PCA9420 datasheet(11/87 Pages) NXP

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NXP Semiconductors

PCA9420

Power management IC for low-power microcontroller applications

from “ON” pin. Refer to ON_CFG_x bit description in the relation registers for more

details.

3. The filtered falling edge on the ON pin resets the bit of EN_MODE_SEL_BY_PIN_X

to the default value, 0, at 22h register. The status of the ON pin is available in reset

monitor register (address 0x71, bit [7]).

8.5 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”.

8.6 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)

PCA9420

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

Product data sheet

Rev. 4.0 — 28 November 2022

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