Moteur de recherche de fiches techniques de composants électroniques
  French  ▼
ALLDATASHEET.FR

X  

SI9122 Fiches technique(PDF) 10 Page - Vishay Siliconix

No de pièce SI9122
Description  500-kHz Half-Bridge DC-DC Converter With Integrated Secondary Synchronous Rectification Drivers
Download  17 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  VISHAY [Vishay Siliconix]
Site Internet  http://www.vishay.com
Logo VISHAY - Vishay Siliconix

SI9122 Fiches technique(HTML) 10 Page - Vishay Siliconix

Back Button SI9122 Datasheet HTML 6Page - Vishay Siliconix SI9122 Datasheet HTML 7Page - Vishay Siliconix SI9122 Datasheet HTML 8Page - Vishay Siliconix SI9122 Datasheet HTML 9Page - Vishay Siliconix SI9122 Datasheet HTML 10Page - Vishay Siliconix SI9122 Datasheet HTML 11Page - Vishay Siliconix SI9122 Datasheet HTML 12Page - Vishay Siliconix SI9122 Datasheet HTML 13Page - Vishay Siliconix SI9122 Datasheet HTML 14Page - Vishay Siliconix Next Button
Zoom Inzoom in Zoom Outzoom out
 10 / 17 page
background image
Si9122
Vishay Siliconix
www.vishay.com
10
Document Number: 71815
S-41944—Rev. F, 18-Oct-04
Current Limit
Current mode control providing constant current operation is
achieved by monitoring the differential voltage between the
CS1and CS2 pins which are connected across a primary
low-side sense resistor. Once this differential voltage exceeds
the 100-mV trigger point, the voltage on the CL_CONT pin is
pulled lower at a rate proportional to the excess voltage and the
value of the external capacitor connected between the
CL_CONT pin and ground. If the voltage between CS1 and CS2
exceeds 150 mV the CL_CONT capacitor is discharged rapidly
resulting in minimum duty cycle and frequency immediately.
Lowering the CL_CONT voltage results in PWM control of the
output drive being taken over by the current limit control loop.
Current control works to initially reduce the switching duty
cycle down to DMIN (12.5%). Further reduction in the duty
cycle is accompanied by a reduction in switching frequency at
a rate proportional to the duty cycle. This prevents the on time
of the primary drivers fnom from reducing below 100 ns and
avoiding a current tail. Frequency reduction occurs to a
maximum of one fifth of the nominal frequency.
With constant current mode control of on time and with
reduced operating frequency, protection of the MOSFET
switches is increased during fault conditions. Minimum duty
cycle and reduced frequency switching continues for the
duration of the fault condition. The converter reverts to voltage
mode operation immediately whenever the primary current
fails to reach the limit level. CL_CONT clamps to 6.5 V when not
in current limit.
The soft-start function does not apply under current limit as this
would constitute hiccup mode operation.
VIN Voltage Monitor –VINDET
The chip provides a means of sensing the voltage of VIN, and
withholding operation of the output drivers until a minimum
voltage of VREF (3.3 V, 300-mV hysteresis), is achieved. This
is achieved by choosing an appropriate resistive tap between
the ground and VIN, and comparing this voltage with the
reference voltage. When the applied voltage is greater than
VREF, the output drivers are activated as normal. VINDET also
provides the input to the voltage feed forward function.
However, if the divided voltage applied to the VINDET pin is
greater than VCC −0.3 V, the high-side driver, DH, will stop
switching until the voltage drops below VCC −0.3 V. Thus, the
resistive tap on the VIN divider must be set to accommodate
the normal VCC operating voltage to avoid this condition.
Alternatively, a zener clamp diode from VINDET to GND may
also be used.
Shutdown Mode
If VINDET is forced below the lower threshold, a minimum of
350 mV(VSD), the device will enter SHUTDOWN mode. This
powers down all unnecessary functions of the controller,
ensures that the primary switches are off and results in a low
level current demand from the VIN or VCC supplies.
CVCC
0.5 mF
CEXT
2 nF
GND
VCC
PNP Ext
REG_COMP
VREF
VIN
VINEXT
Figure 5.
High-Voltage Pre-Regulator Circuit
HVDMOS
14.5 V
REXT
(Si9122)
Auxillary
VCC
+
GM
CEXT
+
AV
AV 150 mV
+
GM
Peak Detect
Blank
CS1
CS2
IPD
0 − 240 mA (nom)
IPU
120 mA (nom)
AV
VOFFSET
OSC
CL_CLAMP
REXT
CL_CONT
Figure 6 .
Current Limit Circuit
AV 100 mV
VCC


Numéro de pièce similaire - SI9122

FabricantNo de pièceFiches techniqueDescription
logo
Vishay Siliconix
SI9122 VISHAY-SI9122 Datasheet
330Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
Rev. J, 14-Jan-08
SI9122 VISHAY-SI9122 Datasheet
322Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
01-Jan-2022
SI9122A VISHAY-SI9122A Datasheet
241Kb / 15P
   500-kHz Half-Bridge DC/DC Controller With Integrated Secondary Synchronous Rectification Drivers
Rev. A, 12-Sep-05
SI9122A VISHAY-SI9122A Datasheet
352Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
Rev. D, 14-Jan-08
SI9122A VISHAY-SI9122A Datasheet
386Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
01-Jan-2022
More results

Description similaire - SI9122

FabricantNo de pièceFiches techniqueDescription
logo
Vishay Siliconix
SI9122E VISHAY-SI9122E_V01 Datasheet
377Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
01-Jan-2022
SI9122A VISHAY-SI9122A_08 Datasheet
352Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
Rev. D, 14-Jan-08
SI9122A VISHAY-SI9122A Datasheet
241Kb / 15P
   500-kHz Half-Bridge DC/DC Controller With Integrated Secondary Synchronous Rectification Drivers
Rev. A, 12-Sep-05
SI9122 VISHAY-SI9122_V01 Datasheet
322Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
01-Jan-2022
SI9122 VISHAY-SI9122_08 Datasheet
330Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
Rev. J, 14-Jan-08
SI9122E VISHAY-SI9122E Datasheet
376Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
Rev. D, 21-Jan-08
SI9122A VISHAY-SI9122A_V01 Datasheet
386Kb / 20P
   500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers
01-Jan-2022
SI9123 VISHAY-SI9123 Datasheet
181Kb / 16P
   500-kHz Half-Bridge DC-DC Converter With Integrated Secondary Synchronous Rectification Control
Rev. B, 20-Mar-03
SI9124 VISHAY-SI9124 Datasheet
172Kb / 16P
   500-kHz Push-Pull DC-DC Converter With Integrated Secondary Synchronous Rectification Control
Rev. B, 20-Mar-03
logo
ON Semiconductor
MC33470 ONSEMI-MC33470_06 Datasheet
189Kb / 15P
   Synchronous Rectification DC/DC Converter Programmable Integrated Controller
August, 2006 ??Rev. 4
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17


Fiches technique Télécharger

Go To PDF Page


Lien URL




Politique de confidentialité
ALLDATASHEET.FR
ALLDATASHEET vous a-t-il été utile ?  [ DONATE ] 

À propos de Alldatasheet   |   Publicité   |   Contactez-nous   |   Politique de confidentialité   |   Echange de liens   |   Fabricants
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