User Guide

CC Technical Documentation System Module

NPM-10 (3595)

The AD converter is calibrated in production.

Battery Voltage Measurement A/D Channel (VBATADC)

The battery voltage is scaled inside the UEM in order to avoid external components. The

maximum battery voltage that gives a full A/D reading is 5.25 V.

Battery voltage can be connected to sample-and-hold circuit either through a resistive

voltage divider or through a voltage-scaling circuit. The voltage-scaling circuit is used to

get larger input voltage range for the converter than what is achieved with the resistive

divider. The sample-and-hold circuit is used to measure the battery voltage during trans-

mit burst. Otherwise, the S/H circuit is bypassed. Note that both the battery voltage

(VBATADC) and the charger voltage (VCHARADC) are sampled whenever the sampling

function is used.

Charger Voltage Measurement A/D Channel (VCHARADC)

This channel is used to measure the charger input voltage VCHAR. The charger input idle

voltage is measured to identify the charger. Associated with the charger voltage

measurement, an envelope detector is used to detect a rectifier bridge type of charger.

Connection of the charger is performed by the rising edge of the charger input. The

charger must be a full-wave rectifier. A half-wave rectifier charger has to be rejected.

This A/D channel has a built-in feature built that allows the charger voltage measure-

ment to be specified to be performed whether the charger switch is closed or open. This

information is provided by the MCU when this channel is addressed.

The charger measurement A/D channel can also be timed to the charger envelop detector

in order to measure the standard charger peak voltage.

Charger Current Measurement A/D Channel (ICHAR)

This A/D channel is used to measure the charger current ICHAR. The current sensor is

implemented using a 0.22 Ω resistor in series between the UEM charging voltage output

and the battery voltage. The voltage drop over the resistor is examined. The charger

current measurement is used for charger detection and maintenance charging PWM

calculations.

VCXOTEMP 0 - 2.7 V Not used in NPM-10 (3595)

HEADINT 0 - 2.7 V

HOOKINT 0 - 2.7 V

LS 0 - 2.7 V Not used in NPM-10 (3595)

KEYB1 0 - 2.7 V Not used in NPM-10 (3595)

KEYB2 0 - 2.7 V Not used in NPM-10 (3595)

Table 22: Slow A/D Converter Input Ranges (Continued)

Signal Min Typ Max Unit Notes