FN8771 Rev 2.00

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Jul.18.19

FN8771

Rev 2.00

Jul.18.19

ISL95521

Hybrid Power Boost (HPB) and Narrow VDC (NVDC) Configurations Combo

Battery Charger with SMBus Interface

DATA SHORT

The ISL95521 is a highly versatile combo battery charger

configurable for operating as either a Hybrid Power Boost

(HPB) charger or a Narrow VDC (NVDC) charger, supporting 2-,

3-, or 4-cell batteries. Both configurations allow the battery to

work with the adapter together to supply the system load when

it exceeds the adapter capability, referred to as system Turbo

mode. The HPB charger configuration reverse-boosts battery

energy to the system bus to help the adapter provide system

power in Turbo mode. The NVDC charger configuration quickly

turns on BGATE to enable the battery to help the adapter

provide system power in Turbo mode.

The ISL95521 uses N-channel MOSFETs (NFETs) for all the

switches to achieve the best performance and lowest BOM

cost. The internal charge pump is capable of turning on all the

NFETs fast or slow depending on the circumstance or the need.

The ability to quickly turn on NFETs prevents system bus

voltage drop when the battery is suddenly removed in Turbo

mode or in battery learn mode.

The ISL95521 provides many protection features including a

PROCHOT# indicator for system low voltage, adapter

overcurrent, battery overcurrent or overheating, with an array

of SMBus programmable parameters for maximum flexibility.

The ISL95521 also features hardware based adapter current

limit and battery-current limit in addition to SMBus

programmable limits.

The ISL95521 provides high accuracy adapter current monitor,

battery current monitor, and system power monitor outputs. To

provide maximum flexibility for working with high power and

low power systems, the ISL95521 provides several

configurable current-sense resistor value options to achieve

the best trade-off of current sensing accuracy vs power loss.

The ISL95521 uses the Renesas Robust Ripple Regulator

(R3™) modulation scheme to provide excellent light-load

efficiency and fast dynamic response. The ISL95521 is

available in a 32 Ld 4mmx4mm QFN package.

Features

• Configurable as an HPB charger or NVDC charger

• Compliant with Intel PROCHOT# and PSYS requirements

• Adapter current monitor and battery discharging current

monitor

• Uses NFET for all the switches

- Supports battery removal during battery learn mode

- Actively controlled inrush current to prevent FET damage

• SMBus programmable settings and high accuracy

• Comprehensive protection features;

- PROCHOT# indicator for system low voltage, adapter

overcurrent, battery overcurrent, and system overheating

- Hardware-based adapter current and battery current

limits

- Supports sudden battery removal in system Turbo mode

• 16 switching frequency options from 350kHz to 1MHz

•Low quiescent current

• SMBus and auto-increment I2C compatible

• Robust Ripple Regulator (R3) modulation scheme provides

excellent light-load efficiency and fast dynamic response

• 32 Ld 4mmx4mm QFN package

• Pb-free (RoHS compliant)

Applications

• Devices with rechargeable 2-, 3-, or 4-cell batteries

Related Literature

• ISL95521 device page

FIGURE 1. HPB CHARGER CONFIGURATION

FIGURE 2. NVDC CHARGER CONFIGURATION

L

ADAPTER

SYSTEM

BGATE

LGATE

PHASE

UGATE

VADP

VSYS

VBAT

BFET

HPB

CHARGER

CMSRC

ASGATE

VBAT

AFET

SFET

Q1

Q2

PROG

L

ADAPTER

BGATE

LGATE

PHASE

UGATE

VADP

VSYS

VBAT

BFET

NVDC

CHARGER

CMSRC

ASGATE

VBAT

AFET

SFET

Q1

Q2

PROG

SYSTEM