AN3008 Datasheet, PDF (1/14 Pages) M/A-COM Technology Solutions, Inc. – Using the DR65-0109 to Drive SPDT PIN Switches

AN3008
Application note
STOD2540, single inductor DC-DC converter
generates multiple supply voltages for E-paper display
Introduction
This application note describes how to use the STOD2540 DC-DC converter to generate
two output voltages using a single inductor and an external charge pump. The circuit shown
in Figure 1 generates a 70 V output from a 3.7 V input voltage.
The STOD2540 is a highly integrated boost converter that can provide an adjustable output
up to 35 V from a 3.0 to 5.5 V input voltage.
The STOD2540 operates in PFM (pulsed frequency modulation) mode. PFM control simply
means that the part only switches when the charge needs to be delivered to the output in
order to keep the output voltage regulated.
The converter is ideal for generating the necessary voltages to supply thin-film transistor
(TFT) LCDs, OLEDs and E-paper shelf labels. The low operating supply current makes the
device ideal for small, portable, battery supplied applications. In shutdown mode the load is
disconnected from the input and the quiescent current is less than 3 µA.
Figure 1. High voltage power supply based on STOD2540
L1
C1
U1
1
VIN
D1
8
SW
CIN
7 _ENABLE
Vcap ⁶
C2
2 _RSET
Vo ⁵
3
AGND
FB ⁴
D2
9 ^PGND
STOD2540
D3
R3
550k
COUT
R4
CIN: 4.7μF
10k
COUT: 2 x 1 μF 100 V
C1: 100 nF 50 V
C2: 4.7 μF 50 V
L1: 4.7 μH
D1, D2, D3: STPS2L40AF
January 2010
Doc ID 16021 Rev 2
1/14
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