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| 型号： | XRP7604EDB-F |
| 厂商： | Exar Corporation |
| 文件页数： | 9/13页 |
| 文件大小： | 0K |
| 描述： | IC CONV PWM STP-DWN BUCK 8SOIC |
| 标准包装： | 46 |
| 恒定电流： | 是 |
| 拓扑： | 高端，PWM，降压（降压） |
| 输出数： | 1 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 通用 |
| 类型 - 次要： | 白色 LED |
| 频率： | 960kHz ~ 1.55MHz |
| 电源电压： | 4.5 V ~ 29 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm Width）裸露焊盘 |
| 供应商设备封装： | 8-SOIC |
| 包装： | 管件 |
| 其它名称： | 1016-1339-5 |
X R P 7 6 0 4
1 A 2 9 V N o n - S y n c . B u c k H i g h P o w e r L E D D r i v e r
100
90
80
70
60
50
40
30
20
10
0
LED current versus PWM Dimming Duty
100Hz 200Hz 500Hz 1kHz
after FB is set at the high state (>1.2V). The
regulator is now in standby and once Vin has
reached steady-state then FB is transitioned
from a high to a low state. The regulator then
starts operating at nominal frequency.
Another benefit of using power sequencing for
power up is that it ensures all internal circuitry
is alive and fully operational before the device
is required to regulate the current through the
LEDs. Since the regulator was “Off” before
power was applied, it is unlikely the LED is
under any type of thermal stress. EXAR does
not recommend using the XRP7604 in
applications where dimming of the LED is
achieved by PWM’ing the actual input power as
is common in automotive dimming
0
10
20
30
40
50
60
70
80
90
100
applications.
0 . 35 V ? ( 1 . 5 × 1 . 15 × I OCP × Rds ( on ))
33 μ A
(1-D) PWM Dimming Duty (%)
Fig. 16: Linearity, LED current vs (1-D) PWM Dimming
Duty Cycle, Vin=12V, Io=0.75A, 2 LED in series
M ODULATOR OPERATION AND POWER
SEQUENCING
The XRP7604 has a unique modulator design
which improves the device’s ability to operate
at very high duty cycle. While seamless in
operation as the duty cycle is increasing (input
voltage falling), when the duty cycle is
decreased (input voltage rising), the user will
observe the switching frequency increasing in
distinct fractions of the switching frequency. If
the device is operating at 100% duty cycle, a
unique advantage of using a p-channel pass
device, and then the input voltage is
increased, the frequency will start at 300kHz,
then 600kHz, and then finally 1.2MHz. The
frequency will tend to increase to the next
higher fraction once the duty cycle reaches 75
to 65 percent. This is the normal operation of
the device and should be expected. There is
no impact on the LED current accuracy. If
PWM dimming is being used as the input
voltage is increased, one will see the
frequency increasing when the duty cycle is <
90%. When power is initially applied the
device will begin operating as if the input
voltage is increasing and may start operation
at one of the fractional operating frequencies.
Many users will prefer to have the device start
operating at the nominal operating frequency,
thus it is recommended that Vin be applied
B UCK OPERATION WITHOUT OUTPUT
CAPACITOR
In order to be able to apply the
aforementioned dimming signal to the LED,
the output filter capacitor that is normally
used with a buck converter has to be removed
from the circuit. Thus the LED current ripple
equals the inductor current ripple. As a rule of
thumb current ripple should be limited to 10%
of ILED. Allowing for a higher current ripple,
up to 30%, while staying within LED
manufacturer ripple guidelines, will reduce
inductance and possibly inductor size.
O VERCURRENT PROGRAMMING
Resistor Rs can be used to program
Overcurrent Protection (OCP). Use the
following equation for calculating the Rs value.
Equ.2:
Rs =
Where Iocp is the programmed overcurrent
and is generally set 50% above nominal
output current, and Rds(on) = 135mohms.
Maximum value of Rs that can be used for
programming OCP is 4k.
I NDUCTOR SELECTION
Select the inductor L1 for inductance, Irms
and Isat. Calculate inductance from
? 2009 Exar Corporation
9/13
Rev. 1.0.0
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相关代理商/技术参数 |
参数描述 |
|---|---|
| XRP7604EDB-F/TR | 功能描述:电压模式 PWM 控制器 1A 29V Non-Sync Buck High Power RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| XRP7604EDBTR-F | 功能描述:LED照明驱动器 Power LED Driver RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| XRP7604EVB | 功能描述:电源管理IC开发工具 Eval Board for XRP7604 Series RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| XRP7613EVB | 功能描述:LED 照明开发工具 XRP7613 Eval Brd RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装: |
| XRP7613IDBTR-F | 功能描述:LED照明驱动器 1.2A 36V SD High Brightness LED Drvr RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
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