THL6521 / THL6523

THL6521 / THL6523 Rev.1.00 E
THL6521 / THL6523
1channel LED Driver
Description
Features
THL6521 / THL6523 are a 1 channel LED driver.
THL6521 / THL6523 have a built-in boost converter,
since back light system can consist of 1 chip.
Soft start / Over current protection / Under voltage
lock out protection / Over voltage protection / Thermal
shut down are built in.
Mounted area is reducible by TSOP23-6.
・Input voltage range : 2.5V - 5.5V
・Boost converter
Maximum output voltage : 38V
Switching frequency range : 1MHz
・LED driver feedback Voltage
THL6521 : 100mV
THL6523 : 300mV
・PWM dimming frequency : 100Hz - 200kHz
・Protection
Soft start
Over current protection
Under voltage lock out protection
Over voltage protection
Thermal shut down
・TSOT23-6 package
Application
・Mobile phone display backlight
・Car Navigator display backlight
・Laptop / Netbook / Tablet PC display backlight
Pin Configuration
Block Diagram
VIN
LX
1
6
VCC
LX
VCC
GND
2
5
NC
FB
3
4
PWM/EN
PWM/EN
UVLO
OVP
Boost
FB
SS
OSC
GND
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THine Electronics, Inc.
THL6521 / THL6523 Rev.1.00 E
Absolute Maximum Ratings
Parameter
Symbol
VCC
VH
VL
Pd
Tj
Tstg
VCC voltage
LX voltage
FB / PWM/EN voltage
Power description
Junction temperature *1
Storage temperature range
Rating
6
43
6
0.4
-40 to +125
-55 to +150
Units
V
V
V
W
℃
℃
*1. The operating temperature range should perform a thermal design, after consulting the thermal characteristic. Please use it in the range which
does not exceed junction temperature.
Recommended Operating Conditions
Parameter
Min
2.5
0.1
VCC voltage
LX voltage
PWM dimming frequency
Typ
-
Max
5.5
38
200
Units
V
V
kHz
Pin Description
Number
Name
1
LX
2
3
GND
FB
4
PWM/EN
5
6
NC
VCC
Function
Boost converter switching
output pin
Ground pin
Feedback input pin
PWM dimming control
input pin / Enable pin
Non connection pin
Input supply voltage pin
Description
This pin is switching output of boost converter.
Ground of LED driver.
LED current is set by the value of the external resistor.
This pin is PWM dimming control and Enable.
If a High level is impressed, the LED driver operate. If A
Low level inputted 20msec or more, it operates as enabling.
IC stops after that.
This pin is non connection pin. Please open.
Power supply pin.
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THine Electronics, Inc.
THL6521 / THL6523 Rev.1.00 E
Power Dissipation
450
Power Dissipation [mW]
400
350
300
250
200
150
100
50
0
-40
-20
0
20
40
60
80
100
120
140
Operating Temperature [℃]
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THL6521 / THL6523 Rev.1.00 E
Electrical Characteristics
Parameter
(at VCC=3.3V , Ta=25℃, unless otherwise noted)
Symbol
Test Conditions
Min
Typ
Max
Units
Input quiescent Current 1
Icc1
Vfb=0V
-
1
2
mA
Input quiescent Current 2
Icc2
Vfb=1.5V
-
400
600
uA
-
-
4
uA
Standby current
Ist
UVLO threshold voltage
Vuvlo
-
2.2
-
V
UVLO hysteresis voltage
dVuvloh
-
100
-
mV
PWM/EN input high voltage
dVuvloh
1.4
-
-
V
PWM/EN input low voltage
Vpwm_h
-
-
0.5
V
PWM/EN sink current
Vpwm_l
-
1
-
uA
PWM/EN dimming frequency
PWM/EN minimum pulse
PWM/EN
Low shoutdown delay time
Boost converter switching
frequency
Boost converter Maximum duty
cycle
Soft start time
FB voltage
Ipwm_leak
VCC rising
0.1
-
200
kHz
Fpwm
-
1
-
us
Tmin_pulse
-
20
-
ms
Fosc
-
1
-
MHz
90
-
-
%
-
5
-
ms
90
100
110
285
300
315
Vfb=0.1V
-
-300
-
-
0.5
-
Ω
Vlx=10V
-
10
-
uA
Dmax
Duty=5%~100%
Vfb=0V
Tss
THL6521
THL6523
FB input bias current
Vfb
Ifb
LX ON-resistance
Ron
LX leakage current
Ilx_leak
mV
nA
Over current threshold
Iocp
1.2
1.5
-
A
Over voltage protection threshold
Vovp
38
39
-
V
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THine Electronics, Inc.
THL6521 / THL6523 Rev.1.00 E
Function
PWM dimming / Enable
Input voltage / Output voltage
The dimming function is carried. It is possible to control
If the difference of input voltage and output voltage
ON/OFF of the constant current output for LED by
becomes large, the ON Duty cycle (Don) will become
inputting in a PWM signal. An LED output becomes
small. Depending on the conditions of input and output
active when a PWM signal is a High level. Please input a
voltage, the pulse width below the minimum pulse width,
dimming signal in 200 kHz from 100 Hz. The minimum
250nsec is needed. In this case, a pulse is skipped and
Duty cycle DPWMmin which can be set up by a PWM
frequency is decreased. Please decide the input and
dimming function is determined by the following
output voltage condition with considering a maximum
formula from PWM minimum pulse width and the
Duty cycle and the minimum pulse width.
frequency fPWM of PWM.
