V
IN
SW
FB
EN
GND
L1
10 μH
D1
R1
2.2 MΩ
R2
160 kΩ
C
FF
22 pF
C2
1 μF
V
OUT
18 V
V
IN
1.8 V to 6 V
C1
4.7 μF
L1: Sumida CR32-100
D1: Motorola MBR0530
C1: Tayo Yuden JMK212BY475MG
C2: Tayo Yuden TMK316BJ105KL
TPS61040
Copyright © 2016, Texas Instruments Incorporated
11
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
8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The TPS6104x is designed for output voltages up to 28 V with an input voltage range of 1.8 V to 6 V and a
switch peak current limit of 400 mA (250 mA for the TPS61041). The device operates in a pulse-frequency-
modulation (PFM) scheme with constant peak current control. This control scheme maintains high efficiency over
the entire load current range, and with a switching frequency up to 1 MHz, the device enables the use of very
small external components. The following section provides a step-by-step design approach for configuring the
TPS61040 as a voltage regulating boost converter for LCD bias power supply, as shown in
Figure 12
.
8.2 Typical Application
The following section provides a step-by-step design approach for configuring the TPS611040 as a voltage
regulating boost converter for LCD bias supply, as shown in
Figure 12
.
Figure 12. LCD Bias Supply
8.2.1 Design Requirements
Table 2. Design Parameters
DESIGN PARAMETER
EXAMPLE VALUE
Input Voltage
1.8 V to 6 V
Output Voltage
18 V
Output Current
10 mA
8.2.2 Detailed Design Procedure
8.2.2.1 Inductor Selection, Maximum Load Current
Because the PFM peak current control scheme is inherently stable, the inductor value does not affect the stability
of the regulator. The selection of the inductor together with the nominal load current, input and output voltage of
the application determines the switching frequency of the converter. Depending on the application, inductor
values from 2.2
μ
H to 47
μ
H are recommended. The maximum inductor value is determined by the maximum on
time of the switch, typically 6
μ
s. The peak current limit of 400 mA/250 mA (typically) should be reached within
this 6-
μ
s period for proper operation.
