High-Power LED Driver with Integrated PWM Dimming MOSFET Driver

GENERAL DESCRIPTION

SM8205

FEATURES

● Wide input operating voltage range from 8V to 48V

● Internal 2% reference voltage

● Integrated PWM dimming N-channel MOSFET driver

● Dimming ratio: 1000:1

● 100KHz to 1MHz programmable high-frequency

operation

● Programmable slope compensation

● Input under-voltage protection

● LED short-circuit protection (SCP)

● LED open-voltage protection (OVP)

● Junction over-temperature shutdown protection

● Drivers LEDs in Boost, Buck-Boost, SEPIC Topology

● Cycle-by-cycle current limit

● Soft start

● Providing SOP-16 Package

● Single-string LED LCD backlighting

● High power LED drivers

● DC/DC Boost / Buck-Boost converter

● Automotive or Industrial

APPLICATIONS

TYPICAL APPLICATION CIRCUIT

www.samhop.com.tw

1

Rev. 2.0 @ 2011/10

The SM8205 is a current mode control wide-input

voltage (8V to 48V) LED driver IC specifically designed

to power one or multi-strings of high power LEDs. The

10V gate driver allow the use of standard level MOSFET

logic and also acts as a reference voltage to set the

current level. An external resistor sets the adjustable

switching frequency of the SM8205. The switching

frequency can be between 100KHz and 1MHz to

optimize efficiency, performance or external component

size. This controller uses a peak-current control scheme

(with programmable slope compensation), and includes

an internal transconductance amplifier to control the

output current in closed loop, enabling high output

current accuracy. Programmable MOSFET current limit

enables current limiting during input under-voltage and

output overload conditions. An internal 8V～48V linear

regulator powers the IC, elimination the need for a

separate power supply for the IC. The SM8205 provides

a TTL compatible PWM dimming input that can accept

an external control signal with a duty ratio of 0～100%

and frequency of up to a few kilohertz. The SM8205 also

provides a FAULT output which can be used to

disconnect the LEDs in case of a fault condition, using

an external disconnect N-channel MOSFET. The

SM8205 also offer the following protection functions:

LED open protection (OVP), LED short-circuit protection

(SCP), Junction over-temperature shutdown and input

under voltage lockout (UVLO).

L1

D1

Q1

Vin

8V to 48V

VCC

SS

RT

CLIM

PWMD

COMP

IREF

GND

FDBK

OVP

SC

FAULT

CS

GATE

VDD

VIN

5

6

7

8

9

10

11

13

12

14

15

16

Rcs

Q2

Rsc

Cout

Rsn

1

2

3

4