AL1677

AL1677
UNIVERSAL, HIGH EFFICIENCY AND ACCURACY LED DRIVER CONVERTER
Description
Pin Assignments
The AL1677 is a universal AC-input (85~277 VAC), high-efficiency and
(Top View)
NEW PRODUCT
high-accuracy Buck LED-driver converter. The AL1677 topology
provides accurate constant current (CC) line and load regulation,
operating at boundary conduction mode (BCM) to ease in EMI/EMC
qualification and testing to meet the latest regulatory laws.
The AL1677 system removes the auxiliary winding and external highvoltage MOSFET with few external components to create a low bill of
material (BOM) cost solution. The AL1677 has rich protection features
to enhance system safety and reliability. With thermal foldback
function, the AL1677 can reduce output current when the driver’s
temperature is higher than the setting value.
GND
1
8
CS
ROVP
2
7
CS
NC
3
6
D
VCC
4
5
D
SO-8
The AL1677 is available in SO-8 package.
Features
Applications



> 90% Efficiency
Valley Detection to Minimize Switching Loss
Universal 85 to 277 VAC Input Range









Internal MOSFET up to 500V
Tight Current Sense Tolerance : ± 3%
Low Startup Current: 170µA
Low Operation Current: 100µA (Static)
Standard Inductor (no auxiliary winding)
Internal Protections
Undervoltage Lockout (UVLO)
-
Leading-Edge Blanking (LEB)
-
Cycle-by-cycle Overcurrent Protection(OCP)
-
Output Open/Short Protection(OVP/OSP)
-
Open-Load and Reload Detection
-
Thermal Foldback Function(TFP)
-
Over-Temperature Protection(OTP)

SO-8 Package

Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)

Halogen and Antimony Free. “Green” Device (Note 3)
Notes:
Retrofit LED Lamps
High Voltage DC-DC LED Driver
General Purpose Constant Current Source
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
AL1677
Document number: DS37526 Rev. 1 - 2
1 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Typical Applications Circuit
R1
R4
D1
+
C3
OUT
L1
F1
AC
Input
R2
DB1
NEW PRODUCT
C1
4
3
2
1
C2
VCC
D
NC
D
ROVP CS
GND CS
5
6
7
8
U1 AL1677
R3
R5
Pin Descriptions
Pin Number
Pin Name
1
GND
2
ROVP
3
NC
4
VCC
5,6
D
7,8
CS
Function
Ground
Setting the Open Voltage of the Output
No Connection
Power Supply for the Device
Internal High Voltage MOSFET’s Drain
Current Sensing
Functional Block Diagram
5,6
VCC
D
4
OFF
STOP
VCC
Fault
VCC
Clamp
Management
UVLO
Management
OVP OSP OTP
VOVP_REF
VREF
OSP
OVP
OVP
ROVP
TOFF
TOFF
Toff Detection
(ZCD)
2
VOVP_REF
S
R
NC
Q
3
Constant
Current Control
7,8
LEB
CS
1
GND
AL1677
Document number: DS37526 Rev. 1 - 2
STOP
Max Ton
Limit
2 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.) (Note 4)
Symbol
VCC
Unit
18
V
AL1677-05BS-13
500
V
AL1677-08BS-13
500
V
AL1677-10BS-13
500
V
AL1677-20BS-13
500
V
AL1677-05BS-13
0.5
A
AL1677-08BS-13
0.8
A
AL1677-10BS-13
1.0
A
AL1677-20BS-13
2.0
A
Voltage on CS Pin
-0.3 to 7
V
Voltage on ROVP Pin
Power Supply Voltage
VD
NEW PRODUCT
Rating
Parameter
Voltage on D Pin
ID
Continuous Drain Current Tc = +25°C
VCS
-0.3 to 7
V
Operating Junction Temperature
-40 to +150
°C
TSTG
Storage Temperature
-65 to +150
°C
TLEAD
Lead Temperature (Soldering, 10 seconds)
+260
°C
PD
Power Dissipation and Thermal Characteristics (TA = +50°C)
0.65
W
JA
Thermal Resistance (Junction to Ambient)
190
°C/W
2,000
V
200
V
VROVP
TJ
ESD (Human Body Model)
ESD (Machine Model)
Note:
4. Stresses greater than those listed under “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 under “Recommended Operating Conditions” is not implied.
Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.
Recommended Operating Conditions
Symbol
TA (Note 5)
Note:
Parameter
Ambient Temperature
Min
Max
Unit
-40
+105
°C
5. The device can operate normally at +125°C ambient temperature under the condition that the junction temperature is less than +150°C.
AL1677
Document number: DS37526 Rev. 1 - 2
3 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Electrical Characteristics
Symbol
(@TA = +25°C, unless otherwise specified.)
Parameter
Conditions
Min
Typ
Max
Unit
–
–
–
14.5
–
–
V
8.5
–
16.2
–
V
–
170
–
µA
–
100
–
µA
AL1677-05BS-13
–
24
26
AL1677-08BS-13
–
16
20
AL1677-10BS-13
–
10
12
AL1677-20BS-13
–
AL1677-05BS-13
5.4
–
6
–
0.5
AL1677-08BS-13
–
–
0.8
AL1677-10BS-13
–
–
1.0
AL1677-20BS-13
–
–
AL1677-05BS-13
500
–
2.0
–
AL1677-08BS-13
500
–
–
AL1677-10BS-13
500
–
–
AL1677-20BS-13
–
–
AL1677-05BS-13
500
–
–
1
AL1677-08BS-13
–
–
1
AL1677-10BS-13
–
–
1
AL1677-20BS-13
–
–
1
Reference Voltage of ROVP pin
–
–
0.5
–
V
Current Sense Reference
Minimum tON
Maximum tON
Maximum tOFF
Minimum tOFF (Note 6)
–
–
–
–
–
0.388
400
–
–
–
0.400
–
35
200
6
0.412
700
–
–
–
V
ns
µs
µs
µs
–
–
+140
–
°C
–
–
+170
–
°C
UVLO Section
VTH (ST)
VOPR(Min)
Vcc_clamp
Startup Threshold
Minimal Operating Voltage
After Turn On
–
Vcc Clamp Voltage
V
NEW PRODUCT
Standby Current Section
IST
ICC (OPR)
VCC = VTH (ST)-0.5V,
Before Start Up
Static
Start-Up Current
Operating Current
Internal High Voltage MOSFET
RDS(on)
IDS
VDS
IDSS
Drain-Source On-State Resistance
Continuous Drain-Source Current
Drain-Source Voltage
Drain-Source Leakage Current
Ω
A
V
µA
ROVP Section
VROVP
Current Sense Section
VCS-REF
tON_MIN
tON_MAX
tOFF_MAX
tOFF_MIN
Thermal Foldback and Over-Temperature Protection Section
TREG
–
Notes:
Overheating Temperature Regulation
(Notes 6 & 8)
Shutdown Temperature (Notes 6 & 7
& 8)
6. These parameters, although guaranteed by design, are not 100% tested in production.
7. The device will latch when OTP happen and the device won’t operate constantly at this temperature.
8. This regulation temperature is junction temperature.
AL1677
Document number: DS37526 Rev. 1 - 2
4 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Performance Characteristics (Note 9)
Start-up Voltage vs. Ambient Temperature
Start-up Current vs. Ambient Temperature
16.0
180
15.5
170
Start-up Current (A)
NEW PRODUC T
Start-up Voltage (V)
15.0
14.5
14.0
13.5
13.0
160
150
140
130
12.5
12.0
-40
-20
0
20
40
60
80
100
120
-40
120
-20
0
20
40
60
80
o
Ambient Temperature ( C)
120
Operating Current vs. Ambient Temperature
10.0
140
9.5
130
9.0
Operating Current (A)
Minimal operating voltage (V)
Minimal Operating Voltage vs. Ambient Temperature
8.5
8.0
7.5
7.0
120
110
100
90
80
6.5
6.0
-40
100
o
Ambient Temperature ( C)
-20
0
20
40
60
80
100
70
-40
120
-20
0
20
