 2016 Microchip Technology Inc.

DS20005597A-page 1

AT9933

Features

• Constant Current LED Driver

• Steps Input Voltage Up or Down

• Low Electromagnetic Interference (EMI)

• Variable Frequency Operation

• Internal 75V Linear Regulator

• Input and Output Current Sensing

• Input Current Limit

• Enable and Pulse-width Modulation (PWM)

Dimming

• Ambient Temperature Rating of up to 125°C

Applications

• LED Lighting Applications

General Description

The AT9933 is a variable frequency PWM controller IC,

designed to control an LED lamp driver using a

low-noise

boost-buck

(Ćuk)

topology.

It

uses

patent-pending Hysteretic Current-mode control to

regulate both the input and the output currents. This

enables superior input surge immunity without the

necessity for complex loop compensation. Input

current control enables current limiting during Startup,

Input Undervoltage and Output Overload conditions.

The AT9933 provides a low-frequency PWM dimming

input that can accept an external control signal with a

duty cycle of 0%–100% and a high dimming ratio.

This AT9933-based LED driver is ideal for LED lamps.

The part is rated for up to 125°C ambient temperatures.

Package Type

REF

CS2

VDD

PWMD

VIN

CS1

GND

GATE

8

7

6

5

1

2

3

4

8-lead SOIC

(Top View)

See Table 2-1 for pin information.

Hysteretic Boost-Buck (Ćuk) LED Driver IC