Semiconductor develops new motor driver

Paul Boughton
Semiconductor manufacturer ROHM has developed the BD65491FV (1-channel) and BD65492MUV (2-channel) high-speed motor drivers for use in a broad range of digital camera lens drive and home appliance motor drive applications.

Increasingly advanced functionality in battery-operated mobile devices, compact office equipment, and home appliances is being accompanied by growing demand for lower power consumption. At the same time, manufacturers are under pressure to lower device drive voltages as the number of battery cells is reduced and more compact actuators developed.

To satisfy these needs, it was necessary to increase switching speeds and lower on-resistance in order to improve drive efficiency, and to eliminate switching transistors’ gate drive step-up circuit (charge pump circuit) in order to lower current consumption.

However, existing technologies required that the current sent to the pre-driver be boosted in order to raise the pre-driver’s capacity sufficiently to accommodate the desired increase in switching speed, creating a bottleneck on the road to lower power consumption.

Additionally, existing designs required a charge pump circuit in order to provide the necessary gate voltage in the operating voltage range, particularly in the low-voltage region (3 V and lower). In its new design, ROHM has combined a state-of-the-art DMOS process with proprietary circuit technology to resolve these roadblocks on the way to lower power consumption, allowing the company to deliver a high-speed drive with low current consumption and low-voltage drive performance down to 1.8 V, without a charge pump.

These innovations paved the way for parts with the industry’s shortest turn-on and turn-off times as well as a wide range of operating voltages, allowing their use to power mobile devices for extended periods of time as well as home appliances needing power supplies of 10V and greater. Along with their compact packages, the ability to eliminate at least two capacitors thanks to the removal of the charge pump will contribute to smaller application systems.

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