New Buck-Boost Converter from ROHM Provides 1.3x Longer Battery Life

ROHM has recently announced the development of a buck-boost DC/DC converter with built-in MOSFET featuring the lowest current consumption in the industry, making it ideal for electronic devices powered by batteries such as electronic dictionaries, remote controls for home appliances, and items such as toys, and other portable electronic devices.

In recent years, the number of portable devices such as smartphones and wearables that incorporate rechargeable batteries (i.e. lithium ion) has risen dramatically. Meanwhile, the adoption of conventional single use batteries in a wide variety of applications is progressing at a rapid pace, increasing the demand for power supply ICs that can provide greater energy savings.

In response, ROHM applied power processes and analog circuit technologies cultivated over many years to develop power supply ICs that meet market needs. This includes this latest converter optimized for devices powered by single use batteries. The BU33UV7NUX outputs the 3.3V necessary for driving MCUs in applications requiring 1-3V input from 1 to 2 batteries. Pursuing lower current consumption in order to prolong operating time in battery-equipped devices allowed ROHM to achieve an industry-low current consumption of 7&#181A (vs functionally equivalent products). This can extend the operating time by as much as 175 days compared to conventional products, from 540 days to 715 days (ROHM study, 50uA load current and assuming standby operation in conventional remote controls driven by 2 alkaline batteries). In addition, a load current mode switching function is built in that allows existing remote controls to support the latest high-performance systems equipped with LCD panels, providing greater energy savings in a wide range of applications.

Key features

1. Low current consumption and low-voltage drive contribute to longer battery life

In order to prolong operating life with single use batteries, ROHM developed original analogue design techniques and power system processes to achieve a current consumption of just 7&#181A, the smallest in the industry among functionally equivalent products. This makes it possible to increase battery life in conventional remote controls typically powered by 2 alkaline batteries by approx. 1.3x over existing solutions, providing an extra 175 days of operation (ROHM study, assuming standby mode and a load current of 50&#181A). In addition, the BU33UV7NUX can be driven by input voltages as low as 0.9V and supports a variety of battery types including lithium, such as the coin cells commonly used. In addition, the built-in battery leak detection function makes it particularly suited for single use battery applications.

2. Load current mode switching improves efficiency in a wide range of applications

A load current mode switching function is included that allows existing remote controls to support the latest high-performance LCD-equipped sets while delivering superior energy savings.

Adopting a low-power mode, Pulse Frequency Modulation (PFM) control, is adopted for 50mA or lower load currents, featuring 7&#181A current consumption. The BU33UV7NUX automatically switches to its high-power Pulse Width Modulation (PWM) mode for high-performance (500mA max. load current, 13&#181A current consumption, PFM/PWM switching control), make it possible to achieve high efficiency power conversion as high as 94% under a wide range of conditions.

Target Applications

  • Electronic dictionaries
  • Remote controls
  • Electronic gadgets (i.e. toys, accessories)
  • Wearables
  • Electric toothbrushes

…and other devices powered by 1-2 single use batteries (1 to 3V) or single cell Lithium batteries.

About ROHM Semiconductor

ROHM Semiconductor is a global company of 352,010 million yen (3,23 billion US$) revenue per March 31th, 2017 with 21,308 employees. ROHM Semiconductor develops and manufactures a very large product range from the Ultra Low Power Microcontroller, Power Management, Standard ICs, SiC Diodes, MOSFETs and Modules, Power Transistors and Diodes, LEDs to passives components such as Resistors, Tantalum Capacitors and LED display units, thermal Printheads in state-of-the-art manufacturing plants in Japan, Korea, Malaysia, Thailand, the Philippines, China and Europe.

LAPIS Semiconductor (former OKI Semiconductor), SiCrystal AG, Kionix are companies of ROHM Semiconductor Group.

ROHM Semiconductor Europe has its head office near Dusseldorf serving the EMEA region (Europe, Middle East and Africa). For further information please contact www.rohm.com/eu