npm1300

System Monitor

The chip includes a 10-bit ADC which is used for measuring internal parameters. It can be used in the following measurement modes:

  • Single-shot
  • Automatic
  • Timed

Measurement request priority

When multiple measurement requests happen at the same time, the priority is as follows:

  1. VBAT
  2. Battery temperature, TBAT
  3. Battery current, IBAT
  4. Die temperature, TDIE
  5. VSYS
  6. VBUS

If a measurement has been requested but the measurement has not started, a higher priority can be requested.

When a low priority measurement is requested and the system has started the measurement, a higher priority can be requested. The system will complete the lower priority measurement before the higher priority measurement.

Parent topic: nPM1300 Product Specification

Single-shot measurements

Single-shot measurements are triggered by a task specific for each measurement.

Table 1. Tasks for single-shot measurements
Value Task
Battery temperature TASKNTCMEASURE
Battery voltage, Single-shot mode and Burst mode

TASKVBATMEASURE

ADCCONFIG
VSYS voltage TASKVSYSMEASURE
Battery current ADCIBATMEASEN (occurs after VBAT measurement)
VBUS voltage TASKVBUS7MEASURE
Die temperature TASKTEMPMEASURE
A VBAT measurement triggered in Burst mode performs four consecutive measurements, with each result available separately. Conversions are run back-to-back and complete in tCONV.
Note: To repeat a measurement, it must be requested once the previous request is complete. Repeat measurement requests are lost when made while the previous conversion is still ongoing. Alternate measurements can be requested, which are queued. See Priority for more information.

Automatic measurements

Automatic measurements for battery voltage are enabled in register ADCCONFIG. The default interval is 1024 ms.

Automatic measurements during charging

Battery temperature and die temperature are measured automatically at regular intervals when the battery is charging. The host software can read this value and returns the latest measurement.

The measurement intervals are as follows:
  • Battery temperature – once every 64, 128, or 1024 ms. This information is used by the charging FSM.
  • Die temperature – once every 4 ms, see Charger thermal regulation.
Note: To enable automatic thermistor and die temperature monitoring, set register TASKAUTOTIMUPDATE. This should also be set after changing the automated period.

Timed measurements

Timed measurements for battery voltage in Single-shot mode and Burst mode are initiated in register ADCDELTIMCONF. See Monitor battery state of charge for more information.

Measurement results

Results from the ADC are stored in registers according to the following table. Some registers hold alternate results when that feature is requested. Host software must concatenate the LSB to the MSB of the result register for full accuracy.

Table 2. ADC measurements
Value/alternate result Register
VBAT ADCVBATRESULTMSB
Battery temperature ADCNTCRESULTMSB
Die temperature ADCTEMPRESULTMSB
VSYS Single-shot mode ADCVSYSRESULTMSB
LSBs for Single-shot mode VSYS, Die temperature, NTC thermistor, and VBAT ADCGP0RESULTLSBS
Burst mode VBAT0 ADCVBAT0RESULTMSB
Burst mode VBAT1 ADCVBAT1RESULTMSB

Burst mode VBAT2

Battery current IBAT

 ADCVBAT2RESULTMSB

Burst mode VBAT3

Single-shot mode VBUS

 ADCVBAT3RESULTMSB
LSBs for Burst mode VBAT0, VBAT1, VBAT2, and VBAT3 ADCGP1RESULTLSBS

The following equations can be used to read the results.

VBAT

The equation for VBAT is given by the following:

Here, VBATADC is the ADC value from the VBAT register and VFSVBAT is the full scale voltage for measuring VBAT.

VBUS

The equation for VBUS is given by the following:

Equation for VBUS

Here, VBUSADC is the ADC value from the VBUS register and VFSVBUS is the full scale voltage for measuring VBUS.

VSYS

Equation for VSYS is given by the following:

Equation for VSYS

Here, VSYSADC is the ADC value from the VBUS register and VFSVSYS is the full scale voltage for measuring VBUS.

Battery temperature (Kelvin)

The battery temperature TBAT (in Kelvin) is given by the following equation:

Equation for battery temperature

Here, T0 = 298.15 K and TBATADC is the ADC value from the battery temperature register ADCNTCRESULTMSB.

Die temperature in °C

The die temperature, TD (in °C), is given by the following equation:

Equation for die temperature

Here, KDIETEMP is the temperature limit code variable.

