 |
Zakładka z wyszukiwarką danych komponentów |
|
|
Zakładka z wyszukiwarką danych komponentów |
|
AD7150 Arkusz danych(PDF) 11 Page - Analog Devices |
|
||||||||||||||||||||||||||||||
AD7150 Arkusz danych(HTML) 11 Page - Analog Devices |
|
|
11 / 28 page  AD7150 Rev. 0 | Page 11 of 28 COMPARATOR AND THRESHOLD MODES The AD7150 comparators and their thresholds can be programmed to operate in several different modes. In an adaptive mode, the threshold is dynamically adjusted and the comparator output indicates fast changes and ignores slow changes in the input (sensor) capacitance. Alternatively, the threshold can be programmed as a constant (fixed) value, and the output then indicates any change in the input capacitance that crosses the defined fixed threshold. The AD7150 logic output (active high) indicates either a positive or a negative change in the input capacitance, in both adaptive and fixed threshold modes (see Figure 25 and Figure 26). POSITIVE THRESHOLD INPUT CAPACITANCE OUTPUT OUTPUT ACTIVE TIME POSITIVE CHANGE Figure 25. Positive Threshold Mode Indicates Positive Change in Input Capacitance NEGATIVE THRESHOLD INPUT CAPACITANCE OUTPUT OUTPUT ACTIVE TIME NEGATIVE CHANGE Figure 26. Negative Threshold Mode Indicates Negative Change in Input Capacitance Additionally, for the adaptive mode only, the comparators can work as window comparators, indicating input either inside or outside a selected sensitivity band (see Figure 27 and Figure 28). POSITIVE THRESHOLD NEGATIVE THRESHOLD INPUT CAPACITANCE OUTPUT OUTPUT ACTIVE TIME INPUT INSIDE THRESHOLD WINDOW Figure 27. In-Window (Adaptive) Threshold Mode POSITIVE THRESHOLD NEGATIVE THRESHOLD INPUT CAPACITANCE OUTPUT OUTPUT ACTIVE TIME INPUT OUTSIDE THRESHOLD WINDOW Figure 28. Out-Window (Adaptive) Threshold Mode ADAPTIVE THRESHOLD In an adaptive mode, the thresholds are dynamically adjusted, ensuring indication of fast changes (for example, an object moving close to a capacitive proximity sensor) and eliminating slow changes in the input (sensor) capacitance, usually caused by environment changes such as humidity or temperature or changes in the sensor dielectric material over time (see Figure 29). THRESHOLD INPUT CAPACITANCE OUTPUT OUTPUT ACTIVE TIME FAST CHANGE SLOW CHANGE Figure 29. Adaptive Threshold Indicates Fast Changes and Eliminates Slow Changes in Input Capacitance DATA AVERAGE The adaptive threshold algorithm is based on an average calculated from previous CDC output data. The response of the average to an input capacitance step change (more exactly, response to the change in the CDC output data) is an exponential settling curve, which can be characterized by the following equation: ) 1 ( ) 0 ( ) ( / TimeConst N e Change Average N Average − + = where: Average(N) is the value of average N complete CDC conversion cycles after a step change on the input. Average(0) is the value before the step change. TimeConst can be selected in the range between 2 and 65,536, in steps of power of 2, by programming the ThrSettling bits in the setup registers. See Figure 30 and the Register Descriptions section. INPUT CAPACITANCE (CDC DATA) CHANGE DATA AVERAGE RESPONSE TIME Figure 30. Data Average Response to Data Step Change |
Podobny numer części - AD7150_15 |
|
Podobny opis - AD7150_15 |
|
|
Link URL |
| Polityka prywatności |
| ALLDATASHEET.PL |
| Czy Alldatasheet okazała się pomocna? [ DONATE ] |
O Alldatasheet | Reklama | Kontakt | Polityka prywatności | Linki | Lista producentów All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Polish ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
