HOLTEK HT7L2102

HT7L2102
Anti-EMI, High Efficiency Dimmable
LED Lighting Driver with Green Mode
and Integrated Protections
Feature
General Description
• Frequency Jitter for EMI Restriction
• Over-Voltage-Protection(OVP) on VCC Pin
The HT7L2102 is an advanced, highly integrated LED
Lighting driver using an AC-DC isolation topology.
The device provides many protection functions and
uses ultra low power circuit design, and is optimized
to restrict EMI. By integrating a Non-Audible Noise
Green Mode Control Structure, users can implement
a single circuit for different LED load levels for
various series/parallel configurations but still maintain
high efficiency for different load conditions. This
device also integrates various protection functions for
LED Lighting requirements such as Cycle-by-Cycle
Current Limiting, Short-Circuit Protection (SCP),
Over-Voltage Protection (OVP), Over-Temperature
Protection (OTP) for external thermistor sensing, and
a Soft-Start function to reduce inrush currents during
LED power system initialization for the prevention of
device burn-out. • Over-Temperature-Protection(OTP) on TS pin for
External Thermistor Sensing
The HT7L2102 provides a 1~99% PWM Dimming
Range with duty-cycle scale precision lower than 1%.
• Integrated Soft-Start Function
• Very Low Operating Current and Start-up Current
(<20mA) for satisfying Energy-Star 2.0 "No-Load
Mode" (Stand-by) Power standard
• ±5% Trimmed Oscillator for Precise Frequency
• Non-Audible-Noise Green Mode Control to
maintain efficiency for both Light and Heavy
Loads
• LEB (Leading-Edge Blanking) on CS Pin
• Internal Slope Compensation
• Cycle-by-Cycle Current Limiting
• Short-Circuit-Protection(SCP) for Short-Circuit
and Over-Load Condition
• 1~99% PWM Dimming Range
• 8-pin SOP package
Applications
• Isolation AC-DC LED Lighting
• AC-DC Switching Power Supply/Adapter
Application Circuits
L
Vac=85V~265V
T1
BD1
R7
C2
N
D1
Vout
7
1
R3
C4
C14
R4
8
D4
U1
C15
Vref
3
D3
VCC
4
C12
5
Q1
GD
RT
R20
R19
R11
ISENSE
TS
Rts
COMP/FB
GND
R28
U2
C19
Q3
Rev. 1.00
1
November 4, 2011
HT7L2102
Block Diagram
Pin Assignment
VREF
8
VCC
7
UVLO
OVP
32V
RT
Internal Bias
& Vref
VCC
Driver
Stage
Green Mode
OSC
4
107uA
TS
2
FB/PDM
1
ISENSE
3
Temperature
Sense
6
GD
5
GND
S Q
R
Soft-Start
14V / 8V
Frequency
Jitter
Slope
Compensation
Constant
Current
Controller
LEB
350ns
FB Compare Level = 2.5V
OTP
SCP
OCP
OCP Level = 1V
Pin Description
Pin No.
Pin Name
Description
1
FB/PDM
Voltage Feedback Pin. Connected to a Photo-Coupler for closed-loop control. This pin also
can be used as a PWM Dimming Pin.
2
TS
Temperature Sense Pin. Connected to an external thermistor as a sense system hot point.
This pin also can be used for an external System-Latch.
3
ISENSE
A voltage proportional to the inductor current is connected to this input. The Constant
Current Controller uses this voltage information to keep the system output current within a
narrow range.
4
RT
The oscillator frequency is programmed by connecting a resistor RT between this pin and
ground. A maximum frequency of 500KHz is possible.
5
GND
6
GD
7
VCC
Positive Supply.
8
VREF
A Temperature-Independent Voltage Reference output.
Combined control circuitry and power ground.
Power MOSFET gate driver output.
Absolute Maximum Ratings
Supply Voltage VCC�������������������������������������������������������������������������������������������������������������������������������� -0.3V~30.0V
FB/PDM, RT, ISENSE, TS Pins���������������������������������������������������������������������������������������������������������������� -0.3V~5.5V
Junction Temperature������������������������������������������������������������������������������������������������������������������������������������������ 150°C
Operating Ambient Temperature��������������������������������������������������������������������������������������������������������������� -40°C~85°C
Storage Temperature Range�������������������������������������������������������������������������������������������������������������������� -65°C~150°C
Package Thermal Resistance (8-Pin SOP)����������������������������������������������������������������������������������������������������� 160°C/W
ESD Protection:
Human Body Model��������������������������������������������������������������������������������������������������������������������������������������3kV
Machine Model�������������������������������������������������������������������������������������������������������������������������������������������200V
Note: These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings”
may cause substantial damage to the device. Functional operation of this device at other conditions beyond
those listed in the specification is not implied and prolonged exposure to extreme conditions may affect
device reliability.
