特性 Features

? Input voltage range: 2.7V to 5.5V

? Drive up to 60 LEDs (10S6P)

? High efficiency LED driver, up to 90

? High frequency step-up converter (940kHz)

? Integrated 40V power MOSFET

? Integrated 6-channel current sinks

? Up to 30mA/ch

? 0.5 Typ. current matching

? 2.0 Typ current accuracy at 20mA

? Wide input PWM dimming frequency range

? 100Hz to 30KHz

? Programmable Mixed-Mode Dimming controls

? Mixed analog dimming and PWM dimming

? Selectable transition point :

25 or 12.5 input PWM duty cycle

? Selectable output PWM dimming

frequency : fixed 22kHz or following input

PWM dimming frequency

? Channel current phase shift in fixed 22kHz

output PWM dimming mode

? Input PWM glitch filter

? LED open/short protection

? Adjustable over-voltage protection

? Cycle-by-cycle inductor current limit (2.5A)

? 0.1 μA shutdown current

? Pb-free TQFN33-16 and WLCSP-16 Package

? -40°C to +85°C Temperature Range

Applications

? Tablet Backlight

? Netbook/Notebook Backlight

? Portable media players

Brief Description

KTD3156 is the ideal power solution for LED backlighting

in medium to large size LCD panels. It is a highly integrated

step-up DC-DC converter with input voltage from 2.7V to

5.5V, accommodating 1-cell lithium ion batteries or 5V

supply. KTD3156 integrates a 40V power MOSFET as well

as six current sinks, which results in a simpler and smaller

solution with fewer external components. High switching

frequency allows the use of a smaller inductor and

capacitor to further reduce the solution size.

Each of the six current sinks regulates up to 30mA. With a

40V rated output, each string of the boost can connect up

to 10 LEDs in series, for a total of 60 LEDs.

KTD3156 features mixed-mode dimming, which switches

between PWM dimming at low dimming duty cycle and

analog (DC current) dimming at high dimming duty cycle to

increase the total power efficiency. The transition point of

these two modes is programmable to 12.5 or 25 PWM

duty cycle. The PWM dimming mode’s output PWM

dimming frequency can be programmed to fixed 22kHz or

following input PWM dimming frequency. For fixed 22kHz

output PWM dimming, phase shift function is implemented

among these six channels to further lower the input current

ripple and output voltage ripple.

Various protection features are built into KTD3156,

including cycle-by-cycle input current limit protection,

output over-voltage protection, LED fault (open or short)

protection and thermal shutdown protection. The leakage

current in shutdown mode is 0.1μA.

KTD3156 is available in a RoHS and Green compliant

16-lead 3 x 3 x 0.75mm ThinQFN or 16-lead 1.65mm x

1.65mm WLCSP package.