®
RT8465
Constant Voltage High Power Factor PWM Boost Driver
Controller for MR16 Application
General Description
The RT8465 is a constant output voltage, active high power
factor, PWM Boost driver controller. It can be used as the
first Boost stage followed by a constant current Buck
converter with input from AC/electronic transformer in
MR16/AR111 application. To achieve high power factor,
the AC input voltage from AC/electronic transformer is
sensed via the SIN pin. An internal power factor correction
circuit follows the sensed sine waveform and modulates
the external MOSFET duty cycle-by-cycle to achieve
constant output voltage.
The output voltage is adjustable via an output resistive
divider. By operating at 220kHz, the filter component size
can be small to fit in tight MR16 space. To drive industrial
grade MOSFET switches, the RT8465 gate driver can
deliver up to 0.8A output current with 9V gate output voltage.
Features
Wide Input Voltage Range : 8V to 32V
High Power Factor Correction with Simple System
Circuits
Adjustable Constant Output Voltage
Built-in High Power Factor Correction Circuit
μ
Typical 250μA Start-Up Supply Current
Low Quiescent Current : 0.1μA
μ
SOP-8 Package
RoHS Compliant and Halogen Free
Applications
MR16, AR111 Lamps
PFC Controller
Simplified Application Circuit
L
AC IN
+
~
-
D2
VCC
R1
SIN
C2
ICOMP
C3
VCOMP
R4
C4
R5
C5
SENSE
GND
R3
FB
GATE
M1
C1
RT8465
R2
D1
RS
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS8465-01 March 2013
www.richtek.com
1
RT8465
Ordering Information
RT8465
Package Type
S : SOP-8
Lead Plating System
Z : ECO (Ecological Element with
Halogen Free and Pb free)
GND
GATE
VCC
SENSE
2
3
4
Pin Configurations
(TOP VIEW)
8
7
6
5
VCOMP
SIN
ICOMP
FB
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.
SOP-8
Marking Information
RT8465ZS : Product Number
RT8465
ZSYMDNN
YMDNN : Date Code
Functional Pin Description
Pin No.
1
2
3
4
Pin Name
GND
GATE
VCC
SENSE
Ground.
Gate Driver for External MOSFET Switch.
Power Supply. For good bypass, place a ceramic capacitor near the VCC pin.
Inductor Current Sense Input. The inductor current is sensed by a resistor between
GND and SENSE pins. The sense pin signal is used as the saw tooth signal to the
PWM comparator. The comparator output will modulate the GATE turn-on duty to
achieve the output voltage regulation.
Output Voltage Sense Input. The Output voltage is sensed through an external
resistive divider. The sensed voltage (which is tied to amplifier negative input) is
compared to an internal reference threshold at 1.2V (which is tied to amplifier
positive input).
Output of the Multiplier. To achieve high power factor, the voltage loop amplifier
output signal is modulated with the sensed input voltage through the SIN pin by an
internal multiplier. A compensation network between ICOMP and GND is needed.
Input Power Voltage Sensing for PFC Function. An external resistor for input
voltage sensing is connected to the power input.
Output of the Internal Voltage Loop GM Amplifier. A compensation network
between VCOMP and GND is needed.
Pin Function
5
FB
6
7
8
ICOMP
SIN
VCOMP
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS8465-01 March 2013
RT8465
Function Block Diagram
+
+
VCC
-
10V/8V
Chip
Enable
8V
OSC
S
R
PWM
Control
Circuit
R
SENSE
Q
200k
GATE
OVP
+
35V
GND
ICOMP
VCOMP
1.2V
FB
+
-
-
PFC
Control
Circuit
SIN
Operation
The RT8465 is a floating-GND Boost PWM current mode
controller with an integrated low side floating gate driver.
The start up voltage of RT8465 is around 10V. Once VCC
is above 10V, the RT8465 will maintain operation until
VCC drops below 8V.
The RT8465's main control loop consists of a 220kHz
fixed frequency oscillator, an internal 1.2V feedback (FB)
voltage sense threshold, and the PFC control circuit with
a PWM comparator. In normal operation, the GATE turns
high when the gate driver is set by the oscillator (OSC).
When the feedback (FB) voltage is below the reference
1.2V threshold, the VCOMP pin voltage will go high. The
ICOMP signal is the result of VCOMP signal multiplied
with SIN signal. Higher ICOMP voltage means longer GATE
turn-on period. The GATE does not always turn off in each
cycle. The GATE will be turned on again by OSC for the
next switching cycle.
