thesis outline - uic engineeringajohar/thesis outline.pdf · 12/16/02 ©amanjyot singh johar, msrc,...
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12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Thesis Outline
Charge Pump based monolithic DC-DC converter with adaptive controller for battery powered micro-electronic devices
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Value Proposition
Oscillator-less design for dynamic switching regulation Unique start-up circuitry to ensure a faster responseNovel mixed signal design as opposed to conventional analog circuits
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Targeted Applications
Battery powered micro-electronic devicesn Wireless communication devicesn Portable computing devicesn Medical electronic devicesGeneral purpose auxiliary power supplies in products requiring multiple voltage levels
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Targeted Specifications
Input Voltage 1.5V to 2.2VOutput Voltage 2.5V to 3.2VOutput Current 40-100mATargeted Efficiency 90%Switching Frequency > 1 MHzTunable Output VoltageFly Capacitance 8uFLoad Capacitance 15uF
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Technology Summary
Inductor-less design leads to lower noiseHigher efficiency due to single stage operationTightly regulated output voltage from an available battery sourceSmaller size and lower cost
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Charge Pump Circuit
VbattCfly
Rlo
ad
Cloa
d
S1S2
S3
S4
Vcfly Vcload
Control SignalsController
Circuit
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Main Functional BlocksSwitching MatrixBand-gap Voltage ReferenceHigh Resolution ComparatorMultiplexer2 bit ADCProgrammable Logic ArrayFinite State Machine based Timing GeneratorsOperational AmplifiersStart-up Circuit Buffers and Inverters
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Control Circuit Structure
Oscillator-less control logicn Saves battery power when device is non
operationaln No EMI due to the oscillator
Dynamic response towards charging and discharging of fly and load capacitorsStart-up from low input voltagesControlled delays to avoid unnecessary switching
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Controller Circuit Design
ADC Reference Selector
Vout
Vref1
Vref2
Vref1
Vref2
Vcfly
Comparator
Comparator
Timing Generator Switching Signals
S0
S1
User Inputs
Choice of Reference Voltages
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Timing Generator
S0 = 0
S1 = 0
S0 = 1
S1 = 1
S0 = 0
S1 = 1
S0 = 1
S1 = 0
A
DC
B
S1 = 1
S1 = 0
S1 = 1
S1 = 0
S0 =
1
S0 =
0
S0 =
1
S0 =
0
•Timing Generator modeled as a 4 state Finite State Machine
•Changes in input to the machine are modeled as changes in the state of the machine
•No oscillator based component required for the control
•Circuit state sensed automatically and control signals generated
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Comparison
Prior Artn Oscillator Based controln Switching frequencies of
100-250 KHzn Low voltage operation
disabledn Huge Capacitor sizes
required (220uF to 2200uF)
n Efficiency = 60-70%
Proposed Model (Mirage)n No oscillator required for
controln State based control of
switchingn Switching frequency
anticipated > 1MHzn Capable of starting up at
low voltagesn Smaller capacitors
required (8uF and 15uF)n Efficiency >80%
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Improvement
Q-chipn Operating Frequency
= 4KHzn Huge Capacitors ~
20uF and 200uF n Oscillator-less control
based on comparator logic
Miragen Operating Frequency
anticipated > 1MHzn Smaller Capacitors ~
8uF and 15uFn Oscillator-less control
based on the finite state of the system
n User programmable variable output voltage
12/16/02©Amanjyot Singh Johar, MSRC, Department of Electrical and Computer
EngineeringUniversity of Illinois at Chicago
Parallel Operation
Vbatt
Cfly
Rlo
adC
loa
d
S1S2
S3
S4
Vcfly Vcload
Control SignalsController Circuit
Cfly
Rlo
adC
loa
d
S1S2
S3
S4
Vcfly Vcload
Control SignalsController Circuit
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