal hardware requirements for ADC, Compensator and DPWM

• ADC architectures: Flash converter, Windowed flash
• ADCs with non-uniform quantization steps
• Delay-line and ring oscillator based structures
• ADC with programmable reference
• Compensator Implementations
• PID compensator
• High-order structures
• Non-linear multi-mode compensators
• A review of DPWM Architectures and their limitations
• Hybrid architectures
• Segmented DPWM
• Segmented ring
• Sigma-delta and dithering structures

• Current sensing (sense FET topology and wide bandwidth amplifier)
• Multi-mode current sense circuits and all digital implementation

• MOSFET vs. Bipolar Power Transistors
• Breakdown Voltage
• Ron, Gate Charge, FOM

• Isolation Techniques: Self, Junction, and Dielectric Isolation
• HVCMOS
• BCD

• Half bridge
• H-bridge
• gate drive circuits, level shifters

• Die Attachment
• Wire Bonding
• High Pin-count Packages

• Display drivers
• Motor Drive
• DC-DC converters