Ultra-compact charger IC for Li-ion batteries, compatible with WPT

XC6810 28 V Multi-Function Charger IC for small Li-Ion Batteries

The new XC6810 is a highly integrated battery charging solution with optimal charge/discharge management and various functions for small Li-ion batteries in wearable, hearable and IoT devices. It is available in a low profile, ultra-small, WLP-12-01 package that measures only 1.17 x 1.57 x 0.33 mm making it ideal for space constrained applications like smart cards.

KEY FEATURES:

Control and discharge prevention suitable for small Li batteries
- Charging current setting from 1 mA, wide charging voltage range from 3.8 V to 4.3 V.
- Prevention of discharge by shutdown, Wake-up by push button / V_IN applying.
- Extensive protection features (over-discharge, short, input current limit).

Monitor outputs for state of charge and battery voltage
- Charge level to MCU (CSO).
- Charge voltage monitor (BATMON) for monitoring of battery voltage by the MCU.

Energy Harvesting and special functions for specific applications
- Can be charged by direct input up to 28 V.
- 2-wire communication of the state of charge to the cradle / charging case.
- The function to switch off the power when VIN is applied, as required by some medical devices.

Typical Application Circuit

Main Functions:

Shutdown, Wake-up
Battery Voltage Monitor or Battery Low Voltage Notification
OUT Line Switch Interlocked by UVLO, Charge Enable
Battery Temperature Monitor
Current Path / Input Current Limit

Protection Features:

Battery Over Discharge Protection
Output Short Protection
Thermal Control
Reverse Current Prevention
Safety Timer for Charging
UVLO

Key Electrical Parameters

SERIES		XC6810
Input Voltage Range:		3.5 V ~ 28.0 V
Charge Voltage:		3.80 V ~ 4.40 V (0.05 V increments)
Charge Current:		1 mA ~ 25 mA (set by external resistor)
Input Current Limit:		110 mA
BAT Sink Current at Shut Down:		10 nA (TYP.)
Op. Amb. Temperature:		-40 ^oC ~ 85 ^oC
Package:		WLP-12-01

Space-Saving, Low-Profile Solution

Utilising the tiny WLP-12-01 ‘chip scale’ package, that measures only 1.17 x 1.57 x 0.33 mm, a solution can be implemented with a small number of external components.

WLP-12-01

Easy Battery Voltage Monitoring

The BATMON pin has two optional functions as outlined below:

BATTERY VOLTAGE MONITOR (option 1)
- When ‘CHG/BATmonEN’ is pulled HIGH, the Battery voltage (V_BAT) x 0.2 is output and this can be read by ADC of the main MCU. Consumption during monitoring is only 0.55 μA.

LOW VOLTAGE NOTIFICATION (option 2)
- Outputs "L" when battery voltage is 3.0 V or lower

Support For Energy Harvesting & Wireless Power Transfer

Wide input voltage range, up to 28 V, supports wireless power transfer and energy harvesting applications where the input voltage can fluctuate, and higher voltage spikes are common.

Many general-purpose Battery Charger IC are not suitable for some energy harvesting application because their OVP function stops charging when V_IN rises above 6.5 V even if the stated input voltage range is wider. In contrast, XC6810 charges and supplies power without restrictions.

EXAMPLE OF WIRELESS POWER TRANSFER

To avoid high voltage from V_IN when driving LED with CSO pin of Battery LED Indicator type, the anode of LED should be connected to PMID pin. PMID pin is 4.8 V constant voltage clamp output.

EXAMPLE OF POWER SUPPLY FROM SOLAR PANEL

An additional diode for reverse current prevention is not required and the XC6810 can be connected directly to the Solar Panel with minimal external components.

Two-Wire Communication Of Charge Status To Cradle

Using the Battery Status Indicator (available on XC6810 E, F, G & J models)

The CSO pin is connected to 5 V V_IN to pulse modulate the current from cradle.
Monitoring charge status by MCU in cradle using two-wire communication via power supply line.
- Enables indication of charge status by LED on the cradle and ON/OFF control of power feeding.

Overview of the Current Detection circuit in the Cradle or Charging Case

When the device with XC6810 inside is seated in its charging cradle, the V_IN is applied, and the state of charge is output in frequency. This modulation can be detected over the power line by the MCU in the charging cradle.

Two-wire communication via V_IN, modulates with 1mA pulses.
Charge level (Sinks in 32 kHz, 16 kHz, 8 kHz pulses for each state of < 60 %, 60 %, 90 %)
Charge completion (4 kHz) / Stopped (OFF) / Error ( 1kHz)
By detecting changes in current, the cradle can display the charge status on LED and control ON/OFF power feeding.

Application Example: Smart Card

Supports both NFC and Contact inputs. Low profile and small PCB area.

All components shown in the circuit diagram above have a maximum height of 0.4 mm or less making it the perfect solution for Smart Cards.

XC6810