參數資料
型號: L5993
廠商: 意法半導體
英文描述: CONSTANT POWER CONTROLLER
中文描述: 恒功率控制器
文件頁數: 10/22頁
文件大小: 200K
代理商: L5993
Pin 5.
VFB (Error Amplifier Inverting Input). The
feedback signal is applied to this pin and is com-
pared to the E/A internal reference (2.5V). The
E/A output generates the control voltage which
fixesthe duty cycle.
The E/A features high gain-bandwidth product,
which allows to broaden the bandwidth of the
overall controlloop, high slew-rate and current ca-
pability, which improves its large signal behavior.
Usually the compensation network, which stabi-
lizes the overall control loop, is connected be-
tweenthis pin and COMP (pin 6).
Pin 6.
COMP (Error Amplifier Output). Usually,
this pin is used for frequency compensation and
the relevant network is connected between this
pin and VFB (pin 5). Compensation networks to-
wards ground are not possible since the L5993
E/A is a voltage mode amplifier (low output im-
pedance). See application ideas for some exam-
ple ofcompensationtechniques.
Pin 7.
SS (Soft-Start). At device start-up, a ca-
pacitor (Css) connected between this pin and
SGND (pin 12) is charged by an internal current
generator, ISSC, up to about 7V. During this
ramp, the E/A output is clamped by the voltage
across Css itself and allowed to rise linearly, start-
ing from zero, up to the steady-state value im-
posed by the control loop. The maximum time in-
terval during which the E/A is clamped, referredto
as soft-starttime, is approximately:
T
ss
3
R
sense
I
Qpk
I
SSC
C
ss
(6)
where R
sense
is the currentsense resistor (see pin
13) and I
Qpk
is the switch peak current (flowing
through R
sense
), which depends on the output
Figure 24. Hiccup modeoperation.
load. Usually, C
SS
is selected for a T
SS
in the or-
der of milliseconds.
As mentioned before, the soft-start intervenes
also in case of severe overload or short circuit on
the output. Referring to fig. 23, pulse-by-pulse
current limitation is somehow effective as long as
the ON-time of the power switch can be reduced
(from A to B). After the minimum ON-time is
reached (from B onwards) the current is out of
control.
To prevent this risk, a comparator trips an over-
current handling procedure, named ’hiccup’ mode
operation,when a voltage above 1.2V (point C) is
detected on current sense input (ISEN, pin 13).
Basically, the IC is turned off and then soft-started
as long as the fault condition is detected.As a re-
sult, the operating point is moved abruptly to D,
creating a foldback effect. Fig. 24 illustrates the
operation.
The oscillation frequency appearing on the soft-
V
OUT
T
ON
D.C.M.
C.C.M.
D
A
B
C
I
Qpk
T
ON(min)
1-2 ·I
Qpk
I
Qpk(max)
I
OUT
I
SHORT
I
OUT(max)
D97IN495
Figure23. Regulation characteristicand re-
latedquantities
7V
T
hic
time
SHORT
I
OUT
I
SEN
FAULT
SS
5V
0.5V
D98IN986
L5993
10/22
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相關代理商/技術參數
參數描述
L5993D 功能描述:開關變換器、穩(wěn)壓器與控制器 Prog Current Mode RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
L5993D013TR 功能描述:開關變換器、穩(wěn)壓器與控制器 Prog Current Mode RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
L5994 功能描述:電流型 PWM 控制器 Adj Triple Out Pwr RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14
L5994_02 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:ADJUSTABLE TRIPLE OUTPUT POWER SUPPLY CONTROLLER
L5994A 功能描述:監(jiān)控電路 ADJT TRIPLE OUTPUT POWER SUPPLY CNTLR RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數: 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關:No Backup 上電復位延遲(典型值):10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel