aduc7032 Analog Devices, Inc., aduc7032 Datasheet - Page 45

• Manufacturer Part Number: aduc7032
• Description: Microconverter Integrated, Precision Battery Sensor
• Manufacturer: Analog Devices, Inc.

Preliminary Technical Data
16-BIT
The ADuC7032 incorporates three independent sigma-delta
ADCs namely, the Current Channel ADC (I-ADC), the Voltage
Channel ADC (V-ADC) and the Temperature Channel ADC
(T-ADC). These precision measurement channels integrate on-
chip buffering, programmable gain amplifier, 16-bit sigma-
delta modulators and digital filtering and are intended for the
precision measurement of current, voltage and temperature
variables in 12V automotive battery systems.
CURRENT CHANNEL ADC (I-ADC)
This ADC is intended to convert battery current sensed
through
programmable gain mean the I-ADC can be configured to
accommodate battery current levels from ±1A to ±1500A
As shown in Figure 15 below, the I-ADC employs a sigma-delta
conversion technique to realize 16 bits of no missing codes
performance. The sigma-delta modulator converts the sampled
input signal into a digital pulse train whose duty cycle contains
IN+
IN-
VREF/
136
GND
REG_AVDD
Diagnostic Current Sources
Two 50uA IIN+ and IIN-
Current Sources
ANALOG INPUT
Diagnostic Voltage Source
VREF/136 Voltage Input
an
ANALOG INPUT
REG_AVDD
external
ANALOG TO DIGITAL CONVERTERS
ALTERNATELY REVERSED
CONVERSION CYCLE.
100μΩ shunt resistor. On-Chip
PROGRAMMABLE
THE INPUTS ARE
ANALOG INPUT
THROUGH THE
CHOPPING
SIGMA_DELTA MODULATOR.
FOR THE PGA DRIVING THE
IMPEDANCE INPUT STAGE
THE BUFFER AMPLIFIER
BUFFER AMPLIFIER
PRESENTS A HIGH
CHOP
ADC BY DEFAULT. AN EXTERNAL
REFRENCEON THE VREF PIN CAN
REFERNCE IS ROUTED TO THE
THE INTERNAL 5PPM/C
ALSO BE SELECTED
PGA
GAIN AMPLIFIER ALLOWS
RANGES FROM ±2.3mV TO
REFERENCE
PRECISION
PROGRAMMABLE GAIN
EIGHT BIPOLAR INPUT
±1.2V (INT V
THE PROGRAMMABLE
AMPLIFIER
BUF
QUANTIZATION NOISE INTRODUCED
BY THE MODULATOR. THE UPDATE
RATE AND BANDWIDTH OF THIS
FILTER ARE PROGRAMMABLE
REF
THE SINC 3 FILTER REMOVES
Figure 15: Current ADC, Top Level Overview
VIA THE ADCFLT MMR
= 1.2V).
PROGRAMMABLE
DIGITAL FILTER
REFERNCE
INTERNAL
VREF
Rev. PrD | Page 45 of 128
MODULATOR
OF WHICH IS ALSO CHOPPED)
THE MODULATOR PROVIDES
DATA STREAM (THE OUTPUT
REPRESENTS THE SAMPLED
THE DUTY CYCLE OF WHICH
SIGMA-
SIGMA-DELTA A/D CONVERTER
DELTA
ANALOG INPUT VOLTAGE.
A HIGH FREQUENCY 1-BIT
TO THE DIGITAL FILTER,
SIGMA-DELTA
MODULATOR
PROGRAMMABLE
THE OUPUT WORD FROM THE
THE CONVERSION RESULT.
DIGITAL FILTER IS SCALED
COEFFICIENTS BEFORE
DIGITAL
FILTER
BY THE CALIBRATION
BEING PROVIDED AS
COMPARED TO A PRESET
OUTPUT SCALING
DIGITAL COMPARATOR
the digital information. A modified Sinc3 programmable low-
pass filter is then employed to decimate the modulator output
data stream to give a valid 16-Bit data conversion result at
programmable output rates from 4Hz to 8 KHz in Normal
mode and 1Hz to 2kHz in Low Power Mode.
The I-ADC also incorporates counter, comparator and
accumulator logic. This allows the I-ADC result to generate an
interrupt after a predefined number of conversions have
elapsed or if the I-ADC result exceeds a programmable
threshold value. A fast ADC-Over-Range feature is also
supported. Once enabled, a 32-bit accumulator automatically
sums the 16-bit I-ADC results.
The time to a first valid (fully settled) result on the current
channel is three ADC conversion cycles with chop mode turned
off and two ADC conversion cycles with chop mode turned on.
THE ADC RESULT IS
COEFFICIENT
COEFFICIENT
THRESHOLD
OFFSET
GAIN
ARCHITECTURE ENSURES
16 BITS NO MISSING
SIGMA-DELTA ADC
THE SIGMA-DELTA
CHOP
CODES.
THRESHOLD
AVERAGE
-
OUTPUT
OUTPUT
FORMAT
RESULT
ADC
ADC
x
COUNTS DOWN/RESET IF ADC
RESULT<THRESHOL. GENER-
+
ATES AN INTERRUPT ON
THRESHOLD COUNTER
AS PART OF THE CHOPPING
RESULT>THRESHOLD
COUNTER OVERFLOW
IMPLEMENTATION, EACH
SUMMED AND AVERAGED
WITH ITS PREDECESSOR
COUNTS UP IF ADC
DATA-WORD OUTPUT
FROM THE FILTER IS
OUTPUT AVERAGE
ACCUMULATES THE ADC
ADC ACCUMULATOR
RESULT
ACCUMULATOR
ADC RESULT
ADC RESULT
THRESHOLD
COUNTER
COUNTER
RESULT
ADC
INTERRUPT IF THE CURRENT
ADuC7032
ADC FAST OVER-RANGE
GENERATES AN ADC
GENERATES AN INTERRUPT
INPUT IS GROSSLY
ON COUNTER OVERFLOW
ADC RESULT COUNTER
OVER-RANGED
COUNTS ADC RESULTS,
ADC INTERRUPT GENERATOR
GENERATES AN ADC RESULT
FROM ANY ONE OF FOUR
SOURCES
INTERRUPT
ADC