Motore di ricerca datesheet componenti elettronici
  Italian  ▼
ALLDATASHEETIT.COM

X  

L6997S Scheda tecnica(PDF) 10 Page - STMicroelectronics

Il numero della parte L6997S
Spiegazioni elettronici  STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS
Download  30 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Produttore elettronici  STMICROELECTRONICS [STMicroelectronics]
Homepage  http://www.st.com
Logo STMICROELECTRONICS - STMicroelectronics

L6997S Scheda tecnica(HTML) 10 Page - STMicroelectronics

Back Button L6997S Datasheet HTML 6Page - STMicroelectronics L6997S Datasheet HTML 7Page - STMicroelectronics L6997S Datasheet HTML 8Page - STMicroelectronics L6997S Datasheet HTML 9Page - STMicroelectronics L6997S Datasheet HTML 10Page - STMicroelectronics L6997S Datasheet HTML 11Page - STMicroelectronics L6997S Datasheet HTML 12Page - STMicroelectronics L6997S Datasheet HTML 13Page - STMicroelectronics L6997S Datasheet HTML 14Page - STMicroelectronics Next Button
Zoom Inzoom in Zoom Outzoom out
 10 / 30 page
background image
L6997S
10/30
so considering zero the output load the output voltage is given by:
(9))
indicating with Vout the final value, the output charging time can be estimated as:
(10)
the minimum CSS value is given imposing this condition:
Tout =TSS
(11)
4.5 Current limit
The current limit comparator senses the inductor current through the low side MOSFET RDSON drop and com-
pares this value with the ILIM pin voltage value. While the current is above the current limit value, the control
inhibits the high side MOSFET Turn On.
To properly set the current limit threshold, it should be noted that this is a valley current limit. The Average cur-
rent depends on the inductor value, VIN VOUT and switching frequency.
The average output current in current limit is given by:
(12)
Thus, to set the current threshold, choose RILIM according to the following equation:
(13)
In overcurrent conditions the system keeps the current constant until the output voltage meets the undervoltage
threshold. The negative valley current limit, for the sink mode, is set automatically at the same value of the pos-
itive valley current limit. The average negative current limit differs from the positive average current limit by the
ripple current; this difference is due to the valley control technique.
The current limit system accuracy is function of the precision of the resistance connected to the ILIM pin and
the low side MOSFET RDSON accuracy. Moreover the voltage on ILIM pin must range between 10mV and 1V
to ensure the system linearity.
Figure 9. Current limit schematic
V
out t,CSS
()
Qt,C
SS
()
C
out
-------------------------
R
ilim /Rdson
K
ILIM
I
SS
t
2
⋅⋅
()
C
out
V
SS
C
SS
2
⋅⋅
()
-----------------------------------------------------------------------------
==
V
out CSS
()
V
out
C
out
V
SS
C
SS
2
⋅⋅
⋅⋅
()
R
ilim /Rdson
K
ILIM
I
SS
⋅⋅
()
----------------------------------------------------------------------------
0.5
=
I
OUT
CL
I
max valley
I
2
-----
+
=
I
max valley
R
ILim
Rds
on
----------------- K
ILIM
=
Positive and negative current limit
R
ILIM
5µA
Current
Comparator
To
logic
PGN
D
PHASE
To inductor
LS


Codice articolo simile - L6997S

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
STMicroelectronics
L6997 STMICROELECTRONICS-L6997 Datasheet
291Kb / 23P
   STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS
L6997D STMICROELECTRONICS-L6997D Datasheet
291Kb / 23P
   STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS
L6997DTR STMICROELECTRONICS-L6997DTR Datasheet
291Kb / 23P
   STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS
More results

Descrizione simile - L6997S

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
STMicroelectronics
L6997 STMICROELECTRONICS-L6997 Datasheet
291Kb / 23P
   STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS
logo
Sipex Corporation
SP6121CN-L SIPEX-SP6121CN-L Datasheet
1Mb / 42P
   Low Voltage, Synchronous Step Down PWM Controller
logo
Maxim Integrated Produc...
MAX1637 MAXIM-MAX1637 Datasheet
211Kb / 20P
   Miniature, Low-Voltage, Precision Step-Down Controller
19-1321; Rev 1; 2/98
logo
Texas Instruments
TPS53124 TI-TPS53124 Datasheet
719Kb / 22P
[Old version datasheet]   Dual Synchronous Step-Down Controller For Low-Voltage Power Rails
TPS53127 TI-TPS53127 Datasheet
482Kb / 23P
[Old version datasheet]   DUAL SYNCHRONOUS STEP-DOWN CONTROLLER FOR LOW VOLTAGE POWER RAILS
TPS53126 TI-TPS53126 Datasheet
979Kb / 30P
[Old version datasheet]   DUAL SYNCHRONOUS STEP-DOWN CONTROLLER FOR LOW VOLTAGE POWER RAILS
TPS53125 TI-TPS53125 Datasheet
462Kb / 22P
[Old version datasheet]   DUAL SYNCHRONOUS STEP-DOWN CONTROLLER FOR LOW VOLTAGE POWER RAILS
TPS53015 TI-TPS53015_15 Datasheet
855Kb / 22P
[Old version datasheet]   Single Synchronous Step-down Controller for Low Voltage Power Rails
TPS53114 TI-TPS53114 Datasheet
789Kb / 20P
[Old version datasheet]   SINGLE SYNCHRONOUS STEP-DOWN CONTROLLER FOR LOW VOLTAGE POWER RAILS
TPS53015 TI-TPS53015 Datasheet
864Kb / 21P
[Old version datasheet]   Single Synchronous Step-down Controller for Low Voltage Power Rails
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30


Scheda tecnica Scarica

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEETIT.COM
Lei ha avuto il aiuto da alldatasheet?  [ DONATE ] 

Di alldatasheet   |   Richest di pubblicita   |   contatti   |   Privacy Policy   |   scambio Link   |   Ricerca produttore
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com