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Hybrid Power Boost and Narrow VDC Configurations Combination Battery Charger with SMBus Interface

Product Status: Mass Production


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.


  • 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)


 Block Diagram


Basic Information
Mass Production
输入电压最小值 (V)
输入电压最大值 (V)
输入限流精度 (%)
电池充电电压 (V)
2-4 cell battery, 16mV step
充电电压精度最大值 (%)
电池充电电压调节 (%)
16mV steps
充电限流精度 (%)
涓流充电限流精度 (%)
256mA, 128mA or 64mA
自动涓流充电典型值 (V)
Set by user
电池泄漏电流最大值 (μA)
R3 modulator
开关频率典型值 (kHz)
350 to 1000
热关断 (°C)
155 °C
Multi-Cell Li+/Polymer
输入电压范围 (V)
4.75 to 25
CAN 采样
-40 to +85

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