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 (1000kHz)

• Integrated 40V power MOSFET

• Integrated 6-channel current sinks

− Up to 30mA/ch

− 0.5 Typ. current matching

− 2 Typ. current accuracy at 20mA

• Wide input PWM dimming frequency range

− 300Hz 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 62.5kHz or following input

PWM dimming frequency

− Channel current phase shift in fixed

62.5kHz 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

• TQFN33-16 and WLCSP-16 Package

• RoHS and Green Compliant

• -40°C to +85°C Temperature Range

Applications

• Tablet Backlight

• Netbook/Notebook Backlight

• Portable media players

Brief Description

KTD3156B 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. KTD3156B 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.

KTD3156B 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 62.5kHz

or following input PWM dimming frequency. For fixed

62.5kHz 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 KTD3156B,

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.

KTD3156B 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.