收藏本站
GENERAL OVERVIEW
RDS ( ON ) ≤ ?
? = 0 . 42 Ohm
If ≥
? 1 ?
? × 0 . 35 A = 0 . 3 A
Note that in applications where duty cycle is
low, Schottky losses comprise a larger
percentage of converter losses. In order to
improve the efficiency in these applications
choose a Schottky that meets the calculated
current rating and has a lower V F .
Feedback resistor R FB
R FB is part of the SP7601 loop compensation
network. Use a 30k ? R FB for V IN of 20V and
larger. Use R FB of 60K ? for V IN less than 20V.
Capacitor C1
This is the decoupling capacitor for the power
supply to the internal driver. Use a 0.1 μ F
capacitor and place it as closely to the VDR
and V IN pins as possible.
4. R DS ( ON ) is calculated from equation (5):
? 350 mV ?
? 1 . 5 × 1 . 5 × 1 . 05 × 0 . 35 A ?
B VDSS should be at least 30V and Q GD should
be less than 10nC. An ANPEC APM4427K with
R DS (ON)=0.14 Ohm, B VDSS =30V and
Q GD =1.1nC can be used.
5. Schottky current rating I F can be calculated
from (6):
? 3 . 3 V ?
? 12 V ?
Voltage rating should be 30V. An SL03 rated at
30V/1.1A or equivalent can be used.
6. Calculate Rs from equation (2):
Design example- Design a drive circuit for a
0.35A LED with a 12V input voltage. Nominal
LED voltage is 3.3V.
Rs =
0.35 V ? ( 1.5 × 1 .05 × 0.525 A × 0.14 Ohm )
33 uA
= 7098 Ohm
1. Calculate R SET from equation (1):
Use the maximum recommended Rs of 3k ?
since the calculated value is larger.
Rset =
0 . 2 V
0 . 35 A
= 0 . 57 Ohm
VIN
M1, ANPEC APM4427K
30V, 0.14 Ohm
L1, COILTRONICS LD1-560
56uH, 0.5Arms
2. Calculate inductor value L1 from (3):
12V
2.2uF
2
3 . 3 V × ( 12 V ? 3 . 3 V )
L 1 = = 57 uH
12 V × 1 . 2 MHz × 0 . 035 A
A COILTRONICS LD-560 inductor rated at
56 μ H, 0.5A RMS and 0.57A SAT can be used.
GND
C1
0.1uF
1
3
Gate
Vin
SP7601
VDR
LX
FB
6
4
3k
D1, Vishay SL03
30V, 1.1A
LED1
GND
60k
3. Select input capacitor:
A 2.2 μ F C IN is needed as shown in table 1.
5
1N4148
Dimming and
Power sequencing
0.57 Ohm
From equation (4), the ripple current rating of
C IN is a fraction of 0.35A. A 2.2uF, 16V ceramic
capacitor easily meets this requirement and
offers low ESR and ESL.
Figure 4. Circuit schematic for design example
Sept25-07 Rev D
SP7601 29V High Voltage LED Driver
Page 7
? 2007 Exar Corporation
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
SP7616EB EVAL BOARD FOR SP7616
SP7648EB EVAL BOARD FOR SP7648
SP7685EB EVAL BOARD FOR SP7665
SP7686EB EVAL BOARD FOR SP7666
SPA6191 RELAY SSR 1A 240VAC SIP ZERO-X
SPFE480D25R RELAY SSR DC 480VAC 25A PCB
SR-7601 RELAY GEN PURPOSE 4PDT 2A 26.5V
SR-7602 RELAY GEN PURPOSE 4PDT 2A 26.5V
相关代理商/技术参数
SP7601EK1-L 功能描述:LED照明驱动器 High Curr DC-to-DC Buck LED Drvr 1.2MHz 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
SP7601EK1-L/TR 功能描述:LED照明驱动器 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
SP7606 制造商:EXAR 制造商全称:EXAR 功能描述:Wide Input Voltage Boost Controller
SP7606ER-L 制造商:EXAR 制造商全称:EXAR 功能描述:Wide Input Voltage Boost Controller
SP7606ER-L/TR 制造商:EXAR 制造商全称:EXAR 功能描述:Wide Input Voltage Boost Controller
SP7611A 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:2-4 Channel Low Dropout Linear LED Driver
SP7611A_07 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:2-4 Channel Low Dropout Linear LED Driver
SP7611AEC6 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:2-4 Channel Low Dropout Linear LED Driver