PCA9420BS datasheet(12/85 Pages) NXP

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NXP Semiconductors

PCA9420

Power management IC for low-power microcontroller applications

8.6 TS

With the temperature sensing pin, the external thermistor (NTC) is connected between the TS pin and ground.

The thermistor may be included in the battery pack to monitor the battery pack temperature, or it may be an

additional component user chooses to have on the board level to monitor the temperature at a chosen area.

The voltage at TS pin is monitored, and the user can enable the feature through I2C-bus interface (NTC_EN)

to implement JEITA compliant charging at a safe temperature. Per JEITA standard, there are four temperature

threshold settings:

1. Cold threshold (T1, 0 °C)

2. Cool threshold (T2, 10 °C)

3. Warm threshold (T3, 45 °C)

4. Hot threshold (T4, 60 °C)

Each of the above temperature thresholds represents a voltage threshold. When the monitored temperature, T,

falls into a different temperature zone, the charger should adjust the charging method accordingly:

1. T > T4 or T < T1, i.e., when the temperature is in a “cold” or “hot” zone, charging is suspended, as well as

the safety timer;

2. T1 < T < T2, charging current is reduced by 50 % of the programmed current level;

3. T2 < T < T3, normal charging;

4. T3 < T < T4, the CV mode regulating voltage should be set as VBAT_REG [5:0] – ΔVBAT_REG(HOT),

140 mV typical

To disable this function, set NTC_EN to “0”.

8.7 Mode setting

When the MCU operates in different modes such as overdrive run mode or low power mode, it may require the

power supply to operate in different settings accordingly (for example, enable/disable of each rail, output voltage

of each rail, etc.) to achieve a better performance and efficiency.

On the PCA9420, there are four modes of registers representing Mode Setting 0/1/2/3 to accommodate

such requirements from MCU, where Mode Setting A is the default mode setting (i.e., the initial mode setting

upon initial power up). Depending on the user’s preference, switching among different mode settings can be

controlled by either the external signal (ON pin), external pins (MODESEL0/1) or I2C.

Within each mode setting, the user can program the follow parameters providing great flexibility to

accommodate different MCU operation modes:

1. Enable/disable of the four output voltage rails

2. Voltage setting of the four output voltage rails

3. Ship mode enable/disable

4. Watchdog timer setting

5. Mode control selection (EN_MODE_SEL_BY_PIN_x, x=0, 1, 2, or 3)

EN_MODE_SEL_BY_PIN_x = 0: under current mode setting, mode setting switch is controlled by internal I2C

ignored.

EN_MODE_SEL_BY_PIN_x = 1: under current mode setting, mode setting switch is controlled by signal

applied on external MODESEL0 and/or MODESEL1 pins only, not by internal I2C register bits MODE0_I2C and

MODE1_I2C.

1. Mode setting switches back to Mode Setting A triggered by ON pin falling edge. Refer to register description

for “ON_CFG_x” bit for more details.

PCA9420

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 4.2 — 26 July 2023

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