Wearable Device Power Solution

Application

Description

Ultra-low power management solution for wearable devices featuring compact chargers, efficient fuel gauging, and minimal standby current using SouthChip power management ICs.

Core Advantages

Industry-leading low power consumption extends battery life
Compact packages enable smallest wearable form factors
Accurate fuel gauging maintains precision over battery lifetime
High integration reduces component count and design complexity
Proven designs accelerate time-to-market

Recommended Bill of Materials (BOM)

Item Part Number Description Quantity Datasheet
1 SC9017 Ultra-Low Power Battery Charger 1 📄 Download
2 SC2720 Ultra-Low Power Fuel Gauge 1 📄 Download
3 SC5325 Power Path Management IC 1 📄 Download
4 Ceramic Capacitors 0201/0402 ceramic capacitors 4 📄 Download
5 Sense Resistor 20mΩ current sense resistor 1 📄 Download
6 Programming Resistor Charge current programming resistor 1 📄 Download
7 Battery Connector Compact battery connector 1 📄 Download
8 USB Connector Micro-USB or USB-C connector 1 📄 Download

Applications

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Technical Specifications

Charge Current
Up to 280mA
Charge Efficiency
~85% (linear)
S O C Accuracy
±3%
Standby Current
<2μA total
Input Voltage
4.5V-5.5V (USB)
Solution Size
<20mm x 20mm
Operating Temperature
-20°C to +60°C

Customer Success Stories

Wearable Device Manufacturer

Consumer Electronics |

Challenge

Needed ultra-low power charging and monitoring for fitness tracker with 7-day battery life target

Solution

Implemented SouthChip wearable power solution with SC9017 charger and SC2720 fuel gauge

Results

  • Achieved 10-day battery life (exceeded target)
  • Reduced solution size by 40%
  • Accurate battery level indication
  • Passed all certification requirements

TWS Earbud OEM

Audio Electronics |

Challenge

Needed compact charging solution for TWS charging case with minimal standby drain

Solution

Implemented SC9017 charger with SC2720 fuel gauge in charging case

Results

  • Sub-1μA standby current achieved
  • Compact solution fit in small case
  • Reliable charging and monitoring
  • Extended case battery life

FAE Expert Insights

S

Sarah Liu

Senior FAE - Battery Management

Professional Insights

I've implemented this wearable power solution in numerous designs, and the results are consistently impressive. The key to success is the combination of SC9017's ultra-low standby current and SC2720's efficient fuel gauging. For a typical 200mAh battery, the total standby drain is less than 2μA - that's negligible compared to the battery's self-discharge. The SC9017's 280mA charge current is perfect for the small batteries used in wearables, and the SOT-23-5 package fits almost anywhere. The SC2720's WLCSP-6 package is incredibly small but still provides accurate gauging. Key design tips: place the fuel gauge sense resistor close to the IC with Kelvin connections, use small ceramic capacitors (0402 or 0201) for minimal size, and ensure good thermal design for the charger even at low currents. The I2C interface allows the main processor to monitor and control all power functions. This solution really shines in applications where battery life is critical.

Key Takeaways

  • Combined standby current <2μA extends battery life significantly
  • Compact packages enable smallest wearable designs
  • Kelvin connections critical for accurate fuel gauging
  • Small passives (0201/0402) minimize solution size

Decision Framework

Steps:
  1. Define battery capacity and target battery life
  2. Select SC9017 for ultra-low standby charging
  3. Add SC2720 for accurate low-power fuel gauging
  4. Include SC5325 for power path management
  5. Design compact PCB with small passives
  6. Implement I2C host control and monitoring

Ready to Implement This Solution?

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Frequently Asked Questions

What battery life can be achieved with this solution?

Battery life depends on device usage and battery capacity: (1) Standby mode - With <2μA standby current, a 200mAh battery can last months in standby. (2) Typical usage - 7-14 days for smartwatches with 200-300mAh batteries. (3) Fitness trackers - 10-30 days depending on sensor usage. (4) TWS case - Weeks to months depending on earbud charging frequency. (5) Factors - Display, sensors, and wireless connectivity affect actual battery life. The ultra-low standby current ensures maximum battery life in always-on applications.

Contact LiTong for battery life estimation and optimization.

How small can the solution be?

The wearable power solution is extremely compact: (1) PCB area - Approximately 15mm x 15mm for all components. (2) Component count - 3 main ICs plus small passives. (3) Height profile - All components under 0.6mm except optional connectors. (4) Passives - Use 0201 or 0402 size for minimal footprint. (5) Layout - 4-layer PCB with components on one side only. This compact size enables integration in the smallest wearable form factors including TWS earbuds and slim fitness bands.

Contact LiTong for compact layout design and miniaturization.

What is the development timeline for Wearable Power Solution?

Development timeline for Wearable Power Solution: (1) Evaluation phase - 1-2 weeks to evaluate reference design. (2) Schematic design - 1 week to adapt to specific requirements. (3) PCB layout - 1-2 weeks for compact wearable layout. (4) Prototype build - 1-2 weeks for PCB fabrication. (5) Testing - 1-2 weeks for validation and optimization. Total timeline typically 5-9 weeks. LiTong provides reference designs to accelerate development.

Contact LiTong for project planning and accelerated development.

What testing is required for wearable power solutions?

Testing requirements: (1) Functional testing - Verify charging, gauging, and power path operation. (2) Power consumption - Measure standby and active current consumption. (3) Battery life - Validate battery life under typical usage patterns. (4) Temperature - Verify operation across temperature range. (5) EMC - Conducted emissions testing for certification. (6) Safety - Battery safety and protection feature validation. LiTong provides test procedures and support.

Contact LiTong for test procedures and validation support.

Can the solution be customized for specific wearable applications?

The wearable power solution can be customized: (1) Charge current - Match to battery size and charging time requirements. (2) Solution size - Optimize layout for specific form factors. (3) Features - Add or remove features based on requirements. (4) Cost optimization - Select alternative components for cost-sensitive applications. (5) Integration - Integrate with specific sensors and processors. LiTong FAEs can help customize the solution for your specific wearable application.

Contact LiTong for solution customization and optimization.