ETC AL9910

AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
NEW PRODUCT
说明
管脚排布
AL9910/A高电压脉冲宽度调制 (PWM) LED驱动器控制器，为
离线高亮度LED灯提供高效率的解决方案，整流线性电压由
85VAC到高达277VAC。AL9910以最高300kHz的开关频率驱动
外部MOSFET，而开关频率由单一电阻来设定。AL9910拓扑
打造了流过多颗LED的恒定电流，带来恒定光线输出。输出电
流通过一个外部电阻进行编程，并最终由选定的外部MOSFET
来决定，因而可驱动多颗低电流LED及数颗高电流LED。
LED 的 亮 度 可 利 用 AL9910 的 LD 管 脚 做 线 性 调 光 ， 或 通 过
PWM_D管脚进行PWM调光。PWM_D输入以0~100%的占空
比率工作，频率可达数 kHz。
AL9910能抵受高达500V的输入电压， 使它可以非常灵活面对
标准主线电压的瞬变。AL9910可以SO-8 和温度增强 SO-8EP
封装供货。
(Top View)
CS 2
7 LD
6 VDD
5 PWM_D
SO-8
(Top View)
8 ROSC
VIN 1
CS 2
AL9910
7 LD
6 VDD
5 PWM_D
GND 3
GATE 4
 效率>90%
注:
AL9910
GND 3
GATE 4
功能
 通用整流85 到277VAC输入范围
 输入电压高达500V
 内部稳压器省掉启动电阻
o 7.5V MOSFET驱动 – AL9910
o 10V MOSFET驱动 – AL9910A
 更严格电流感测容测：5% AL9910-5
 驱动兼备高及低电流LED的LED灯具
 以线性及PWM调光提供LED亮度控制
 内部温度保护 (OTP)
 采用“绿色”模塑合成材料的SO-8和SO-8EP封装 (无溴和锑
) ，具有无铅涂料/ 符合RoHS (注1)
8 ROSC
VIN 1
SO-8EP
应用





LED离线灯具
高电压直流-直流LED驱动器
标志和装饰LED照明
平板显示屏的背灯
通用恒定电源
1. EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) 。所有相关的 RoHS 豁免都适用。请访问我们的网页：
http://www.diodes.com/products/lead_free.html.
典型应用电路
D1
VAC IN
VDD
C1
BR1
VIN
L1
Q1
AL9910/A
LD
C3
GATE
C2
PWM_D
ROSC
GND
CS
RSENSE
ROSC
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 1 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
管脚说明
NEW PRODUCT
管脚名称
SO-8
说明
SO-8EP
VIN
1
1
输入电压
CS
2
2
检测LED灯串和外部MOSFET开关电流
GND
3
3
器件接地
Gate
4
4
驱动外部MOSFET开关的栅极
PWM_D
5
5
低频率PWM调光管脚 ，以及 Enable输入。内部 200kΩ下拉至GND
VDD
6
6
内部稳压电源电压。

DAL9910和AL9910-5G为7.5V标识

AL9910A为10V标识
能够为外部电路供应高达1 mA 电流。当整流交流输入接近零交叉时，一个 充足的存储电容
会用来提供存储。
LD
7
7
线性调光输入。改变电流感测比较器的电流限制阈值，并更改平均 LED电流。
ROSC
8
8
振荡控制。连接这支管脚与地的电阻将设定PWM频率。 器件可通过将ROSC管脚连接到外
部MOSFET栅极与外部振荡电阻之间，切换至恒定关断时间 (PFM) 模式。
EP PAD
N/A
EP
外露焊垫 (底层)。 在封装之下直接连接到 GND。
功能性方块图
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 2 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
极限参数 (注 2)
符号
参数
单位
VIN(MAX)
最大输入电压， VIN， 到GND
-0.5 to +520
V
VCS
最大 CS输入管脚电压对GND
-0.3 to +0.45
V
VLD
VPWM_D
VGATE
NEW PRODUCT
额定值
VDD(MAX)
最大LD 输入管脚电压对GND
-0.3 to (VDD +0.3)
V
最大PWM_D输入管脚电压对GND
-0.3 to (VDD +0.3)
V
最大GATE管脚电压对GND
-0.3 to (VDD +0.3)
V
12
V
最大VDD 管脚电压对GND
持续功率耗散 (TA = 25C)
TJ
SO-8 (在+25C以上，每度降低6.3mW)
630
mW
SO-8EP (在+25C以上，每度降低22mW)
2200
mW
结温范围
+150
°C
-65 to +150
°C
存储温度范围
TST
ESD HBM
人体模型 ESD 保护(注 3)
1500
V
ESD MM
机器模型 ESD 保护 (注 3)
300
V
注：
2. 超过以上列出的极限参数或会对器件造成永久损害。这些只是应力额定值，而在这些数据或其它超过这个规格说明的操作部分所刊载的条件下，并
不表示器件能够正常运作。若器件长时间暴露在极限参数，器件的可靠性将受到影响。
所有电压皆参考对地。电流为正输入特定的终端，并由该终端负输出。
3. 半导体器件对静电释放 (ESD) 敏感，并且可能因暴露在 ESD 下而受到损害。当处理和运送这些器作时应该进行适当的 ESD 防护。
建议工作条件
符号
VINDC
TA
VDD
参数
输入直流供应电压范围
环境温度范围 (注 4)
最小
最大
AL9910
AL9910-5
15.0
500
AL9910A
20.0
500
AL9910_S
-40
+85
AL9910_SP
-40
+105
AL9910
AL9910-5
加诸 VDD 管脚的最大建议电压 (注 5)
V
°C
10
AL9910A
V
11
VEN(LO) 管脚 PWM_D 输入低电压
0
1
VEN(HI) 管脚 PWM_D 输入高电压
2.4
VDD
注:
单位
V
4. 最大环境温度范围受可允许功率耗散限制。外露焊垫 SO-8EP 凭藉其较低热阻抗，允许这些变数利用该封装来扩展可允许最大环境温度范围。
5. 若于隔离 LED 灯应用 AL9910，就必须使用一组辅助绕组。
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 3 页 (共 16 页)
www.diodes.com
2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
电气特性
(除非另有说明，否则采用建议的工作环境- TA = 25°C)
除非另有说明，否则规格适用于 AL9910、 AL9910A 和 AL9910-5
符号
参数
关闭模式电源电流
NEW PRODUCT
IINSD
VDD
IDD(ext)
条件
管脚 PWM_D 到 GND,
VIN = VIN(MIN) (注 6)
典型
最大
AL9910
AL9910-5
0.50
1
AL9910A
0.65
1.2
AL9910
AL9910-5
7.0
7.5
8.0
AL9910A
9.5
10
10.5
内部稳压
VIN = VIN(MIN)~500V, (注 6)
lDD(ext) = 0, Gate 管脚开路
供外部电路使用的 VDD 电流
VIN = VIN(Min) 到 100V (注 6 及 7)
在电压闭锁阈值下的 VDD
VDD 上升
UVLO
在电压闭锁滞回下的 VDD
∆UVLO
VDD 下降
RPWM_D PWM_D 下拉电阻
VCS(HI)
最小
电流感测阈值电压
AL9910
AL9910-5
6.4
6.7
7
AL9910A
8.4
9
9.6
AL9910
AL9910-5
500
AL9910A
750
VPWM_D = 5V
全环境温度范围 (注 8)
1.0
单位
mA
V
mA
V
mV
150
200
250
AL9910
AL9910A
225
250
275
AL9910-5
237.5
250
262.5
kΩ
mV
VGATE(HI) GATE 高输出电压
IOUT = 10mA
VDD -0.3
VDD
V
VGATE(LO) GATE 低输出电压
IOUT = -10mA
0
0.3
V
ROSC = 1MΩ
20
25
30
ROSC = 226kΩ
80
100
120
fOSC
震荡频率
DMAXhf 最大震荡 PWM 占空比
fPWMhf = 25kHz， 于 GATE，
CS 到 GND。
线性调光管脚电压范围
全环境温度范围 (注 8), VIN = 20V
tBLANK
电流感测消隐间隔
VCS = 0.45V, VLD = VDD
tDELAY
由 CS trip 到 GATE lo 的延迟
VLD
注:
kHz
100
%
0
-
250
mV
160
250
440
ns
300
ns
VIN = 20V, VLD = 0.15,
VCS = 0 到 0.22V，在 TBLANK 之后
tRISE
GATE 输出上升时间
CGATE = 500pF
30
50
ns
tFALL
GATE 输出下降时间
CGATE = 500pF
30
50
ns
TSD
温度关闭
150
TSDH
温度关闭滞回
50
JA
结至环境热阻
JC
结至外壳热阻
6.
7.
8.
9.
10.
SO-8 (注 9)
110
SO-8EP (注 10)
66
SO-8 (注 9)
22
SO-8EP (注 10)
9
C
C/W
C/W
AL9910 的 VIN(MIN)为 15V，AL9910A 的就为 20V。
同时受制予封装功率耗散界限，视乎哪个较低。
AL9910-5S、AL9910AS 和 AL9910S 的全环境温度范围为 -40 到+85°C；AL9910-5SP、AL9910ASP 与 AL9910SP 的则为 -40 到+105°C。
器件贴装在 FR-4 PCB (25 毫米 x 25 毫米 1 安士铜，最小建议焊热布局在上层。为达到较好热性能，散热器必须使用较大的铜垫。
器件贴装在 FR-4 PCB (51 毫米 x 51 毫米 2 安士铜，最小建议焊热布局在上层，热力穿过到底层地平面。为达到较好热性能，散热器必须使用较大
的铜垫。
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 4 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
460
2.5
440
2.0
420
INPUT CURRENT (µA)
CURRENT SENSE THRESHOLD (mV)
3.0
1.5
1.0
0.5
0.0
V IN = 400V
400
V IN = 15V
380
360
340
-0.5
320
-1.0
300
-1.5
-40
280
-40
-15
10
35
60
85
AMBIENT TEMPERATURE (°C)
Change in Current Sense Threshold vs. Ambient Temperature
85
Input Current vs. Ambient Temperature
SHORT CIR CUIT OU TPUT CURRENT (mA)
1.0
CHANGE IN FREQUENCY (%)
-15
10
35
60
AMBIENT TEMPERATURE (° C)
450
1.5

0.5
R OSC = 226k
0.0
-0.5
ROSC = 1M 
-1.0
-1.5
-2.0
-40
-15
10
35
60
85
AMBIENT TEMPERATURE (°C)
Change in Oscillation Frequency vs. Ambient Temperature
ILED(NOM) = 180mA
400
350
300
250
200
150
85 105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Short Circuit Output Current vs. Input Voltage
100
ILED = 281mA
90
V IN = 264V
TA = 23.5C
80
70
IOUT MAX (%)
NEW PRODUCT
典型特性
60
50
40
30
20
10
0
0
100
150
200
250
V LD DIMMING CONTROL (mV)
I OUT MAX vs. V LD Dimming Control
50
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
300
第 5 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
典型特性(續) ──使用 AL9910EV4 时进行测量
200
95
15 LEDs
14 LEDs
190
18 LEDs
EFFICIENCY (%)
IOUT MAX (mA)
16 LEDs
170
17 LEDs
160
90
17 LEDs
14 LEDs
16 LEDs
85
15 LEDs
150
18 LEDs
140
85
80
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Output Current vs. Input Voltage
0.95
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Efficiency vs. Input Voltage
12
17 LEDs
18 LEDs
18 LEDs
0.9
POWER (W)
10
POWER FACTOR
NEW PRODUCT
180
16 LEDs
0.85
17 LEDs
0.8
16 LEDs
8
15 LEDs
14 LEDs
15 LEDs
6
0.75
14 LEDs
0.7
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Power Factor vs. Input Voltage
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
4
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Input Power Dissipation vs. Input Voltage
第 6 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
应用信息
AL9910非常灵活，能够在隔离或非隔离拓朴中工作。它亦可以在持续或非持续导通模式下工作。
VIN
VIN
7.5/10V
LDO
OSC
VDD
VDD
250mV
NEW PRODUCT
ROSC
S
R
LD
O
GATE
CS
OTP
PWM_D
100k
AL9910/AL9910A
RSENSE
GND
图. 1 基础方块图
AL9910包含了一个高电压LDO (参见图1) 。该LDO的输出为包括栅极驱动器在內的内部电路提供導电轨。于LDO输出的 UVLO
防止在VIN 管脚的低输出电压下出现错误工作。
在非隔离降压LED驱动器中，当栅极管脚变为高电平，外部功率MOSFET Q1便会启动，使电流流过LED、电感器 (L1) 和电流
感测电阻 (RSENSE) 。如RSENSE的电压超过电流感测管脚阈值，外部MOSFET Q1就会关闭。存储在电感器里的电力将使电流
继续通过二极管D1流过LED。
AL9910的LDO为IC的其它部分提供全部功率，包括栅极驱动，所以不需要大型高功率启动电阻。这表示系统需要由高电压导电
轨提供大约0.5mA，方能正常工作。LDO也可以同时用来为外部电路供应高达1mA的电流。
AL9910通过限制外部MOSFET的尖峰电流来工作和调节。尖峰电流感测阈值一般设定为250mV。
相同的基本工作也适用于隔离式拓朴，只是在这种情况下，变压器存储的电力可于外部MOSFET处予关断周期时为LED提供能
源。
设计参数
设定LED电流
在非隔离降压转换器拓朴 (图1) ，平均LED电压并不等如把尖峰电流除以2。然而，电感器内尖峰电流与平电流之间的差异导致
一定的误差。下列方程式便说明了这个误差：
250mV
R SENSE 
.
ILED  (0.5 * IRIPPLE ))
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 7 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
应用信息(续)
设定工作频率
NEW PRODUCT
AL9910能够于25~300kHz的频率范围内操作。开关频率可通过连接ROSC 管脚与地的外部电阻来进行编程。相关的震荡周期
是：
 22
R
tOSC = osc
µs
ROSC 以 k計算
25
开关频率为震荡周期的倒数。ROSC 的典型值可由 75k 到 1M 不等。
若要驱动较少数量的 LED，就必须小心确保 tON > tBLANK。最简单的方法莫如通过提高 ROSC 值来降低/限制开关频率。减少开
关频率亦能改善效率。
应用以降压模式操作时，设计师应紧记输入电压必须保持高于跨越LED的正向电压降的2倍。当AL9910以大于0.5的占空比运
作，输出电流便可能出现不稳定性，而上述限制则与这种不稳定性相关。该不稳定性将由处予开关频率的次谐波 (SBO) 的输
出电流震荡反映出来。
最好的解决方案就是采用所谓的恒定关断时间操作 (如图2) 。电阻 (ROSC) 既定为接地，以设定工作频率。为了迫使AL9910进
入恒定关断时间模式，ROSC与外部MOSFET的栅极连接。这将通过增加以tOFF + tON计算的总周期，从50%进一步减少占空
比。
VIN
VDD
LD
VIN
Q1
AL9910/A GATE
PWM_D
ROSC
GND
CS
ROSC
图. 2 恒定关断时间配置
以上的震荡周期方程式现在决 定 AL9910 的关断时间 tOFF。
若使用这个模式，标识开关频率便已选定，所以关断时间也可凭藉标识输入和输出电压计算出来：

VOUT(nom ) 
 1
t OFF  1 
 fOSC

V
IN
(
nom
)


利用这个计时电阻可以计算出 ROSC： R OSC  t OFF (µs)  25   22(k)
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 8 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
应用信息 (续)
电感器选择
NEW PRODUCT
应用通常选用如图1所示的非融离式降压电路。它有2个操作模式：持续和非持续导通模式。降压功率级可将于负载电流超过某
个水平时 (通常为全负载的15%~30%) ，以持续模式运作为设计目标。一般来说，输入电压范围、输出电压和负载电流，都取
决于功率级的规格。这使电感值成为唯一用来维持持续导通模式的设计参数。下列的示例显示如何计算维持持续导通模式所需
的电感器最少值。
所需的电感值取决于电感器中理想的尖峰-尖峰LED纹波电流，通常约为标称LED电流的30%。
VIN  VLEDs   D
當中的D為占空比
L=
0.3  ILED   fOSC
下一步便是决定于LED灯串两端的总电压降。例如，若灯串由10颗高亮度LED灯组成，同时每颗二极管在标识电流下的正向电
压降为3.0V，总LED电压VLEDS就会是30V。
调光
LED的亮度可以视乎应用，采用线性 (利用LD管脚) 、脉冲宽度调制 (使用PWM-D管脚) ，又或者是两者结合的方式来进行调
节。把PWM_D管脚连接到地将关闭AL9910。当AL9910被停用时，其静态电流一般为0.5mA (如是AL9910A，则为0.65mA)。
降低 LD电压将减少LED电流，但由于的有限消隐周期的关系，并不会完全关闭外部功率晶体管和LED电流。只有PWM_D管脚
可关闭功晶体管。
线性调光可通过为LD管脚提供一个45~250mV的模拟信号来完成。这将盖过CS管脚的缺省250mV阈值并减少输出电流。如果
提供给LD的输入电压超过250mV，输出电压就不会改变。
LD管脚也可以为软启动提供一个经济的解决方案。通过于LD管脚初始上电时利用一颗电容器将 LD管脚连接到地，LD管脚便会
维持在低水平，使感测阈值也偏低。随着电容器上电，电流感测阈值将提高，结果导致平均 LED电流增加。
PWM调光是通过给予PWM_D管脚一个外部PWM信号来实现。LED电流与PWM占空比成正比，同时光输出可在0与100%之间
进行调节。该PWM信号会启动和关闭AL9910，从而调制LED电流。调光的最终精度只受制予最小栅极脉冲宽度，也就是低频
率占空比的极少部分。LED灯的PWM调光，则可通过利用低频50Hz~1000Hz TTL逻辑水平信号开启或关闭转换器来完成。
采用这两种调光模式都无法使平均亮度高于由AL9910的电流感测阈值所设定的水平。若应用需要较大的LED电流，就应该采用
一颗较小的感测电阻。
输入开路保护
因为 LED 与电感器以串联方法连接在一起，所以非隔离降压 LED 驱动器拓朴能够提供针对 LED 灯串中的开路状况的固有保护
功能。如 LED 灯串变为开路，开关就不会发生，电路继而永远维持在这个状态，且对电路其它部分造成损害。
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 9 页 (共 16 页)
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AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
应用信息 (续)
交流/直流离线LED驱动器
AL9910是经济的离线降压LED驱动器控制器，特别为驱动LED灯串而设计。它适合于整流交流线或任何介乎15~500V之间的直
流电压中操作。参看图3 的典型电路。
LED +
NEW PRODUCT
D1
VAC IN
VDD
C1
BR1
C2
LD
VIN
C3
L1
LED -
AL9910/A
Q1
GATE
PWM_D
ROSC
GND
CS
RSENSE
ROSC
图. 3 典型应用电路 (无 PFC)
降压设计方程式:
D
VLEDs
VIN
t ON 
L
D
fosc
( VIN  VLEDs )  t ON
0.3  ILED
R SENSE 
0.25
当中 ILED x 0.3 = IRIPPLE
ILED  (0.5  (ILED  0.3))
设计示例
若交流线电压为120V，标称整流输入电压 VIN = 120V*1.41 = 169V。凭此及LED串电压，就可以决定占空比：
D = VLEDs /VIN = 30/169 = 0.177
所需的外部MOSFET 导通时间可利用开关频率来计算，例如当fOSC = 50kHz：
tON = D/fOSC = 3.5 µs
如果LED电流为350mA，相关电感值就会如下：
L = (VIN - VLEDs) * tON /(0.3 * ILED) = 4.6mH
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 10 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
应用信息(续)
输入储能电容
离线灯需要一个输入储能电容去确保整流交流电压于整个交流线周期中，都保持于LED串电压的2倍。
CIN 
PIN  (1  D CH )
2  VLINE _ MIN  2fL  VDC _ MAX
NEW PRODUCT
其中
Dch : Capacity charge work period，一般大約為 0.2~0.25
fL :全范围的输入频率 (85~265VRMS)
VDC _ MAX 应该设定为 2 VLINE _ MIN 的10~15%
若电容器拥有一道15%的电压纹波，以下这条简化方程式便可用来大约计算储能输入电容器的最低值：
I
 VLEDs  0.06
CMIN = LED
VIN2
功率参数校正
如功率参数需要改善，同时输入功率低于25W，便可以把一个简单的无源功率参数校正电路加到典型的AL9910应用电路。图4
展示了无源 PFC电路 (3颗电流控制二极管和2颗相同的电容器) 没有对电路其余部分造成显著影响。简单的无源PFC改善了线
电流谐波失真，更达到高于0.85的功率参数。
Passive PFC
LED +
C4
C1
D1
VAC IN
VDD
BR1
LD
C2
C3
VIN
AL9910/A
PWM_D
ROSC
GND
Q1
LED L1
GATE
CS
RSENSE
ROSC
图. 4 配备无源 PFC 典型应用电路
这2颗相同的电容器每一颗都必须额定为输入电压的一半，且拥有相等于从欠缺无源PFC之降压转换电路计算所得的CMIN 的2倍
电容量(参阅先前关于储能电容器计算的章节)。
欲知更多设计信息，请访问Diodes的网站，查看AN75。
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 11 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
应用信息(续)
直流-直流降压LED驱动器
于前一个章节所展示的交流输入降压 LED 驱动器设计程序，同样适用于直流输入 LED 驱动器。
当驱动 LED 长串时，必须注意不要引起 SBO，也就是最高 LED 串的电压应该减少 VIN 的一半。因此最大占空比必须保持低于
50%，或使用恒定关断时间以消除问题。
NEW PRODUCT
直流-直流升压LED驱动器
基于 AL9910 LED 驱动器控制的拓朴，器件可用于升压配置，只是精度会下调。相关设计只要利用运算放大器来测量 LED 电
流，并且以该运算放大器的输出去驱动 LD 管脚，便可改善精度。
假如LED灯串的正向电压降高于输入电源电压，就须采用一个升压LED驱动器。比方说，若输入电压由一个48V电源供电，而
且相关的LED灯串由20伙HB LED灯组成 (可见于街灯)，升压拓朴便会适用。
L1
VDD
C1
VIN
VIN
D1
Q1
AL9910/A
PWM_D
GATE
C2
LD
ROSC
CS
C3
GND
ROSC
RSENSE
图. 5 升压LED驱动器
在升压转换器中，外部MOSFET导通之后，电力便会存储于电感器，然后当该外部MOSFET关闭，电力则全供应至输出。如存
储在电感器中的电力并没有在下一个开关周期前完全耗尽 (持续导通模式) ，输入与输出电压之间的直流转换由下列方程式决
定：
V
 VIN
V
VOUT  IN  D  OUT
VOUT
1 D
MOSFET的导通时间可用开关频率 fOSC和下列方程式计算；
D
t ON 
fOSC
再进而决定所需电感值：
V t
L  IN ON
0.3  ILED
升压拓朴LED驱动器需要一枚输出电容，在外部MOSFET导通时供应电流予LED串。
在升压LED驱动器拓朴内，如果 LED须要开路，便可能对功率开关造成损害，所以器件要备有侦测功能以提供过压侦测或保
护。
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 12 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
订购信息
AL9910 X XX XX - 13
Variant
NEW PRODUCT
Blank : 7.5V VDD
A : 10V VDD
器件
AL9910-5S-13
AL9910-5SP-13
AL9910AS-13
AL9910ASP-13
AL9910S-13
AL9910SP-13
注:
VCS Tolerance
Blank : 10%
-5 : 5%
Package
Packing
S : SO-8
SP : SO-8EP
VCS 容差
封装编码
封装
(注 10)
±5%
±5%
±10%
±10%
±10%
±10%
S
SP
S
SP
S
SP
SO-8
SO-8EP
SO-8
SO-8EP
SO-8
SO-8EP
13 : 13” Tape & Reel
数量
2500/卷带
2500/卷带
2500/卷带
2500/卷带
2500/卷带
2500/卷带
13 寸卷带
封装编码后缀
-13
-13
-13
-13
-13
-13
10. 焊垫布局如 Diodes 公司的建议焊垫布局文件 AP02001，该文件刊载于我们的网站
http://www.diodes.com/datasheets/ap02001.pdf .
标识信息
(1) SO-8
(2) SO-8EP
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 13 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
封装外型尺寸 (所有尺寸以毫米展示)
0.254
(1) 封装类别: SO-8
NEW PRODUCT
E1 E
Gauge Plane
Seating Plane
A1
L
Detail ‘A’
7°~9°
h
45°
Detail ‘A’
A2 A A3
SO-8
尺寸
最小
最大
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

所有尺寸以毫米展示
b
e
D
(2) 封装类别: SO-8EP
Exposed Pad
8
5
E1
1
H
4
F
b
Bottom View
E
9° (All sides)
N
7°
A
e
D
A1
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
45°
Q
C
4° ± 3°
Gauge Plane
Seating Plane
E0
SO-8EP (SOP-8L-EP)
尺寸 最小 最大 典型
A
1.40 1.50 1.45
A1
0.00 0.13
b
0.30 0.50 0.40
C
0.15 0.25 0.20
D
4.85 4.95 4.90
E
3.80 3.90 3.85
E0
3.85 3.95 3.90
E1
5.90 6.10 6.00
e
1.27
F
2.75 3.35 3.05
H
2.11 2.71 2.41
L
0.62 0.82 0.72
N
0.35
Q
0.60 0.70 0.65
所有尺寸以毫米展示
L
第 14 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
建议焊垫布局
(1) 封装类别: SO-8
NEW PRODUCT
X
C1
C2
尺寸
X
Y
C1
C2
数值 (毫米)
0.60
1.55
5.4
1.27
尺寸
X
Y
X1
Y1
C1
C2
数值 (毫米)
0.60
1.55
3.30
2.66
5.4
1.27
Y
(2) 封装类别: SO-8EP
X
Exposed Pad
X1
C1
Y1
Y
C2
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 15 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
通用高电压、高亮度 LED 驱动器
注意事项
美商達爾科技股份有限公司 (Diodes Incorporated)不对本文件做任何明确或隐含的保证，包括但不限于针对特定用途的适销性和适用性的隐
含保证 (及任何管辖法律下的等同事项) 。
NEW PRODUCT
美商達爾科技股份有限公司及其附属公司保留权利，对本文件及在此处描述的任何产品进行修改、完善、改进、修正或其他更改，恕不另行通
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A.
生命维持设备或系统是：
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2.用来维持或支撑生命；并且若在按照标签提供的使用指示的正确使用情况下出现故障，可合理地预期将对用户构成显着伤害。
B.
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客户表示对其生命维持设备或系统，拥有一切与安全及法规分支相关的必备专门知识；并且承认及同意就其产品或任何在这些安全关键的生命
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www.diodes.com
AL9910/AL9910A/AL9910-5
文件编号: DS35103 Rev. 7 - 2
第 16 页 (共 16 页)
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2012 年 9 月
© Diodes Incorporated
AL9910/ AL9910A/ AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Description
Pin Assignments
(Top View)
The AL9910/A high voltage PWM LED driver-controller provides an
efficient solution for offline high brightness LED lamps from rectified
line voltages ranging from 85VAC up to 277VAC. The AL9910 drives
8 ROSC
VIN 1
CS 2
GND 3
external MOSFETs at switching frequencies up to 300kHz, with the
switching frequency determined by a single resistor. The AL9910
topology creates a constant current through the LEDs providing
AL9910
GATE 4
constant light output. The output current is programmed by one
external resistor and is ultimately determined by the external
7 LD
6 VDD
5 PWM_D
SO-8
MOSFET chosen and therefore allows many low current LEDs to be
driven as well as a few high current LEDs.
