ZLED7022

Low-Voltage Six-Channel LED Driver

© 2010

Zentrum Mikroelektronik Dresden AG - Rev. 1.0

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The information furnished in this publication is subject to changes without notice.

Brief Description

The ZLED7022, one of our ZLED family of LED control

ICs, is a low-noise, constant-frequency charge pump

DC/DC converter that can drive up to six LED channels,

providing a programmable constant current level ranging

from 1.8mA to 20mA per LED channel. It can also drive

higher current LEDs because its current sinks can

operate in parallel. It enables white or other color LED

applications that require uniform intensity and/or linear

progressions in brightness. Capable of operating effi-

ciently with DC voltage supplies ranging from 2.8V to

5.5V, it is ideal for small, battery-powered applications

because very few external components are needed:

typically one small-dimension 1μF capacitor across the

C+ and C- pins and two small-dimension 2.2μF capaci-

tors to GND from the VCC and Vout pins.

The ZLED7022’s Pulse Count Control (PCC) serial digi-

tal input is used to enable/disable the LEDs and set the

current level (14 settings using a nearly logarithmic

scale to provide a linear brightness progression). This

simple, high-speed interface allows efficient real-time

management of LEDs via microcontrollers or control

systems.

The ZLED7022’s features include integrated soft-start

circuitry to protect against excessive in-rush current dur-

ing power-on and a low-current shutdown mode that

reduces quiescent current consumption to approximately

1μA (typical) by disconnecting the load from the input

when the EN/SET pin is low for a specified time.

Features

 Low quiescent current in low-current shutdown

mode: 1μA typical; <2μA maximum

 Integrated thermal shutdown protection prevents

damage by shutting down the ZLED7022 if the die

junction temperature exceeds 160°C (typical)

 Fixed charge pump switching frequency: 1MHz (typ.)

 Soft-start feature protects against excessive

inrush current during power-on

Benefits

 Current matching accuracy: ±0.9% (typical)

 One-pin on/off or brightness control for up to six

LEDs via a simple PCC serial interface—no pulse-

width modulation or additional control circuit needed

 14 programmable current levels for achieving real-

time control of effects such as LED fade-out or

sudden changes in brightness

 Low EMI and back-injected noise because the

charge pump is not inductor-based

 Very few external components needed for operation

 Flexible design enables diverse LED applications: up

to 20mA per channel

 LED driver family concept with low-voltage

four-channel LED driver ZLED7012

Available Support

 Evaluation Kit

Physical Characteristics

 Voltage supply: 2.8V to 5.5V DC

 Operating temperature: -40°C to 85°C

 Small footprint 12-pin UTQFN package (2mm×2mm)

ZLED7022 Application Circuit

Cin

Cout

.

12

n<=14

1μF

VCC

EN/SET

GND

C+

C-

Vout

D0

D1

D2

D3

D4

D5

2.8V to 5.5V

2.2μF

2.2μF

ZLED7022

Cpump