I
peak(typ)
I
LIM
V
IN
L
100 ns
I
peak(typ)
400 mA
V
IN
L
100 ns for the TPS61040-Q1
I
peak(typ)
250 mA
V
IN
L
100 ns for the TPS61041-Q1
=
=
=
+
+
+
×
×
×
+
+
-
RS Latch
Logic
S
R
Gate
Driver
_
Current Limit
Power MOSFET
N-Channel
R
SENSE
Soft
Start
6 s Max
m
On Time
V
REF
= 1.233 V
Error Comparator
400 ns Min
Off T ime
Under Voltage
Lockout
Bias Supply
VIN
FB
EN
GND
SW
Copyright © 2016, Texas Instruments Incorporated
9
TPS61040, TPS61041
www.ti.com
SLVS413I – OCTOBER 2002 – REVISED DECEMBER 2016
Product Folder Links:
TPS61040 TPS61041
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Copyright © 2002–2016, Texas Instruments Incorporated
7 Detailed Description
7.1 Overview
The TPS6104x is a high-frequency boost converter dedicated for small to medium LCD bias supply and white
LED backlight supplies. The device is ideal to generate output voltages up to 28 V from a dual-cell NiMH/NiCd or
a single cell device Li-Ion battery.
7.2 Functional Block Diagram
7.3 Feature Description
7.3.1 Peak Current Control
The internal switch turns on until the inductor current reaches the typical dc current limit (I
LIM
) of 400 mA
(TPS61040) or 250 mA (TPS61041). Due to the internal propagation delay of typical 100 ns, the actual current
exceeds the dc current limit threshold by a small amount. The typical peak current limit can be calculated:
(1)
The higher the input voltage and the lower the inductor value, the greater the peak.
By selecting the TPS6104x, it is possible to tailor the design to the specific application current limit requirements.
A lower current limit supports applications requiring lower output power and allows the use of an inductor with a
lower current rating and a smaller form factor. A lower current limit usually has a lower output voltage ripple as
well.