The RT8465 provides several protections, including input
voltage Under Voltage Lockout (UVLO), Over Current
Protection (OCP) and VCC Over Voltage Protection (OVP).
Additionally, to ensure the system reliability, the RT8465
is built with internal thermal protection function.
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS8465-01 March 2013
www.richtek.com
3
RT8465
Absolute Maximum Ratings
(Note 1)
−0.3V
to 40V
−0.3V
to 16V
−0.3V
to 4V
−0.3V
to 2V
−1V
to 0.3V
VCC, SIN to GND ----------------------------------------------------------------------------------------------------------
GATE to GND (Note 6) -------------------------------------------------------------------------------------------------
VCOMP, ICMOP to GND ------------------------------------------------------------------------------------------------
FB to GND ------------------------------------------------------------------------------------------------------------------
SENSE to GND ------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
SOP-8 ------------------------------------------------------------------------------------------------------------------------ 0.53W
Package Thermal Resistance (Note 2)
SOP-8,
θ
JA
------------------------------------------------------------------------------------------------------------------ 188°C/W
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Model) ----------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
(Note 4)
Supply Input Voltage, VCC ---------------------------------------------------------------------------------------------- 8V to 32V
Junction Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
CC
= 24V
DC
, C
LOAD
= 1nF, R
LOAD
= 2.2Ω in series, T
A
= 25°C, unless otherwise specified)
Parameter
Input Start-Up Voltage
Under Voltage Lockout Threshold
Under Voltage Lockout Threshold
Hysteresis
Input Supply Current
Input Quiescent Current
Oscillator
Switching Frequency
Maximum Duty in Transient
Operation
Maximum Duty in Steady State
Operation
Blanking Time
Minimum Turn-Off Time
Current Sense Amplifier
Current Sense Voltage
Sense Input Current
Symbol
V
ST
V
UVLO
ΔV
UVLO
I
CC
I
QC
f
SW
D
MAX(TR)
D
MAX
t
BLANK
Test Conditions
Min
--
7
--
Typ
10
8
2
2
0.1
220
--
97
--
650
−100
10
Max
11
--
--
5
--
250
100
--
--
--
--
--
Unit
V
V
V
mA
μA
kHz
%
%
ns
ns
mV
μA
After Start-Up, V
CC
= 24V
Before Start-Up, V
CC
= 7V
V
SIN
= 14V
VC = 3V
--
--
190
--
--
200
(Note 5)
V
SENSE
I
SENSE
V
COMP
= 1V, S
IN
= 15V
Sense = 100mV
(Note 5)
--
--
--
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS8465-01 March 2013
RT8465
Parameter
Gate Driver Output
GATE Pin Maximum Voltage
High
GATE Voltage
Low
GATE Drive Rise and Fall Time
GATE Drive Source and Sink
Peak Current
Multiplier
SIN Pin Input Current
ICOMP Threshold for PWM
Switch Off
VC Output Current
Feedback Voltage
Feedback Input Current
OVP and Soft-Start
Over Voltage Protection
Thermal Protection
Thermal Shutdown
Temperature
SIN Pin Input Resistance
T
SD
--
--
150
200
--
--
°C
kΩ
V
OVP
VCC Pin
32
35
38
V
V
ICOMP
I
VCOMP
V
FB
I
FB
V
FB
= 1.2V
(Note 5)
0.5V
≤
VC
≤
2.4V
(Note 5)
V
SIN
= 14V
V
SIN
= 28V
50
80
--
--
1.1
--
60
100
1.2
16
1.2
1
70
120
--
--
1.3
--
μA
V
μA
V
μA
V
GATE_L
V
GATE
V
GATE_H
No Load at GATE Pin
I
GATE
=
−20mA
I
GATE
=
−100μA
I
GATE
= 20mA
I
GATE
= 100μA
1nF Load at GATE
1nF Load at GATE
(Note 4)
--
--
--
--
--
--
--
9.5
9.1
9.4
0.75
0.5
70
0.5
16
--
--
--
--
100
0.8
V
V
V
ns
A
Symbol
Test Conditions
Min
Typ
Max
Unit
Note 1.
Stresses beyond those listed
“Absolute
Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2.
θ
JA
is measured at T
A
= 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7.
Note 3.
Devices are ESD sensitive. Handling precaution is recommended.
Note 4.
The device is not guaranteed to function outside its operating conditions.
Note 5.
Guaranteed by design; not subject to production test.
Note 6.
The GATE voltage is internally clamped and varies with operating conditions.
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS8465-01 March 2013
www.richtek.com
5
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