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參數(shù)資料
| 型號： | LM2753 |
| 廠商： | National Semiconductor Corporation |
| 元件分類： | LED驅動器 |
| 英文描述： | High Power Switched Capacitor Voltage Convertor/Flash LED Driver |
| 中文描述： | 高功率開關電容電壓轉爐/閃光燈LED驅動器 |
| 文件頁數(shù)： | 7/8頁 |
| 文件大?。?/td> | 520K |
| 代理商： | LM2753 |
Application Information
(Continued)
MULTI-LEVEL SWITCH ARRAY.
In order to supply high load currents across the entire V
IN
operating range, especially at lower V
IN
, switches in the
charge pump are normally designed to have low on-
resistance. However at high input voltages and low load
currents, this low resistance results in high output voltage
ripple due to the output capacitor being charged too quickly.
To solve this problem, while still being able to deliver the
needed output current, the LM2753 has a switch array with
multiple switches connected in parallel.
The number of switches used in parallel depends on the
input voltage applied to the LM2753. At lower input voltages
all paralleled switches are used, and as the input voltage
rises, switches are removed from the parallel configuration.
The highest switch resistance is achieved as the input volt-
age reaches the maximum operating voltage, which helps
with voltage management.
THERMAL PROTECTION
When the junction temperature exceeds 140C (typ.), the
LM2753 internal thermal protection circuitry disables the
part. This feature protects the device from damage due to
excessive power dissipation. The device will recover and
operate normally when the junction temperature falls below
125C (typ.). It is important to have good thermal conduction
with a proper layout to reduce thermal resistance.
POWER EFFICIENCY
Charge-Pump efficiency is derived in the following two ideal
equations (supply current and other losses are neglected for
simplicity):
I
IN
= G x I
OUT
E = (V
OUT
x I
OUT
) ÷ (V
IN
x I
IN
) = V
OUT
÷ (G x V
IN
)
In the equations, G represents the charge pump gain. Effi-
ciency is at its highest as G x V
approaches V
. Refer to
the efficiency graph in the
Typical Performance Character-
istics
section for the detailed efficiency data.
POWER DISSIPATION
The power dissipation (P
DISSIPATION
) and junction tempera-
ture (T
J
) can be approximated with the equations below. P
IN
is the product of the input current and input voltage, P
OUT
is
the power consumed by the load connected to the output,
T
A
is the ambient temperature, and
θ
JA
is the junction-to-
ambient thermal resistance for the LLP-10 package. V
IN
is
the input voltage to the LM2753, V
is the voltage at the
output of the device, and I
is the total current supplied to
the load(s) connected to both V
OUT
and I
OUT
.
P
DISSIPATION
= P
IN
- P
OUT
= (V
IN
x I
OUT
) (V
VOUT
x I
OUT
)
T
J
= T
A
+ (P
DISSIPATION
x
θ
JA
)
The junction temperature rating takes precedence over the
ambient temperature rating. The LM2753 may be operated
outside the ambient temperature rating, so long as the junc-
tion temperature of the device does not exceed the maxi-
mum operating rating of 120C. The maximum ambient tem-
perature rating must be derated in applications where high
power dissipation and/or poor thermal resistance causes the
junction temperature to exceed 120C.
L
www.national.com
7
相關PDF資料 |
PDF描述 |
|---|---|
| LM2753SDX | High Power Switched Capacitor Voltage Convertor/Flash LED Driver |
| LM2765 | Switched Capacitor Voltage Converter |
| LM2765M6 | Switched Capacitor Voltage Converter |
| LM2765M6X | Switched Capacitor Voltage Converter |
| LM2781 | Ultra-Low Ripple Switched Capacitor Voltage Inverter |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LM2753SD | 功能描述:LED照明驅動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:SO-16N |
| LM2753SD | 制造商:Texas Instruments 功能描述:VOLT CONV FLASH DRIVER POWERWISE |
| LM2753SD/NOPB | 功能描述:LED照明驅動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:SO-16N |
| LM2753SDX | 功能描述:LED照明驅動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:SO-16N |
| LM2753SDX/NOPB | 功能描述:LED照明驅動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:SO-16N |
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