Rev. 1.00
2
November 4, 2011
HT7L2102
Electrical Characteristics
Unless otherwise stated, this specifications apply for 0°C ≤ Ta ≤ 70°C, VCC=15V, RT=10kW
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
Supply Voltage (VCC Pin)
IST
Startup Current
ICC
Operating Current
VTL
UVLO (Off)
VTH
UVLO (On)
VCC
OVP Trip Level
VD-OVP
OVP Strobe Time
VCC=12.9V
—
12
30
mA
VFB/PDM=0V
—
2.0
3.0
mA
—
2.5
—
mA
7
8
9
V
V
VFB/PDM=3V
—
—
VCC(Over Voltage Protection)
—
13
14
15
26.5
28.0
29.5
V
—
100
—
ms
Reference Section (VREF Pin)
VREF
Output Voltage
Tj=25°C, IO=1mA
—
5.5
—
V
∆VREF
Line Regulation
12V ≤ VCC ≤ 25V
—
3
20
mV
∆VREF
Load Regulation
1mA ≤ IO ≤ 10mA
—
4
25
mV
Current Sensing (ISE NSE Pin)
VIS(OFF)
Maximum Input Voltage, Vcs(off)
—
0.9
1.0
1.1
V
tLEB
Leading Edge Blanking Time
—
—
350
—
ns
Delay to Output
—
—
100
—
ns
Oscillator (RT pin)
fOSC
∆fOSC
∆TA
∆fOSC
∆VREF
DMAX
Oscillator Frequency
Tj=25°C, RT=10kW to GND
49
52
55
kHz
Temperature Stability
-40°C ~105°C
—
5
—
%
Voltage Stability
VCC=10V~25V
—
0.2
1.0
%/V
Maximum Duty
—
—
75
—
%
Frequency Jitter
—
—
±4
—
%
—
—
1
V
Gate Drive Output (GD Pin)
VOL
Output Low Level
VCC=15V, Isink=20mA
VOH
Output High Level
VCC=15V, Isource=20mA
9
—
—
V
tr
Rising Time
Tj=25°C, Load Capacitance=1nF
—
50
150
ns
tf
Falling Time
Tj=25°C, Load Capacitance=1nF
—
50
150
ns
Voltage Feedback (FB/PDM Pin)
ISINK
Short Circuit Current
VFB/PDM=0V
—
1.5
2.2
mA
VFB/PDM
Open Loop Voltage
FB/PDM pin open
—
5.5
—
V
SCP Trip Level
VFB/PDM (SCP)
—
4.7
—
V
SCP Delay Time (See Note)
fS=52kHz
—
75
—
ms
Soft-Start Time
RT=10kW
—
10
—
ms
V
SCP (Short Circuit Protection)
VFB/PDM
Soft-Start
tSTART
External OTP(Over Temperature Protection, TS Pin)
VOTP-On
OTP Enable Trigger Level
0.95
1.00
1.05
VOTP-Reset
OTP Disable Trigger Level
—
1.2
—
V
ITS
Pull up Current Source
96
107
118
mA
Note: These Parameters, although guaranteed, are not 100% tested in production.
Rev. 1.00
3
November 4, 2011
HT7L2102
Typical Performance Characteristics
15.5
10
9.5
UVLO (off)(V)
UVLO (on)(V)
15
14.5
14
13.5
13
12.5
8
7.5
7
12
11.5
9
8.5
6.5
-40
-20
0
20
40
60
80
100
6
120
-40
10
60
Figure 1. UVLO (on) (V) vs. Temperature
Figure 2. UVLO (off) (V) vs. Temperature
57
56
55
54
53
52
51
50
49
48
47
-40
57
56
55
54
53
52
51
50
49
48
47
11
-20
0
20
40
60
80
100
120
13
15
17
Temperature (degree C)
-20
0
20
40
60
80
100
23
25
31
29
27
25
23
21
19
17
15
11
120
Temperature (degree C)
13
15
17
19
21
23
25
Vcc (V)
Figure 6. Green Mode Frequency vs. VCC
Figure 5. VFB/PDM for SCP vs. Temperature
Rev. 1.00
21
Figure 4. Frequency vs. VCC
Green Mode Frequency (KHz)
4.9
4.85
4.8
4.75
4.7
4.65
4.6
4.55
4.5
4.45
4.4
-40
19
Vcc (V)
Figure 3. Frequency vs. Temperature
Vcomp (V)
110
Temperature (degree C)
Frequency (KHz)
Frequency (KHz)
Temperature (degree C)
4
November 4, 2011
HT7L2102
Application Information
Operation Overview
The HT7L2012 is a highly functionally integrated
PWM controller for LED lighting and is optimized to
restrict EMI. The device offer a dimming precision of
less than 1% and has a dimming range of 1% to 99%.
