ETC IRS2980

International Rectifier - The Power Management Leader
产 品 系 列 销 售 支 持 技 术 资 料 设 计 支 持 技 术 支 持 中 心 产品型号搜索
新闻发布
产品应用
IR 针对非隔离式驱动器应用推出高电压 IRS2980 LEDrivIR IC
可提升性能与成本效益
2011年10月28日
全球功率半导体和管理方案领导厂商国际整流器公司
公司资料
(International Rectifier，简称IR) 近日推出 IRS2980
新闻发布
IR 展览会
产品宣传资料
杂志广告
技术文章
技术支持中心
高电压降压稳压器控制IC，适合 LED 灯泡替换、LED 灯
管照明及其它非隔离式 LED 驱动器应用。
IRS2980 是高电压 LEDrivIR IC 系列的首款产品，额定
值为 600V，使用滞后平均电流模式控制来实现精准的电
流调节。新款 LED 降压驱动器搭载附有高电压内部稳压
器和高侧电流感应功能的低侧 MOSFET 驱动器。转换器可兼容电子脉冲宽度调制 (PWM) 调光，电流控
制范围为0% 至100%。
IR 亚太区销售副总裁潘大伟表示：“固态照明产业发展迅速，因此对于能够为高亮度及高功率LED提供
恒流输出的低成本驱动器电子器件的需求与日俱增。与其它适合非隔离式LED 驱动器应用的解决方案相
比，全新的 IRS2980 LEDrivIR IC 能够提供更低系统成本和更高性能。”
采用 SO-8 封装的 IRS2980 使用整合了最新高压电平位移和终端技术的 IR 先进高电压 IC 加工工
艺，提供卓越的电气过应力保护和更高的现场可靠性。新器件还具有其他新功能与强化性能。
产品规格
器件编号
IRS2980SPBF
交流 -- 直流
家用电器
汽车
直流 -- 直流
照明
网络通信
封装
电压
VTH
Io
最高频率
SO8
600 V
0.5V
+/- 80/260mA
150kHz
相关数据资料和应用说明，以及采用 IRS2980DS 的参考设计IRPLLED7，请浏览 IR 的网站
www.irf.com。
http://www.irf.com.cn/irfsite/news/2011/323.asp?utm_source=supplyFrame&utm_medium=Ads[2012-6-14 6:21:28]
宇航/高可靠性
音响
桌上电脑/服务器
企业用电源
电机驱动
便携产品
International Rectifier - The Power Management Leader
有关产品现已接受批量订单。新器件不含铅，也符合电子产品有害物质管制规定 (RoHS) 。
专利和商标
LEDrivIR? 是国际整流器公司 (International Rectifier Corporation) 的商标，IR? 是国际整流器
公司的注册商标。文中所提及其它产品名称均为对应持有人所有的商标。
IR简介
国际整流器公司 (简称 IR，纽约证交所代号 IRF) 是全球功率半导体和管理方案领导厂商。IR 的模拟
及混合信号集成电路、先进电路器件、集成功率系统和器件广泛应用于驱动高性能计算设备及降低电机
的能耗 (电机是全球最大耗能设备) ，是众多国际知名厂商开发下一代计算机、节能电器、照明设备、
汽车、卫星系统、宇航及国防系统的电源管理基准。
IR 成立于 1947 年，总部设在美国洛杉矶，在二十个国家设有办事处。IR 全球网站：www.irf.com，
中国网站：www.irf.com.cn。
新 闻 发 布 索 引
产品系列
产品目录
参数搜索
HEXFET 功率 MOSFET
集成电路
栅驱动器IC
IGBTs
微电子继电器
SupIRBuck
XPhase
芯片产品
销售支持
技术资料
技术支持中心
如何购买
产品搜索
搜索替代产品
产品变更通知
制造厂
联系 IR 中国
IR 中国代理商
目录元件经销商
应用训练指南
应用笔记
设计提示
封装信息
质量与可靠性报告
技术文章
技术支持
设计工具
SupIRBuck设计工具
同步整流
IGBT选择工具
总线转换器
照明镇流器没计
IPM仿真器
MCE编译器
功率因素校正
Point of Load
SyncBuck MOSFET工具
参考设计
模型
搜寻FAQ
在线提问
问题追踪
International Sites: | English | Korean ??? | Japanese 日本語 |
京ICP备05048912号
About International Rectifier | Contact Us | Privacy ? 1995-2009 International Rectifier
http://www.irf.com.cn/irfsite/news/2011/323.asp?utm_source=supplyFrame&utm_medium=Ads[2012-6-14 6:21:28]
January 20th, 2012
IRS2980S
LED DRIVER CONTROL IC
Product Summary
IC Features
•
•
•
•
•
•
•
•
Dimming LED driver controller
Hysteretic Current Regulation
Closed-loop LED current dimming control
Analog/PWM Dimming Input
Internal High Voltage Regulator
Internal 15.6V zener clamp diode on Vcc
Micropower startup (250μA)
Latch immunity and ESD protection
•
•
•
Buck
VOFFSET (breakdown)
600 V
VOUT
VCC
IO+ & IO- (typical)
180mA & 260mA
Package Types
LED Driver System Features
•
•
•
Topology
Single chip dimming solution
Simple LED current dimming control method
No external protection circuits required (fully
internal)
Low external component count
Easy to use for fast design cycle time
Increased manufacturability and reliability
SO8
Typical applications
•
•
LED incandescent/CFL replacement lamps
LED driver module
Typical Connection Diagram
IRS2980
www.irf.com
© 2011 International Rectifier
1
IRS2980S
Table of Contents
Page
Description
3
Block Diagram
3
Qualification Information
4
Absolute Maximum Ratings
5
Recommended Operating Conditions
6
Electrical Characteristics
7
Input/Output Pin Equivalent Circuit Diagram
9
Lead Definitions
10
Lead Assignments
10
Application Information and Additional Details
11
Package Details
15
Tape and Reel Details
16
Part Marking Information
17
Ordering Information
18
www.irf.com
© 2011 International Rectifier
2
IRS2980S
Description
The IRS2980S utilizes International Rectifier's control and high-voltage technologies to realize a simple,
high-performance Buck LED driver solution. This solution is based on hysteretic output current regulation
typically operating from 25 kHz to 120 kHz. Frequency and duty cycle vary to maintain a tightly regulated
average output current over variations in line and load. Output current ripple will depend on inductor
selection in conjunction with input and output voltages as well as output current and component selection.
The IRS2980S uses a unique floating high side differential current sense and level shift scheme allowing
hysteretic operation with a low side switching MOSFET optimizing size and cost. In addition, the IRS2980S
includes a high voltage regulator able to operate up to 450V eliminating the need for an external VCC supply.
A PWM dimming interface is also included that can be controlled from a 0 to 2V analog or 3.3 or 5V logic
control signal able to operate up to 1kHz offering brightness control from 0 to 100%. A programmable on
board PWM oscillator is used with DC dimming control.
Block Diagram
HV 1
5
ADIM
6
RAMP
7
OUT
4
COM
0.5V
VCC
Ref
CS 8
2V
0.2V
15.6V
VS 2
High Side
Well
1V
REGULATOR
UVLO
VCC
VCC 3
NOISE FILTER +
MAXIMUM
FREQUENCY
TIMING
15.6V
www.irf.com
© 2011 International Rectifier
3
IRS2980S
†
Qualification Information
Qualification Level
Moisture Sensitivity Level
Machine Model
ESD
Human Body Model
IC Latch-Up Test
RoHS Compliant
Industrial††
Comments: This family of ICs has passed JEDEC’s Industrial
qualification. IR’s Consumer qualification level is granted by
extension of the higher Industrial level.
MSL2†††
(per IPC/JEDEC J-STD-020C)
Class B
(per JEDEC standard JESD22-A115)
Class 2
(per EIA/JEDEC standard EIA/JESD22-A114)
Class I, Level A
(per JESD78)
Yes
†
††
Qualification standards can be found at International Rectifier’s web site http://www.irf.com/
Higher qualification ratings may be available should the user have such requirements. Please contact
your International Rectifier sales representative for further information.
†††
Higher MSL ratings may be available for the specific package types listed here. Please contact your
International Rectifier sales representative for further information.
www.irf.com
© 2011 International Rectifier
4
IRS2980S
Absolute Maximum Ratings
Absolute Maximum Ratings indicate sustained limits beyond which damage to the device may occur. All
voltage parameters are absolute voltages referenced to COM; all currents are defined positive into any lead.
The Thermal Resistance and Power Dissipation ratings are measured under board mounted and still air
conditions.
Symbol
Definition
†
Min.
Max.
Units
VHV
High Voltage Input
-0.3
450
VOUT
Low-Side Output Voltage
-0.3
VCC + 0.3
VADIM
VRAMP
DIM Input Voltage
-0.3
RAMP Input Voltage
-0.3
VCC + 0.3
VCC + 0.3
---
20
-500
500
---
0.625
W
ºC/W
††
ICC
PD
Supply Current
Maximum allowable current at OUT due to external
power transistor Miller effect.
†††
Maximum Power Dissipation @ TA ≤ +25ºC
RθJA
Thermal Resistance, Junction to Ambient
---
128
TJ
Junction Temperature
-55
150
TS
Storage Temperature
-55
150
TL
Lead Temperature (Soldering, 10 seconds)
---
300
IOMAX
V
mA
ºC
†
The IRS2980S uses an HVIC process capable of withstanding up to 600V, however the internal
regulator maximum input voltage rating is limited to 450V maximum due to package power
dissipation. The device can withstand transient voltages up to 600V for short periods.
††
This IC contains a zener clamp structure between the chip VCC and COM which has a nominal
breakdown voltage of 15.6V. This supply pin should not be driven by a DC, low impedance power
source greater than the VCLAMP specified in the Electrical Characteristics section.
†††
Power dissipation is dependent on VHV and switching frequency. In order to limit device
temperature rise some thermal relief may be required in the form of copper on the PCB located
under and around the device. Alternatively a small heat sink may be attached to the top of the
device. Thermally conductive potting compounds can also provide excellent heat transfer.
www.irf.com
© 2011 International Rectifier
5
IRS2980S
Recommended Operating Conditions
For proper operation the device should be used within the recommended conditions.
Symbol
†
Definition
†
Min.
Max.
Units
VHV
VCC
ICC
High Voltage Input
Supply Voltage
Supply Current
0
10.0
---
375
VCLAMP
5
mA
VRAMP
VENN Pin Voltage
0
6
V
VADIM
VENN Pin Voltage
0
6
V
VENN
VENN Pin Voltage
0
6
V
TJ
Junction Temperature
-40
125
ºC
V
Operation above this voltage level and below 450V is possible with sufficient heat sinking.
www.irf.com
© 2011 International Rectifier
6
IRS2980S
Electrical Characteristics
VHV=100V, VCC=14V, CVCC=0.1μF, CHVS=22nF, and TA = 25°C unless otherwise specified. The output
voltage and current (VO and IO) parameters are referenced to COM and are applicable to OUT.
Symbol
Definition
Min
Typ
Max
Units
Test Conditions
14.6
15.6
16.6
V
ICC = 10mA
---
250
---
µA
VCC = 6V
Low Voltage Supply Characteristics
VCLAMP
VCC Zener Clamp Voltage
IQCCUV
Micropower Startup VCC Supply Current
High Voltage Regulator Characteristics
VCCREG
VCC Regulation Voltage
8.9
9.9
10.9
V
ICC = 1mA
IREG_MAX
Maximum Regulator Current
---
3
5
mA
Vcc = 0V
†
---
60
---
V
VHVS+
High Side UVLO Positive Threshold
8.3
9.3
10.3
VHVS-
High Side UVLO Negative Threshold
6.3
7.3
8.3
---
150
---
kHz
---
100
---
%
---
0.5
---
V
---
100
---
mV
RAMP Pin Charging Current
---
15
---
µA
VRAMP+
RAMP Pin Shutdown Threshold
---
2.0
---
VRAMP-
RAMP Pin Re-start Threshold
---
0.2
---
Dimming Duty Cycle
0
VHVMIN
Minimum HV required for regulator
High Side Voltage Supply Characteristics
V
Control Characteristics
fMAX
Maximum Output Frequency
dMAX
Buck Duty Cycle
VCS
VCS-HYS
Current Regulation Threshold
Current Regulation Hysteresis
††
Dimming Characteristics
IRAMP
dPWM
100
%
†
VCC can be supplied from an alternative source for the IRS2980S to operate with bus voltages
below this level.
††
Various tolerances on VCS are available upon request
www.irf.com
© 2011 International Rectifier
7
IRS2980S
Electrical Characteristics
VHV=100V, VCC= 14V, CVCC=0.1µF, CHVS=22nF and TA = 25°C unless otherwise specified. The output
voltage and current (VO and IO) parameters are referenced to COM and are applicable to OUT.
Symbol
Definition
Min
Typ
Max
Units
Test Conditions
Gate Driver Output Characteristics (OUT)
VOH
High-Level Output Voltage
---
VCC
---
IO = 0A
VOL
Low-Level Output Voltage
---
COM
---
IO = 0A
---
IO = 0A,
VCC ≤ 8.0V
VOL_UV
---
UV-Mode Output Voltage
COM
tr
Output Rise Time
---
120
220
tf
Output Fall Time
---
50
80
IO+
Output source current
---
180
---
IO-
Output sink current
---
260
---
www.irf.com
ns
mA
© 2011 International Rectifier
8
IRS2980S
I/O Pin Equivalent Circuit Diagrams
www.irf.com
© 2011 International Rectifier
9
IRS2980S
Lead Definitions
Pin #
Symbol
Description
1
HV
High Voltage Bus
2
VS
High Side Floating Supply Return
3
VCC
VCC Supply
4
COM
Ground / Common
5
ADIM
Linear / Analog Dimming Input
6
RAMP
Ramp Waveform for Analog Dimming
7
OUT
8
CS
Gate Drive Output
Load Current Sense
Lead Assignments
1
VS
2
VCC
3
COM
4
IRS2980
HV
www.irf.com
8
CS
7
OUT
6 RAMP
5 ADIM
© 2011 International Rectifier
10
IRS2980S
Application Information and Additional
Details
operating conditions imposed by the input and
output voltages, output current and inductor value.
The IRS2980S is primarily intended for use in
Buck LED drivers operating with average current
regulation using hysteretic control. The circuit
topology uses a low side MOSFET referenced to
the 0V bus driven by a low side gate driver circuit
within the IRS2980S and an additional fast
recovery freewheeling diode. In order to minimize
switching losses the reverse recovery time of this
diode should be no more than 35nS. The
MOSFET should be selected for low capacitance
to reduce switching losses and low gate charge
(less than 25nC is recommended) to minimize
gate drive current. The LED load is referenced to
the DC bus and not 0V. The IRS2980S
incorporates floating high side current sense
inputs allowing the LED current to be sensed both
when the MOSFET is switched on and off. This
enables hysteretic operation, switching the
MOSFET off when the current rises above an
upper threshold and off when the current falls
below a lower threshold.
The current sense threshold Vcs is nominally
500mV with approximately 100mV of hysteresis
making the upper limit Vcs+50mV and the lower
limit Vcs-50mV. Some overshoot typically occurs
due to propagation delays and a small undershoot
is also possible. These vary depending on di/dt of
the ripple current, which is a function of input and
output voltage, inductor value and frequency as
well as RC filter values (RF and CF). The average
current is maintained at approximately the midpoint over a wide input and output voltage range
due to the inherent accuracy of hysteretic control.
The LED output current is set by selecting the
value of the current sense resistor RCS. This is
determined by the formula:
The following diagram shows the rise and fall of
the LED current as the MOSFET switches on and
off:
RCS =
Figure 1: MOSFET gate drive and inductor/LED
current.
The following formulae model the operation of the
IRS2980S based Buck LED driver:
t on ≈
Q
0.2 ⋅ L ⋅ I LED
+ RF ⋅ C F + G + t dr
VBUS _ DC − VLED
0.18
t off ≈
Q
0.2 ⋅ L ⋅ I LED
+ RF ⋅ C F + G + t df
VLED
0.26
f SW =
d=
1
(switching frequency)
t on + t off
t on
(duty cycle)
t on + t off
Where,
VCS
I LED
RF and CF are the current sense filter
components,
L is the inductor value,
QG is the MOSFET gate charge,
tdr and tdf are propagation delays
(These values vary depending on circuit
conditions, tdr decreases with input voltage. tdf is
normally negligible. For a first order approximation
these terms may be ignored.)
Where ILED is the average LED output current.
The peak to peak ripple ∆ILED will be 20% of the
average LED current ILED due to the hysteretic
operation plus some additional ripple due to circuit
delays. These are caused mainly by the current
sense filter and MOSFET gate drive.
Since the IRS2980S uses hysteretic current
control to switch the Buck MOSFET on and off,
the LED current (which is equal to the inductor
current) is maintained between upper and lower
thresholds. Because of this the switching
frequency and duty cycle vary to meet the
www.irf.com
© 2011 International Rectifier
11
IRS2980S
pin of the IRS2980S is rated up to 450V, the
actual maximum voltage that can be applied is
limited by the by the power dissipation of the IC.
The internal VCC regulator is recommended for
use up to 200VDC or with a passive valley fill PFC
circuit operating from up to 250VAC input. It can
be operated at higher voltages only with sufficient
heat sinking.
Operating frequency and duty cycle will vary when
there is ripple in the DC bus voltage. For example
where a passive valley fill circuit is used for power
factor correction (PFC) the LED current will be
regulated dynamically by constantly changing
frequency and duty cycle to maintain a constant
average.
Current Sense Filter Selection
The recommended values for RF and CF are
100Ohms and 1nF. This is sufficient to prevent
instability due to switching noise appearing at the
current sense input. These values have negligible
effect on the frequency and ripple. In a test
application using a 3.3mH inductor to drive a
17.5V LED panel, the output current varied from
338mA to 347mA (2.7%) over a DC voltage input
range of 40V to 200V.
A resistor (RG) between the gate driver output
and the gate of the power MOSFETs is also
recommended to reduce switching transients by
reducing dv/dt. A value of 10Ohms is
recommended, however this can be increased to
reduce noise if required.
Filter values may be increased in order to lower
the running frequency without increasing inductor
size. This results in higher current ripple and
higher current change over input voltage
variations. This may be an acceptable
compromise depending on the application
specification.
Figure 2: Passive valley fill PFC circuit
Frequency Limiter
The switching frequency of the IRS2980S is
internally limited to approximately 150 kHz (fMAX).
The IRS2980S is designed for use below this
frequency in order to limit current consumption in
the VCC and floating high side bias supplies. This
is necessary because the IRS2980S uses internal
regulators to supply these voltages, which can
supply only a limited current. This restriction is
acceptable in most LED driver applications.
Where higher frequency operation is needed the
IRS25401/11 is recommended.
Figure 3: Passive valley fill PFC bus voltage (blue)
and line input current (red) waveforms.
The VCC current (ICC) drawn by the IRS2980S
can be estimated from the following formula:
I CC ≈ 1mA + QG ⋅ f SW
High Voltage Regulator
The IRS2980S includes a high voltage regulator
to supply VCC from the DC input bus voltage.
This eliminates the need for external VCC supply
circuitry. A VCC capacitor of 1uF is recommended
for reliable startup and smooth operation. The
IRS2980S may shut down if CVCC is not present
or too small.
If necessary the internal regulator may also be
bypassed by supplying an external DC supply
from 14V to 15V to the VCC pin. Although the HV
Therefore power dissipation due to the high
voltage regulator can be calculated as:
PREG = VBUS _ DC _ AV ⋅ I CC
Floating Differential Current Sense
The floating high side current sense incorporated
in the IRS2980S is able to operate up to 450V and
withstand voltage surges up to 600V. An internal
bias supply is derived between the HV and VS
www.irf.com
© 2011 International Rectifier
12
IRS2980S
pins by a 1mA current source pulling down on VS
so that a supply voltage is produced across the
external capacitor CHVS to supply the high side
circuitry. A value of 22nF is recommended for
CHVS. The internal bias supply also dissipates
some power, which can be calculated from the
formula:
PBIAS = (VBUS _ DC _ AV − 10) ⋅1mA
In order for the high side current sense circuitry to
function, a minimum bus voltage of 30V is
required to provide adequate bias supply current
and standoff voltage.
Figure 4: Thermal relief example
In addition if the IRS2980S is used in an
application where the circuit is encapsulated in
thermally conductive filler the die temperature rise
is also greatly reduced.
Figure 4 shows an example of thermal relief
placed around the IRS2980S in a high voltage
application. The top side copper layer is shown as
red and the bottom side is blue.
With thermal relief ∆T becomes:
Thermal Considerations
Since the IRS2980S dissipates some power
during normal operation, temperature rise of the
IC die must be considered as part of the design
process.
The SO8 IC package has a maximum power
rating (PD) of 625mW, therefore the sum of PREG
and PBIAS should not exceed this value.
The junction temperature should remain below
125°C to ensure operation within specifications.
The junction temperature is normally 10°C above
the case temperature for an SO8 package
therefore the case temperature should not exceed
115°C at maximum ambient.
The junction to ambient thermal resistance of the
package (RθJA) is 128°C/W. This would give an
80°C temperature rise without any thermal relief at
the maximum PD value of 625mW.
⎡ RθJA ⋅ RθHS ⎤
ΔT = PD ⋅ ⎢
⎣ RθJA + RθHS ⎥⎦
Where RθHS is the thermal resistance of the
thermal relief area or heat sink, which will
normally be lower than RθJA.
Dimming
The IRS2980S includes a PWM dimming
oscillator that generates a linear ramp waveform
at the RAMP pin with the frequency determined by
an external capacitor to COM (CRAMP). A DC
voltage is applied to the ADIM pin which is
compared to this ramp to produce a gating signal
that enables and disables the high frequency
switching of the MOSFET gate drive. By varying
the ADIM voltage the duty cycle is adjusted
allowing brightness to be adjusted from zero to
100%. This is accomplished by operating the LED
driver in burst mode and varying the duty cycle of
the bursts. The LED current during dimming is
shown in figure 5:
ΔT = PD ⋅ RθJA
In order to reduce the junction temperature rise
thermal relief should be added around the
IRS2980S on the PCB. With adequate thermal
relief the die temperature rise can be greatly
reduced. The recommended method is to place
an area of copper on the opposite side of the PCB
to the IC in the same position with several vias
added underneath the IC to conduct heat through
to the other side.
www.irf.com
© 2011 International Rectifier
13
IRS2980S
being used in dim mode place a capacitor
CDIM from the ADIM pin to COM and keep
the capacitor as close to the IC as possible
with the shortest possible traces.
4) If the IRS2980S is being used in non-dimming
mode the RAMP pin can be connected to
COM. If it is being used in dimming mode
CRAMP should be located close to the IC with
the shortest possible traces to the RAMP pin
and COM.
5) Connect IC COM to power GND at one
connection only. Do NOT route power GND
through the programming components or IC
COM.
Figure 5: LED current during dimming.
The dimming level can also be controlled from a
digital input by replacing CRAMP with a 68k
resistor. This sets a DC threshold at the RAMP
pin to approximately 1V so that a logic level PWM
dimming control signal can be applied to the ADIM
pin to directly switch the output on and off.
PCB Layout Guidelines
Proper care should be taken when laying out a
PCB board ensure correct functionality of the
IRS2980S. Transients caused by high dV/dt
during switching could potentially cause some
false triggering of the hysteretic circuit therefore a
small filter comprising RF and CF is
recommended. CF should be located close to the
IC pins with the trace from HV to RCS and the
traces from RCS to CS through RF kept as short
as possible. The 0V load return power ground
should be connected to the IC COM pin and at a
single point to avoid ground loops. The values of
RF and CF are normally chosen to provide noise
filtering without adding excessive delay to the
circuit, however in some case these are
deliberately made larger to lower the running
frequency as this reduces switching losses and
ICC current.
The following guidelines should be followed during
PCB board layout:
1) Place VCC supply decoupling capacitor
(CVCC) as close as possible to the VCC and
COM pins.
2) Place high side decoupling capacitor (CVF) as
close as possible to the HV and VS pins.
3) If the IRS2980S is being used in non-dimming
mode connect the ADIM pin to VCC. If it is
www.irf.com
© 2011 International Rectifier
14
IRS2980S
Package Details
www.irf.com
© 2011 International Rectifier
15
IRS2980S
Tape and Reel Details
LOADED TAPE FEED DIRECTION
A
B
H
D
F
C
NOTE : CONTROLLING
DIM ENSION IN M M
E
G
CARRIER TAPE DIMENSION FOR
Metric
Code
Min
Max
A
7.90
8.10
B
3.90
4.10
C
11.70
12.30
D
5.45
5.55
E
6.30
6.50
F
5.10
5.30
G
1.50
n/a
H
1.50
1.60
8SOICN
Imperial
Min
Max
0.311
0.318
0.153
0.161
0.46
0.484
0.214
0.218
0.248
0.255
0.200
0.208
0.059
n/a
0.059
0.062
F
D
C
B
A
E
G
H
REEL DIMENSIONS FOR 8SOICN
Metric
Code
Min
Max
A
329.60
330.25
B
20.95
21.45
C
12.80
13.20
D
1.95
2.45
E
98.00
102.00
F
n/a
18.40
G
14.50
17.10
H
12.40
14.40
www.irf.com
Imperial
Min
Max
12.976
13.001
0.824
0.844
0.503
0.519
0.767
0.096
3.858
4.015
n/a
0.724
0.570
0.673
0.488
0.566
© 2011 International Rectifier
16
IRS2980S
Part Marking Information
Part number
IRSxxxxx
Date code
YWW ?
Pin 1
Identifier
?
MARKING CODE
P
Lead Free Released
IR logo
? XXXX
Lot Code
(Prod mode –
4 digit SPN code)
Assembly site code
Per SCOP 200-002
Non-Lead Free Released
www.irf.com
© 2011 International Rectifier
17
IRS2980S
Ordering Information
Standard Pack
Base Part Number
IRS2980S
Package Type
SOIC8N
Complete Part Number
Form
Quantity
Tube/Bulk
95
IRS2980SPBF
Tape and Reel
2500
IRS2980STRPBF
The information provided in this document is believed to be accurate and reliable. However, International Rectifier assumes no
responsibility for the consequences of the use of this information. International Rectifier assumes no responsibility for any
infringement of patents or of other rights of third parties which may result from the use of this information. No license is granted by
implication or otherwise under any patent or patent rights of International Rectifier. The specifications mentioned in this document are
subject to change without notice. This document supersedes and replaces all information previously supplied.
For technical support, please contact IR’s Technical Assistance Center
http://www.irf.com/technical-info/
WORLD HEADQUARTERS:
233 Kansas St., El Segundo, California 90245
Tel: (310) 252-7105
www.irf.com
© 2011 International Rectifier
18
IR Part Summary Page - IRS2980SPBF An LED Driver Control IC
Part Search
Part: IRS2980SPBF
Description: An LED Driver Control IC
Support Docs: Datasheet
News Release
Reference Design
Latch immunity and ESD protection LED
Driver System Features
IC Features
Dimming LED driver controller
Hysteretic Current Regulation
Closed-loop LED current dimming control
Analog/PWM Dimming Input
Internal High Voltage Regulator
Internal 15.6V zener clamp diode on Vcc
Micropower startup (250礎)
Single chip dimming solution
Simple LED current dimming control
method
No external protection circuits required (fully
internal)
Easy to use for fast design cycle time
Increased manufacturability and reliability
Long Description
The IRS2980 utilizes International Rectifier's control and high-voltage technologies to realize a simple,
highperformance dimming LED driver solution. This solution is based on a hysteretic topology where the
high frequency AC output current is controlled by adjusting the oscillator frequency and duty cycle.
Functional Block Diagram
Detailed functional block diagram available in PDF
Typical Connection
Specifications
Parameter
Value
https://ec.irf.com/v6/en/US/adirect/ir?cmd=catProductDetailFrame&productID=IRS2980SPBF[2012-6-14 6:22:13]
Site Search
IR Part Summary Page - IRS2980SPBF An LED Driver Control IC
Package
Circuit
Offset Voltage (V)
Output Source Current min (mA)
Output Sink Current min (mA)
PbF
t r (ns)
t f (ns)
8-lead SOIC
LED Driver
600
180
260
Yes
120
50
Packaging Options
Product ID
Description
Standard 1K Budgetary
Pack
Pricing (USD)
Status
An IRS2980S with
Standard Packaging
An IRS2980SPBF shipped
IRS2980STRPBF
on Tape and Reel
IRS2980SPBF
Qty
Active
95
$0.76
1
Active
2500
$0.76
1
Package Support Docs
8-Lead SOIC
Case Outline
REACH Compliance
RoHS/PbF Compliance
IRPLLED7
90-250V AC input voltage LED Driver
Featuring IRS2980S HVIC LED driver
Non-isolated buck regulator
90-250V AC input voltage
0-50V DC output voltage
Regulated output current of 350mA
PWM dimmable
Click here to display Distributor Inventory
Part Search: International Sites: | Chinese 简体中文 | Korean ??? | Japanese 日本語 |
About International Rectifier | Contact Us | Privacy ?1995- 2010 International Rectifier https://ec.irf.com/v6/en/US/adirect/ir?cmd=catProductDetailFrame&productID=IRS2980SPBF[2012-6-14 6:22:13]
IR’s High-voltage IRS2980 LEDrivIR™ IC for Non-isolated LED Driver Applications Offers Improved Performance and Greater Cost Efficiency
IR’s High-voltage IRS2980 LEDrivIR™ IC for Non-isolated LED Driver
Applications Offers Improved Performance and Greater Cost Efficiency
Part Search
EL SEGUNDO, Calif. — International Rectifier, IR® (NYSE: IRF), a world leader in power
management technology, today introduced the IRS2980 high-voltage buck regulator control IC for
LED light bulb replacement, LED tube lighting and other non-isolated LED driver applications.
Rated at 600 V, the IRS2980 is the first in a family of high-voltage LEDrivIR™ ICs, and utilizes
hysteretic average current mode control for precise current regulation. The LED buck driver features
low-side MOSFET drive with high-voltage internal regulator and high-side current sensing. The
converter is compatible with electronic PWM dimming allowing for 0%-100% current control.
Site Search
AC-DC
Appliances
Automotive DC-DC
Lighting
NetCom
A&D/HiRel
Audio
Desktop/Server
Enterprise Power
Motor Control
Portables
About IR
Careers
Contact Us
Investor Relations
Site Index
Press Room
Corporate Social Responsibility
Awards
Featured Articles
Print Advertising
Request Literature
Trade Show Calendar
Editorial Contacts
“In the rapidly growing solid state lighting sector, there is a need for low cost driver electronics to
supply constant current output to high brightness, high power LEDs. The new IRS2980 LEDrivIR™ IC
offers improved performance at a lower system cost than alternative solutions for non-isolated LED
driver applications,” said Peter Green, LED Group Manager, IR’s Energy Saving Products Business
Unit.
All News Releases
New Product Releases
New Catalog Additions
Investor News
E-Mail News
RSS Feeds
Available in an SO-8 package, the IRS2980 utilizes IR’s advanced high-voltage IC process which
incorporates latest-generation high-voltage level-shifting and termination technology to deliver
superior electrical over-stress protection and higher field reliability, in addition to other new features
and enhancements.
Specifications
Part Number
IRS2980SPBF
Package
Voltage
VTH
Io
Max Frequency
SO8
600 V
0.5V
+/- 180/260mA
150kHz
Design Tools
A datasheet and application note are available on the International Rectifier website at www.irf.com.
A reference design, the IRPLLED7, featuring the IRS2980DS is also available.
Availability and Pricing
Pricing for the IRS2980 begins at US $0.60 each in quantities of 10,000-units. The IRPLLED7 costs
US $99 per kit. Production quantities are available immediately. The devices are lead free and RoHS
compliant. Prices are subject to change.
International Sites: | Chinese ???? | Korean ??? | Japanese ??? |
http://www.irf.com/whats-new/nr111025.html[2012-6-14 6:23:03]
About International Rectifier | Contact Us | Privacy ©1995- 2012 International Rectifier IR Part Summary Page - IRPLLED7 90-250VAC Offline LED Driver using LEDrivIR IRS2980
Part Search
Site Search
Part: IRPLLED7
Description: 90-250VAC Offline LED Driver using LEDrivIR IRS2980
Support Docs: Datasheet
Application Note
News Release
Featured Part Datasheet
IRPLLED7
90-250V AC input voltage LED Driver
Featuring IRS2980S HVIC LED driver
Non-isolated buck regulator
90-250V AC input voltage
0-50V DC output voltage
Regulated output current of 350mA
PWM dimmable
Specifications
Parameter
Value
Package
Featured Part
Line Input
Lamps
Design Kit
IRS2980
90-250 VAC
LED
Packaging Options
Product ID
IRPLLED7
Description
A IRPLLED7 with Standard
Packaging
Standard 1K Budgetary
Pack
Pricing (USD)
Status
Active
1
$125.00
Qty
1
Click here to display Distributor Inventory
Part Search: International Sites: | Chinese 简体中文 | Korean ??? | Japanese 日本語 |
About International Rectifier | Contact Us | Privacy ?1995- 2010 International Rectifier https://ec.irf.com/v6/en/US/adirect/ir?cmd=catProductDetailFrame&productID=IRPLLED7[2012-6-14 6:23:31]
Application Note AN-1171
IRPLLED7
90-250VAC Offline LED Driver
using
IRS2980
By Peter B. Green
Table of Contents
Page
1. Introduction ......................................................................................2
2. Constant Current Control .................................................................3
3. High Voltage Regulator ....................................................................5
4. Current Sense Level Shifter .............................................................5
5. PWM Dimming .................................................................................6
6. IRPLLED7 Circuit Schematic ...........................................................7
7. Bill of Materials.................................................................................8
8. PCB Layout ......................................................................................9
9. Test Results .....................................................................................10
10. Component Temperatures .............................................................12
11. Design Procedure Summary ..........................................................10
Safety Warning!
The IRPLLED7 LED driver does not provide safety isolation. When operating the output drive to
the LEDs can produce potentially dangerous voltages. This board is intended for evaluation
purposes only and should be handled by qualified electrical engineers only!
www.irf.com
AN-1171
1
EVALUATION BOARD - IRPLLED7
1. Introduction
Solid state light sources are now available that offer viable alternatives to
Fluorescent and HID lamps and far surpass incandescent lamps. Luminous
efficacy expressed in Lumens per Watt has now reached levels enabling LEDs to
be used for general illumination. High brightness LEDs also possess the added
advantages of longer operating life span up to 50000 hours and greater
robustness than other less efficient light sources making them suitable for
outside applications such as street lighting.
High power LEDs are ideally driven with constant regulated DC current,
requiring a "driver" or "converter" to provide the required current from an AC or
DC power source. A simple single stage power converter based around the
IRS2980 LED driver IC provides a controlled current output over a wide AC line
or DC voltage input range.
The IRPLLED7 evaluation board is an off line non-isolated constant current
Buck regulator LED driver designed to supply a 350mA DC output current. The
LED output voltage can be up to 90% of the input voltage, operating from an AC
line input voltage between 90 and 250VAC 50/60Hz. It also includes PWM
dimming capability from 10% to 100% of light output controlled by an on board
potentiometer.
Important Safety Information
The IRPLLED7 does not provide galvanic isolation of the LED drive output from
the line input. Therefore if the system is supplied directly from a non-isolated
input, an electrical shock hazard exists at the LED outputs and these should not
be touched during operation. Although the output voltage is low this electrical
shock hazard still exists.
It is recommended that for laboratory evaluation that the IRPLLED7 board be
used with an isolated AC or DC input supply. The IRS2980 series Buck topology
www.irf.com
AN-1171
2
is suitable only for final applications where isolation is either not necessary or
provided elsewhere in the system.
Figure 1: IRPLLED7 Block Diagram
2. Constant current control
The IRS2980 is a hysteretic Buck controller operating in continuous conduction
mode (CCM) and using a low side switching MOSFET as the controlled switch
and a fast recovery diode as the uncontrolled switch connected to the positive
DC bus. This mode of operation is opposite to the IRS25401 and includes a
differential floating high side current sense circuit, which is used to hysteretically
control the output current by sensing the voltage drop across a sense resistor
and regulating the average to 0.5V. The IRS2980 is designed for use in current
regulated circuits and not voltage regulated circuits.
Figure 2: IRS2980 Basic Schematic
www.irf.com
AN-1171
3
Figure 2 illustrates how the current is sensed by differentially measuring the
voltage between the HV and CS inputs, RF and CF have been added to provide
noise filtering. When the MOSFET (MBUCK) is switched on the current in the
inductor LBUCK rises linearly according to the relationship:
Vin − Vout = Lbuck .
di
dt
Where Vin is the bus voltage rectified from the AC line voltage and Vout is the
combined series voltage of the string of LEDs making up the load.
When the voltage at HV rises to 0.55V with respect to CS the gate drive to
MBUCK switches off. When the MBUCK is off the inductor current flows instead
through DBUCK. During this period the current decreases linearly according to
the relationship:
Vout = − Lbuck .
di
dt
When the voltage at HV falls to 0.45V with respect to CS the gate drive to
MBUCK switches on. The cycle repeats continuously to provide an average
current in LBUCK which supplies the LED load. The frequency and duty cycle are
dependent on the input and output voltages and the value of the LBUCK as can
be inferred from the equations.
The output current can be set by selecting the appropriate value of RCS
according to the relationship:
Iout (avg ) =
VCS
RCS
where VCS is 0.5V, therefore for an RCS of 1.5V, the output current will be
nominally 333mA. In practice there are some additional propagation delays in the
circuit which give rise to some error in the current regulation and some variation
over input voltage, however the performance is more than adequate for LED
applications as shown in the test results section. Accuracy of regulation and
amplitude of the current ripple are tradeoffs against inductor size.
The IRS2980 incorporates a frequency limiting function that prevents the
frequency from exceeding approximately 150kHz. This is necessary in order to
limit the VCC current consumption since the internal high voltage regulator can
supply only a limited current (ICC) which is dominated by gate drive current. Gate
current charges and discharges the MOSFET gate capacitance during each
switching cycle and therefore increases with frequency.
www.irf.com
AN-1171
4
3. High Voltage Regulator
The IRS2980 contains an internal high voltage regulator to supply VCC from the
high voltage DC bus. Figure 2 shows that pin 1 (HV) is connected directly the DC
bus. Current is supplied to the VCC supply at pin 2 through an internal current
source capable of operating up to 450V. The internal regulator can supply up to
3mA, which is sufficient to supply VCC for most MOSFET gate capacitances and
frequencies normally required in an LED driver. ICC can be reduced by selecting
a MOSFET with a low gate capacitance (25nC or less) and selecting an
inductance (LBUCK) that will allow the regulator to operate at a reduced
frequency. A regulator operating at 60kHz for example will require much less ICC
than one operating at 120kHz. As explained earlier this is a tradeoff against
inductor size. It is also important to consider the temperature rise of the IRS2980.
Since the internal regulator operates linearly the associated power loss is
dependent on bus voltage and ICC.
More care must be taken at higher bus voltages to minimize frequency and ICC
to minimize the IC operating temperature. The addition of heat sinking in the form
of large areas of copper on the PCB or thermally conductive potting compounds
can significantly reduce temperature. Inductor values are generally larger for
220V off line AC applications than for 120V in order to reduce switching
frequency, which lowers power dissipation in the circuit.
4. Current sense level shifter
The IRS2980 uses a floating differential current sense circuit to measure the LED
current in the high side of the supply circuit. The Buck regulator configuration
uses a low side switch, which is opposite to the IRS25401. In order to realize
average current control the current must be sensed both when the MOSFET
(MBUCK) is switched on and when it is switched off and therefore must be
sensed at the high side. In order to accomplish this the hysteretic current sensing
circuitry within the IRS2980 is situated within a floating high side well constructed
by means of International Rectifiers HVIC technology. A floating supply voltage
(nominally 8V) for the circuitry contained within this well is developed between
the HV and VS pins of the IC. The supply is provided by a current source located
between VS and COM.
The high side contains a comparator with defined hysteresis connected to a
-0.5V reference with respect to HV. The output from the comparator is
transferred through high voltage level shift circuitry to the gate driver circuitry,
which is referenced to COM. The incorporation of the floating high side well
allows the LED current to be sensed at voltages up to 450V above COM.
www.irf.com
AN-1171
5
5. PWM Dimming
The IRS2980 includes a PWM dimming oscillator that provides a linear ramp
waveform at the RAMP pin with the frequency determined by an external
capacitor to COM (CRAMP). The IRPLLED7 demo board uses a passive valley
fill circuit comprising two electrolytic capacitors, three diodes and one resistor to
provide a high power factor (>0.9) without the additional cost of an additional
active stage. This circuit (C2,C5,D2,D3,D4 and R3) can be seen in the schematic
shown in section 6. The passive valley fill circuit however, creates a high ripple
on the DC bus at twice the line frequency (50-60Hz). The constant current Buck
regulator is easily capable of compensating for this, however in PWM dimming
designs it means that the PWM frequency needs to be significantly higher than
120Hz in order to avoid visible flicker of the LEDs. The PWM dimming frequency
in the IRPLLED7 demo board is approximately 800Hz determined by a CRAMP
value of 10nF. The dimming ramp varies between 0 and 2V and is compared with
a DC dimming control voltage from 0 to 2V applied to the ADIM input at pin 5.
The IRPLLED7 board includes a pot which adjusts the ADIM input over the 0 to
2V range to provide the full range of dimming.
Figure 3: IRPLLED7 PWM Dimming
Figure 3 shows the output current to the LED load at a dimming level of about
30%. It can be seen that the amount of current ripple varies slightly due to the
DC bus voltage created by the passive valley fill circuit. At this PWM frequency
there is no noticeable flicker during dimming.
The IRS2980 is designed for PWM not linear dimming. For linear dimming
applications the IRS25401 may be used, which can operate in either or both
modes.
An IRS2980 based circuit could be produced that would be dimmable from a triac
based dimmer, however this would require the addition of external phase
detection and bleed circuitry (please refer to IRS2981 for this application).
www.irf.com
AN-1171
6
6. IRPLLED7 Circuit Schematic
Figure 4: IRPLLED7 Complete Schematic
www.irf.com
AN-1171
7
7. Bill of Materials
Item
Description
Part Number
Manufacurer
Quantity
Reference
1
IC, LED Controller
IRS2980S
International
Rectifier
1
IC1
2
Rectifier ,1A , 400V,
SMA
S1G-13-F
Diodes Inc
3
D2,D3,D4
3
Diode, 1A, 600V, 35nS,
SMB
MURHS160T3G
On
Semiconduct
or
1
D1
DF10S
Fairchild
1
BR1
IRFR812
International
Rectifier
1
M1
B32652A3104J
Epcos
1
C1
1206A102JAT2A
AVX
1
C4
GRM319R71H10
4KA01D
Murata
2
C6, C9
EEU-EB2E220
Panasonic
2
C2, C5
Vishay
1
C3
AVX
1
C8
Murata
1
C7
ERJ-1TYJ1R5U
Panasonic
1
R2
PR01000101009
JR500
Vishay
2
R1, R3
ERJ-8GEYJ153V
Panasonic
1
R4
ERJ-8GEYJ100V
Panasonic
1
R5
ERJ-8GEYJ102V
Panasonic
1
R6
3386P-1-502LF
Bourns Inc
1
R7
B82477G4105M
Epcos
2
L1, L2
5009
Keystone
2
5005
Keystone
1
5006
Keystone
1
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Bridge, 1000V, 1.5A,
4SDIP
MOSFET, 500V,
2.2Ohm, DPAK
Capacitor, 100nF,
250VAC, Radial
Capacitor, 1nF, 50V,
5%, 1206
Capacitor, 0.1uF, 50V,
10%, 1206
Capacitor, 22uF,
250VDC, 20%
Capacitor, 0.22uF,
500VDC, 2225
Capacitor, 22nF, 50V,
1206
Capacitor, 0.01uF, 50V,
10%, 1206
Resistor, 1.5Ohm, 1W,
5%, 2512
Resistor, 10Ohm, 1W,
5%, Axial
Resistor, 15K, 0.25W,
5%, 1206
Resistor, 10, 0.25W,
5%, 1206
Resistor, 1K, 0.25W,
5%, 1206
Pot, 5K, 0.5W, Single,
Top adjust
Inductor, 1mH, 0.55A,
1.68Ohm
Test point, 0.063"D
Yellow
Test point, 0.063"D
Red
Test point, 0.063"D
Black
PCB
www.irf.com
VJ2225Y224KXE
AT
12065C223KAT2
A
GRM319R71H10
3KA01D
IRPLLED7 Rev C
AN-1171
1
8
8. PCB Layout
Top Overlay
Top Copper
Bottom Overlay
Bottom Copper
Layout Considerations
It is very important when laying out the PCB for the IRS2980 based LED driver to
consider the following points:
1. CVCC (C6) and CHVS (C8) must be as close to IC1 as possible.
2. The feedback path should be kept to a minimum length and separated as
much as possible from high frequency switching traces to minimize noise
at the CS input.
3. The current sense filter components RF (R6) and CF (C4) should be
located close to the IRS2980 with short direct traces.
4. It is essential that all signal and power grounds should be kept separated
from each other to prevent noise from entering the control environment.
www.irf.com
AN-1171
9
Signal and power grounds should be connected together at one point only,
which must be at the COM pin of the IRS2980. The IRS2980 may not
operate in a stable manner if these guidelines are not followed!
All low side components associated with the IC should be connected to
the IC signal ground (COM) with the shortest path possible.
5. All traces carrying the load current need to be sized accordingly.
6. Gate drive traces should also be kept to a minimum length.
9. Test Results
Measurements were carried out using a variable DC power supply and a load of
7 white LEDs being driven at a nominal 350mA.
DC Input
Voltage
(V)
60
70
80
90
100
110
120
130
140
150
160
170
180
DC Input
Current
(A)
0.14
0.12
0.11
0.10
0.09
0.08
0.07
0.07
0.07
0.06
0.06
0.06
0.05
Output
Voltage
(V)
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.1
20.1
Output
Current
(mAav)
335
340
344
349
353
357
360
364
367
370
373
375
377
Ripple
(mApp)
Frequency Duty
(kHz)
Cycle (%)
120
140
150
160
180
190
190
200
200
210
220
230
240
98
99
99
97
95
94
92
89
87
85
83
81
80
40
36
30
26
23
21
19
17.6
16.2
15.2
14.2
13.4
12.6
Table 1: IRPLLED7 Test Results
As expected table 1 indicates that the duty cycle is approximately equal to
Vout/Vin, the LED total voltage drop divided by the supply voltage. It can be seen
that the current ripple increases as the duty cycle reduces since the voltage
difference is increasing. This is because:
Vin − Vout = Lbuck .
di
dt
and therefore di/dt is increasing, which results in more overshoot in the hysteretic
comparator due to inevitable propagation delays in the system. These delays
actually provide an advantage because the operating frequency is decreasing
with higher input voltage which limits ICC and switching losses in both MBUCK
(M1) and DBUCK (D1).
www.irf.com
AN-1171
10
The gate drive and output current waveforms are displayed in Figure 5:
Input = 60VDC
Efficiency = 80.2%
Input = 180VDC
Efficiency = 75.3%
Green Trace = Gate Drive
Blue Trace = Output Current
Figure 5: IRPLLED7 Test Waveforms
In the example shown in table 1, the efficiency is calculated at 80.2% for 60VDC
input and 20V output at a current of 335mA. When the input for the same load is
increased to 180VDC the efficiency falls to 75.3% and the output current
increases to an average of 377mA. These efficiency results are reasonable for
9W LED load. If the board is connected to a 120VAC line input the efficiency
would be close to 80% due to the reduced bus voltage provided by the passive
valley fill circuit over much of the AC cycle.
The IRPLLED7 board uses an inductor of 1mA. Increasing this value would
reduce frequency and ripple. Ripple can also be reduced by adding a capacitor to
the output although this is not necessary in most applications and may reduce
the PWM dimming range.
In the example shown in figure 6 below, where a load of fewer series LEDs was
attached an efficiency of 86% was calculated:
www.irf.com
AN-1171
11
Yellow = Gate, Green = LED Current
Vin = 60V, Iin = 0.09A, Pin = 5.4W
Vout = 13.87, Iout = 0.338A, Pout = 4.66W
Efficiency = 86.0%
Figure 6: IRPLLED7 Efficiency Meaasurement
10. Component Temperatures
In the following example, an combination of LEDs was connected with a
combined voltage drop of approximately 30V. The board is capable of operating
down to 60VDC input, below which the high voltage regulator does not operate.
In applications requiring a lower input voltage VCC can be supplied directly from
an alternate source, the simplest option being a resistor from the DC bus to VCC.
DC Bus
Voltage (V)
60
70
80
90
100
110
120
130
140
150
160
170
180
Output
Voltage
(V)
30.76
30.60
30.55
30.52
30.43
30.43
30.43
30.43
30.44
30.45
30.47
30.49
30.51
Output
Current
(mAav)
334
330
329
329
331
332
335
337
340
343
346
349
353
Ripple
(mApp)
Frequency
(kHz)
Duty Cycle
(%)
100
110
120
130
140
150
150
160
170
170
170
170
170
150
154
155
155
157
157
158
159
159
160
160
161
161
54.4
46
41.8
37.3
33.0
30.3
27.4
25.2
25
23.1
21.6
20.5
19.6
Table 2: IRPLLED7 Additional Test Results
www.irf.com
AN-1171
12
In this case the body temperature in free air at ambient 25ºC was measured
using a thermocouple giving a result of 73ºC at 180V input. For a 120VAC supply
the temperature rise would be expected to be smaller since the bus voltage is
lower for most of the line cycle.
Since the IRS2980 incorporates an internal high voltage regulator and level
shifting circuitry it dissipates some heat during operation which increases with
frequency and line voltage. It is necessary as with the MOSFET (MBUCK) and
diode (DBUCK) to ensure that these components do not overheat in the
application. This is done by providing additional copper around the components
on the PCB to allow heat conduction from the devices. In 220VAC off line
applications is is necessary to use a suffliciently large inductor (LBUCK) in order
to maintain a low operating frequency in the 30 to 60kHz range. This will
substantially reduce heat dissipation in all of the components mentioned. The
1mH inductor used in the IRPLLED7 demo board may not be adequate in a
220VAC input design without sufficient heat sinking. A value of 3.3mH is typically
used for a 350mA LED output current at 220VAC.
11. Design Procedure Summary
1. Determine the systems requirements: input/output voltage and current
needed
2. Calculate current sense resistor
3. Determine the operating frequency required.
4. Select LBUCK so that they maintain supply into the load during t_HO_on.
5. Select the switching MOSFET and diode) to minimize gate drive current
and switching losses.
IR WORLD HEADQUARTERS: 101 N. Sepulveda Blvd., El Segundo, California 90245 Tel: (310) 252-7105
Data and specifications subject to change without notice. 9/8/2011
www.irf.com
AN-1171
13