Driver Controller. RT7306 Datasheet

RT7306 Controller. Datasheet pdf. Equivalent

RT7306 Datasheet
Recommendation RT7306 Datasheet
Part RT7306
Description Primary-Side Regulation Dimmable LED Driver Controller
Feature RT7306; RT7306 Primary-Side Regulation Dimmable LED Driver Controller with Active-PFC General Description .
Manufacture Richtek
Datasheet
Download RT7306 Datasheet




Richtek RT7306
RT7306
Primary-Side Regulation Dimmable LED Driver Controller
with Active-PFC
General Description
The RT7306 is a constant current LED driver with active
power factor correction. It supports high power factor
across a wide range of line voltages, and it drives the
converter in the Quasi-Resonant (QR) mode to achieve
higher efficiency. By using Primary Side Regulation
(PSR), the RT7306 controls the output current
accurately without a shunt regulator and an opto-coupler
at the secondary side, reducing the external component
count, the cost, and the volume of the driver board.
RT7306 is compatible with analog dimming. The output
current can be modulated by the DIM pin. An in-house
design high voltage (HV) start-up device is integrated in
the RT7306 to minimize the power loss and shorten the
start-up time.
The RT7306 embeds comprehensive protection
functions for robust designs, including LED open-circuit
protection, LED short-circuit protection, output diode
short-circuit protection, VDD Under-Voltage Lockout
(UVLO), VDD Over-Voltage Protection (VDD OVP),
Over-Temperature Protection (OTP), and cycle-by-cycle
current limitation.
Features
Tight LED Current Regulation
No Opto-Coupler and TL431 Required
Power Factor Correction (PFC)
Compatible with Analog Dimming
Built-in HV Start-up Device
Quasi-Resonant
Maximum/Minimum Switching Frequency
Clamping
Maximum/Minimum on-Time Limitation
Wide VDD Range (up to 34V)
THD Optimization
Input-Voltage Feed-Forward Compensation
Multiple Protection Features
LED Open-Circuit Protection
LED Short-Circuit Protection
Output Diode Short-Circuit Protection
VDD Under-Voltage Lockout
VDD Over-Voltage Protection
Over-Temperature Protection
Cycle-by-Cycle Current Limitation
Applications
AC/DC LED Lighting Driver
Simplified Application Circuit
Flyback Application Circuit
Buck-Boost Application Circuit
Line
Neutral
BD
CIN
RHV
VDD HV
CVDD
GD
RT7306
TX1 DOUT
Q1
VOUT+
COUT
VOUT-
Line
Neutral
COMP
CCOMP
RPC
CS
Analog
Dimming
Signal
DIM
ZCD
GND
DAUX
RCS
RZCD1
RZCD2
BD
CIN
RHV
HV
VDD
CVDD
RT7306 GD
TX1
DOUT
Q1
VOUT-
COUT
VOUT+
COMP
CCOMP
CS
Analog
Dimming
Signal
DIM
ZCD
GND
DAUX
RPC
RCS
RZCD1
RZCD2
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
DS7306-02 January 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek RT7306
RT7306
Ordering Information
RT7306
Package Type
S : SOP-8
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
RoHS compliant and compatible with the current
requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Marking Information
RT7306
GSYMDNN
RT7306GS : Product Number
YMDNN : Date Code
Pin Configurations
(TOP VIEW)
HV
GND
COMP
DIM
2
3
4
8 VDD
7 GD
6 CS
5 ZCD
SOP-8
Functional Pin Description
Pin No. Pin Name
Pin Function
1 HV
High Voltage Input for Startup.
2 GND
Ground of the Controller.
3
COMP
Compensation Node. Output of the internal trans-conductance amplifier.
4 DIM
Analog Dimming Signal Input. LED driving current can be adjusted by an analog
voltage.
5 ZCD
Zero Current Detection Input. This pin is used to sense the voltage at auxiliary winding
of the transformer.
6 CS
Current Sense Input. Connect this pin to the current sense resistor.
7 GD
Gate Driver Output for External Power MOSFET.
8 VDD
Supply Voltage (VDD) Input. The controller will be enabled when VDD exceeds VTH_ON
and disabled when VDD is lower than VTH_OFF.
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS7306-02 January 2016



Richtek RT7306
RT7306
Function Block Diagram
ZCD
CS
HV
Clamping
Circuit
Valley
Detector
Feed-Forward
Compensator
THD
Optimizer
Ramp
Generator
Valley Signal
HV Start-Up
Control
Starter
Circuit
UVLO
Under-Voltage
Lockout
(16V/9V)
Constant
Current
ICS Control
Output
Over-Voltage
Protection
Leading
Edge
Blanking
Dimming
Control
+
-
Constant on-Time
Comparator
PWM
Control
Logic
+
VCS_CL
1.2V
-
Current-Limit
Comparator
Output Diode
Short-Circuit
Protection
Over-
Temperature
Protection
OTP
Output OVP
VDD OVP
VDD
Over-Voltage
Protection
VCLAMP 13V
PWM
Gate
Driver
RGD
VDD
GD
GND
DIM COMP
Operation
Critical-Conduction Mode (CRM) with Constant
On-Time Control
Figure 1 shows a typical flyback converter with input
voltage (VIN). When main switch Q1 is turned on with
a fixed on-time (tON), the peak current (IL_PK) of the
magnetic inductor (Lm) can be calculated by the
following equation :
IL_PK
VIN
Lm
tON
TX1
NP:NS
DOUT
IL
+ IOUT
Lm COUT VOUT ROUT
VIN -
Q1
If the input voltage is the output voltage of the
full-bridge rectifier with sinusoidal input voltage
(VIN_PKsin()), the inductor peak current (IL_PK) can be
expressed as the following equation :
IL_PK
VIN_PK
sin(θ)
Lm
tON
When the converter operates in CRM with constant
on-time control, the envelope of the peak inductor
current will follow the input voltage waveform with
in-phase. Thus, high power factor can be achieved, as
shown in Figure 2.
Figure 1. Typical Flyback Converter
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
DS7306-02 January 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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