MAX77972 datasheet(21/171 Pages) AD

21 / 171 page

MAX77972

AccuCharge + ModelGauge 1-Cell Fuel Gauge

and 3A Charger with Integrated USB Type-C

Detection

www.analog.com

Analog Devices | 21

Detailed Description

The MAX77972 is a highly integrated USB Type-C autonomous charger and ultra-low power fuel gauge for a 1-cell lithium-

ion (Li+) or lithium polymer (LiPoly) battery. The fuel gauge offers OCV keep-out region for special chemistry battery such

as lithium iron phosphate (LiFePo4) battery. The MAX77972 can operate with input range from 4.5V to 13.7V to support

5V, 9V, and 12V AC adapter and USB input. The fast charge current, charge termination current, and charge termination

voltage are both I2C and resistor configurable. The MAX77972 controls charging current, voltage, temperature, and power

limit modes. With the aid of the ModelGauge m5 EZ fuel gauge, MAX77972 provides appropriate charging voltage and

charging current to safely charge the battery depending on the state of the battery and the temperature. The MAX77972

offers 9-zone JEITA temperature settings and 5-zone step-charging where fast charging current and charge termination

voltage are automatically adjusted according to temperature change. That ensures fast charging speed under the

condition of battery safety.

The MAX77972 contains an ultra-low power fuel gauge which implements the Analog Devices’ ModelGauge m5 EZ

algorithm. The IC accurately measures voltage, current, and temperature to produce fuel gauge results. The ModelGauge

m5 EZ robust algorithm provides tolerance against battery diversity. This additional robustness enables simpler

implementation for most applications and batteries by avoiding time-consuming battery characterization. The

ModelGauge m5 algorithm combines the short-term accuracy and linearity of a coulomb counter with the long-term

stability of a voltage-based fuel gauge, along with temperature compensation, to provide industry-leading fuel gauge

accuracy. The IC automatically compensates for battery age, temperature, and discharge rate and provides an accurate

state of charge (SOC) in % and remaining capacity in mAh over a wide range of operating conditions. Additionally, fuel

gauge error always converges to 0% as the cell approaches empty.

The MAX77972 runs BC1.2 and USB Type-C CC detection upon input insertion and configure input source to max power

option and charger input current limit to max power. The fast charge current, charge termination current, and battery

regulation voltage can be programmed with external resistors. The input voltage regulation with adaptive input current

limit feature (AICL) allows charging to continue even with a weak adapter by preventing it from collapsing or folding back.

The power path design provides system power even when the battery is fully discharged, and the charger supplements

current from the battery and charges input automatically when the system demands a higher current. Reverse boost from

the battery can be enabled through the I2C interface to allow 5.1V/1.5A OTG to CHGIN pin.

Buck Charger

Charging Control

Lithium-ion/polymer batteries are very common in various portable electronic devices because they have a very high

energy density, minimal memory effect, and low self-discharge. However, care must be taken to avoid overheating or

overcharging these batteries to prevent damage, potentially resulting in dangerous outcomes/explosive results. By

operating in safe temperature ranges, at safe voltages and under safe current levels, the overall safety of the lithium-

ion/polymer batteries can be assured throughout the life of the battery. Using AccuCharge technology, the MAX77972

controls the charging voltage and current dynamically based on the JEITA charge profile, step-charging and battery

temperature. The charge current is reduced at low battery voltage (prequel), low and high temperature, or when the

battery voltage reaches the battery regulation voltage. Figure 1 shows an example of the charge profile without step

charging and JEITA profile changing the target charge current and charge voltage. Real time target charging current and

charging voltage are available at ChargingVoltage and ChargingCurrent registers, automatically modulated by

temperature and step-charging. See nIChgCfg1/2, nVChgCfg1/2, nStepVolt, nStepCurr, and nTPrtTh1, nTPrtTh2 for

configuration details in Fast Charge - Step Charging and FAST CHARGE - JEITA sections.

PRECHARGE: The battery is charged with IPRECHG 55mA (typ) to check if it is safe to charge until it reaches VPRECHG

2.5V (typ). MAX77972 can support battery down to 0V in this state.

TRICKLE CHARGE: The battery is charged with ITRICKLE 300mA (typ) until it reaches trickle charge threshold 3.1V (typ).

Charger enters Fast Charge CC stage when battery voltage is above trickle charge threshold. This state can be disabled

by setting ChgConfig0.PQEN = 0. When disabled, the charger moves from the precharge state directly to the Fast Charge

CC state.

FAST CHARGE/STEP CHARGING: The battery is charged to this terminal voltage in Fast Charge stage. Charging profile

shown in Figure 1 has disabled step charging for simplicity. See Step Charging section for detailed configurations.

MAX77972 Datasheet(PDF) 21 Page - Analog Devices

MAX77972 Datasheet(HTML) 21 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL