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參數(shù)資料
| 型號： | LT1950EGN |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Single Switch PWM Controller with Auxiliary Boost Converter |
| 中文描述： | 0.18 A SWITCHING CONTROLLER, 560 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | 0.150 INCH, PLASTIC, SSOP-16 |
| 文件頁數(shù)： | 12/20頁 |
| 文件大小： | 285K |
| 代理商： | LT1950EGN |
LT1950
12
sn1950 1950fs
N-channel power MOSFET even though V
IN
voltage is very
low. High GATE drive voltage reduces MOSFET R
DS(ON)
,
improves efficiency and increases the range of MOSFETs
that can be selected. A small switching regulator at the
BOOST pin, with fixed current limit and fixed off time,
generates the V
IN2
supply. With an external inductor
connected between the BOOST pin and V
IN
(see Figure 5),
the BOOST pin will draw current until approximately
125mA is reached, turn off for 0.5
μ
s and then turn back on.
The cycle is repeated for as long as the switcher is enabled.
By using a diode connected from BOOST to V
IN2
and a
capacitor from V
IN2
to ground, energy from the external
inductor is transferred to the V
IN2
capacitor during the off-
time of the internal switcher. An auxiliary boost converter
is realized providing a supply to the V
IN2
pin. The typical
inductor current, V
IN2
voltage and BOOST pin voltage
waveforms are shown in Figure 5. When V
IN2
reaches 11V,
the internal switcher is disabled. Since V
IN2
supplies the
output driver of the LT1950, switching at the GATE pin will
eventually discharge the V
IN2
capacitor until V
IN2
reaches
a lower level of approximately 10V. At this level the internal
switcher is re-enabled and switches until V
IN2
returns to
APPLICATIU
W
U
U
Figure 6. Oscillator Frequency (f
OSC
) vs R
OSC
R
OSC
(k
)
50
F
400 450 500
1950 F06
100 150
250
200
300 350
500
450
400
350
300
250
200
150
100
11V. This hysteretic (burst mode) operation for the inter-
nal switcher minimizes power dissipation from V
IN
.
The V
REF
output is a 2.5V reference supplying most of the
LT1950 control circuitry. It is available for external use
with maximum current capability of 2.5mA. The pin should
be bypassed to ground using a 0.1
μ
F capacitor. Internal
undervoltage lockout thresholds for V
IN
and V
IN2
of ap-
proximately 2.6V and 6.8V respectively must be exceeded
before V
REF
becomes active.
Programming Oscillator Frequency
The oscillator frequency of the LT1950 is programmed
using an external resistor connected between the R
OSC
pin
and ground. Figure 6 shows typical f
OSC
vs R
OSC
resistor
values. The LT1950 is programmable for a free-running
oscillator frequency in the range of 100kHz to 500kHz.
Stray capacitance and potential noise pickup on the R
OSC
pin should be minimized by placing the R
OSC
resistor as
close as possible to the R
OSC
pin and keeping the area of
the R
OSC
node as small as possible. The ground side of the
R
OSC
resistor should be returned directly to the GND
(analog ground) pin.
Figure 5. V
IN2
Generation Using the BOOST Pin
BOOST
LT1950
V
IN2
V
IN
L1
D1
C1
MIN
3V
5
μ
s/DIV
12
10
0.25
0
0.25
0
15
0
(V)
(V)
(A)
(A)
1950 F05
BOOST
V
IN2
I
D1
I
L1
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1950EGN#PBF | 功能描述:IC REG CTRLR PWM CM 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1950EGN#TR | 功能描述:IC REG CTRLR PWM CM 16-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1950EGN#TRPBF | 功能描述:IC REG CTRLR PWM CM 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1950IGN | 功能描述:IC REG CTRLR PWM CM 16-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1950IGN#PBF | 功能描述:IC REG CTRLR PWM CM 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,000 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:50% 電源電壓:9 V ~ 10 V 降壓:無 升壓:是 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:8-TSSOP（0.173"，4.40mm 寬） 包裝:帶卷 (TR) |
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