<<Notes>>
This product contains the over
D PWM min [%] = 1[ μ sec] × f PWM [ MHz ] × 100
current protection
circuit in order to protect destruction of IC from the
When not use a dimming function, please input the
output abnormality of a boost converter. Please refer
signal of a high level to PWM terminal. If a dimming
to Over current protection (OCP) for details. After a
signal which is less than 100Hz is inputted, a boost
power supply is inputted, the voltage difference of input
converter is stopped and it performs the same operation
voltage and output voltage becomes the largest at the
as EN. PWM does not have restriction of an input
moment of Under voltage lock out (UVLO) being
sequence. If inputted into PWM before the input of VCC,
canceled.
there is no problem.
In this condition, most much current flows from an input.
If you do not use a dimming function, please use it as EN.
When input voltage is inputted slowly, the over-current
The standby function is carried. When EN input terminal
protection circuit is operated for the above-mentioned
is made into a low level 20msec or more, it will be in a
reason. In that case, please input into VCC after inputting
standby state.
EN input or PWM input. In inputting into VCC, please
And a boost converter and an LED drive
output are suspended. The consumed current is set to less
use the conditions that it does not become an
than 4uA in a standby state. EN does not have restriction
over-current.
of an input sequence. If inputted into EN before the input
of VCC, there is no problem.
Boost converter
The boost converter for an LED drive is built in. The
LED Constant current output setup
voltage of an LED constant current output OUT terminal
LED current is determined by resistance connected to
is feedback, and the suitable voltage for the anode of
between FB terminal and GND. Please use it according
LED is supplied.
to the following formula from feedback voltage.
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THine Electronics, Inc.
THL6521 / THL6523 Rev.1.00 E
・ THL6521 : VFB=100mV
overshooting and rush current occur when input voltage
・ THL6523 : VFB=300mV
is inputted.
I LED =
VFB
RFB
Over Voltage protection (OVP)
Over voltage protection is built in. If LED is
disconnecting, the output voltage of a boost converter is
100Ω
stopped and destruction of IC is prevented.
FB pin
RFB
Over current protection (OCP)
Fig. 1
In order to restrict the over-current by the abnormalities
Filter setup of FB input
of load, etc., the over-current protection circuit is built in.
<<Notes>>
Over-current detection of pulse-by-pulse system is
Over voltage is added to FB terminal when LED is
adopted. An output transistor is turned off if the current
short-circuited. IC may be destroyed by it. It
which flows into an output transistor reaches boost
recommends inserting the resistance (Fig. 1) of 100ohm
converter limit current (Iocp). The output transistor
in a FB terminal for fracture prevention.
operates again in reset time in IC after that. An
over-current protection circuit detects the peak current of
an inductor. Input-and-output voltage and not only LED
Protection circuits
constant current but ripple current is taken into
Under voltage lock out (UVLO)
consideration.
The UVLO function is carried in order to prevent
malfunction in the state where input voltage is low. A
boost converter and an LED constant current output are
Thermal shut down (TSD)
suspended to the power supply voltage which can carry
In order to prevent destruction by heat, the thermal
out operational stability. UVLO is released by more than
shutdown circuit is built in. If the junction temperature
2.2V input voltage. And a boost converter carries out
Tj is 125oC or more, the thermal shutdown circuit will
LEDs constant current drive, after starting soft start
operate and it will stop switching operation. Moreover,
operation.
the hysteresis of a thermal shutdown circuit is 20 oC. If
Tj falls, output voltage will return.
Soft start (SS)
The boost converter carries the soft start function in
order to prevent the rush current at a start-up. This
function is to raise output voltage slowly. It is because
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THine Electronics, Inc.
THL6521 / THL6523 Rev.1.00 E
Package Dimensions
TSOP23-6
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THine Electronics, Inc.
THL6521 / THL6523 Rev.1.00 E
Notices and Requests
1. The product specifications described in this material are subject to change without prior notice.
2. The circuit diagrams described in this material are examples of the application which may not always apply to the
customer’s design. We are not responsible for possible errors and omissions in this material. Please note if errors or
omissions should be found in this material, we may not be able to correct them immediately.
3. This material contains our copyright, know-how or other proprietary. Copying or disclosing to third parties the
contents of this material without our prior permission is prohibited.
4. Note that if infringement of any third party's industrial ownership should occur by using this product, we will be
exempted from the responsibility unless it directly relates to the production process or functions of the product.
5. This product is presumed to be used for general electric equipment, not for the applications which require very high
reliability (including medical equipment directly concerning people's life, aerospace equipment, or nuclear control
equipment). Also, when using this product for the equipment concerned with the control and safety of the
transportation means, the traffic signal equipment, or various Types of safety equipment, please do it after applying
appropriate measures to the product.
6. Despite our utmost efforts to improve the quality and reliability of the product, faults will occur with a certain small
probability, which is inevitable to a semi-conductor product. Therefore, you are encouraged to have sufficiently
redundant or error preventive design applied to the use of the product so as not to have our product cause any social
or public damage.
7. Please note that this product is not designed to be radiation-proof.
8. Customers are asked, if required, to judge by themselves if this product falls under the category of strategic goods
under the Foreign Exchange and Foreign Trade Control Law.
9. The product or peripheral parts may be damaged by a surge in voltage over the absolute maximum ratings or
malfunction, if pins of the product are shorted by such as foreign substance. The damages may cause a smoking
and ignition. Therefore, you are encouraged to implement safety measures by adding protection devices, such as
fuses.
THine Electronics, Inc.
[email protected]
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