LB11850VA
Single‐phase Full‐wave
Pre‐driver with Speed
Control Function
for Fan Motor
Monolithic Digital IC
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
www.onsemi.com
SSOP24
CASE 565AR
MARKING DIAGRAM
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YMDDD
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Y
M
DDD
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PIN ASSIGNMENT
1
OUT2P
OUT2N
VCC
SENSE
CVI
CVO
CTL
RC
SOFT
CPWM
FG
RD
12
(Top View)
24
OUT1P
OUT1N
SGND
5VREG
C
EO
EI
LIM
CT
IN+
HB
IN−
13
ORDERING INFORMATION
See detailed ordering and shipping information on page 14 of
this data sheet.
© Semiconductor Components Industries, LLC, 2013
1
March, 2018 − Rev. 1
Publication Order Number:
LB11850VA/D