LED恒流驱动芯片 SHT6088

SHT6088 是一款驱动 LED 的恒流控制芯
片，系统应 用电压范围从 12V 到 450V，
占空比从 0-100%。支 持交流 85V-265V
输入，主要应用于非隔离的 LED 驱动系
统。SHT6088 采用**技术的恒流控制方
法， 使得 LED 电流从交流 85V-265V 范
围内变化小于
±5％。而且，SHT6088 采用专门技术的系
统结构， 使得系统 18W 的 LED 日

SHT6088
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Current mode Control LED driver IC
GENERAL DESCRIPTION
The SHT6088 is a current mode control LED
driver IC. The SHT6088 can support DC
voltage which ranges from 12V to 450V, with
duty cycle up to 100%. TheSHT6088 can be
used in non-isolation LEDs driving system and
can support AC supply voltage from 85V to
265V. The SHT6088 uses Specialized
technique for source driver and constant
current compensation, so LEDs current has ±5
％ accuracy with AC supply voltage variation
from 85V to 265V. What’s more, the
Specialized technique for the driving scheme
ensures 90% higher efficiency in the
application of 18W LEDs lighting with AC
voltage range from 85V to 265V. In AC voltage
range from 85V to 265V, the SHT6088 can
drive 3W-36W LEDs array which is widely
used in E14/E27/PAR30/PAR38/GU10 lighting
and tube LEDs lighting. The SHT6088 has
multiple LED protections, including LED
open-circuit protection, LED short-circuit
protection and thermal shutdown protection. If
system has a failure, the SHT6088 will operate
in protection mode until system recovers.
FEATURES
l System DC supply voltage: 12V to 450V.
System AC supply voltage: 85V to 265V.
l Duty Cycle up to 100%.
l Typical ±5% output current accuracy.
l Up to 93% system efficiency.
l LED open-circuit protection; LED
short-circuit protection.
l Internal thermal shutdown protection.
l Single DIM pin for dynamic temperature
compensation and brightness control
using DC voltage or PWM signal
l Adjustable constant current output control
TYPICAL APPLICATIONS
l LED Tube lighting
l E14/PAR30/PAR38/GU10/E27 LED
spotlight
l LED projective lighting
l LED Signal lighting
l LED landscape lighting
SHT6088 used sop8 package.
Typical Application Circuit
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PIN
PIN ASSIGNMENTS
Pin No. Name Description
1 GND Signal and power ground. Connect directly to ground plane
2 LN Line voltage compensation of the peak threshold. Sensing the voltage
between LN and VDD
3 VDD Input Supply Pin. Must be locally bypassed
4 OUT Drain of internal power switch, source of external power switch
5 NC No connection
6 CS Current sense input, sampling resistor connected between CS and GND
7 RT Fixed turn off time setting
8 DIM Enable switch, analog and PWM dimming input.
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Ordering Information
Order Type Package Temperature range Tape and Reel Print
SHT6088 sop8 -40 ℃to 85 ℃ Tape and Reel SHT6088
Absolute Maximum Rating
Symbol Items Value Unite
VDD Supply Voltage − 0.3～ 18 V
LN Line voltage compensation − 0.3～ 18 V
OUT Drain of internal power switch − 0.3～ 24 V
CS Pin of current sense − 0.3～ 6 V
DIM Enable switch, analog and PWM dimming input. − 0.3～ 6 V
RT Fixed turn off time setting − 0.3～ 6 V
IOUT Output current of power switch 0.8 A
PD-MAX Power Dissipation 0.5 W
PTR Thermal Resistance SOP8（θJA） 150 ℃ /W
TJ Operation Junction Temperature Range − 40～ 85 ℃
Tstg Storage Temperature − 55～ 150 ℃
ESD Susceptibility 3000 V
Note: The maximum power dissipation must be decreasing with elevating temperatures and is
dictated by TJMAX, θJA, and the ambient temperature TA. The maximum allowable power
dissipation is PDMAX = (TJMAX - TA)/ θJA or the lower number given in Absolute Maximum
Ratings
Recommend Operating Range
Symbol Items Value Unite
VDD VDD Supply Voltage 0～ 16 V
TOPT Operating Temperature − 40～ +85 ℃
Electrical Characteristics
Symbol Items Conditions Min. Typ. Max. Unite
VDD Input Voltage 11 16 V
VUVLO Under voltage lock out VDD rising 8.5 10 V
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VUVLO, HYS UVLO hysteresis 2.5 V
Current Sense
VCS-TH
Current sense threshold
voltage ΔVLN = 0 240 250 260 mV
TLEB Current sense blank interval VCS=VCS-TH+50mV 500 ns
TDELAY Delay to output VCS=VCS-TH+50mV 600 ns
ΔVCS-TH @
ΔVLN
ΔVLN =VLN -VDD ΔVLN = 1V −30 mV
Fixed Toff control
TOFF Fixed turn off interval RT=270K 9.7 10.8 12 μs
VRT RT voltage 1.1 1.25 1.4 V
IRT RT circuit RT=270K 5 μA
Operating Current
IOFF
Quiescent supply current with
output off VDIM < 0.4 V 90 μA
IOP Operating supply current fOSC = 50 kHz 200 μA
DIM Input
VDIM Internal supply voltage DIM floating 5.2 V
VDIM_H DIM input voltage High 2.8 V
VDIM_L DIM input voltage Low 0.8 V
VDIM_DC DC brightness control 0.8 2.8 V
RDIM
DIM pull up resistor to Internal
supply voltage 150 kΩ
IDIM_L DIM input leakage low VDIM = 0 33 μA
Output Switch
RSW SW On Resistance VDD = 12 V 0.8 Ω
ISWmean Continuous SW Current 700 mA
ILEAK SW Leakage Current 0.5 5 μA
Thermal Shutdown
TSD Thermal Shutdown Threshold 150 ℃
TSD-HYS Thermal Shutdown hysteresis 20 ℃
Application Information
The SHT6088 is a special constant current
LEDs driver. SHT6088 operates in continuous
conduction mode step-down converter system.
By controlling LEDs peak current and ripple
current, SHT6088 can regulate LEDs mean
current. Using a few external components,
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SHT6088 provides a solution to constant
current control, with DC voltage dimming and
PWM signal dimming.
The resistor connected to RT programs
MOSFET turn off time. At the beginning of
each cycle, MOSFET is turned on until the
inductor current ramps up to its peak value IP =
VREF / RCS (mA).
Once the MOSFET is turned off, its off time is
set by TOFF=4 ×10
−5
× RT （μs）. When the off
time is complete, MOSFE is turned on again
and repeats this operation. The off time control
the ripple current
(mA)
L
10 ×T × V
I = OFF LED
3
R and LED mean
current ILED =IP －0.5×IR（mA）.
In the case of fixed quantity LEDs system,
voltage of each LED is relatively stable. So
LEDs output current is constant, when inductor
value is settled. It is remarkable that,
theoretically, LEDs current is independent on
the line voltage (Vbulk). However, practically,
because of system delay, the peak current will
follow with the increasing input line voltage.
The SHT6088 uses a Specialized technique to
compensate the peak current variation. The
pin ‘LN’ is used to detect input line voltage and
compensate output current. For example, if the
potential difference of LN and VDD is 1V, the
reference voltage will decrease 15mV. In this
way, system can provide constant current in a
wider voltage range. Moreover, the LN pin can
compensate the output voltage variation, as
well.
In order to solve the deviation of LED ripple
current caused by the difference of forward
voltage drop,Recommended to increases the
value of the inductance under the premise of
meeting the current ability.which can reduce
the influence of the LED ripple current on the
average LED current
To achieve high system efficiency, SHT6088
utilizes special technique to drive power
MOSFET by source driver scheme. In this
way, the chip operating current is extremely
low. On the same time, system efficiency is
greatly enlarged by using power MOSFET’s
dissipation to supply chip through the feeding
diode.
DIM pin of SHT6088 can receive simulate or
PWM dimming signal. The features graph is
shown.
SHT6088 has the feature of thermal shutdown,
output LEDs short-circuit protection and
open-circuit protection. This device is suitable
for high efficient LEDs tube lighting and
spotlight.
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PACKAGING INFORMATION
SOP8
mm inches
符号
*小值 *大值 *小值 *大值
A 1.350 1.750 0.053 0.069
A1 0.100 0.250 0.004 0.010
A2 1.350 1.550 0.053 0.061
b 0.330 0.510 0.013 0.020
c 0.170 0.250 0.006 0.010
D 4.700 5.100 0.185 0.200
E 3.800 4.000 0.150 0.157
E1 5.800 6.200 0.228 0.244
e 1.270(BSC) 0.050(BSC)
L 0.400 1.270 0.016 0.050
θ 0° 8° 0° 8°