1 5. Application Examples 5.1. Programmable compensation for analog circuits (Automated Calibration, Optimal tuning, Parameter adjustment) 5.2. Programmable delays in high-speed digital circuits (Clock skew compensation) 5.3. Automated discovery/invention by Evolutionary Algorithms (Creative Design) 5.4. EDA Tools, analog circuit design 5.5. Adaptation to extreme temperature electronics (Survivability by EHW) 5.6. Fault-tolerance and fault-recovery 5.7. Evolvable antennas (In-field adaptation to changing environment) 5.8. Adaptive filters (Function change as result of mission change) 5.9 Evolution of controllers

Analogue EHW chip for cellular phones –Higuchi, Japan Off-line analogue ＥＨＷ Intermediate Frequency Filter –Analogue Band-pass Filter –Must be compact and fast: LSI required –Large market Variations in analogue components performance are adjusted by GA. Installed in cellular phones since Dec From presentation by T. Higuchi, Japan, at EH-2003

3 Values of the manufactured analog circuit components differ from the precise specifications Poor yield rates especially for high-end analogue circuits e.g. IF filter: a 1% discrepancy from the center frequency unacceptable From presentation by T. Higuchi, Japan, at EH-2003 Process Variations in Analog LSIs

4 Cures Conventional Approach Use “large” analog components –Manufacturing error due to process variations becomes relatively small –Price: Higher manufacturing cost Greater power consumption AI/GA Approach Use GA to control calibration –Provide many adjustment/calibration points in the circuit Improved Yield Rates –adjustment for each circuit Smaller Circuits –use of smaller size analog components Less Power Consumption Calibration at a LSI tester – a few seconds per a chip Mass-ProductionFrom presentation by T. Higuchi, Japan, at EH-2003

5 Gm amplifier Transconductance value: Variations by up to as much as 20% Calibration by varying bias currents Bias Current From presentation by T. Higuchi, Japan, at EH-2003

6 Review: Transconductance amplifiers The OTA is a transconductance type device, which means that the input voltage controls an output current by means of the device transconductance, labeled gm. What is important and useful about the OTA’s transconductance parameter is that it is controlled by an external current, the amplifier bias current, IABC. Active filters are a standard application of the op-amp which can benefit greatly from the controllability of the OTA. What makes the OTA so attractive in these circuits is the ability to form filter circuits with voltage-variable control (via the IABC input) over a n umber of key performance parameters of the filter. The controlled parameter can be the midband gain of the circuit. Alternatively, OTA- based active filters can use the external bias setting to control the location of the critical frequency, or 3-dB frequency, in a filter. The next logical step in controllability is the provision for independent gain and critical frequency setting. A number of other active filters can be realized with th e OTA. These provide the ability to not only change the critical frequency, the gain, or both, but also to preserve the shape of the response. For instance, one might want to control the critical frequency of the filter, but without altering the passband ripple. It is even possible to change the type of response from lowpass to allpass to highpass by continuous adjustment of the transconductance gm.

7 Calibration by GA Configuration Bits 100 i 0 2 i 0 i 0 Register Bias Current Controller The bias currents can be varied subtly. 4 i 0 Bias Current The GA seeks the optimal configuration bits. evaluation : the measured gain and group delay From presentation by T. Higuchi, Japan, at EH-2003

8 GA-calibrated IF filter ( Gm : Transconductance Amplifier ) OUT

9 Gm-C IF Filter LSI Intermediate Frequency Filter –Center Frequency : 455kHz –Bandwidth : 21kHz 39 Gm amplifiers within the filter –GA calibrate all Gm values to conform to the specifications From presentation by T. Higuchi, Japan, at EH-2003

10 Specifications for the IF filter Group delay : less than 20 usec Frequency (kHz) Gain (dB) Gain (dB) Frequency (kHz) Spec. ( -3dB Points) Ideal Response From presentation by T. Higuchi, Japan, at EH-2003

11 Filter Architecture IF OUT IF IN Filter 2 w 6,…,w 11 Q 6,…,Q 11 a 1 CLK PLL Bias Current Controller Configuration Bits Filter 1 w 0,…,w 5 Q 0,…,Q 5 a 0 Filter 3 w 12,…,w 17 Q 12,…,Q 17 a 2 39 parameters Gm values w 0,…,w 17 center freq. Q 0,…,Q 17 band width a 0,…,a 2 filter gain 6th order Gm-C filter From presentation by T. Higuchi, Japan, at EH-2003

12 Calibration Experiments Yield : 97% After Calibration Before Calibration Frequency Spec. Gain 29 out of the 30 test chips could be calibrated (No chip could meet the spec. without calibration!) From presentation by T. Higuchi, Japan, at EH-2003

13 Results of GA-calibrated IF Filter Chip Filter area was reduced by 63% Power dissipation reduced by 26% Photo of the die Yield rates improved (97%) This approach can be applied to a wide variety of analog circuits Good approach for low feature size! From presentation by T. Higuchi, Japan, at EH-2003 Filter 1 Filter 2 Filter 3 PLL DAC