ROHM has announced the development of a built-in MOSFET boost-buck DC/DC converter that offers the lowest current consumption in the industry, making it ideal for battery-powered electronic devices such as electronic dictionaries, remote controls for household appliances, and other devices (e.g., toys and other portable electronics). In recent years, the number of portable devices, such as smartphones and wearables, incorporating rechargeable batteries (e.g., lithium-ion) has increased dramatically. Meanwhile, the adoption of conventional disposable batteries in a wide variety of applications is progressing rapidly, increasing the demand for power integrated circuits that can provide greater energy savings.
In response, ROHM has applied electrical processes and analog circuit technologies perfected over many years to develop integrated power supply circuits that meet market needs. This includes their latest converter, optimized for devices powered by disposable batteries. The BU33UV7NUX outputs the 3.3V required to drive MCUs in applications that need a 1-3V input from one or two batteries. The pursuit of lower current consumption to extend operating time in battery-powered devices has enabled ROHM to achieve an industry-leading current consumption of 7µA (compared to functionally equivalent products). This can extend operating time to up to 175 days compared to conventional products, from 540 days to 715 days (ROHM study, 50µA load current, starting from standby operation in conventional remote controls powered by two alkaline batteries). In addition, a load current mode switching function is incorporated, allowing existing remote controls to be compatible with 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.
To extend the lifespan of disposable batteries, ROHM has developed original analog design techniques and power supply system processes to achieve a current consumption of only 7µA, the lowest in the industry among functionally equivalent products. This makes it possible to increase battery life in conventional remote controls typically powered by two alkaline batteries by approximately 1.3 times compared to existing solutions, providing an additional 175 days of operation (ROHM study, based on standby mode and a charging current of 50µA). Furthermore, the BU33UV7NUX can be powered by input voltages as low as 0.9V and supports a wide range of battery types, including lithium-ion batteries such as commonly used coin cell batteries. In addition, the integrated battery leak detection function makes it particularly suitable for disposable battery applications.
2. Load current mode switching improves efficiency in a wide range of applications
A load current mode switching function is included, allowing existing remote controls to support the latest high-performance LCD-equipped devices while simultaneously delivering superior energy savings.
A low-power mode, Pulse Frequency Modulation (PFM) control, is adopted (for load currents of 50mA or less and with a current consumption of 7µA). The BU33UV7NUX automatically switches to its high-power Pulse Width Modulation (PWM) mode for high performance (500mA max. load current, 13µA current consumption, and PFM/PWM switching control), enabling high-efficiency power conversion of up to 94% across a wide range of conditions.
Target applications
• Electronic dictionaries
• Remote controls
• Electronic devices (e.g. toys and accessories)
• Wearables
• Electric toothbrushes
…and other devices powered by 1 or 2 disposable batteries (1 to 3V) or single-cell lithium batteries.
