Datasheet
MAX17113
Low-Cost, Multiple-Output
Power Supply for LCD TVs
16 ______________________________________________________________________________________
Typical Operating Circuit
The typical operating circuit (Figure 1) of the
MAX17113 is a complete power-supply system for TFT
LCD panels in monitors and TVs. The circuit generates
a +3.3V logic supply, a +16V source driver supply, a
+34.5V positive gate driver supply, and a -6V negative
gate driver supply from a 12V ±10% input supply.
Table 1 lists some selected components and Table 2
lists the contact information for component suppliers.
Detailed Description
The MAX17113 is a multiple-output power supply
designed primarily for TFT LCD panels used in monitors
and TVs. It contains a step-down switching regulator to
generate the logic supply rail, a step-up switching regu-
lator to generate the source driver supply, and two
charge-pump regulators to generate the gate driver
supplies. Each regulator features adjustable output volt-
age, digital soft-start, and timer-delayed fault protection.
Both the step-down and step-up regulators use a fixed-
frequency current-mode control architecture. The two
switching regulators are 180° out-of-phase to minimize
the input ripple. The internal oscillator offers two pin-
selectable frequency options (450kHz/600kHz), allowing
users to optimize their designs based on the specific
application requirements. In addition, the MAX17113
features a high-voltage switch-control block, a PGOOD
logic block, an internal 5V linear regulator, a 1.25V refer-
ence output, well-defined power-up and power-down
sequences, and thermal-overload protection. Figure 2
shows the MAX17113 functional diagram.
Step-Down Regulator
The step-down regulator consists of an internal n-chan-
nel MOSFET with gate driver, a lossless current-sense
network, a current-limit comparator, and a PWM con-
troller block. The external power stage consists of a
Schottky diode rectifier, an inductor, and output capac-
itors. The output voltage is regulated by changing the
duty cycle of the n-channel MOSFET. A bootstrap cir-
cuit that uses a 0.1μF flying capacitor between LX2 and
BST provides the supply voltage for the high-side gate
driver. Although the MAX17113 also includes a 10Ω
(typ) low-side MOSFET, this switch is used to charge
the bootstrap capacitor during startup and maintains
fixed-frequency operation at light load and cannot be
used as a synchronous rectifier. An external Schottky
diode (D2 in Figure 1) is always required.
Table 1. Component List
DESIGNATION DESCRIPTION
C1, C2, C3
10μF ±20%, 16V X5R ceramic capacitors
(1206)
Taiyo Yuden EMK325BJ106MD
TDK C3225X7R1C106M
C5
22μF ±10%, 6.3V X5R ceramic capacitor
(1206)
Taiyo Yuden JMK316BJ226KL
Murata GRM31CR60J226M
C15, C16, C24
10μF ±20%, 25V X5R ceramic capacitors
(1210)
TDK C3225X5R1E106M
D1, D2
3A, 30V Schottky diodes (M-Flat)
Toshiba CMS02 (TE12L,Q)
Central Semiconductor
D3, D4, D5
200mA, 100V dual ultra-fast diodes
(SOT23)
Fairchild MMBD4148SE (top mark D4)
Central Semiconductor CMPD1001S lead
free (top mark L21)
L1
Low-profile 4.7μH, 3.5A inductor
(2mm height)
TOKO FDV0620-4R7M
L2
Low-profile 2.4μH, 2.6A inductor
(1.8mm height)
TOKO 1124BS-2R4M (2.4μH)
Würth 744052002 (2.5μH)
Table 2. Component Suppliers
SUPPLIER PHONE FAX WEBSITE
Fairchild Semiconductor 408-822-2000 408-822-2102 www.fairchildsemi.com
Sumida Corp. 847-545-6700 847-545-6720 www.sumida.com
TDK Corp. 847-803-6100 847-390-4405 www.component.tdk.com
Toshiba America Electronic Components, Inc. 949-455-2000 949-859-3963 www.toshiba.com/taec