homeback to menu

Leading Change at Work

Technology is changing the way we work. At Ricoh, we ensure that change is positive for your teams and your business. We guide you through every step of the journey to ensure a seamless transition to a fully digital workspace.
Discover more
seamless digital workspace experience
Digital Workspace

Access everywhere

Hybrid and on-the-go set-ups are shaping our future. We take a holistic approach to designing, integrating and supporting your digital workspaces to nurture employee engagement and help you reach new levels of performance.
Discover more
Business Process Management

Synched for success

Manual tasks no longer need to hold your staff back. We optimise your business processes to enable your staff to deliver more; providing the technology, expertise and support to streamline and simplify processes across your organisation.
Discover more
Cloud & Infrastructure

Cloud & clear

Capturing the full value of cloud requires the right roadmap and team to execute it. We provide cloud solutions and expertise that make your business operations more agile, cost-effective and secure while pursuing next-generation innovation.
Discover more

No more risky business

Internet-enabled devices create new vulnerabilities to cyberattacks. We help you go on the offensive against cybercrime with intelligent cybersecurity services and solutions aligned to your core business processes.
Discover more
Digital Experience

A new level of experience

An excellent customer experience starts with a superior employee experience. Our highly-skilled team of data scientists and developers design, build, implement and service the solutions you need to exceed expectations at every touchpoint.
Discover more
Graphic Communications

Future proof your business

The possibilities with print are endless. At Ricoh, we help you evolve, digitalise and create a sustainable business advantage; providing solutions on hardware, software and services that enable new opportunities within professional printing.
Discover more
Graphic Communication
Office Products & Software

Best-in-class quality

Ricoh is well known for high-quality printers, digital duplicators and multifunction printers/scanners/copiers. With plenty of choices in speed, size and capabilities, you can select from the models and features that work best for your workgroup, office or classroom.
Discover all our office products & software

A multi-faceted service and support platform

All the product and service support you need in one place. We provide support, advice and solutions to keep your business up and running.
Get support
AV technology and management

Your one-stop resource

Find out everything about our business news, product innovations and people, along with the events we’re hosting and attending.
Keep informed
News and events from Ricoh
The Company

Who we are and what we do

At Ricoh, we endeavour to always listen to our customers and provide you with innovative solutions, products and services that align with your business goals. We strive to add value to your services and products. We adapt to changing business climates.
Learn more about Ricoh

We love to hear from you

Whether you have a pricing question about our solutions or products, need help managing your account or already using our products and have a support question, our team is there to help.
Get in touch
customer and employee engagement

Helping you to stay one step ahead

Explore and read our lastest insights from what matter the most in business solutions.
Discover the latest insights
Ricoh Insights - Overview

Ricoh launches two tiny Li-Ion protection ICs for wearable devices

Osaka, Japan, September 11, 2018 – Ricoh Electronic Devices Co., Ltd. in Japan has launched the R5441 and R5443 single cell Li-Ion battery protection ICs in a Wafer Level Chip Scaled Package (WLCSP). These ultra-small products are specifically designed for use in rechargeable smart watches, hearing aid instruments, fitness trackers, wireless earbuds and other small portable devices.

Wearable devices incorporate a small rechargeable Li-Ion battery with a capacity in the range from 50 to 100 mAh and have new challenging requirements for its internal components, like an ultra-small package size, low current consumption in on and standby mode but also sophisticated safety circuits. The R5441 and R5443 fully comply with these requirements. The R5443 is the smallest version and has a board space area of only 1.05 mm2. With a thickness of 0.36 mm, it is considered as one of the smallest single cell Li-Ion protection ICs available today. It is around 53% smaller compared to the popular protection ICs in a 1.4 x 1.4 mm DFN package.

Significant detail for the R5441 / R5443 is that the current consumption of the ICs is equal or lower than most other available solutions on the market and contributes reducing the self-discharge rate of the battery pack. In normal operation, the current consumption is respectively 3.5 µA and 2.5 µA. As soon the battery voltage decreases below the over-discharge voltage threshold, the product enters a standby mode and disables several internal circuits to lower the current consumption to 0.04 µA, ensuring further discharge of the battery is kept to a minimum.

Li-Ion batteries are safe in general when used according to the specifications but can become a potential hazard in case of an internal or mechanical malfunction. Overheating, emitting fumes or even worse can be the result; therefore, the protection IC monitors the charge and discharge process and interrupts as soon the process is at risk of going beyond the safe operation range of the battery cell. The following processes are monitored:

  • Over-charge voltage: Battery voltage exceeds the charge threshold for a certain period.
  • Over-discharge voltage: Battery voltage exceeds the discharge threshold for a certain period.
  • Over-discharge current: Battery current exceeds the discharge threshold for a certain period.
  • Over-charge current: Battery current exceeds the charge threshold for a certain period.
  • Short current: Battery current exceeds the short discharge threshold for a certain period.

Both the R5441 and R5443 have an improved over-charge voltage threshold accuracy of ±10 mV versus ±30 mV for regular products. The idea behind this feature is to increase the charge voltage whilst maintaining the same safety level. As a result, the battery voltage will increase with 40 mV and extends the battery lifetime, which is important for applications with a small battery capacity.

Traditionally one makes use of the MOSFET on-resistance in order to measure the current flow of the battery pack. However, the on-resistance level is most inaccurate as it depends on various criteria such as ambient temperature, gate voltage and MOSFET type. In order to achieve a higher standard of current sensing, the R5441 and R5443 make use of an external current sense resistor. Such resistor can be ordered with your preferred resistance value and accuracy level. The great advantage of using an external resistor is that the over-current threshold margin improves significantly in comparison to the MOSFET current sense method.

The R5441 has an additional circuit to monitor the temperature of the battery pack by connecting an external NTC resistor to the Tin pin. In case of an over-temperature event, the charging or discharging process is interrupted. It is even possible to set different temperature threshold settings for the over-charge and over-discharge threshold.

Optional functions:
  • Optional latch and auto-release functions for the over-charge and over-discharge monitoring circuits are available. A latch function keeps the charge or discharge process interrupted until a load or charger is connected. The auto-release function releases the interruption at the same condition and when the release threshold is exceeded.
  • Circuit delay times are fixed internally and do not need any external components.
  • With 0V battery charge function, it is possible to prevent recharging when the battery voltage decreases below the deep discharge threshold. In such case, it would take a long time to recharge the battery and/or it may cause excessive heat dissipation.

R5441 R5443 Features:
Absolute Maximum Rating12 V
Supply Current at Normal ModeTyp.3.5 μA
Standby CurrentMax.0.04 μA
Over-charge Detection Voltage4.2 V to 4.6 V (in 0.005 V step, ±10 mV)
Over-discharge Detection Voltage2.0 V to 3.4 V (in 0.005 V step, ±2.0%)
Discharge Overcurrent Detection Voltage0.015 V to 0.150 V
0.015 V to 0.050 V in 0.001 V step / 0.050 V to 0.150 V in 0.005 V step
0.015 V to 0.030 V: ±3 mV / 0.030 V to 0.050 V: ±10% / 0.050 V to 0.150 V: ±5 mV
Charge Overcurrent Detection Voltage-0.150 V to -0.015V
-0.030 V to -0.015 V in 0.001 V step / -0.150 V to -0.030 V in 0.005 V step
-0.020 V to -0.015 V: ±4 mV / -0.040 V to -0.020 V: ±20% / -0.150 V to -0.040 V: ±8 mV
Short-circuit Detection Voltage0.040 V to 0.280 V (in 5 mV step, ±5 mV)
Thermal Detection Temperature (R5443 only)40°C to 70°C (in 5°C step, ±3°C)
Thermal Release Hysteresis Temperature (R5443 only)0°C to 5°C (in 1°C step)
Over-charge Detection Delay Time1.0 s
Over-discharge Detection Delay Time16 / 32 / 128 ms
Discharge Overcurrent Detection Delay Time8 /16 / 32 / 128 / 256 / 512 / 1024/ 3072 ms
Short-circuit Detection Delay Time280 μs
Charge Overcurrent Detection Delay Time8 ms
Thermal Detection Delay Time (R5443 only)128 / 256 / 512 / 1024 ms
Thermal Release Delay Time (R5443 only)128 ms
0 V-battery Charge OptionAvailable / Unavailable
Discharge Overcurrent Release OptionAuto Release Type / Latch Type
Package R5441 / R5443WLCSP-8-P2 / WLCSP-6-P7
Dimensions R5441 / R5443W1.51 x L0.92 x H0.36 mm / W1.25 x L0.84 x H0.36 mm
Datasheet R5441https://www.e-devices.ricoh.co.jp/en/products/lithium_ion/r5441/
Datasheet R5443https://www.e-devices.ricoh.co.jp/en/products/lithium_ion/r5443/

| About Ricoh |

Ricoh is empowering digital workplaces using innovative technologies and services that enable individuals to work smarter from anywhere.

With cultivated knowledge and organizational capabilities nurtured over its 85-year history, Ricoh is a leading provider of digital services, information management, and print and imaging solutions designed to support digital transformation and optimize business performance.

Headquartered in Tokyo, Ricoh Group has major operations throughout the world and its products and services now reach customers in approximately 200 countries and regions. In the financial year ended March 2022, Ricoh Group had worldwide sales of 1,758 billion yen (approx. 14.5 billion USD).

For further information, please visit www.ricoh-europe.com

© 2023 RICOH COMPANY, LTD. All rights reserved. All referenced product names are the trademarks of their respective companies.

For further information, please contact: 
Ricoh Europe PLC
Jack Gibson
E-mail: media@ricoh-europe.com
Homepage: www.ricoh-europe.com
Join us on Facebook: www.facebook.com/ricoheurope
Follow us on Twitter: www.twitter.com/ricoheurope
Follow us on LinkedIn: http://linkedin.com/company/ricoh-europe
Visit the Ricoh media centre at: www.ricoh-europe.com/press