Events and interrupts

An event register and interrupt are available for each measurement and are issued once the measurement has been completed.

See registers EVENTSADCSET, EVENTSADCCLR, INTENEVENTSADCSET, and INTENEVENTSADCCLR.

Battery temperature measurement

Before using a battery temperature measurement, the appropriate NTC thermistor must be configured. See Monitor battery temperature for information about suitable thermistors and how to configure.

Monitor battery state of charge

The host runs the fuel gauge algorithm and periodically requests measurements from the ADC. These measurements update the algorithm parameters and allow the state of charge to be determined.

The algorithm must be provided with the battery model parameters for accurate fuel gauge readings. The battery model parameters can be created from the nPM PowerUP application.

Once the battery is modeled over the operating temperature range, the fuel gauge algorithm is optimized to operate over the full range of battery voltages, temperatures, and application currents.

Battery current measurement

Host software can request a VBAT measurement by setting bit IBAT.MEAS.ENABLE to 1 in register ADCIBATMEASEN. This allows consecutive VBAT and IBAT measurements. When both measurements are available in the ADC registers, the ADCIBATRDY event is generated. See register ADCIBATMEASSTATUS for more information about the IBAT measurement.

Measurements are invalid and a new measurement is needed when bit IBAT.MEASE.INVALID is set.

Direction of current flow is shown in bit BCHARGER.MODE.

A value of 01 means the battery is discharging. During a discharge, the full scale current is the sum of registers BCHGISETDISCHARGEMSB and BCHGISETDISCHARGELSB.

A value of 11 means the battery is charging. When charging, the full scale current is the sum of registers BCHGISETMSB and BCHGISETLSB multiplied by 1.25.

Electrical specification

Table 3. System Monitor electrical specification
Symbol Description Min. Typ. Max. Unit
VFSVBAT Full scale voltage for VBAT measurement   5.0   V
VBATACCUR

Accuracy of the VBAT measurement

(3 V < VBAT < 4.5V)

 -1   +1 %
VFSVBUS Full scale voltage for VBUS measurement   7.5   V
VBUSACCUR

Accuracy of the VBUS measurement

   1.5   %
VFSVSYS Full scale voltage for VSYS measurement   6.375   V
VSYSACCUR

Accuracy of the VSYS measurement

   1.5   %
CBATNTC Capacitance in parallel with the thermistor 0   100 pF
VFSTEMP Full scale for battery and die temperature measurements   1.5   V
tCONV Conversion time   250   μs
DNL Differential non-linearity   < 0.5   LSB
IADCAUTO Current consumption, automatic measurements active       μA
IADCDIE Current consumption during die temperature measurement       μA

Registers

Instances

Instance Base address Description
ADC 0x00000500

SAADC registers

ADC register map

Register overview

Register Offset Description
TASKVBATMEASURE 0x0

Task Take VBAT measurement
TASKNTCMEASURE 0x1

Task Take NTC measurement
TASKTEMPMEASURE 0x2

Task Take Die Temperature measurement
TASKVSYSMEASURE 0x3

Task Take VSYS measurement
TASKIBATMEASURE 0x6

Task Take IBATmeasurement
TASKVBUS7MEASURE 0x7

Task Take VBUS 7V range measurement
TASKDELAYEDVBATMEASURE 0x8

Task Take delayed VBAT measurement
ADCCONFIG 0x9

ADC Configuration
ADCNTCRSEL 0xA

Select Battery NTC register
ADCAUTOTIMCONF 0xB

Auto measurement intervals
TASKAUTOTIMUPDATE 0xC

update toggle for NTC and Die temp AutoTime register bits
ADCDELTIMCONF 0xD

Vbat Delay timer control
ADCIBATMEASSTATUS 0x10

Battery current measurement status
ADCVBATRESULTMSB 0x11

ADC VBAT measurement result MSB
ADCNTCRESULTMSB 0x12

ADC NTC measurement result MSB
ADCTEMPRESULTMSB 0x13

ADC DIE TEMP measurement result MSB
ADCVSYSRESULTMSB 0x14

ADC VSYS measurement result MSB
ADCGP0RESULTLSBS 0x15

ADC result LSB's (Vbat, Ntc, Temp and Vsys)
ADCVBAT0RESULTMSB 0x16

ADC VBAT0 Burst measurement result MSB
ADCVBAT1RESULTMSB 0x17

ADC VBAT1 Burst measurement result MSB
ADCVBAT2RESULTMSB 0x18

ADC VBAT2 Burst measurement result MSB
ADCVBAT3RESULTMSB 0x19

ADC VBAT3 Burst or VBUS measurement result MSB
ADCGP1RESULTLSBS 0x1A

ADC result LSB's (Vbat_burst0, 1, 2 and 3)
ADCIBATMEASEN 0x24

Enable auto IBAT measurement
Parent topic: nPM1300 Product Specification

TASKVBATMEASURE

Address offset: 0x0

Task Take VBAT measurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKVBATMEASURE

  

Start VBAT Measurement
     

NOEFFECT

0

no effect
     

TRIGGER

1

Trigger task
Parent topic: nPM1300 Product Specification

TASKNTCMEASURE

Address offset: 0x1

Task Take NTC measurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKNTCMEASURE

  

Start Battery NTC thermistor Measurement
     

NOEFFECT

0

no effect
     

TRIGGER

1

Trigger task
Parent topic: nPM1300 Product Specification

TASKTEMPMEASURE

Address offset: 0x2

Task Take Die Temperature measurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKTEMPMEASURE

  

Start Die Temperature Measurement
     

NOEFFECT

0

no effect
     

TRIGGER

1

Trigger task
Parent topic: nPM1300 Product Specification

TASKVSYSMEASURE

Address offset: 0x3

Task Take VSYS measurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKVSYSMEASURE

  

Start VSYS Measurement
     

NOEFFECT

0

no effect
     

TRIGGER

1

Trigger task
Parent topic: nPM1300 Product Specification

TASKIBATMEASURE

Address offset: 0x6

Task Take IBATmeasurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKIBATMEASURE

  

Start IBAT Measurement
     

NOEFFECT

0

no effect
     

TRIGGER

1

Trigger task
Parent topic: nPM1300 Product Specification

TASKVBUS7MEASURE

Address offset: 0x7

Task Take VBUS 7V range measurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKVBUS7MEASURE

  

Start VBUS 7Volt range Measurement
     

NOEFFECT

0

no effect
     

TRIGGER

1

Trigger task
Parent topic: nPM1300 Product Specification

TASKDELAYEDVBATMEASURE

Address offset: 0x8

Task Take delayed VBAT measurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKDLYDVBATMEASURE

  

Start delayed VBAT Measurement
     

NOEFFECT

0

no effect
     

TRIGGER

1

Trigger task
Parent topic: nPM1300 Product Specification

ADCCONFIG

Address offset: 0x9

ADC Configuration

Bit number 7 6 5 4 3 2 1 0
ID             B A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

RW

VBATAUTOENABLE

  

Enable VBAT Auto measurement every 1 Second
     

NOAUTO

0

Single measurement when triggered
     

AUTOENABLE

1

Make measurement every 1s
B

RW

VBATBURSTENABLE

  

Enable VBAT Burst mode VBAT0, VBAT1, VBAt2, VBAT3
     

SINGLEMODE

0

Make a Single measurement
     

BURSTMODE

1

Make 4 consecutive measurements
Parent topic: nPM1300 Product Specification

ADCNTCRSEL

Address offset: 0xA

Select Battery NTC register

Bit number 7 6 5 4 3 2 1 0
ID             A A
Reset 0x01 0 0 0 0 0 0 0 1
ID R/W Field Value ID Value Description
A

RW

ADCNTCRSEL

  

Select value and TRIM to match Battery NTC resistance
     

Hi_Z

0

No thermistor
     

10K

1

NTC10K
     

47K

2

NTC47K
     

100K

3

NTC100K
Parent topic: nPM1300 Product Specification

ADCAUTOTIMCONF

Address offset: 0xB

Auto measurement intervals

Bit number 7 6 5 4 3 2 1 0
ID         B B A A
Reset 0x03 0 0 0 0 0 0 1 1
ID R/W Field Value ID Value Description
A

RW

NTCAUTOTIM

  

NTC thermistor measurement interval during Charging
     

4MS

0

4ms
     

64MS

1

64ms
     

128MS

2

128ms
     

1024MS

3

1024ms
B

RW

TEMPAUTOTIM

  

