Fan Controller. RT8749A Datasheet

RT8749A Controller. Datasheet pdf. Equivalent

RT8749A Datasheet
Recommendation RT8749A Datasheet
Part RT8749A
Description Digital Single-Phase Full Wave BLDC Fan Controller
Feature RT8749A; ® RT8749A Digital Single-Phase Full Wave BLDC Fan Controller General Description The RT8749A is a .
Manufacture Richtek
Datasheet
Download RT8749A Datasheet




Richtek RT8749A
®
RT8749A
Digital Single-Phase Full Wave BLDC Fan Controller
General Description
The RT8749A is a highly integrated digital controlled pre-
driver IC for regulating single-phase full wave brushless
DC (BLDC) fans at a programmed speed. The controller
IC accepts a Pulse-Width Modulated (PWM) signal
provided by the host. The decoded duty-ratio will then be
used for mapping to the programmed speed which is stored
at the embedded flash memory. This speed profile can be
programmed by the user for different fan models and
applications.
A frequency generator output is included to provide
commutation signals to the host to know the current
rotating speed. The control IC also provides several
protection features, including the peak-current limit, the
thermal shutdown protection, the under-voltage protection
and the motor lock protection. An automatic restart circuit
is designed to rotate the motor after the lock condition is
released.
Applications
Instrumentation Fans
Central Heating Blowers
Automotive Climate Control
Features
Embedded Flash Memory
External PWM Speed Control
Wide Range External PWM Input Frequency
(1kHz to 100kHz)
Built-in Frequency Generator with Selectable FG
or FG/2 Output Signal
Built-in Peak Current Limit
Built-in Motor Lock Protection and Automatic
Restart Circuit
Built-in Thermal Shutdown Protection
Low Power Standby Mode (when PWM Input is
Low)
Thin 16-Lead WDFN Package
RoHS Compliant and Halogen Free
Marking Information
1K= : Product Code
1K=YM
DNN
YMDNN : Date Code
Simplified Application Circuit
VM
VIN
V5DDA
RFG
PWM Signal
ROSC
RT8749A
VDD12
VM
UGB1
FG
PWM
LG1
VSS12
ROSC
V5DDD
RNF
ZD1 R1
R2
R5
RFILTER
CFILTER
V5DDA
HN
LG2
HP UGB2
GND
HN Hall V5DDA
HP
RRNF
R3
R4
R6
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8749A-00 May 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek RT8749A
RT8749A
Ordering Information
RT8749A
Package Type
QW : WDFN-16L 4x4 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Pin Configurations
(TOP VIEW)
UGB1 1
LG1 2
NC 3
VDD12 4
VSS12 5
ROSC 6
FG 7
PWM 8
GND
17
16 RNF
15 UGB2
14 LG2
13 V5DDD
12 GND
11 V5DDA
10 HN
9 HP
WDFN-16L 4x4
Functional Pin Description
Pin No.
Pin Name
Pin Function
1
UGB1
Channel 1 Open-Drain Output to High-Side P-MOSFET.
2 LG1 Channel 1 Output to Low-Side N-MOSFET.
3 NC
No Internal Connection.
4
VDD12
Power Input for Internal Circuits.
5
VSS12
Ground of Internal Circuits.
6
ROSC
Internal Oscillator Frequency Setting. Connect a resistor with low temperature
coefficient between this pin and ground.
7 FG
Frequency Generator with Open-Drain Output.
8
PWM
External PWM Input. With an internal pull-high resistor (200k).
9 HP
Positive Input Signal of Hall Sensor.
10 HN
Negative Input Signal of Hall Sensor.
11
V5DDA
Regulated 5V Power Source for Hall Sensor. It will be disabled in standby mode.
12,
17 (Exposed Pad)
GND
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
13
V5DDD
Regulated 5V Power Source for Digital Circuit.
14 LG2
Channel 2 Output to Low-Side N-MOSFET.
15
UGB2
Channel 2 Open-Drain Output to High-Side P-MOSFET.
16
RNF
Output Current Detection. Connect to a resistor for H-Bridge over-current
protection.
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8749A-00 May 2014



Richtek RT8749A
Function Block Diagram
RT8749A
PWM
GND
ROSC
Prog
Confi.
Regs
OSC
Prog Intf.
Flash Memory
Duty-to-RPM
Hall Intf
Regulator
Digital
Controller
Driver
Prog
OTP
OCP
UGB1
LG1
UBG2
LG2
RNF
FG
Operation
The highly integrated digital controlled fan controller
RT8749A integrates several functions as follows :
OTP
The over-temperature protection block is activated when
the junction temperature exceeds 150°C. It will be released
when the temperature cools below 120°C. The hysteresis
is 30°C.
OCP
The RT8749A features over-current protection function to
protect the power MOSFET. Users need to add a resistor
RRNF between the low-side N-MOSFET and GND. If over-
current protection is activated, the RT8749A will be
shutdown.
Regulator
The inherent voltage regulator generates regulated 5V
output for V5DDD & V5DDA respectively.
Hall Interface
The Hall Interface receives hall element signal and then
helps the RT8749A to recognize the fan position. The
controller will control the current direction by recognized
fan position.
Oscillator
The Oscillator generates the high accuracy 1MHz clock
signal for PWM output frequency. The PWM output
frequency is 31.25kHz typically.
Digital Controller
This block generates control signal to the driver for motor
operation control. It controls the motor speed depending
on duty to RPM converter, reference speed table and
control parameters which are stored in the flash memory.
Program Interface
The Program Interface is used for programming flash
memory purpose.
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8749A-00 May 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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