Typical application circuit, Detailed description – Rainbow Electronics MAX17117 User Manual

Page 12

Internal-Switch Boost Regulator with Integrated

7-Channel Scan Driver, Op Amp, and LDO

MAX17117

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Typical Application Circuit

The MAX17117 typical application circuit (Figure 1) gen-
erates a +8.5V source-driver supply and approximately
+23V and -6V gate-driver supplies for TFT displays. The
input voltage range for the IC is from +2.3V to +5.5V,
but the circuit in Figure 1 is designed to run from 2.5V to
3.6V. Table 1 lists the recommended components and
Table 2 lists the component suppliers.

Detailed Description

The MAX17117 includes a high-performance step-up
regulator, a 350mA low-dropout (LDO) linear regulator,
a high-speed operational amplifier, and a high-voltage,
level-shifting scan driver with gate-shading control.
Figure 2 shows the functional diagram.

Step-Up Regulator

The step-up regulator employs a peak current-mode
control architecture with a fixed 1.2MHz switching fre-
quency that maximizes loop bandwidth and provides
a fast-transient response to pulsed loads found in
source drivers of TFT LCD panels. The high switching
frequency allows the use of low-profile inductors and
ceramic capacitors to minimize the thickness of LCD
panel designs. The integrated high-efficiency MOSFET
reduces the number of external components required.
The output voltage can be set from V

to 15V with an

external resistive voltage-divider.

Table 1. Component List

Table 2. Component Suppliers

DESIGNATION

DESCRIPTION

C1, C2

1FF

±10%, 16V X5R ceramic capacitors

(0603)
Murata GRM188R61C105K
TDK C1608X5R1C105K

10FF Q10%, 10V X5R ceramic capacitor
(0805)
TDK C2012X5R1A106K
Murata GRM21BR61A106K

C4, C5, C6

10FF Q10%, 16V X5R ceramic capaci-
tors (1206)
Murata GRM31CR61C106K
TDK C3216X5R1C106K

1A, 30V Schottky diode (S-Flat)
Central CMMSH1-40 LEAD FREE
Nihon EP10QY03
Toshiba CRS02 (TE85L, Q, M)

D2, D3, D4

200mA, 100V dual diodes (SOT23)
Fairchild MMBD4148SE (Top Mark: D4)
Central CMPD7000+ (Top Mark: C5C)

6.2V, 200mW zener diode (SOD-323)
ROHM UDZSTE-176.2B
Fairchild MM3Z6V2B

10FH, 1.85A, 74.4mI inductor (6mm x
6mm x 3mm)
Sumida CDRH5D28RHPNP-100M

SUPPLIER

WEBSITE

Central Semiconductor Corp.

www.centralsemi.com

Fairchild Semiconductor

www.fairchildsemi.com

Murata Electronics North America, Inc.

www.murata-northamerica.com

Nihon Inter Electronics Corp.

www.niec.co.jp

ROHM Co., Ltd.

www.rohm.com

Sumida Corp.

www.sumida.com

TDK Corp.

www.component.tdk.com

Toshiba America Electronic Components, Inc.