Die Temp measurement interval during Charging
     

4MS

0

4ms
     

8MS

1

8ms
     

16MS

2

16ms
     

32MS

3

32ms
Parent topic: nPM1300 Product Specification

TASKAUTOTIMUPDATE

Address offset: 0xC

update toggle for NTC and Die temp AutoTime register bits

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

W

TASKAUTOTIMUPDATE

  

update toggle, handshake signal to flag NtcAutoTim and TempAutoTim change
     

NOEFFECT

0

no effect
     

UPDATEAUTOTIM

1

Register new NtcAutoTim, TempAutoTim value
Parent topic: nPM1300 Product Specification

ADCDELTIMCONF

Address offset: 0xD

Vbat Delay timer control

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

RW

VBATDELTIM

  

Delayed Vbat measurement control 4ms(value 0) to 514ms(value 255) and the step size is 2ms.
Parent topic: nPM1300 Product Specification

ADCIBATMEASSTATUS

Address offset: 0x10

Battery current measurement status

Bit number 7 6 5 4 3 2 1 0
ID       C B B A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

BCHARGERICHARGE

  

Battery current charge
B

R

BCHARGERMODE

  

Battery charger mode
C

R

IBATMEASEINVALID

  

Ibat mesaurement Invalid flag
Parent topic: nPM1300 Product Specification

ADCVBATRESULTMSB

Address offset: 0x11

ADC VBAT measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VBATRESULTMSB

  

ADC VBAT measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCNTCRESULTMSB

Address offset: 0x12

ADC NTC measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

NTCRESULTMSB

  

ADC NTC thermistor Battery measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCTEMPRESULTMSB

Address offset: 0x13

ADC DIE TEMP measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

TEMPRESULTMSB

  

ADC Die Temperature measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCVSYSRESULTMSB

Address offset: 0x14

ADC VSYS measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VSYSRESULTMSB

  

ADC VSYS measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCGP0RESULTLSBS

Address offset: 0x15

ADC result LSB's (Vbat, Ntc, Temp and Vsys)

Bit number 7 6 5 4 3 2 1 0
ID D D C C B B A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VBATRESULTLSB

  

VBAT measurement result LSBs
B

R

NTCRESULTLSB

  

Battery NTC thermistor measurement result LSBs
C

R

TEMPRESULTLSB

  

Die Temperature measurement result LSBs
D

R

VSYSRESULTLSB

  

VSYS measurement result LSBs
Parent topic: nPM1300 Product Specification

ADCVBAT0RESULTMSB

Address offset: 0x16

ADC VBAT0 Burst measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VBAT0RESULTMSB

  

ADC VBAT0 Burst measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCVBAT1RESULTMSB

Address offset: 0x17

ADC VBAT1 Burst measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VBAT1RESULTMSB

  

ADC VBAT1 Burst measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCVBAT2RESULTMSB

Address offset: 0x18

ADC VBAT2 Burst measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VBAT2RESULTMSB

  

ADC VBAT2 Burst measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCVBAT3RESULTMSB

Address offset: 0x19

ADC VBAT3 Burst or VBUS measurement result MSB

Bit number 7 6 5 4 3 2 1 0
ID A A A A A A A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VBAT3RESULTMSB

  

If TASK_VBAT_MEASURE is triggered in BURST mode, this register will contain ADC VBAT3 Burst measurement result upper 8-bits If TASK_VBUS7_MEASURE is triggered, this register will contain VBUS measurement result upper 8-bits
Parent topic: nPM1300 Product Specification

ADCGP1RESULTLSBS

Address offset: 0x1A

ADC result LSB's (Vbat_burst0, 1, 2 and 3)

Bit number 7 6 5 4 3 2 1 0
ID D D C C B B A A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

R

VBAT0RESULTLSB

  

Burst VBAT0 measurement result LSBs
B

R

VBAT1RESULTLSB

  

Burst VBAT1 measurement result LSBs
C

R

VBAT2RESULTLSB

  

Burst VBAT2 measurement result LSBs
D

R

VBAT3RESULTLSB

  

Burst VBAT3 measurement result LSBs
Parent topic: nPM1300 Product Specification

ADCIBATMEASEN

Address offset: 0x24

Enable auto IBAT measurement

Bit number 7 6 5 4 3 2 1 0
ID               A
Reset 0x00 0 0 0 0 0 0 0 0
ID R/W Field Value ID Value Description
A

RW

IBATMEASENABLE

  

Enable Auto IBAT measurement after VBAT task
Parent topic: nPM1300 Product Specification