AXP288D datasheet(49/110 Pages) XPOWER

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AXP288

PMIC Optimized For Multi-Core High-Performance System

AXP288 Datasheet V1.06

9.4 Adaptive PWM Charger

The AXP288 battery charger solution has two charging modes that it can be in. It is specifically designed to charge Li Ion or

Li Polymer type batteries. The two modes are 1) Pre Charge Mode and 2) Fast Charge Mode. The delineation between these

two modes is based on the battery voltage level of VTRKL which is set at 3.0V.

When battery voltage, VBATSENSE is between 0V to 3.0V (VTRKL), the charger is in Pre Charge Mode where charging current

is limited to a value of ITRKL (10% of ICHRG, default value is 120mA). This mode of operation is intended to prevent damage to the

battery. Once VBATSENSE ≥ VTRKL, the charger will enter Fast Charge Mode. The Fast Charge Mode can be subdivided into two

phases, namely the constant current phase (CC) and the constant voltage phase (CV). The CC phase takes place when VBATSENSE

is in between VTRKL and VTRGT. It will charge with constant ICHRG. When VBATSENSE reach VTRGT, charger will operate at CV phase. At

this phase, charger will charge with constant voltage of VTRGT.

9.4.1 Charger Overview

ITRKL

VTRKL

ICHRG

VTRGT

Figure 9-22

VTRGT is programmed in REG 33H[6:5] and ICHRG is in REG 33H[3:0] whereas VTRKL is fixed at 3V and ITRKL is set as 10% of ICHRG.

9.4.2 Charging start and stop

When VBATSENSE is between 0V to 3.0V (VTRKL), the charge operation will start when VBUS insert and REG 33H[7] is set to 1.

The charging operation will cease when VBATSENSE is > VTRGT-0.1V and charging current < 10% of ICHRG.

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