DA9021 datasheet(114/142 Pages) DIALOG

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DA9021/22

System PMIC with high efficiency USB power manager

Datasheet

Revision 2.5

17-Feb-2017

CFR0011-120-00 Rev 5

114 of 142

20 Monitoring ADC and touch screen interface

20.1 ADC overview

The DA9021/22 provides an Analogue to Digital Converter (ADC) with 10-bit resolution and track and

hold circuitry combined with an analogue input multiplexer. The analogue input multiplexer allows

conversion of up to 10 different inputs. The track and hold circuit ensures stable input voltages at the

input of the ADC during the conversion.

The ADC is used to measure the following inputs:

● Channel 0: VDDOUT – measurement of the system voltage

● Channel 1: ICH – internal battery charger current measurement

● Channel 2: TBAT – output from the battery NTC

● Channel 3: VBAT – measurement of the battery voltage

● Channel 4: ADC_IN4 – high impedance input (0 – 2.5 V)

● Channel 5: ADC_IN5 – high impedance input (0 – 2.5 V)

● Channel 8: Internal T

JUNC.-sense (internal temp. sensor)

MUX

TRACK AND

HOLD

ADC

2.5V Vref

Power

Manager

Registers

ADCIN4,5

TBAT

CONNECTIONS

FROM CHARGER

VDDOUT

ICH

TBAT

VBAT

Figure 46: ADC block diagram

20.1.1

Input MUX

The MUX selects from and isolates the inputs and presents the channel to be measured to the ADC

input. When selected, an input amplifier on the VDDOUT (and VBAT) channel subtracts the

VDDCORE reference voltage and scales the signal to the correct value for the ADC.

20.1.2

ADC

The ADC uses a sample and hold successive approximation switched capacitor architecture. It is

supplied from internal core supply rail VDDCORE (2.5 V). It can be used either a HIGH SPEED

mode with measurements sequences repeated every 1 ms or in ECONOMY mode with sequences

performed every 10 ms.

20.2 MANUAL CONVERSION mode

For manual measurements the ADC powers up, one conversion is done on the specified channel and

the 10-bit result is stored. After the conversion is completed, the ADC powers down again and an

IRQ event flag is set (end of manual conversion). The generation of this IRQ can be masked by the

IRQ mask.

DA9021 Datasheet(PDF) 114 Page - Dialog Semiconductor

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