PCA9420BS datasheet(19/85 Pages) NXP

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NXP Semiconductors

PCA9420

Power management IC for low-power microcontroller applications

Figure 9 shows the charging profile with a dead battery condition. Once the cell has charged to the regulation

voltage (VBAT_REG) the voltage loop takes control and holds the battery at the regulation voltage until the current

tapers to the termination threshold (ICHG_TOPOFF).

CHG_LOCK [4:0] bits on Battery charger control_0 (CHG_CTL0, address 10h) register should be set to ‘10101’

to be able to perform I2C “write” command. Otherwise, when “write” command is performed on the ‘locked

registers’, it keeps the present register value.

8.13.1 Battery charging management

Battery charging management supports typical constant current/constant voltage charging profile for single

cell Li-Ion battery, as well as pre-qualification (dead battery, low battery), top-off mode, etc.; JEITA and thermal

regulation compliant.

In PCA9420, there is an initial stage in the charger operation which sources ICHG_DEAD current into VBAT and

compares the voltage to 1.9 V level.

• If the voltage is higher than this threshold, the charger immediately proceeds to the next state (pre-charge/

ICHG_LOW current).

• Otherwise, there is a timer running for 5...40s (I2C programmable) called ICHG_DEAD_TIMER, bits [7:6] in

ICHG_DEAD_CURRENT is sourced by the charger and is I2C programmable.

The dead charge fault timer can assert an interrupt (bit [6] (ICHG_DEAD_TIMER_INT_MASK) from

Sub_INT1_Mask register 05h), and the software can make the final decision. If left masked, the charger

always proceeds to the next stage. This is the default PCA9420 operation. If the interrupt was enabled and has

triggered, the charger is disabled.

PCA9420

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Product data sheet

Rev. 4.2 — 26 July 2023

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PCA9420BS Datasheet(PDF) 19 Page - NXP Semiconductors