aduc7033bstz-8l-rl Analog Devices, Inc., aduc7033bstz-8l-rl Datasheet - Page 45

• Manufacturer Part Number: aduc7033bstz-8l-rl
• Description: Integrated Precision Battery Sensor For Automotive
• Manufacturer: Analog Devices, Inc.

VOLTAGE/TEMPERATURE CHANNEL ADC
(V/T-ADC)
The voltage/temperature channel ADC (V/T-ADC) converts
additional battery parameters such as voltage and temperature.
The input to this channel can be multiplexed from one of three
input sources, namely: an external voltage, an external tempera-
ture sensor circuit, and an on-chip temperature sensor.
As with the current channel ADC, the V/T-ADC employs an
identical Σ-Δ conversion technique, including a modified Sinc3
low-pass filter to give a valid 16-bit data conversion result at
programmable output rates from 4 Hz to 8 kHz. An external RC
filter network is not required because this is internally imple-
mented in the voltage channel.
VTEMP
*R = 70kΩ
VBAT
DIVIDE-BY-24, INPUT
DIFFERENTIAL
ATTENUATOR
ATTENUATOR
45R*
2R*
1R*
BUF
BUF
INTERNAL
TEMP
IMPEDANCE INPUT STAGE
THE BUFFER AMPLIFIERS
FOR THE ANALOG INPUT.
BUFFER AMPLIFIERS
PRESENT A HIGH
EXTERNAL REFERENCE ON
REFERENCE IS ROUTED TO
THE ADC BY DEFAULT. AN
THE VREF PIN CAN ALSO
PRECISION REFERENCE
THE INTERNAL 5ppm/°C
MUX
BE SELECTED.
CHOP
Figure 18. Voltage/Temperature ADC, Top Level Overview
REFERENCE
PROGRAMMABLE CHOPPING
THROUGH THE CONVERSION
INTERNAL
ALTERNATELY REVERSED
VREF
MODULATOR
THE INPUTS ARE
ANALOG INPUT
Σ-Δ
CYCLE.
Σ-Δ ADC
Rev. 0 | Page 45 of 136
PROGRAMMABLE
QUANTIZATION NOISE INTRODUCED
DIGITAL FILTER
BY THE MODULATOR. THE UPDATE
FILTER ARE PROGRAMMABLE VIA
RATE AND BANDWIDTH OF THIS
SCALED BY THE CALIBRATION
COEFFICIENTS BEFORE BEING
THE SINC3 FILTER REMOVES
THE OUTPUT WORD FROM
THE DIGITAL FILTER IS
CONVERSION RESULT.
THE ADCFLT MMR.
PROVIDED AS THE
OUTPUT SCALING
PROGRAMMABLE
CYCLE OF WHICH REPRESENTS
THE DIGITAL FILTER, THE DUTY
THE MODULATOR PROVIDES A
THE SAMPLED ANALOG INPUT
DIGITAL FILTER
HIGH FREQUENCY 1-BIT DATA
WHICH IS ALSO CHOPPED) TO
STREAM (THE OUTPUT OF
The external battery voltage (VBAT) is routed to the ADC input
via an on-chip, high voltage (divide-by-24), resistive attenuator.
This must be enabled/disabled through HVCFG1[7].
The battery temperature is derived through 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 voltage/temperature channel is three
ADC conversion cycles with chop mode turned off.
This ADC is again buffered, but unlike the current channel, has
a fixed input range of 0 V to V
on VBAT (assuming an internal 1.2 V reference). A top level
overview of this ADC signal chain is shown in Figure 18.
Σ-Δ MODULATOR
VOLTAGE.
COEFFICIENT
COEFFICIENT
OFFSET
GAIN
CHOP
INTERRUPT ONCE A VOLTAGE
ADC INTERRUPT GENERATOR
CONVERSION IS COMPLETED.
AVERAGE
FORMAT
OUTPUT
RESULT
OUTPUT
NO MISSING CODES.
ADC
ENSURES 16 BITS
GENERATES AN ADC
ARCHITECTURE
OR TEMPERATURE
Σ-Δ ADC
THE Σ-Δ
REF
INTERRUPT
TO VOLTAGE OR
TEMPERATURE
DATA MMR
on VTEMP and 0 V to 28.8 V
ADC
THE FILTER IS SUMMED AND
AS PART OF THE CHOPPING
DATA-WORD OUTPUT FROM
IMPLEMENTATION, EACH
AVERAGED WITH ITS
OUTPUT AVERAGE
PREDECESSOR.
ADuC7033