Its integrated features include Green mode (NonAcoustic-Noise), internal slope compensation, high
efficiency under different load conditions within a
wide operating temperature range of -40°C to 85°C.
The devices also includes a range of protection
functions, SCP, OVP, UVLO, current limit, LEB, soft start, OTP for external thermistor sensing. These
features not only enhance system performance,
but also ensure high stability of the whole circuit
application even under extreme environmental
conditions such as high temperature or high EMI
levels.
Advanced Precision Oscillator for
Green-Mode Switching and Non-Acoustic
Noise Requirement
A Trimmed Precision Green Mode Oscillator is
implemented in the device to enhance the conversion
efficiency under light load conditions. As Fig. 7
shows, the efficiency difference between light loads
and heavy loads is less than 1%, while the average
efficiency is only 89.5%, the peak efficiency is 90%.
Figure 8. Oscillator Behavior Compared with
HT7L2102 and Other Green Mode PWM Controller
Frequency Jitter for EMI Restriction
EMI restriction is accomplished using a Frequency
Jitter function, which spreads the energy over a wider
frequency range than the bandwidth measured by
the EMI test equipment. An internal Frequency Jitter
circuit changes the switching frequency between +4%
and -4% of the central frequency with a period of
4ms.
Figure 7 HT7L2102 Efficiency Performance
between Light-Load and Heavy-Load
The Green Mode Oscillator types supplied by other
PWM Controller providers are plagued by AcousticNoise problems. This is because, under light load
conditions, the frequency will keep decreasing
through the Human Acoustic Range (from 20Hz
to 20kHz), and these audio frequencies may create
audible noise in the transformer. Holtek’s HT7L2102
patented Green Mode Oscillator designed using an
advanced Non-Acoustic Noise structure prevents
the generation of frequencies in the audio frequency
band, thus eliminating any transformer noise.
Rev. 1.00
Figure 9 Frequency Jitter Function Spreads Energy
Over a Period to Accomplish EMI Restraining
5
November 4, 2011
HT7L2102
Under Voltage Lockout (UVLO)
Internal Slope-Compensation
An UVLO comparator is implemented in to ensure
that the device is fully functional before the output
stage is enabled. As shown in Fig. 10, hysteresis
is provided to prevent the PWM Controller from
shutting down during any voltage dips which
might occur during startup. The turn-on and turnoff threshold levels are set at 16.0V and 10.0V,
respectively.
An important issue with current mode control
structures is instability due to Sub-Harmonic
Oscillation when the Duty-Cycle > 50%. To prevent
this problem from occurring, a Slope-Compensation
function is always necessary. In traditional
currentmode PWM Controller application, many
external components are necessary to implement
a Slope-Compensation function. However in the
HT7L2102, the internal Slope-Compensation
eliminates the need for these external components
resulting in a simplified the application circuit design.
Short-Circuit Protection (SCP) and
Over-Load Protection (OLP)
To protect all the devices in a system from being
damaged due to over load or short circuit conditions,
a smart SCP function is implemented in the device.
Here the feedback system will force the voltage loop
to move toward a saturation value and then pull up
the voltage on the COMP pin. Whenever the VCOMP
increases to the SCP threshold of 4.7V and remains
there for longer than 40mS, the protection scheme will
activate and then turn off the gate output to stop the
power circuit switching. By using such a protection
mechanism, the average input power can be reduced
to a very low level so that component temperature and
stress can be controlled within safe operating levels.
Figure 10. UVLO Scheme and Start-Up Current
Current Sense and Leading-Edge
Blanking (LEB)
A Leading-Edge Blanking Scheme is integrated in
the device to prevent false triggering due to feedback
current spikes which may appear on the CS pin,
further eliminating the need for an R-C filter which
is always a requirement in traditional current mode
PWM Controller applications.
Figure 12. SCP Function Behavior
Figure 11. LEB with R-C Filter Removed
Rev. 1.00
6
November 4, 2011
HT7L2102
VCC Pin Over-Voltage Protection (OVP)
Oscillator Frequency Tuning
VCC Over-Voltage Protection is integrated in the
device to prevent component damage due to over
voltage conditions on the VCC pin. The OVP is
triggered when VCC reaches 28V and lasts for 100uS.
