ES5120
3 3/4 DIGIT A/D CONVERTER
１０．ERAL THEORY OF OPERATION
10.1 Analog Section :
In addition to the basic integrate and deintegrate
dual slope phases discussed above, the ES5120 design
incorporates an "Auto Zero" phase. The additional phase
ensure that the integrator starts at zero volts (even
after a severe over-range conversion) and that all offset
voltage errors (buffer amplifier, integrator and compar-
ator) are removed from the conversion. A true digital
zero reading is assured without any external adjustments.
A complete conversion consists of four distinct phases :
(1) Auto Zero Phase
(2) Signal Integrate Phase
(3) Reference Deintegrate Phase
(4) ADC SYSTEM Timing
(1) Auto Zero Phase
During the Auto Zero phase, the differential input signal is
disconnected from the measurement circuit by opening
internal analog switches and the internal nodes are shorted
to Analog Common (0 volt ref.) to establish a zero input
condition. Additional analog switches close a feedback
loop around the integrator and comparator to permit
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