Datasheet

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1 Applications
The TPS61185 is an excellent solution for computer notebook and monitor LCD display backlighting.
2 TPS61185EVM-335 Electrical Performance Specifications
Table 1 provides a summary of the TPS61185EVM-335 performance specifications. All specifications are
given for an ambient temperature of 25°C.
Table 1. TPS61185EVM-335 Electrical and Performance Specifications
Parameter Notes and Conditions
(1)
Min Typ Max Unit
Input Characteristics
V
IN
Input Voltage 7 24 V
En EN Logic high 2.1 20 V
PWM PWM Logic high 2.1 20 V
I
q_VIN
Input Quiescent Current Device enable, switching, f
S
= 1 MHz, V
IN
= 24 V; No load 0.5 3 mA
Input UVLO V
IN
ramp down 3.6 3.9 4.0 V
V
IN_UVLO
V ramp up 3.8 4.2
Output Characteristics
J6 connected to 10 WLED configured WLEDEVM-260, JP1 31 35 V
shorted, JP5-12 pins 1-2 shorted, EN/PWM = VDD
V
OUT
V(TP1)
J6 connected to 10 WLED configured WLEDEVM-260, JP1 open, 36 38 40 V
JP5-12 shorted, EN/PWM = VDD, OVP active
I
OUT
I(JP1) = 8 X IFBx V
IN
= 12 V, R
ISET
= 62 kΩ, PWM=VDD 155 mA
System Characteristics
f
S
Oscillator Frequency R
FSW
= 604 kΩ 0.8 1.0 1.2 MHz
(1)
The user can estimate the input current by solving the power balance equation, eff = P
OUT
/P
IN
= (V
O
× I
O
)/(V
IN
× I
IN
), for I
IN
and
estimating the efficiency to be a conservative 85%. For example, for V
O
= 32 V, V
IN
= 7 V and I
O
= 8 × 20 mA = 160 mA, I
IN
= (31
V × 160 mA)/(7 V × 0.85) = 0.83 A
3 Modifications
See the data sheet (SLVSAA1) when changing components such as R1 to set the LED current or R3 and
R4 to set the OVP threshold. To aid in such customization of the EVM, the board was designed with
devices having 0603 or larger footprints. A real implementation likely occupies less total board space.
Note that changing components can improve or degrade EVM performance. For example, using inductors
with larger saturation current rating allows the use of lower input voltages.
2
TPS61185EVM-335 SLVU308–May 2010
Copyright © 2010, Texas Instruments Incorporated