ZLED7012

Low-Voltage Four-Channel LED Driver

Data Sheet

November 9, 2010

© 2010

Zentrum Mikroelektronik Dresden AG — Rev. 1.0

All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without

the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.

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The current sinks [D3:D0] are controlled by the PCC serial data input on the EN/SET pin. Data is written to an internal data

register that sets the outputs to one of 14 current levels. The Vout pin provides a shared supply voltage for the LEDs. The

capacitor across the C+ and C- pins is the “pump capacitor” used by the charge pump.

2.3.

ZLED7012 Soft-Start Feature

The soft-start feature protects against excessive inrush currents during the start-up of the charge pump circuit. This prevents

potential transient noise effects that can affect initial performance, especially in battery-operated applications toward the end of

the battery life.

2.4.

ZLED7012 Low-Current Shutdown Mode

internal data register that controls output current is reset to 0, which disables the outputs.

2.5.

LED Current Control

The ZLED7012’s Pulse Count Control (PCC) serial digital interface is used to enable/disable the LED outputs and set the

constant current level to one of 14 settings using a nearly logarithmic scale (approximately 1.5dB difference between settings)

to provide a linear brightness progression as the current level increases/decreases. See Table 2.1 for the current level

settings.

Because [D3:D0] are independent constant current sinks, the voltage at the LED output being driven is determined by the

Table 2.1

Current Output Settings

Data Level

Current Output per Channel (mA)

1

20.0

2

17.0

3

14.0

4

12.0

5

10.0

6

8.6

7

7.0

8

6.0

9

5.0

10

4.2

11

3.6

12

3.0

13

2.4

14

1.8