32207 MS IM 20070301-S00003 / D0606 MH IM 20060619-S00002 No.A0609-1/15

http://onsemi.com

Semiconductor Components Industries, LLC, 2013

May, 2013

LB11850VA

Overview

The LB11850VA is a single-phase bipolar fan motor driver with speed control function that works with a speed

feedback signal. A highly efficient, quiet and low power consumption motor driver circuit, with a high speed

accuracy and large variable speed can be implemented by adding a small number of external components.

This pre-driver is optimal for driving large scale fan motors (with large air volume and large current) such as those

used in servers and consumer products.

Functions and features

• Pre-driver for single-phase full-wave drive

→PMOS-NMOS is used as an external power TR, enabling high-efficiency and low-power-consumption drive by

means of the low-saturation output and single-phase full-wave drive.

• On-chip speed control circuit

→The speed control (closed loop control) using a speed feedback signal makes it possible to achieve higher speed

accuracy and lower speed fluctuations when supply voltage fluctuates or load fluctuates, compared with an

open-loop control system. Separately excited upper direct PWM control method is used as the variable-speed

control system.

• External PWM input or analog voltage input enabling variable speed control

→The speed control input signal is compatible with PWM duty ratio or analog voltages.

• On-chip soft start circuit

• Lowest speed setting pin

→The lowest speed can be set with the external resistor.

• Current limiter circuit incorporated

→Chopper type current limit at start or lock.

• Reactive current cut circuit incorporated

→Reactive current before phase change is cut to enable silent and low-consumption drive.

• Constraint protection and automatic reset functions incorporated

• FG (speed detection), RD (lock detection) output

• Constant-voltage output pin for hall bias

Ordering number : ENA0609A

Monolithic Digital IC

For Fan Motor

Single-Phase Full-Wave Pre-Driver

with Speed Control Function