(Top View)
The LED brightness can be varied by both Linear and PWM dimming
8 ROSC
VIN 1
using the AL9910’s LD and PWM_D pins respectively. The PWM_D
CS 2
GND 3
GATE 4
input operates with duty ratio of 0-100% and frequency of up to
several kHz.
The AL9910 can withstand input voltages up to 500V which makes it
AL9910
7 LD
6 VDD
5 PWM_D
very resilient to transients at standard mains voltages. As well as
SO-8EP
standard SO-8 package the AL9910 is available in the thermally
enhanced SO-8EP package.
Applications
Features
•
•
>90% Efficiency
Universal Rectified 85 to 277VAC Input Range
•
Input Voltage Up to 500V
•
Internal Voltage Regulator Removes Start-Up Resistor
ƒ
7.5V MOSFET drive – AL9910
ƒ
10V MOSFET drive – AL9910A
•
Tighter current sense tolerance: 5% AL9910-5
•
Drives LED Lamps with Both High and Low Current LEDs
•
LED Brightness Control with Linear and PWM Dimming
•
Internal Thermal Protection (OTP)
•
Available in SO-8 and SO-8EP Packages
•
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
•
Halogen and Antimony Free. “Green” Device (Note 3) Notes:
•
LED Offline Lamps
•
High Voltage DC-DC LED Driver
•
Signage and Decorative LED Lighting
•
Back Lighting of Flat Panel Displays
•
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 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.
AL9910/ AL9910A/ AL9910-5
Document number: DS35103 Rev. 8 - 2
1 of 15
www.diodes.com
December 2012
© Diodes Incorporated
AL9910/ AL9910A/
A
A
AL9910-5
Typical Ap
pplications
s Circuit
D1
VAC IN
N
VDD
C1
BR1
VIN
L1
Q1
AL99
910/A
LD
C3
GATE
C2
PWM_D
ROSC
ND
GN
CS
RSENSE
ROSC
Pin Descriiptions
Pin
Name
Pin Numberr
SO-8
SO-8
8EP
Function
VIN
CS
GND
Gate
PWM_D
1
1
age
Input Volta
2
3
4
5
2
3
4
5
VDD
6
6
LD
7
7
ROSC
8
8
EP PAD
N/A
EP
Senses LE
ED string and exxternal MOSFET switch current
Device Grround
Drives the
e gate of the exte
ernal MOSFET switch.
Low Frequ
uency PWM Dim
mming pin, also Enable
E
input. Inte
ernal 200kΩ pull-down to GND.
Internally regulated supplyy voltage.
ƒ
7.5V nominal for AL9910 and AL
L9910-5
10V nominal forr AL9910A.
ƒ
Can supply up to 1 mA forr external circuitrry. A sufficient sto
orage capacitor is
i used to provide storage when
the rectifie
ed AC input is ne
ear the zero crosssing.
Linear Dim
mming Input. Cha
anges the curren
nt limit threshold at current sense
e comparator and
d changes the
average LED
L
current.
Oscillator Control. A resisttor connected be
etween this pin and ground sets the PWM frequen
ncy. The devicess
can be sw
witched into constant off time (PFM) mode by connecting the exterrnal oscillator ressistor between
ROSC pin and
a the gate of the
t external MOS
SFET.
Exposed Pad
P (bottom). Connect
C
to GND directly
d
undernea
ath the package.
Functiona
al Block Dia
agram
AL9910/ AL9
9910A/ AL9910-5
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AL9910/ AL9910A/ AL9910-5
Absolute Maximum Ratings (Note 4) (@TA = +25°C, unless otherwise specified.)
Symbol
VIN(MAX)
Parameter
Maximum input voltage, VIN, to GND
Ratings
Unit
-0.5 to +520
V
VCS
Maximum CS input pin voltage relative to GND
-0.3 to +0.45
V
VLD
Maximum LD input pin voltage relative to GND
-0.3 to (VDD +0.3)
V
Maximum PWM_D input pin voltage relative to GND
-0.3 to (VDD +0.3)
V
Maximum GATE pin voltage relative to GND
-0.3 to (VDD +0.3)
V
12
V
VPWM_D
VGATE
VDD(MAX)
Maximum VDD pin voltage relative to GND
Continuous Power Dissipation (TA = +25°C)
SO-8 (derate 6.3mW/°C above +25°C)
SO-8EP (derate at 22mW/°C above 25°C)
630
mW
2200
mW
TJ
Junction Temperature Range
+150
°C
TST
ESD HBM
ESD MM
Storage Temperature Range
-65 to +150
°C
1500
300
V
V
Notes:
Human Body Model ESD Protection (Note 5)
Machine Model ESD Protection (Note 5)
4. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional
operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure
to absolute maximum rating conditions for extended periods may affect device reliability.
All voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal.
5. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when
handling and transporting these devices
Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.)
Symbol
VINDC
TA
VDD
Parameter
Input DC Supply Voltage Range
Ambient Temperature Range (Note 6)
Maximum Recommended Voltage Applied to VDD Pin (Note 7)
AL9910
AL9910-5
AL9910A
AL9910_S
AL9910_SP
AL9910
AL9910-5
AL9910A
Min
Max
15.0
500
20.0
-40
-40
500
+85
+105
10
9.5
11
VEN(LO)
Pin PWM_D Input Low Voltage
0
1
VEN(HI)
Pin PWM_D Input High Voltage
2.4
VDD
Notes:
Unit
V
°C
V
V
6. Maximum ambient temperature range is limited by allowable power dissipation. The Exposed pad SO-8EP with its lower thermal impedance allows
the variants using this package to extend the allowable maximum ambient temperature range.
7. When using the AL9910 in isolated LED lamps an auxiliary winding might be used.
AL9910/ AL9910A/ AL9910-5
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AL9910/ AL9910A/ AL9910-5
Electrical Characteristics (@TA = +25°C, unless otherwise specified.)
