aduc7032 Analog Devices, Inc., aduc7032 Datasheet - Page 46

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

Preliminary Technical Data
VOLTAGE CHANNEL ADC (V-ADC)
This ADC is intended to convert battery voltage As with the
Current Channel ADC described previously, this ADC employs
an identical sigma-delta conversion technique, including a
modified Sinc3 low-pass filter to give a valid 16-Bit data
conversion result at programmable output rates from 4Hz to 8
KHz. An external RC filter network is not required as this is
implemented internally in the voltage channel.
The external battery voltage (VBAT) is routed to the ADC
input via an on-chip high voltage, resistive attenuator This
must be enabled/disabled via HVCFG1[7].
The time to a first valid (fully settled) result on the voltage
channel is three ADC conversion cycles with chop mode turned
off and two ADC conversion cycles with chop mode turned on.
This ADC is again buffered but unlike the current channel has
a fixed VBAT input range of 0 V to 28.8V (assuming an
internal 1.2V reference). A top level overview of this ADC
signal chain is shown in Figure 16 below.
VBAT
DIVIDE BY 24, INPUT
45R
2R
1R
DIFFERENTIAL
ATTENUATOR
ATTENUATOR
BUF
IMPEDANCE INPUT STAGE
FOR THE ANALOG INPUT.
THE BUFFER AMPLIFIER
BUFFER AMPLIFIER
PRESENTS A HIGH
CHOP
REFRENCEON THE VREF PIN CAN
ADC BY DEFAULT. AN EXTERNAL
Figure 16 : Voltage/ Temperature ADC, Top Level Overview
REFERNCE IS ROUTED TO THE
ALTERNATELY REVERSED
THE INTERNAL 5PPM/C
ALSO BE SELECTED
CONVERSION CYCLE.
PROGRAMMABLE
THE INPUTS ARE
ANALOG INPUT
REFERENCE
THROUGH THE
PRECISION
CHOPPING
QUANTIZATION NOISE INTRODUCED
BY THE MODULATOR. THE UPDATE
RATE AND BANDWIDTH OF THIS
FILTER ARE PROGRAMMABLE
THE SINC 3 FILTER REMOVES
VIA THE ADCFLT MMR
Rev. PrD | Page 46 of 128
PROGRAMMABLE
DIGITAL FILTER
REFERNCE
INTERNAL
MODULATOR
OF WHICH IS ALSO CHOPPED)
DATA STREAM (THE OUTPUT
THE MODULATOR PROVIDES
THE DUTY CYCLE OF WHICH
REPRESENTS THE SAMPLED
SIGMA-
VREF
DELTA
SIGMA-DELTA A/D CONVERTER
ANALOG INPUT VOLTAGE.
A HIGH FREQUENCY 1-BIT
TO THE DIGITAL FILTER,
SIGMA-DELTA
MODULATOR
TEMPERATURE CHANNEL ADC (T-ADC)
This ADC is intended to convert battery temperature. The
battery temperature can be derived via the on-chip temperature
sensor or an external temperature sensor input.
The time to a first valid (fully settled) result after an input
channel switch on the temperature channel is three ADC
conversion cycles with chop mode turned off and two ADC
conversion cycles with chop mode turned on.
As with the Current and Voltage Channel ADCs, this ADC
employs an identical sigma-delta conversion technique,
including a modified Sinc3 low-pass filter to give a valid 16-Bit
data conversion result at programmable output rates from 4Hz
to 8 KHz
PROGRAMMABLE
THE OUPUT WORD FROM THE
THE CONVERSION RESULT.
DIGITAL FILTER IS SCALED
COEFFICIENTS BEFORE
DIGITAL
FILTER
BY THE CALIBRATION
FINAL (16-BIT) ADC RESULT
BEING PROVIDED AS
OUTPUT SCALING
COEFFICIENT
ADC RESULT
COEFFICIENT
OFFSET
GAIN
ARCHITECTURE ENSURES
16 BITS NO MISSING
SIGMA-DELTA ADC
THE SIGMA-DELTA
CHOP
CODES.
AVERAGE
-
OUTPUT
FORMAT
RESULT
OUTPUT
ADC
x
+
AS PART OF THE CHOPPING
SUMMED AND AVERAGED
WITH ITS PREDECESSOR
IMPLEMENTATION, EACH
DATA-WORD OUTPUT
FROM THE FILTER IS
OUTPUT AVERAGE
ADuC7032