40
60
80
100
120
o
Ambient Temperature ( C)
Ambient Temperature ( C)
VCS Reference vs. Ambient Temperature
VROVP Reference vs. Ambient Temperature
o
0.50
0.60
0.45
0.40
VROVP Reference (V)
VCS Reference (V)
0.55
0.35
0.30
0.50
0.45
0.40
0.25
0.35
0.20
-40
-20
0
20
40
60
80
100
120
0.30
-40
o
AL1677
Document number: DS37526 Rev. 1 - 2
-20
0
20
40
60
80
100
120
o
Ambient Temperature ( C)
Ambient Temperature ( C)
5 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Performance Characteristics (continued) (Note 9)
VCC Clamp Voltage vs. Ambient Temperature
Vcs Reference vs. Ambient Temperature
0.50
20
0.45
0.40
0.35
Vcs reference (V)
NEW PRODUC T
VCC Clamp Voltage (V)
18
16
14
0.30
0.25
0.20
0.15
0.10
12
0.05
10
-40
-20
0
20
40
60
80
100
120
0.00
-40
Ambient Temperature ( C)
Note:
-20
0
20
40
60
80
100
120
140
160
180
o
Ambient Temperature ( C)
o
9. These electrical characteristics are tested under DC condition. The ambient temperature is equal to the junction temperature of the device.
AL1677
Document number: DS37526 Rev. 1 - 2
6 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Application Information
Convertor Operation
The AL1677 is designed for single-inductance buck application and is an extremely low BOM cost solution widely used in non-isolated situations.
The AL1677 operates at boundary conduction mode (BCM) which can get good EMI performance. The device internally integrates a 500V highvoltage MOSFET. The AL1677 adopts a novel method to detect the tOFF time and achieve an extremely low operation current, so the device does
not need the auxiliary winding for VCC supply and detecting the tOFF time. It also has good constant current control which can guarantee the
NEW PRODUC T
system current accuracy.
R1
R4
D1
+
C3
OUT
L1
F1
AC
Input
R2
DB1
C1
4
3
2
1
C2
R3
VCC
D
NC
D
ROVP CS
GND CS
5
6
7
8
U1 AL1677
R5
Figure 1 Typical Application Circuit
Start-up and Supply Voltage
Before start-up, the VCC capacitor C2 is charged by the startup resistors (R1, R2) from the high voltage mains. When the start-up voltage is
reached, the AL1677 starts switching. During normal operation, the VCC supply is provided by start-up resisters (R1, R2) and internal source
driver circuit.
The AL1677 has an internal VCC clamp voltage (typical 16.2V), which is limited by one internal active Zener diode.
When VCC voltage drops to below the undervoltage lockout (UVLO), switching is stop, the IC can restart when the voltage on VCC pin is
exceeding the startup voltage (VTH (ST)).
Protections
Undervoltage Lockout (UVLO)
When the voltage on the VCC pin drops to below VOPR(Min), the IC stops switching. The IC can restart when the voltage on VCC is exceeds the
startup voltage (VTH(ST))
Leading-Edge Blanking (LEB)
To prevent false detection of the peak current of the inductor, a blanking time following switch-on is designed. When the internal switch turns on, a
short current spike can occur because of the capacitive discharge of the voltage over the drain and source. It is disregarded during the LEB time
(tON_MIN).
Cycle-by-cycle Overcurrent Protection (OCP)
The AL1677 has a built-in peak current detector. It triggers when the voltage on CS pin reaches the peak level VCS_CLAMP. The R5 is connected to
the CS pin to sense the current of the inductor. The maximum peak current (IPEAK(MAX))of the inductor can be calculated as below:
I PEAK 
VCS _ REF
R5
The detection circuit is activated after the LEB time. When the detection circuit sense the CS voltage is higher than 0.4V, the IC will turn off the
switching to limit the output current. It automatically provides protection for the maximum LED current during operation. A propagation delay exists
between overcurrent detection and actual source-switch off, so the actual peak current is a little higher than the OCP level set by the R5.
Output-Short Protection (OSP)
When LED is shorted, the device cannot detect the tOFF time, and the device controls the system operation at 5kHz low frequency.
AL1677
Document number: DS37526 Rev. 1 - 2
7 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Application Information (continued)
Output Open Protection (OVP)
AL1677 has output open-voltage protection controlled when the LED is open, which can prevent the output voltage from increasing to a very high
value. This feature can help the system designer select a smaller volume capacitor. The output voltage is set by the external resistor R3, shown in
Figure 1.
NEW PRODUC T
When LED is open, the toff time can be calculated as:
toff 
L1  VCS _ REF
VOVP  R 5
Where
VOVP is the output open voltage,
The output voltage is set by R3, and R3 is:
R3 
VROVP _ REF  t off
12  C REF VCS _ REF

VROVP _ REF  L1
12  C REF VOVP  R5
Where
VROVP_REF is the internal ROVP pin 0.5V’s reference,
CREF is the internal 6pF capacitor.
Thermal Foldback Protection (TFP)
AL1677 has a thermal foldback function and adopts a self-adaptive control method, which can prevent the system from breaking down due to high
temperatures. The overheating temperature is set at +140°C typical. When the junction temperature of the IC is higher than +140°C typical, the
device will linearly decrease the internal reference voltage to decrease the output current. As a result of this feature, the device can control the
system’s output power at high ambient temperatures, to control the quantity of heat of the system. This enhances the safety of the system at high
temperatures.
The thermal foldback waveform is shown below:
Output current
100%
50%
TFOLD=140
OTP
Junction temperature/°C
Figure 2. Thermal foldback waveform
Over-Temperature Protection (OTP)
The AL1677 has OTP protection function. When the junction temperature reach to +170°C typical, the IC will trigger an over-temperature
protection condition which causes the device to shut down and latched. Once OTP has triggered, the system will resume after the system’s AC
source supply has been reset and power up.
Design Parameters
Setting the Current Sense Resistor R5
The AL1677 uses peak current control method to obtain constant current control and senses the peak current of the inductance cycle by cycle.
The sample value is compared with the internal 0.4V reference. When the sampling value is up to 0.4V, the IC control of the internal MOSFET will
turn off.
The peak current of the inductance is:
AL1677
Document number: DS37526 Rev. 1 - 2
8 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Application Information (continued)
I peak 
VCS _ REF
R5
Where,
VCS_REF is the reference of the current sense, and the typical value is 0.4V.
R5 is the current sense resistor.
NEW PRODUC T
In no PF buck topology, the system operates at boundary conduct mode. The output current is:
1
I o _ mean   I peak
2
Therefore, the current sense resistor R5 is determined:
R5 
1 VCS _ REF