Symbol
Parameter
Shut-Down Mode Supply Current
IINSD
Internally Regulated Voltage
VDD
Conditions
Pin PWM_D to GND,
VIN = VIN(MIN) (Note 6)
VIN = VIN(MIN) ~500V, (Note 8)
lDD(ext) = 0, Gate pin open
IDD(ext)
VDD Current Available for External
Circuitry
UVLO
VDD Under Voltage Lockout Threshold VDD rising
∆UVLO
RPWM_D
VCS(HI)
VDD Under Voltage Lockout Hysteresis
PWM_D Pull-Down Resistance
Current Sense Threshold Voltage
Typ
Max
AL9910
AL9910-5
Min
0.50
1
AL9910A
0.65
1.2
AL9910
AL9910-5
7.0
7.5
8.0
AL9910A
9.5
10
11
1.0
VIN = VIN(MIN) to 100V (Notes 8 & 9)
VDD falling
AL9910
AL9910-5
6.4
6.7
7
AL9910A
8.4
9
9.8
AL9910
AL9910-5
500
AL9910A
750
VPWM_D = 5V
Full ambient temperature range
(Note 10)
AL9910
AL9910A
AL9910-5
Unit
mA
V
mA
V
mV
150
200
250
225
250
275
237.5
250
262.5
kΩ
mV
VGATE(HI) GATE High Output Voltage
IOUT = 10mA
VDD -0.3
VDD
V
VGATE(LO) GATE Low Output Voltage
IOUT = -10mA
0
0.3
V
ROSC = 1MΩ
20
25
30
ROSC = 226kΩ
80
100
120
Oscillator Frequency
fOSC
DMAXhf
Maximum Oscillator PWM Duty Cycle
VLD
Linear Dimming Pin Voltage Range
tBLANK
tDELAY
fPWMhf = 25kHz, at GATE,
CS to GND.
Full ambient temperature range (Note 10),
VIN = 20V
Current Sense Blanking Interval
VCS = 0.45V, VLD = VDD
Delay From CS Trip to GATE lo
VIN = 20V, VLD = 0.15,
VCS = 0 to 0.22V after TBLANK
kHz
100
%
0
-
250
mV
160
250
440
ns
300
ns
tRISE
GATE Output Rise Time
CGATE = 500pF
30
50
ns
tFALL
GATE Output Fall Time
CGATE = 500pF
30
50
ns
TSD
Thermal Shut Down
150
TSDH
Thermal Shut Down Hysteresis
50
SO-8 (Note 11)
SO-8EP (Note 12)
SO-8 (Note 11)
Thermal Resistance Junction-to-Case
SO-8EP (Note 12)
110
66
22
9
θJA
θJC
Notes:
Thermal Resistance Junction-toAmbient
°C
°C/W
°C/W
8. VIN(MIN) for the AL9910 is 15V and for the AL9910A it is 20V.
9. Also limited by package power dissipation limit, whichever is lower.
10. Full ambient temperature range for AL9910-5S, AL9910AS and AL9910S is -40 to +85°C; for AL9910-5SP, AL9910ASP and AL9910SP is
-40°C to +105°C.
11. Device mounted on FR-4 PCB (25mm x 25mm 1oz copper, minimum recommended pad layout on top. For better thermal performance, larger
copper pad for heat-sink is needed.
12. Device mounted on FR-4 PCB (51mm x 51mm 2oz copper, minimum recommended pad layout on top layer and thermal vias to bottom layer ground
plane. For better thermal performance, larger copper pad for heat-sink is needed.
AL9910/ AL9910A/ AL9910-5
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AL9910/ AL9910A/ AL9910-5
3.0
460
2.5
440
2.0
420
INPUT CURRENT (µA)
CURRENT SENSE THRESHOLD (mV)
Typical Characteristics
1.5
1.0
0.5
0.0
V IN = 400V
400
V IN = 15V
380
360
340
-0.5
320
-1.0
300
-1.5
-40
280
-40
-15
10
35
60
85
AMBIENT TEMPERATURE (°C)
Change in Current Sense Threshold vs. Ambient Temperature
450
SHORT CIRCUIT OUTPUT CURRENT (mA)
ILED = 281mA
V IN = 264V
TA = 23.5C
80
IO UT MAX (%)
70
60
50
40
30
20
10
0
85
Input Current vs. Ambient Temperature
100
90
-15
10
35
60
AMBIENT TEMPERATURE (° C)
0
50
100
150
200
250
V LD DIMMING CONTROL (mV)
I OUT MAX vs. V LD Dimming Control
ILED(NOM) = 180mA
400
350
300
250
200
150
85 105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Short Circuit Output Current vs. Input Voltage
300
1.5
CHANGE IN FREQUENCY (%)
1.0
0.5
0.0
R OSC = 226kΩ
-0.5
ROSC = 1M Ω
-1.0
-1.5
-2.0
-40
-15
10
35
60
85
AMBIENT TEMPERATURE (°C)
Change in Oscillation Frequency vs. Ambient Temperature
AL9910/ AL9910A/ AL9910-5
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AL9910/ AL9910A/ AL9910-5
Typical Characteristics (cont.) measured using AL9910EV4
200
95
15 LEDs
14 LEDs
190
18 LEDs
EFFICIENCY (%)
IOUT MAX (mA)
180
16 LEDs
170
17 LEDs
160
90
17 LEDs
14 LEDs
16 LEDs
85
15 LEDs
150
18 LEDs
140
85
80
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Output Current vs. Input Voltage
0.95
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Efficiency vs. Input Voltage
12
17 LEDs
18 LEDs
18 LEDs
0.9
POWER (W)
POWER FACTOR
10
16 LEDs
0.85
17 LEDs
0.8
16 LEDs
8
15 LEDs
14 LEDs
15 LEDs
6
0.75
14 LEDs
0.7
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Power Factor vs. Input Voltage
AL9910/ AL9910A/ AL9910-5
Document number: DS35103 Rev. 8 - 2
4
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Input Power Dissipation vs. Input Voltage
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AL9910/ AL9910A/ AL9910-5
Application Information
The AL9910 is very versatile and is capable of operating in isolated or non-isolated topologies. It can also be made to operate in continuous as
well as discontinuous conduction mode.
VIN
VIN
7.5/10V
LDO
OSC
ROSC
VDD
VDD
250mV
S
R
LD
O
GATE
CS
OTP
PWM_D
100k
AL9910/AL9910A
RSENSE
GND
Figure 1. Functional Block Diagram
The AL9910 contains a high voltage LDO (see Figure 1) the output of the LDO provides a power rail to the internal circuitry including the gate
driver. A UVLO on the output of the LDO prevents incorrect operation at low input voltage to the VIN pin.
In a non-isolated Buck LED driver when the gate pin goes high the external power MOSFET Q1 is turned on causing current to flow through the
LEDs, inductor (L1) and current sense resistor (RSENSE). When the voltage across RSENSE exceeds the current sense pin threshold the external
MOSFET Q1 is turned off. The stored energy in the inductor causes the current to continue to flow through the LEDs via diode D1.
The AL9910’s LDO provides all power to the rest of the IC including Gate drive this removes the need for large high power start-up resistors. This
means that operate correctly it requires around 0.5mA from the high voltage power rail. The LDO can also be used to supply up to 1mA to external
circuits.
The AL9910 operates and regulates by limiting the peak current of the external MOSFET; the peak current sense threshold is nominally set at
250mV.
The same basic operation is true for isolated topologies, however in these the energy stored in the transformer delivers energy to LEDs during the
off-cycle of the external MOSFET.
Design Parameters
Setting the LED Current
In the non-isolated buck converter topology, figure 1, the average LED current is not the peak current divided by 2 - however, there is a certain
error due to the difference between the peak and the average current in the inductor. The following equation accounts for this error:
R SENSE =
250mV
(ILED + (0.5 * IRIPPLE )))
AL9910/ AL9910A/ AL9910-5
Document number: DS35103 Rev. 8 - 2
.
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AL9910/ AL9910A/ AL9910-5
Applications Information (cont.)
Setting Operating Frequency
The AL9910 is capable of operating over a 25 and 300 kHz switching frequency range. The switching frequency is programmed by connecting an
external resistor between ROSC pin and ground. The corresponding oscillator period is:
tOSC =
R osc + 22
µs
25
with ROSC in kΩ
The switching frequency is the reciprocal of the oscillator period. Typical values for ROSC vary from 75kΩ to 1MΩ
When driving smaller numbers of LEDs, care should be taken to ensure that tON > tBLANK. The simplest way to do this is to reduce/limit the
switching frequency by increasing the ROSC value. Reducing the switching frequency will also improve the efficiency.
When operating in buck mode the designer must keep in mind that the input voltage must be maintained higher than 2 times the forward voltage
drop across the LEDs. This limitation is related to the output current instability that may develop when the AL9910 operates at a duty cycle greater
than 0.5. This instability reveals itself as an oscillation of the output current at a sub-harmonic (SBO) of the switching frequency.
The best solution is to adopt the so-called constant off-time operation as shown in Figure 2. The resistor (ROSC) is, connected to ground by
default, to set operating frequency. To force the AL9910 to enter constant OFF time mode ROSC is connected to the gate of the external MOSFET.
This will decrease the duty cycle from 50% by increasing the total period, tOFF + tON.
VIN
VDD
LD
VIN
Q1
AL9910/A GATE
CS
PWM_D
ROSC
GND
ROSC
Figure 2. Constant Off-Time Configuration
The oscillator period equation above now defines the AL9910 off time, tOFF.
When using this mode the nominal switching frequency is chosen and from the nominal input and output voltages the off-time can be calculated:
⎛
VOUT(nom ) ⎞
⎟∗ 1
t OFF = ⎜1 −
⎟
⎜
V
IN(nom ) ⎠ fOSC
⎝
(
)
From this the timing resistor, ROSC, can be calculated: R OSC = t OFF (µs) ∗ 25 − 22(kΩ )
Inductor Selection
The non-isolated buck circuit, Figure 1, is usually selected and it has two operation modes: continuous and discontinuous conduction modes. A
buck power stage can be designed to operate in continuous mode for load current above a certain level usually 15% to 30% of full load. Usually,
the input voltage range, the output voltage and load current are defined by the power stage specification. This leaves the inductor value as the
only design parameter to maintain continuous conduction mode. The minimum value of inductor to maintain continuous conduction mode can be
determined by the following example.
The required inductor value is determined from the desired peak-to-peak LED ripple current in the inductor; typically around 30% of the nominal
LED current.
L=
(VIN − VLEDs ) × D
(0.3 × ILED ) × fOSC
Where D is duty cycle
The next step is determining the total voltage drop across the LED string. For example, when the string consists of 10 High-Brightness LEDs and
each diode has a forward voltage drop of 3.0V at its nominal current; the total LED voltage VLEDS is 30V.
AL9910/ AL9910A/ AL9910-5
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AL9910/ AL9910A/ AL9910-5
Applications Information (cont.)
Dimming
The LED brightness can be dimmed either linearly (using the LD pin) or via pulse width modulation (using the PWM-D pin); or a combination of
both - depending on the application. Pulling the PWM_D pin to ground will turn off the AL9910. When disabled, the AL9910’s quiescent current is
typically 0.5mA (0.65 for AL9910A). Reducing the LD voltage will reduce the LED current but it will not entirely turn off the external power
transistor and hence the LED current – this is due to the finite blanking period. Only the PWM_D pin will turn off the power transistor.
Linear dimming is accomplished by applying a 45mV to 250mV analog signal to the LD pin. This overrides the default 250mV threshold level of the
CS pin and reduces the output current. If an input voltage greater than 250mV is applied to the LD then the output current will not change.
The LD pin also provides a simple cost effective solution to soft start; by connecting a capacitor to the LD pin down to ground at initial power up
the LD pin will be held low causing the sense threshold to be low. As the capacitor charges up the current sense threshold will increase thereby
causing the average LED current to increase.
PWM dimming is achieved by applying an external PWM signal to the PWM_D pin. The LED current is proportional to the PWM duty cycle and the
light output can be adjusted between zero and 100%. The PWM signal enables and disables the AL9910 - modulating the LED current. The
ultimate accuracy of the PWM dimming method is limited only by the minimum gate pulse width, which is a fraction of a percentage of the low
frequency duty cycle. PWM dimming of the LED light can be achieved by turning on and off the converter with low frequency 50Hz to 1000Hz TTL
logic level signal.
With both modes of dimming it is not possible to achieve average brightness levels higher than the one set by the current sense threshold level of
the AL9910. If a greater LED current is required then a smaller sense resistor should be used
Output Open Circuit Protection
The non-isolated buck LED driver topology provides inherent protection against an open circuit condition in the LED string due to the LEDs being
connected in series with the inductor. Should the LED string become open circuit then no switching occurs and the circuit can be permanently left
in this state with damage to the rest of the circuit.
AC/DC Off-Line LED Driver
The AL9910 is a cost-effective off-line buck LED driver-controller specifically designed for driving LED strings. It is suitable for being used with
either rectified AC line or any DC voltage between 15V to 500V. See Figure 3 for typical circuit.
LED +
D1
VAC IN
VDD
C1
BR1
VIN
C2
LD
C3
L1
LED -
AL9910/A
PWM_D
ROSC
GND
Q1
GATE
CS
RSENSE
ROSC
Figure 3. Typical Application Circuit (without PFC)
Buck Design Equations:
D=
VLEDs
VIN
t ON =
L≥
D
fosc
( VIN − VLEDs ) × t ON
0.3 × ILED
R SENSE =
0.25
where ILED x 0.3 = IRIPPLE
ILED + (0.5 × (ILED × 0.3))
AL9910/ AL9910A/ AL9910-5
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AL9910/ AL9910A/ AL9910-5
Applications Information (cont.)
Design Example
For an AC line voltage of 120V the nominal rectified input voltage VIN = 120V*1.41 = 169V. From this and the LED chain voltage the duty cycle
can be determined:
D = VLEDs /VIN = 30/169 = 0.177
From the switching frequency, for example fOSC = 50kHz, the required on-time of the external MOSFET can be calculated:
tON = D/fOSC = 3.5 µs
The value of the inductor for an LED current of 350mA is determined as follows:
L = (VIN - VLEDs) * tON /(0.3 * ILED) = 4.6mH
Input Bulk Capacitor
For Offline lamps an input bulk capacitor is required to ensure that the rectified AC voltage is held above twice the LED string voltage throughout
the AC line cycle. The value can be calculated from:
CIN ≥
PIN × (1 − D CH )
2 × VLINE _ MIN × 2fL × ΔVDC _ MAX
Where
Dch : Capacity charge work period, generally about 0.2 to 0.25
fL : Input frequency for full range (85 to 265VRMS)
ΔVDC _ MAX Should be set 10 to15% of
2 VLINE _ MIN
If the capacitor has a 15% voltage ripple then a simplified formula for the minimum value of the bulk input capacitor approximates to:
I
× VLEDs × 0.06
CMIN = LED
VIN 2
Power Factor Correction
If power factor improvement is required then for the input power less than 25W, a simple passive power factor correction circuit can be added to
the AL9910 typical application circuit. Figure 4 shows that passive PFC circuitry (3 current steering diodes and 2 identical capacitors) does not
significantly affect the rest of the circuit. Simple passive PFC improves the line current harmonic distortion and achieves a power factor greater
than 0.85.
Passive PFC
LED +
C4
C1
D1
VAC IN
VDD
BR1
LD
C2
C3
VIN
AL9910/A
PWM_D
ROSC
GND
Q1
LED L1
GATE
CS
RSENSE
ROSC
Figure 4. Typical Application Circuit with Passive PFC
Each of these identical capacitors should be rated for half of the input voltage and have twice as much capacitance as the calculated CMIN of the
buck converter circuit without passive PFC (see above section on bulk capacitor calculation).
For further design information please see AN75 from the Diodes website.
AL9910/ AL9910A/ AL9910-5
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AL9910/ AL9910A/ AL9910-5
Applications Information (cont.)
DC-DC Buck LED Driver
The design procedure for an ac input buck LED driver outlined in the previous chapters equally applies DC input LED drivers.
When driving long LED chains care should be taken not to induce SBO – maximum LED chain voltage should be less half of VIN. So either
maximum duty cycle should be kept below 50% or use of constant off-time removes this issue.
DC-DC Boost LED Driver
Due to the topology of the AL9910 LED driver-controller it is capable of being used in boost configurations – at reduced accuracy. The accuracy
can be improved by measuring the LED current with an op amp and use the op amp’s output to drive the LD pin.
A Boost LED driver is used when the forward voltage drop of the LED string is higher than the input supply voltage. For example, the Boost
topology can be appropriate when input voltage is supplied by a 48V power supply and the LED string consists of twenty HB LEDs, as the case
may be for a street light.
L1
VDD
C1
VIN
VIN
D1
Q1
AL9910/A
PWM_D
GATE
C2
LD
ROSC
CS
C3
GND
ROSC
RSENSE
Figure 5. Boost LED Driver
In a Boost converter, when the external MOSFET is ON the energy is stored in the inductor which is then delivered to the output when the external
MOSFET switches OFF. If the energy stored in the inductor is not fully depleted by the next switching cycle (continuous conduction mode) the DC
conversion between input and output voltage is given by:
VOUT =
V
− VIN
VIN
Î D = OUT
VOUT
1− D
From the switching frequency, fOSC, the on-time of the MOSFET can be calculated:
t ON =
D
fOSC
From this the required inductor value can be determined by:
L=
VIN ∗ t ON
0.3 ∗ ILED
The Boost topology LED driver requires an output capacitor to deliver current to the LED string during the time that the external MOSFET is on.
In boost LED driver topologies if the LEDs should become open circuit damage may occur to the power switch and so some form of detection
should be present to provide Over-voltage detection/protection.
AL9910/ AL9910A/ AL9910-5
Document number: DS35103 Rev. 8 - 2
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AL9910/ AL9910A/
A
A
AL9910-5
Ordering Information
n
A
AL9910
X XX XX - 13
Variant
Blank : 7.5V
7
VDD
A : 10V VDD
Part Numberr
AL9910-5S-13
AL9910-5SP-13
AL9910AS-13
AL9910ASP-13
AL9910S-13
AL9910SP-13
VCS Toleranc
ce
Pac
ckage
Blank : 10%
%
-5 : 5%
S : SO-8
SP : SO-8EP
VCS Tolerrance
ckage
Pac
C
Code
Packaging
±5%
±5%
±10%
%
±10%
%
±10%
%
±10%
%
S
SP
S
S
S
SP
S
S
SP
SO-8
SO-8EP
SO-8
SO-8EP
SO-8
SO-8EP
Packing
1 : 13” Tape
13
e & Reel
13” Tap
pe and Reel
Qua
antity
Part Numbe
er Suffix
2500/Tap
pe & Reel
-13
2500/Tap
pe & Reel
-13
2500/Tap
pe & Reel
-13
2500/Tap
pe & Reel
-13
2500/Tap
pe & Reel
-13
2500/Tap
pe & Reel
-13
Marking In
nformation
n
(1) SO-8
(2) SO-8EP
AL9910/ AL9
9910A/ AL9910-5
Document numberr: DS35103 Rev. 8 - 2
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AL9910/ AL9910A/ AL9910-5
Package Outline Dimensions (All dimensions in mm.)
Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version.
SO-8
0.254
(1)
E1 E
Gauge Plane
Seating Plane
A1
L
Detail ‘A’
7°~9°
h
45°
Detail ‘A’
A2 A A3
b
e
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°
θ
All Dimensions in mm
D
(2)
SO-8EP
Exposed Pad
8
5
E1
1
H
4
F
b
Bottom View
E
9° (All sides)
N
7°
A
e
D
A1
AL9910/ AL9910A/ AL9910-5
Document number: DS35103 Rev. 8 - 2
45°
Q
C
4° ± 3°
Gauge Plane
Seating Plane
E0
L
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SO-8EP (SOP-8L-EP)
Dim Min Max Typ
A 1.40 1.50 1.45
A1 0.00 0.13
b 0.30 0.50 0.40
C 0.15 0.25 0.20
D 4.85 4.95 4.90
E 3.80 3.90 3.85
E0 3.85 3.95 3.90
E1 5.90 6.10 6.00
e
1.27
F 2.75 3.35 3.05
H 2.11 2.71 2.41
L 0.62 0.82 0.72
N
0.35
Q 0.60 0.70 0.65
All Dimensions in mm
December 2012
© Diodes Incorporated
AL9910/ AL9910A/ AL9910-5
Suggested Pad Layout
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.
(1)
SO-8
X
Dimensions
X
Y
C1
C2
C1
Value (in mm)
0.60
1.55
5.4
1.27
C2
Y
(2)
SO-8EP
X2
Dimensions
C
X
X1
X2
Y
Y1
Y2
Y1
Y2
X1
Y
C
AL9910/ AL9910A/ AL9910-5
Document number: DS35103 Rev. 8 - 2
Value
(in mm)
1.270
0.802
3.502
4.612
1.505
2.613
6.500
X
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December 2012
© Diodes Incorporated
AL9910/ AL9910A/ AL9910-5
IMPORTANT NOTICE
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LIFE SUPPORT
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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
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use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
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representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2012, Diodes Incorporated
www.diodes.com
AL9910/ AL9910A/ AL9910-5
Document number: DS35103 Rev. 8 - 2
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December 2012
© Diodes Incorporated