preliminary stuff

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Preliminary stuff. Prof. Paul Hasler. Capacitor Circuits. C 2. Q. I. V out (t). GND. dV out (t) dt. dQ(t) dt. Capacitor Circuits. C 2. . = I in. C 2 = - I in. Q. I. V out (t). We get an integration…. GND. dV out (t) dt. dQ(t) dt. Capacitor Circuits. - PowerPoint PPT Presentation


  • Preliminary stuffProf. Paul Hasler

  • Capacitor CircuitsVout(t)GNDC2QI

  • Capacitor CircuitsVout(t)GNDC2QC2 = - IinI = IinWe get an integration.

  • Capacitor CircuitsVout(t)GNDC2QC2 = - IinVout(t) = Vstart - t C2IinI = IinWe get an integration.For constant I, we get

  • Capacitor CircuitsVout(t)GNDC2QC2 = - IinVout(t) = Vstart - t C2IinI = IinWe get an integration.For constant I, we gettVout(t)

  • Capacitor CircuitsVddCVdVrefVoutVtuntVout(t)InjectionTunneling

  • Floating-Gate SystemsProf. Paul Hasler

  • Floating-Gate Devices Information Storage Floating-Gate Transistor Modifying Floating-Gate Charge- UV photo-injection- Electron tunneling- Hot-electron injection Digital Memory (EEPROMs) Analog Memory Floating-Gate Circuits Floating-Gate Systems Floating-Gate Adaptation

  • Floating-Gate Circuits Decrease Floating-Gate charge by hot-electron injection Increase Floating-Gate charge by electron tunnelingCapacitor-Based Circuits Resistors and Inductors define the circuit dynamics Capacitors are the natural elements on silicon ICsCharge Modification

  • Electron TunnelingIncreasing the applied voltage decreases the effective barrier widthThe range of tunneling currents span many orders of magnitude.(oxide voltage)-1

  • pFET Hot-Electron InjectionThe injected electrons are generated by hole impact ionizations.**Injection current is proportional to source current, and is an exponential function of Fdc.

  • Offset elimination-303-800Differential Input VoltageDifferential Output Current (nA)Direction of offset due to hot-electron injection ontothe floating gate devices. 80Small Linear RangeHuge Linear RangeOffset is less than 1 mV.

  • Tunable Voltage SourcesCfVrefTunneling CircuitryInjectSelectTunnelSelectInjectionCircuitryOutput Voltage: (if selected)

    Decreased by Tunneling

    Increased by Injection

  • Arrays of Prog.Voltage SourcesEPot elements are arranged in a linear array with a shift register selecting one element at a timeSpeed used: ~1V/ms ( range is 100V/ms to very very slow)

  • Translinear Element using Floating-Gate DevicesGNDGNDGNDIoutI1I2VddVdd

  • A Single-Ended Gm-C filter using Floating-Gate DevicesGNDGNDI1I2VddVdd-1CCCVoutVinC

  • Programming / Selectivity in FG Array channel current (Gate voltage)Large Source to drain voltage (high field for hot electrons)2 conditions for injection

  • Programming a Floating-gate DeviceTunnelingRemove charge from floating-gateLess control per deviceUsed as global eraseDecrease current for a given thresholdHot-electron injectionAdd electrons to the floating-gateIsolate devices wellProgram accuratelyIncrease current for a given gate voltage

  • Basic Programming StructureInjectionGate: Column isolationSource-Drain: Row isolationBoth: Device isolation

  • Programming a FGVtunVin+A+-OffchipBring chip up to program voltageBring drain up to match Vds(run)Set Gate volt to read currentRead Current through deviceCalculate next pulse on drainPulse Drain voltageRinse and repeat

  • Basic Programming Structure(M. Kucic, P. Smith, P. Hasler, 2000-2001)

  • Programming Board InterfaceAdditionalUserCircuitsToDrainCurrentMonitorBlockDACSPIRegulatorToGateLevelShiftersSelection LogicProgramming BoardTesting Board

  • Programming Board, v0.1

  • Answers to Typical QuestionsIs storing analog charge levels on a floating-gate reliable?Yes, we have seen little to no movement over months (like 0.01mV in EPots)Isnt floating-gate programming is slow?We are currently programming in ms times, should get to 1-10ms times as in EEPROM, and the process can operate in parallel. Does this require specialized processes?Can be built in either Double Poly or Single Poly (i.e. digital) processes

  • Automatic Floating-Gate Programming010203040506070024681012Floating-Gate Bias Current (nA)Position along the Arraycosine-cosineMeasure Current< targetCompute Drain VYesNoInject ElementSelect Next ElementSTARTGet in RangeProgramming ResultsProgramming Algorithm(NSF ITR)

  • Array Programmingo Circuit

  • Applications of Floating-Gate Circuits in Systems Programmable Filters / Adaptive Filters

    Auditory / Accoustical Signal Processing

    Image Processing

    ADCs, DACs, etc.

  • Single-Transistor pFET Synapses1. Store a weight value2. Input x stored W3. dW/dt = correlation of the f( input , a given error signal)Programmable and Adaptive Analog Processing(NSF CAREER)

  • Fourier-Based Programmable FiltersFG tuning of bandpass filters as well as coefficients(M. Kucic, P. Hasler, et. al. 1999-2001)

  • Analog Speech Front-End BlocksAnalog HMM ClassifierVQ ClassifierAnalog CepstrumOutputsCepstrumVQHMMMicrophoneDigital SignalProcessing

  • Transform ImagerOur approach allows for Bio-inspired (Retina) computation A programmable architecture High-fill factor (~50%) pixels like CMOS imagers. Can build in other neuromorphic designs into this structure

  • Layout of Imager Cell30l = 9mm39l = 11.7mm Fill Factor ~ 50%

    Fabricated in 0.5mm CMOS0.5mm 0.25mm

    Photo 8mmx6mm 3.2mmx2.4mm

    Array 128 x 128 512 x 512 (Size) (1.72mm2) (4.4mm2)

  • Adaptive Floating-Gate Circuits Full range of floating-gate circuits abilities Continuously programming (tunneling / injecting) therefore, circuits at a slower timescaleFundamental operation for adaptive systems: Adaptive Filters, Neural Networks, Neuromorphic Models of LearningEquilibrium point: Tunneling current = Injection current

  • AFGA Behavior

  • Autozeroing Floating-Gate Amplifier (AFGA)

  • Adaptive Diff-PairCan be directly extended to: Multipliers / Mixers Bump Circuits

  • Translinear Element using Floating-Gate DevicesGNDGNDIoutIinVddCCV1V2