Micrel Inc.

MIC4802

January 2011

6

M9999-013111-B

Functional Diagram

Figure 1. MIC4802 Functional Block Diagram

Functional Description

The MIC4802 is a single channel linear LED driver with a

maximum 800mA current capability. The LED driver is

designed to maintain proper current regulation with LED

current accuracy of ±10%. The dropout is 280mV at

800mA. The low dropout of the linear drivers allows the

LEDs to be driven directly from the battery voltage and

eliminates the need for boost or large and inefficient

charge pumps. The maximum LED current for each

channel is set via an external resistor. Dimming is

controlled by applying a PWM signal to the EN pin. The

MIC4802 accommodates a wide PWM frequency range

as outlined in the application information section.

Block Diagram

As shown in Figure 1, the MIC4802 consists of current

The linear LED drivers have a designated control block

for enabling and dimming of the LEDs. The MIC4802

dimming is controlled by the Ultra Fast PWM

block that receives PWM signals for dimming.