Motore di ricerca datesheet componenti elettronici
  Italian  ▼
ALLDATASHEETIT.COM

X  

L6995STR Scheda tecnica(PDF) 7 Page - STMicroelectronics

Il numero della parte L6995STR
Spiegazioni elettronici  LOSSLESS CURRENT LIMIT
Download  26 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Produttore elettronici  STMICROELECTRONICS [STMicroelectronics]
Homepage  http://www.st.com
Logo STMICROELECTRONICS - STMicroelectronics

L6995STR Scheda tecnica(HTML) 7 Page - STMicroelectronics

Back Button L6995STR Datasheet HTML 3Page - STMicroelectronics L6995STR Datasheet HTML 4Page - STMicroelectronics L6995STR Datasheet HTML 5Page - STMicroelectronics L6995STR Datasheet HTML 6Page - STMicroelectronics L6995STR Datasheet HTML 7Page - STMicroelectronics L6995STR Datasheet HTML 8Page - STMicroelectronics L6995STR Datasheet HTML 9Page - STMicroelectronics L6995STR Datasheet HTML 10Page - STMicroelectronics L6995STR Datasheet HTML 11Page - STMicroelectronics Next Button
Zoom Inzoom in Zoom Outzoom out
 7 / 26 page
background image
Obsolete
Product(s)
- Obsolete
Product(s)
7/26
L6995S
quency after a load transient as well as to mask PWM comparator output against noise and spikes.
The system has not an internal clock, because this is a hysteretic controller, so the turn on pulse will start if three
conditions are met contemporarily: the FB pin voltage is lower than the reference voltage, the minimum off time
is passed and the current limit comparator is not triggered (i.e. the inductor current is below the current limit
value). The voltage on the OSC pin must range between 50mV and 2V to ensure the system linearity.
4.2 Closing the loop
The loop is closed connecting the output voltage (or the output divider middle point) to the FB pin. The FB pin
is linked internally to the comparator negative pin and the positive pin is connected to the reference voltage
(0.9V Typ.) as in Figure 2. When the FB goes lower than the reference voltage, the PWM comparator output
goes high and sets the flip-flop output, turning on the high side MOSFET. This condition is latched to avoid noise
spike. After the on-time (calculated as described in the previous section) the system resets the flip-flop and then
turns off the high side MOSFET and turns on the low side MOSFET. Internally the device has more complex
logic than a flip-flop to manage the transition in correct way. For more details refers to the Figure 3.
The voltage drop along ground and supply metals connecting output capacitor to the load is a source of DC
error. Further the system regulates the output voltage valley value not the average, as in the Figure 5 is shown.
So the voltage ripple on the output capacitor is a source of DC static error (as the PCB traces). To compensate
the DC errors, an integrator network must be introduced in the control loop, by connecting the output voltage to
the INT pin through a capacitor and the FB pin to the INT pin directly as in Figure 6. The internal integrator am-
plifier with the external capacitor CINT1 introduces a DC pole in the control loop. CINT1 also provides an AC path
for output ripple.
Figure 6. Valley regulation
The integrator amplifier generates a current, proportional to the DC errors, that increases the output capacitance
voltage in order to compensate the total static errors. A voltage clamper within the device forces INT pin voltage
ranges from VREF-50mV, VREF+150mV. This is useful to avoid or smooth output voltage overshoot during a load
transient. Also, this means that the integrator is capable of recovering output error due to ripple when its peak-
to-peak amplitude is less than 150mV in steady state.
In case of the ripple amplitude is larger than 150mV, a capacitor CINT2 can be connected between INT pin and
ground to reduce ripple amplitude at INT pin, otherwise the integrator can operate out of its linear range. Choose
CINT1 according to the following equation:
Eq 5
where GINT=50 µs is the integrator transconductance,
αOUT is the output divider ratio given from Eq4 and FU
is the close loop bandwidth. This equation also holds if CINT2 is connected between INT pin and ground. CINT2
is given by:
Time
Vout
Vref
<Vout>
DC Error Offset
C
INT1
g
INT
α
OUT
2
π F
u
⋅⋅
-------------------------------
=


Codice articolo simile - L6995STR

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
STMicroelectronics
L6995 STMICROELECTRONICS-L6995 Datasheet
336Kb / 25P
   STEP DOWN CONTROLLER FOR HIGH DIFFERENTIAL INPUT-OUTPUT CONVERSION
L6995D STMICROELECTRONICS-L6995D Datasheet
336Kb / 25P
   STEP DOWN CONTROLLER FOR HIGH DIFFERENTIAL INPUT-OUTPUT CONVERSION
L6995DTR STMICROELECTRONICS-L6995DTR Datasheet
336Kb / 25P
   STEP DOWN CONTROLLER FOR HIGH DIFFERENTIAL INPUT-OUTPUT CONVERSION
More results

Descrizione simile - L6995STR

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Maxim Integrated Produc...
MAX8537EVKIT MAXIM-MAX8537EVKIT Datasheet
228Kb / 11P
   Lossless Adjustable Hiccup Current Limit
Rev 0; 7/04
logo
Richtek Technology Corp...
RT2530Q RICHTEK-RT2530Q Datasheet
141Kb / 10P
   Current Limit
logo
Advanced Monolithic Sys...
AMS3131 ADMOS-AMS3131 Datasheet
319Kb / 9P
   Current Limit protection
AMS3132 ADMOS-AMS3132 Datasheet
439Kb / 10P
   Current Limit protection
logo
STMicroelectronics
STEVAL-ISA052V2 STMICROELECTRONICS-STEVAL-ISA052V2 Datasheet
137Kb / 4P
   Negative current limit
May 2008 Rev 1
logo
M.S. Kennedy Corporatio...
MSK146 MSK-MSK146_15 Datasheet
246Kb / 8P
   Programmable Current Limit
logo
STMicroelectronics
STEVAL-ISA052V1 STMICROELECTRONICS-STEVAL-ISA052V1 Datasheet
123Kb / 4P
   Negative current limit
November 2010 Rev 1
logo
Unisonic Technologies
LR1112G-XX-AE5-R UTC-LR1112G-XX-AE5-R Datasheet
177Kb / 6P
   Current limit protection
logo
Texas Instruments
PT5071-12V TI1-PT5071-12V Datasheet
150Kb / 4P
[Old version datasheet]   Output Current Limit
logo
Solid State Optronic
AD4C111-L SSOUSA-AD4C111-L_15 Datasheet
221Kb / 5P
   Current Limit Protection
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


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