- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄67757 > LT1937ES5#TR (LINEAR TECHNOLOGY CORP) 0.32 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PDSO5 PDF資料下載
參數(shù)資料
| 型號： | LT1937ES5#TR |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.32 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PDSO5 |
| 封裝： | PLASTIC, TSOT-23, 5 PIN |
| 文件頁數(shù)： | 9/12頁 |
| 文件大小： | 355K |
| 代理商： | LT1937ES5#TR |
6
LT1937
1937f
LED Current Control
The LED current is controlled by the feedback resistor (R1
in Figure 1). The feedback reference is 95mV. The LED
current is 95mV/R1. In order to have accurate LED current,
precision resistors are preferred (1% is recommended).
The formula and table for R1 selection are shown below.
R1 = 95mV/ILED
(1)
Table 4. R1 Resistor Value Selection
ILED (mA)
R1 (
)
5
19.1
10
9.53
12
7.87
15
6.34
20
4.75
Open-Circuit Protection
In the cases of output open circuit, when the LEDs are
disconnected from the circuit or the LEDs fail, the feed-
back voltage will be zero. The LT1937 will then switch at
a high duty cycle resulting in a high output voltage, which
may cause the SW pin voltage to exceed its maximum 36V
rating. A zener diode can be used at the output to limit the
voltage on the SW pin (Figure 5). The zener voltage should
be larger than the maximum forward voltage of the LED
string. The current rating of the zener should be larger than
0.1mA.
APPLICATIO S I FOR ATIO
WU
UU
Dimming Control
There are four different types of dimming control circuits:
1. Using a PWM Signal to SHDN Pin
With the PWM signal applied to the SHDN pin, the LT1937
is turned on or off by the PWM signal. The LEDs operate
at either zero or full current. The average LED current
increases proportionally with the duty cycle of the PWM
signal. A 0% duty cycle will turn off the LT1937 and
corresponds to zero LED current. A 100% duty cycle
corresponds to full current. The typical frequency range of
the PWM signal is 1kHz to 10kHz. The magnitude of the
PWM signal should be higher than the minimum SHDN
voltage high. The switching waveforms of the SHDN pin
PWM control are shown in Figures 6a and 6b.
Figure 5. LED Driver with Open-Circuit Protection
200
s/DIV
1937 F06a
FB
100mV/DIV
SHDN
2V/DIV
(6a) 1kHz
20
s/DIV
1937 F06b
FB
100mV/DIV
SHDN
2V/DIV
(6b) 10kHz
Figure 6. PWM Dimming Control Using the SHDN Pin
PWM
LT1937
SHDN
VIN
SW
LT1937
L
22
H
COUT
0.22
F
CIN
1
F
1937 F05
VIN
SHDN
R1
6.34
R2
1k
FB
D
GND
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT1937ESC6#PBF | 0.32 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PDSO6 |
| LT3484EDCB-0#PBF | SPECIALTY ANALOG CIRCUIT, PDSO6 |
| LT3484EDCB-2#PBF | SPECIALTY ANALOG CIRCUIT, PDSO6 |
| LT3484EDCB-1#PBF | SPECIALTY ANALOG CIRCUIT, PDSO6 |
| LT3493EDCB#PBF | 2.2 A SWITCHING REGULATOR, 815 kHz SWITCHING FREQ-MAX, PDSO6 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1937ESC6 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:White LED Step-Up Converter in SC70 and ThinSOT |
| LT1937ESC6#PBF | 制造商:Linear Technology 功能描述:LED DRVR 6Segment 3.3V/5V/9V 6-Pin SC-70 制造商:Linear Technology 功能描述:SP-SWREG/LED Driver, CUT TAPE White LED Step-up Converter |
| LT1937ESC6#TR | 功能描述:IC LED DRVR WHITE BCKLGT SC-70-6 RoHS:否 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動器 系列:- 標準包裝:6,000 系列:- 恒定電流:- 恒定電壓:- 拓撲:開路漏極，PWM 輸出數(shù):4 內(nèi)部驅(qū)動器:是 類型 - 主要:LED 閃爍器 類型 - 次要:- 頻率:400kHz 電源電壓:2.3 V ~ 5.5 V 輸出電壓:- 安裝類型:表面貼裝 封裝/外殼:8-VFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-HVSON 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C 其它名稱:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| LT1937ESC6#TRM | 功能描述:IC LED DRVR WHITE BCKLGT SC-70-6 RoHS:否 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動器 系列:- 標準包裝:6,000 系列:- 恒定電流:- 恒定電壓:- 拓撲:開路漏極，PWM 輸出數(shù):4 內(nèi)部驅(qū)動器:是 類型 - 主要:LED 閃爍器 類型 - 次要:- 頻率:400kHz 電源電壓:2.3 V ~ 5.5 V 輸出電壓:- 安裝類型:表面貼裝 封裝/外殼:8-VFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-HVSON 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C 其它名稱:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| LT1937ESC6#TRMPBF | 功能描述:IC LED DRVR WHITE BCKLGT SC-70-6 RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動器 系列:- 標準包裝:6,000 系列:- 恒定電流:- 恒定電壓:- 拓撲:開路漏極，PWM 輸出數(shù):4 內(nèi)部驅(qū)動器:是 類型 - 主要:LED 閃爍器 類型 - 次要:- 頻率:400kHz 電源電壓:2.3 V ~ 5.5 V 輸出電壓:- 安裝類型:表面貼裝 封裝/外殼:8-VFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-HVSON 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C 其它名稱:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。