Electronic Components Datasheet Search |
|
ICL7149CPL Datasheet(PDF) 6 Page - Intersil Corporation |
|
ICL7149CPL Datasheet(HTML) 6 Page - Intersil Corporation |
6 / 13 page 3-38 Range 1 Deintegrate At the beginning of the deintegrate cycle, the polarity of the voltage on the integrator capacitor (CINT) is checked, and either the DElNT+ or DElNT- is asserted. The integrator capacitor CINT is then discharged with a current equal to VREF/RDElNT. The comparator monitors the voltage on CINT. When the voltage on CINT is reduced to zero (actually to the VOS of the comparator), the comparator output switches, and the current count is latched. If the CINT voltage zero-crossing does not occur before 4000 counts have elapsed, the over- load flag is set. “OL” (overload) is then displayed on the LCD. If the latched result is between 360 and 3999, the count is trans- ferred to the output latches and is displayed. When the count is less than 360, an underrange has occurred, and the ICL7139 and ICL7149 then switch to range 2 - the 40V scale. Range 2 The range 2 measurement begins with an autozero cycle similar to the one that preceded range 1 integration. Range 2 cycle length however, is one AC line cycle, minus 360 clock cycles. When performing the range 2 cycle, the signal is inte- grated for 100 clock cycles, distributed throughout one line cycle. This is done to maintain good normal mode rejection. Range 2 sensitivity is ten times greater than range 1 (100 vs 10 clock cycle integration) and the full scale voltage of range 2 is 40V. The range 2 deintegrate cycle is identical to the range 1 deintegrate cycle, with the result being displayed only for readings greater than 360 counts. If the reading is below 360 counts, the ICL7139 and ICL7149 again asserts the internal underrange signal and proceeds to range 3. Range 3 The range 3V or 4V full scale measurement is identical to the range 2 measurement, except that the input signal is inte- grated during the full 1000 clock cycles (one line frequency cycle). The result is displayed if the reading is greater than 360 counts. Underrange is asserted, and a range 4 measure- ment is performed if the result is below 360 counts. Range 4 This measurement is similar to the range 1, 2 and 3 mea- surements, except that the integration period is 10,000 clock cycles (10 line cycles) long. The result of this measurement is transferred to the output latches and displayed even if the reading is less than 360. Autozero After finding the first range for which the reading is above 360 counts, the display is updated and an autozero cycle is entered. The length of the autozero cycle is variable which results in a fixed measurement period of 24,000 clock cycles (24 line cycles). DC Current Figure 4 shows a simplified block diagram of the analog section of the ICL7139 and ICL7149 during DC current measurement. The DC current measurements are very similar to DC voltage measurements except: 1) The input voltage is developed by passing the input current through a 0.1 Ω (HI current ranges), or 9.9Ω (LOW current ranges) + - + - + - TRIPLE POINT CAZ CINT RDEINT AZ DEINT- DEINT- VREF INTEGRATOR COMPARATOR TO LOGIC SECTION 6.7V ANALOG LOW I RINTI INT I 80 µA CAZ CINT RDEINT AZ AZ AZ COMMON T T DEINT+ DEINT+ V+ V- T = (INT)(AR)(AZ) AR = AUTORANGE CHOPPER AZ = AUTOZERO INT = INTEGRATE VREF 9.9 Ω 0.1 Ω HIGH I I COMMON FIGURE 4. DETAILED CIRCUIT DIAGRAM FOR DC CURRENT MEASUREMENT ICL7139, ICL7149 |
Similar Part No. - ICL7149CPL |
|
Similar Description - ICL7149CPL |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List 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 |