Driver Controller. RT8458A Datasheet


RT8458A Controller. Datasheet pdf. Equivalent


Part Number

RT8458A

Description

High Efficiency PWM Buck LED Driver Controller

Manufacture

Richtek

Total Page 13 Pages
Datasheet
Download RT8458A Datasheet


RT8458A
®
RT8458A
High Efficiency PWM Buck LED Driver Controller
General Description
The RT8458A is a PWM controller with an integrated high
side gate driver. It is used for step down converters by
well controlling the external MOSFET and regulating a
constant output current. The output duty cycle of the
RT8458A can be up to 100% for wider input voltage
application, such as E27 and PAR30 off-line LED lighting
products.
The RT8458A also features a 47kHz fixed frequency
oscillator, an internal 220mV precision reference, and a
PWM comparator with latching logic. The accurate output
LED current is achieved by an averaging current feedback
loop and the LED current dimming can be easily controlled
via the ACTL pin. The RT8458A also has multiple features
to protect the controller from fault conditions, including
Under Voltage Lockout (UVLO), Over Current Protection
(OCP) and Over Voltage Protection (OVP). Additionally,
to ensure the system reliability, the RT8458A is built with
the thermal protection function.
The RT8458A is housed in a TSOT-23-6 package. Thus,
the components in the whole LED driver system can be
made very compact.
Features
Low Cost and Efficient Buck Converter Solution
Universal Input Voltage Range with Off-Line
Topology
Programmable Constant LED Current
Dimmable LED Current by ACTL
Output LED String Open Protection
Output LED String Short Protection
Output LED String Over Current Protection
Built-in Thermal Protection
TSOT-23-6 Package
RoHS Compliant and Halogen Free
Applications
E27, PAR30, Offline LED Lights
Marking Information
07=DNN
07= : Product Code
DNN : Date Code
Simplified Application Circuit
VIN
CIN RVCC1
RVCC2
CVCC
CVC2
RVC
CVC1
RT8458A
VCC ACTL
VC GATE
GND SENSE
Analog
Dimming
Q1
D2
RS L1
D1 COUT
LED+
LED-
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8458A-09 August 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1

RT8458A
RT8458A
Ordering Information
RT8458A
Package Type
J6 : TSOT-23-6
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)
SENSE VC ACTL
654
23
VCC GND GATE
TSOT-23-6
Functional Pin Description
Pin No.
1
2
3
4
5
6
Pin Name
VCC
GND
GATE
ACTL
VC
SENSE
Pin Function
Supply Voltage Input of the Chip. For good bypass, a ceramic capacitor near the
VCC pin is required.
Ground of the Chip.
Gate Driver Output for External MOSFET Switch.
Analog Dimming Control Input. The effective dimming range is between 0.1V to
1.2V. If VACTL is greater than 1.2V, the ACTL dimming signal high is internally
clamped around 1.3V. If dimming is not used, a pull up resistor or a voltage holding
capacitor between ACTL and GND pins should be used.
PWM Loop Compensation Node.
LED Current Sense Input. The Typical sensing threshold is 220mV between the
SENSE and GND pin.
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8458A-09 August 2014


Features ® RT8458A High Efficiency PWM Buck LED Driver Controller General Description The RT8458A is a PWM controller with a n integrated high side gate driver. It is used for step down converters by wel l controlling the external MOSFET and r egulating a constant output current. Th e output duty cycle of the RT8458A can be up to 100% for wider input voltage a pplication, such as E27 and PAR30 off-l ine LED lighting products. The RT8458A also features a 47kHz fixed frequency o scillator, an internal −220mV precisi on reference, and a PWM comparator with latching logic. The accurate output LE D current is achieved by an averaging c urrent feedback loop and the LED curren t dimming can be easily controlled via the ACTL pin. The RT8458A also has mult iple features to protect the controller from fault conditions, including Under Voltage Lockout (UVLO), Over Current P rotection (OCP) and Over Voltage Protec tion (OVP). Additionally, to ensure the system reliability, the RT8458A is built with the thermal protect.
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