The PWM pulses are disabled when OVP is enabled.
By choosing an appropriate value of an external
resistor between the RT Pin and GND, a suitable
operating frequency can be generated. The relationship
between the value of RT and the operating frequency
is provided in Figure 13.
TS Pin Over-Temperature Protection (OTP)
An Over-Temperature Protection (OTP) function is
integrated in the device.This function with external
thermistor sensing will disable the PWM controller at
1V and supports high a temperature alert and prevents
damage occurring in the application circuit.
Figure 13. RT Resistor value vs.
Operating Frequency
Rev. 1.00
7
November 4, 2011
HT7L2102
Package Information
8-pin SOP (150mil) Outline Dimensions
MS-012
Symbol
Min.
Nom.
Max.
A
0.228
―
0.244
B
0.150
―
0.157
C
0.012
―
0.020
C'
0.188
―
0.197
D
―
―
0.069
E
―
0.050
―
F
0.004
―
0.010
G
0.016
―
0.050
H
0.007
―
0.010
α
0°
―
8°
Symbol
Rev. 1.00
Dimensions in inch
Dimensions in mm
Min.
Nom.
Max.
A
5.79
―
6.20
B
3.81
―
3.99
C
0.30
―
0.51
C'
4.78
―
5.00
D
―
―
1.75
E
―
1.27
―
F
0.10
―
0.25
G
0.41
―
1.27
H
0.18
―
0.25
α
0°
―
8°
8
November 4, 2011
HT7L2102
Reel Dimensions
SOP 8N (150mil)
Symbol
Description
Dimensions in mm
A
Reel Outer Diameter
B
Reel Inner Diameter
100.0±1.5
C
Spindle Hole Diameter
13.0 +0.5/-0.2
D
Key Slit Width
T1
Space Between Flange
T2
Reel Thickness
Rev. 1.00
330.0±1.0
2.0±0.5
12.8 +0.3/-0.2
18.2±0.2
9
November 4, 2011
HT7L2102
Carrier Tape Dimensions
 SOP 8N (150mil)
Symbol
Description
W
Carrier Tape Width
P
Cavity Pitch
E
Perforation Position
Dimensions in mm
12.0+0.3/-0.1
8.0±0.1
1.75±0.10
F
Cavity to Perforation (Width Direction)
5.5±0.1
D
Perforation Diameter
1.55±0.1
D1
Cavity Hole Diameter
1.50 +0.25/-0.00
P0
Perforation Pitch
4.0±0.1
P1
Cavity to Perforation (Length Direction)
2.0±0.1
A0
Cavity Length
6.4±0.1
B0
Cavity Width
5.2±0.1
K0
Cavity Depth
t
Carrier Tape Thickness
C
Cover Tape Width
Rev. 1.00
2.1±0.1
0.30±0.05
9.3±0.1
10
November 4, 2011
HT7L2102
Holtek Semiconductor Inc. (Headquarters)
No.3, Creation Rd. II, Science Park, Hsinchu, Taiwan
Tel: 886-3-563-1999
Fax: 886-3-563-1189
http://www.holtek.com.tw
Holtek Semiconductor Inc. (Taipei Sales Office)
4F-2, No. 3-2, YuanQu St., Nankang Software Park, Taipei 115, Taiwan
Tel: 886-2-2655-7070
Fax: 886-2-2655-7373
Fax: 886-2-2655-7383 (International sales hotline)
Holtek Semiconductor Inc. (Shenzhen Sales Office)
5F, Unit A, Productivity Building, No.5 Gaoxin M 2nd Road, Nanshan District, Shenzhen, China 518057
Tel: 86-755-8616-9908, 86-755-8616-9308
Fax: 86-755-8616-9722
Holtek Semiconductor (USA), Inc. (North America Sales Office)
46729 Fremont Blvd., Fremont, CA 94538, USA
Tel: 1-510-252-9880
Fax: 1-510-252-9885
http://www.holtek.com
Copyright© 2011 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time of publication.
However, Holtek assumes no responsibility arising from the use of the specifications described.
The applications mentioned herein are used solely for the purpose of illustration and Holtek makes
no warranty or representation that such applications will be suitable without further modification,
nor recommends the use of its products for application that may present a risk to human life due to
malfunction or otherwise. Holtek's products are not authorized for use as critical components in life
support devices or systems. Holtek reserves the right to alter its products without prior notification. For
the most up-to-date information, please visit our web site at http://www.holtek.com.tw.
Rev. 1.00
11
November 4, 2011