Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

TK65433M Datasheet(PDF) 11 Page - TOKO, Inc

Part # TK65433M
Description  STEP-DOWN CONVERTER WITH BATTERY MONITOR
Download  28 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  TOKO [TOKO, Inc]
Direct Link  http://www.toko.com
Logo TOKO - TOKO, Inc

TK65433M Datasheet(HTML) 11 Page - TOKO, Inc

Back Button TK65433M Datasheet HTML 7Page - TOKO, Inc TK65433M Datasheet HTML 8Page - TOKO, Inc TK65433M Datasheet HTML 9Page - TOKO, Inc TK65433M Datasheet HTML 10Page - TOKO, Inc TK65433M Datasheet HTML 11Page - TOKO, Inc TK65433M Datasheet HTML 12Page - TOKO, Inc TK65433M Datasheet HTML 13Page - TOKO, Inc TK65433M Datasheet HTML 14Page - TOKO, Inc TK65433M Datasheet HTML 15Page - TOKO, Inc Next Button
Zoom Inzoom in Zoom Outzoom out
 11 / 28 page
background image
September 1999 TOKO, Inc.
Page 11
TK654xx
ADVANCED INFORMATION
THEORY OF OPERATION (CONT.)
cycle will be dependent upon the duration of the preceding
"on" cycle and the sensed input and the output voltages.
The approximate duration of the "off" cycle can be predicted
as follows:
T
OFF = TON X (VIN - VOUT) / VOUT
During the majority of the "off" cycle, a power switch is
turned on. The turn-on point of the switch is synchronized
with the initiation of the "off" cycle. The turn-off point is near
the end of the "off" cycle. The addition of this switch
reduces the voltage drop across the external rectifying
device and provides significant improvements in converter
efficiency.
BATTERY MONITOR SECTION
In a typical voltage monitor, which uses an external resistive
divider for setting the voltage monitor threshold, the input
bias current to the monitor pin is essentially zero. In this
type of scenario, the voltage on the monitor input would be
a resistively divided version of the battery voltage. The
Battery Monitor of the TK654xx introduces a small feedback
current (-I
LBI) which introduces a “plateau” into the transfer
characteristics between the battery voltage and the voltage
monitoring pin. The width of this plateau is dependent
upon the current range of the feedback current (-I
LBI) and
the values of the external resistor network. Figure 2
illustrates the typical relationship between the battery
voltage (V
IN), the feedback current (-ILBI) and the voltage
on the monitoring pin (V
LBI).
In selecting a resistor divider network, there are typically
two degrees of freedom when selecting values. The first
criteria in selecting the divider is the ratio of the two
resistors. Selecting the ratio defines the upper threshold of
the voltage monitor. The second degree of freedom when
selecting the resistor divider is the absolute resistance
values. This second degree of freedom can be utilized to
set a secondary monitoring threshold (V
OFF) lesser than
the first.
Typically, when the battery voltage is relatively high, the
voltage on the LBI input pin will be a resistively divided
version of the battery voltage.
As the battery voltage drops, the voltage on the V
LBI pin will
drop proportionately. When the voltage on the LBI input pin
passes through approximately 1.22 V, the output of the
first comparator (LBO) will transition from a high to a low
state and the synchronous rectifier N-channel MOSFET
will stop being switched. There is about 50 mV of hysteresis
between the LBO trip point and its reset point. Shortly after
the LBO output has been asserted, as the input voltage
continues to drop, the magnitude of the current out of the
V
LBI pin will begin to flow and proportionately increase as
the input voltage decreases. An op-amp feedback loop
internal to the Battery Monitor of the TK654xx will attempt
to maintain the voltage on the V
LBI pin at a constant value
of approximately 1.22 V (thus, the plateau). As the battery
voltage continues to drop, there comes a point where the
feedback current stops increasing at about 720 nA. At this
point, the voltage on the LBI pin will resume a proportional
drop with the input voltage and the TK654xx converter will
turn off.
For details on how to properly select the resistor divider,
refer to the “Design Considerations” section.
FIGURE 2: BATTERY MONITOR OPERATION
GRAPHS
VLBI
LBO
OFF
1.22 V
VLBO
VOFF
VIN
720 nA
0 nA
-ILBI


Similar Part No. - TK65433M

ManufacturerPart #DatasheetDescription
logo
TOKO, Inc
TK65010 TOKO-TK65010 Datasheet
51Kb / 8P
   BATTERY VOLTAGE MONITOR
TK65010TL TOKO-TK65010TL Datasheet
51Kb / 8P
   BATTERY VOLTAGE MONITOR
TK65015 TOKO-TK65015 Datasheet
116Kb / 8P
   STEP-UP VOLTAGE CONVERTER WITH VOLTAGE MONITOR
TK65015M TOKO-TK65015M Datasheet
116Kb / 8P
   STEP-UP VOLTAGE CONVERTER WITH VOLTAGE MONITOR
TK65015MBX TOKO-TK65015MBX Datasheet
116Kb / 8P
   STEP-UP VOLTAGE CONVERTER WITH VOLTAGE MONITOR
More results

Similar Description - TK65433M

ManufacturerPart #DatasheetDescription
logo
TOKO, Inc
TK653XX TOKO-TK653XX Datasheet
29Kb / 2P
   HIGH CURRENT STEP-UP CONVERTER WITH BATTERY MONITOR
logo
ams AG
AS1346 AMSCO-AS1346 Datasheet
657Kb / 16P
   Dual Step-Down Converter with Battery Monitoring
logo
Asahi Kasei Microsystem...
AK7903 AKM-AK7903 Datasheet
372Kb / 10P
   DCDC Step-down Converter for NiH2 Battery
logo
Maxim Integrated Produc...
MAX1774 MAXIM-MAX1774 Datasheet
398Kb / 21P
   Dual, High-Efficiency, Step-Down Converter with Backup Battery Switchover
19-1810; Rev 1; 1/02
logo
ams AG
AS7620 AMSCO-AS7620 Datasheet
623Kb / 2P
   500mA Hysteretic High Voltage Step-Down Converter with Dual Power Monitor
AS7620 AMSCO-AS7620_1 Datasheet
1Mb / 16P
   500mA Hysteretic High Voltage Step-Down Converter with Dual Power Monitor
logo
Analog Devices
ADP5303 AD-ADP5303 Datasheet
764Kb / 21P
   50 mA/500 mA, Ultralow Power Step-Down Regulator With Battery Voltage Monitor
Rev. B
ADP5302 AD-ADP5302 Datasheet
549Kb / 22P
   50 mA/500 mA, Ultralow Power Step-Down Regulator with Battery Voltage Monitor
Rev. B
logo
TOKO, Inc
TK65015 TOKO-TK65015 Datasheet
116Kb / 8P
   STEP-UP VOLTAGE CONVERTER WITH VOLTAGE MONITOR
TK65025 TOKO-TK65025 Datasheet
106Kb / 12P
   STEP-UP VOLTAGE CONVERTER WITH VOLTAGE MONITOR
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


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
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com