參數(shù)資料
型號(hào): L6910A
廠商: STMICROELECTRONICS
元件分類: 穩(wěn)壓器
英文描述: 1.3 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
封裝: EXPOSED PAD, HTSSOP-16
文件頁數(shù): 15/30頁
文件大?。?/td> 763K
代理商: L6910A
L6910 - L6910A
22/29
10 APPLICATION IDEA 2: POSITIVE BUCK-BOOST REGULATOR 3V TO 13.2V
INPUT / 5V 2.5A OUTPUT
In some applications the input voltage changes in a very wide range while the output must be regulated to a
fixed value. In this case a Buck-Boost topology can be required in order to keep the output voltage in regulation.
The schematic below shows how to implement a Buck-Boost regulating 5V at the output from both 3.3V and 5V
and 12V input buses.
In a Buck-Boost topology the current is delivered to the output during the OFF phase only. So, for a given current
limit, the maximum output current depends strongly on the duty cycle. Assuming a 100% efficiency and neglect-
ing the current ripple across the inductor, the relationship betweent the current limit and the maximum output
current is the following:
Where ILIM is the current limit and D is the duty cycle of the application.
The worst case is with DMAX. Since, in a Buck-Boost application, D is given by the following formula:
The worst case is with VINMIN.
Obviously, since the efficiency is lower than 100% and the ripple is usually not negligible, the maximum output
current is always lower than the value calculated in the above formula
Figure 30. Positive buck-boost regulator 3V to 13.2V input / 5V 2.5A Output Circuit
I
OMAX
I
LIM
1D
()
=
D
V
O
V
IN
V
O
+
-----------------------
=
L1
R1
C1- C2
C3
Q2
Q1
D2
C6
13
14
10
11
3
1
U1
L6910/A
VIN (3.3V-5V-12V BUSES)
VOUT ( 5V 2.5A )
6
12
5
4
2
15
7
9
VCC
GND
VREF
SS
OSC
OCSET
UGATE
PHASE
LGATE
PGND
PGOOD
VF
B
CO
M
P
C9
C8
C4
D1
-14
C13-14
C13
GNDOUT
R2
C12
C7
C5
R7
C10
8
GNDIN
VCC (12V BUS)
R5
G1
R6
EAREF
BOOT
Q3
Q4
R3
R4
C11
GNDCC
相關(guān)PDF資料
PDF描述
L6910GTR 1.3 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
L6917BD SWITCHING CONTROLLER, 600 kHz SWITCHING FREQ-MAX, PDSO28
L6917BDTR SWITCHING CONTROLLER, 600 kHz SWITCHING FREQ-MAX, PDSO28
L6917D SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO28
L6918ADTR SWITCHING CONTROLLER, 1200 kHz SWITCHING FREQ-MAX, PDSO28
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L6910GTR 功能描述:電壓模式 PWM 控制器 Adjustable Step Down Controller RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
L6910R 功能描述:DC/DC 開關(guān)控制器 5.0 to 12V Step-Down RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
L6910RTR 功能描述:DC/DC 開關(guān)控制器 5.0 to 12V Step-Down RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK