Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

ISL6336B Datasheet(PDF) 24 Page - Renesas Technology Corp

Part No. ISL6336B
Description  6-Phase PWM Controller with Light Load Efficiency Enhancement and Current Monitoring
Download  32 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  RENESAS [Renesas Technology Corp]
Direct Link  http://www.renesas.com
Logo RENESAS - Renesas Technology Corp

ISL6336B Datasheet(HTML) 24 Page - Renesas Technology Corp

Back Button ISL6336B Datasheet HTML 20Page - Renesas Technology Corp ISL6336B Datasheet HTML 21Page - Renesas Technology Corp ISL6336B Datasheet HTML 22Page - Renesas Technology Corp ISL6336B Datasheet HTML 23Page - Renesas Technology Corp ISL6336B Datasheet HTML 24Page - Renesas Technology Corp ISL6336B Datasheet HTML 25Page - Renesas Technology Corp ISL6336B Datasheet HTML 26Page - Renesas Technology Corp ISL6336B Datasheet HTML 27Page - Renesas Technology Corp ISL6336B Datasheet HTML 28Page - Renesas Technology Corp Next Button
Zoom Inzoom in Zoom Outzoom out
 24 / 32 page
background image
ISL6336B
FN6696 Rev 3.00
Page 24 of 32
May 5, 2016
Based on the VCC voltage, ISL6336B converts the TM pin
voltage to a 6-bit digital signal for temperature compensation.
With the non-linear A/D converter of ISL6336B, the TM digital
signal is linearly proportional to the NTC temperature. For
accurate temperature compensation, the ratio of the TM
voltage to the NTC temperature of the practical design should
be similar to that in Figure 15.
Depending on the location of the NTC and the air-flowing,
the NTC may be cooler or hotter than the current sense
component. The TCOMP pin voltage can be utilized to
correct the temperature difference between the NTC and the
current sense component. When a different NTC type or
different voltage divider is used for the TM function, the
TCOMP voltage can also be used to compensate for the
difference between the recommended TM voltage curve in
Figure 16 and that of the actual design. According to the
VCC voltage, ISL6336B converts the TCOMP pin voltage to
a 4-bit TCOMP digital signal as TCOMP factor N.
TCOMP factor N is an integer between 0 and 15. The
integrated temperature compensation function is disabled for
N = 0. For N = 4, the NTC temperature is equal to the
temperature of the current sense component. For N < 4, the
NTC is hotter than the current sense component. The NTC is
cooler than the current sense component for N > 4. When
N > 4, the larger TCOMP factor N, the larger the difference
between the NTC temperature and the temperature of the
current-sense component.
ISL6336B multiplexes the TCOMP factor N with the TM digital
signal to obtain the adjustment gain to compensate the
temperature impact on the sensed channel current. The
compensated channel current signal is used for droop and
overcurrent protection functions.
Design Procedure
1. Properly choose the voltage divider for TM pin to match
the TM voltage vs temperature curve with the
recommended curve in Figure 15.
2. Run the actual board under the full load and the desired
cooling condition.
3. After the board reaches the thermal steady state, record
the temperature (TCSC) of the current sense component
(e.g., inductor) and the voltage at TM and VCC pins.
4. Use Equation 23 to calculate the resistance of the TM
NTC, and find out the corresponding NTC temperature
TNTC from the NTC datasheet.
5. Use Equation 24 to calculate the TCOMP factor N:
6. Choose an integral number close to the above result for
the TCOMP factor. If this factor is higher than 15, use
N = 15. If it is less than 1, use N = 1.
7. Choose the pull-up resistor RTC1 (typical 10k);
8. If N = 15, do not need the pull-down resistor RTC2,
otherwise obtain RTC2 by Equation 25:
9. Run the actual board under full load again with the proper
resistors to TCOMP pin.
10. Record the output voltage as V1 immediately after the
output voltage is stable with the full load; Record the
output voltage as V2 after the VR reaches the thermal
steady state.
11. If the output voltage increases over 2mV as the
temperature increases, i.e. V2 - V1 >2mV, reduce N and
redesign RTC2; if the output voltage decreases over 2mV
as the temperature increases, i.e. V1 - V2 >2mV,
increase N and redesign RTC2.
A design spreadsheet is available to speed aid calculations.
External Temperature Compensation
By pulling the TCOMP pin to GND, the integrated
temperature compensation function is disabled. In addition,
one external temperature compensation network, shown in
Figure 18, can be used to cancel the temperature impact on
the droop (i.e. load line).
The sensed current will flow out of the FB pin and develop the
droop voltage across the resistor (RFB) between FB and
VDIFF pins. If the RFB resistance reduces as the temperature
increases, the temperature impact on the droop can be
compensated. An NTC thermistor can be placed close to the
power stage and used to form RFB. Due to the non-linear
temperature characteristics of the NTC, a resistor network is
needed to make the equivalent resistance between FB and
VDIFF pin reverse proportional to the temperature.
The external temperature compensation network can only
compensate the temperature impact on the droop, while it
has no impact to the sensed current inside ISL6336B.
Therefore this network cannot compensate for the
temperature impact on the overcurrent protection function.
RNTC T
NTC

VTMxRTM1
VCC V
TM
--------------------------------
=
(EQ. 23)
N
209x TCSC T
NTC

3xTNTC 400
+
-------------------------------------------------------- 4
+
=
(EQ. 24)
RTC2
NxRTC1
15 N
-----------------------
=
(EQ. 25)
FIGURE 18. EXTERNAL TEMPERATURE COMPENSATION
VDIFF
o
C
COMP
ISL6336B
INTERNAL
CIRCUIT
FB


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  31  32 


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
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