LINEAR High Efficiency USB Power Management System Safely Charges Li-Ion Polymer Batteries from Automotive Supplies Data Manual Safety Notes Design Note 464
Summary
Elevate your portable electronics design with this high-efficiency USB Power Manager and Li-Ion battery charger system. Engineered specifically for harsh, automotive environments, it guarantees safe and robust battery charging from demanding power sources while maintaining full USB compatibility. The accompanying technical guide details best practices for implementing advanced features like Bat-Track™ and comprehensive overvoltage protection (up to 100V), ensuring reliable performance even during severe electrical transients or load dumps. Ideal for engineers designing automotive, GPS, and other mission-critical electronics.
Page 1 Text Content
High Effi ciency USB Power Management System Safely Charges Li-Ion/Polymer Batteries from Automotive Supplies – Design Note 464 George H. Barbehenn
Introduction In this circuit, the LTC®4098 USB power manager/Li- Automotive power systems are unforgiving electronic Ion battery charger controls an LT3480 HV step-down environments. Transients to 90V can occur when the regulator. The LTC4098’s Bat-Track™ feature provides nominal voltage range is 10V to 15V (ISO7637), along with a high effi ciency, low power dissipation battery charger battery reversal in some cases. It’s fairly straightforward from low and high voltages alike. The Bat-Track feature to build automotive electronics around this system, but controls an internal input current-limited switching regula- increasingly end users want to operate portable elec- tor to regulate VOUT to approximately VBAT + 0.3V which tronics, such as GPS systems or music/video players, maximizes battery charger effi ciency, and thus minimizes and to charge their Li-Ion batteries from the automotive power dissipation by operating the battery charger with battery. To do so requires a compact, robust, effi cient minimal headroom. Furthermore, the Bat-Track feature and easy-to-design charging system. reduces charge time by allowing a charge current greater than the USB input current limit—the switching regulator
Complete USB/Battery Charging Solution for Use in
behaves like a transformer exchanging output voltage for
Large Transient Environments
output current.
Figure 1 shows such a design. This complete Power Path™
The LTC4098 can extend the Bat-Track concept to an
manager and battery charger system seamlessly charges
auxiliary regulator via the WALL and VC pins. When
the Li-Ion battery from a wide ranging high voltage or
suffi cient voltage is present on WALL, Bat-Track takes
USB source.
L, LT, LTC and LTM are registered trademarks and Power Path and Bat-Track are trademarks of Linear Technology Corporation. All other trademarks are the property of
their respective owners.
ZXMP10A18G ZXMP10A18G
VIN C7 L2
AUTOMOTIVE, VIN BOOST 0.47μF 10μH HVBUCK D1 C6 R2
FIREWIRE, C1 SW
MMBZ524- 68n F 150k
ETC. R5 4.7μF
0BLT1G LT3480 R11 C4
10k RUN/SS
RT FB
1k PG GNDVC BD SYNC
M3 R4 ZXMN10A08E6
USB VBUS VC WALL ACPR SW
OVGATE
OVGATE VOUT
OVSENS IDGATE
15-17 SYSTEM
TO μC D0–D2 BAT
LTC4098
TO μC CHRG NTCBIAS
NTC CLPROG PROG GND BATSENS
2.94k 1k Li-Ion DN464 F01
Figure 1. LTC4098 USB Power Manager/Li-Ion Battery Charger Works with an LT®3480 HV Buck Regulator to Accept Power from an Automotive Environment or Firewire System. Overvoltage Protection Protects Both ICs and Downstream Circuits
Page Summary Contents For LINEAR High Efficiency USB Power Management System Safely Charges Li-Ion Polymer Batteries from Automotive Supplies Data Manual Safety Notes Design Note 464
Manual Details
| Brand | Linear |
|---|---|
| Pages | 2 |
| File Size | 95.67 KB |
| Published | June 18, 2026 |
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Frequently Asked Questions
Does this circuit handle automotive voltage spikes?
Yes, it includes overvoltage protection covering transients up to 100V and is designed for harsh automotive environments.
How does the Bat-Track feature improve charging performance?
It maximizes charger efficiency by allowing a charge current greater than the USB input limit, which reduces total charge time.
What is the circuit's overvoltage shutdown threshold?
The system shuts down protection when HVIN exceeds approximately 24V, ensuring safety in high-voltage supply environments.
Is this charger suitable for portable electronics?
Yes, it provides a robust and efficient solution for powering Li-Ion batteries for devices like GPS systems or music players.