MC13783 Datasheet, PDF (41/50 Pages) Freescale Semiconductor, Inc – Power Management and Audio Circuit

Functional Description
4.4.2.3.1 Starting Conversions
The ADC will have the ability to start a series of conversions based on a rising edge of the ADTRIG signal
or directly initiated by SPI.
Once conversion is initiated all 8 channels will be sequentially converted and stored in registers or eight
conversions on one channel will be performed and stored. The conversion result can digitally be compared
with respect to a preset value for threshold detection.
The conversion will begin after a delay set between 0 and 8 ms. The delay between conversions can be
made equal to this delay.
To avoid that the ADTRIG input involuntarily triggers a conversion, a bit can be set which will make the
ADC ignores any transition on the ADTRIG pin.
4.4.2.3.2 Reading Conversions
Once a series of eight A/D conversions is complete, they are stored in one set of eight internal registers
and the values can be read out by software.
4.4.2.4 Pulse Generator
A SPI controllable pulse generator is available at ADOUT synchronized with the ADC conversion. This
pulse can be used to enable or drive external circuits only during the period of 4 or 8 ADC conversions.
4.4.2.5 Dedicated Channels Reading
4.4.2.5.1 Battery Current
Traditional battery capacity estimation is based on battery terminal voltage reading combined with
estimated phone current drain based on emitted PA power. For improved battery capacity estimation,
especially in non transmit mode like gaming, this method is too approximate. To improve the estimation,
the current out of the battery must be quantified more accurately. For this, on the MC13783, the current
flowing out of and into the battery can be read via the ADC by monitoring the voltage drop over the sense
resistor between BATT and BATTISNS.
4.4.2.5.2 Charge Current
The charge current is read by monitoring the voltage drop over the charge current sense resistor.
4.4.2.5.3 Battery Thermistor
If a battery is equipped with a battery thermistor, its value can be read out via the ADC input ADIN5. The
biasing and sensing circuit is entirely integrated and is only powered during the A to D conversions.
4.4.2.5.4 Die Temperature and UID
The die temperature can be read out on the ADIN7 channel. Alternatively, the UID voltage can be read out
on the ADIN7 channel.
MC13783 Technical Data, Rev. 3.4
Freescale Semiconductor
41