2 I o _ mean
Inductance Selection (L1)
The AL1677 controls the system operating at boundary conduction mode, and the systems’ operating frequency does not keep constant because
of the fluctuation of the bus voltage. Set the minimum switching frequency fmin at the maximum bus voltage, and the buck inductance value L1 can
be calculated by:
L1 
( 2Vin _ rms  Vo )  R5 Vo
Vcs _ ref  2Vin _ rms  f min
Where,
Vo is the output voltage.
Vin_rms is the RMS value of the input voltage.
According to the Faraday’s Law of Induction, the winding number of the inductance can be calculated by:
N L1 
L1  I peak
Ae  Bm

L1  VCS _ REF
Ae  Bm  R5
Where,
Ae is the core effective area.
Bm is the maximum magnetic flux density.
The AL1677 has designed the minimum tON time and maximum tON time. The tON_MIN is about 700ns and the tON_MAX time is about 35µs. In buck
topology we can get the equation Vin_rms-VO=L*Ipeak/tON. If the inductance is very small, leading the tON to become smaller, when the system’s tON
is smaller than tON_MIN, the device cannot detect the peak current of the system, leading to incorrect output current. If the inductance is very large,
leading tON to become larger when the system’s tON is larger than the tON_MAX, the system’s output current will decrease because of the limit of the
tON_MAX. Therefore, the suitable value of the inductance is very important.
The AL1677 tOFF_MIN time is about 6µS and tOFF_MAX time is about 200µs. In buck topology we use the equation VO=L*Ipeak/tOFF. If the inductance
is very small, leading the tOFF to become much smaller when the system’s tOFF is smaller than tOFF_MIN, the system will enter DCM mode, and the
output current will be incorrect. If the inductance is very large, leading tOFF to become much larger when the system’s tOFF is larger than the
tOFF_MAX, the system will enter CCM mode, and the output current will also be incorrect. Therefore, the suitable value of the inductance is very
important.
Consider these parameters, two examples of the typical application inductance is recommended as below:
System Spec.
Inductance Value
System Frequency
TON Min
TOFF
60V/150mA
(185~265VAC)
2.3mH
60K(230 VAC)
2.5µS(265 VAC)
11.5µS
42V/100mA (85~265 VAC)
2.5mH
62K(230 VAC)
1.7µs(265 VAC)
12.1µS
AL1677
Document number: DS37526 Rev. 1 - 2
9 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Application Information (continued)
NEW PRODUC T
Recommended Applications
The AL1677 integrates different MOSFETs to adapt different wattage applications. The output current is limited by the internal integrated MOSFET,
and the SO-8 package’s heat dissipation capability. The minimum output voltage is limited by the LEB time, and is recommended to 15V. The
recommended application is given below:
Device
Output Power Coverage
Maximum Output Current (Note 10)
Minimum Output Voltage
AL1677-05BS-13
≤5W
≤100mA
15V
AL1677-08BS-13
≤8W
≤120mA
15V
AL1677-10BS-13
≤10W
≤180mA
15V
AL1677-20BS-13
≤15W
≤240mA
15V
Note:
10.The higher output current is possible with extra power dissipation solution.
AL1677
Document number: DS37526 Rev. 1 - 2
10 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Ordering Information
AL1677–XX X XX–13
NEW PRODUC T
Current Option
05 : 0.5A
08 : 0.8A
10 : 1.0A
20 : 2.0A
Packing
Package
Mosfet Voltage
B: 500V
S : SO-8
Part Number
Package Code
Package
AL1677-05BS-13
S
AL1677-08BS-13
13 :13" Tape & Reel
13” Tape and Reel
Quantity
Part Number Suffix
SO-8
4,000/Tape & Reel
-13
S
SO-8
4,000/Tape & Reel
-13
AL1677-10BS-13
S
SO-8
4,000/Tape & Reel
-13
AL1677-20BS-13
S
SO-8
4,000/Tape & Reel
-13
Marking Information
(Top View)
8
7
6
5
Logo
YY WW X X
1
AL1677
Document number: DS37526 Rev. 1 - 2
YY : Year : 15,16,17 ~
WW : Week : 01~52; 52
represents 52 and 53 week
X X : Internal Code
1677- ZZZ
Part Number
1677-05B for 0.5A/500V
1677-08B for 0.8A/500V
1677-10B for 1.0A/500V
1677-20B for 2.0A/500V
2
3
4
11 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
Package Outline Dimensions (All dimensions in mm (inch).)
0.254
Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for the latest version.
E1 E
A1
NEW PRODUC T
L
Gauge Plane
Seating Plane
Detail ‘A’
7°~9°
h
45°
Detail ‘A’
A2 A A3
b
e
D
SO-8
Dim
Min
Max
A
1.75
A1
0.10
0.20
A2
1.30
1.50
A3
0.15
0.25
b
0.3
0.5
D
4.85
4.95
E
5.90
6.10
E1
3.85
3.95
e
1.27 Typ
h
0.35
L
0.62
0.82
0°
8°

All Dimensions in mm
Suggested Pad Layout
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version
X
Dimensions
X
Y
C1
C2
C1
Value (in mm)
0.60
1.55
5.4
1.27
C2
Y
AL1677
Document number: DS37526 Rev. 1 - 2
12 of 13
www.diodes.com
November 2015
© Diodes Incorporated
AL1677
IMPORTANT NOTICE
NEW PRODUC T
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated
website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or
indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
noted herein may also be covered by one or more United States, international or foreign trademarks.
This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any
use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its
representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2015, Diodes Incorporated
www.diodes.com
AL1677
Document number: DS37526 Rev. 1 - 2
13 of 13
www.diodes.com
November 2015
© Diodes Incorporated
Similar pages