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Ultra low noise application example
The document describes how to make a low noise LED driver, using MLX10803.
A combined stop, turn, tail lamp has been selected as an example. The demonstration lamp circuit
complies with the American (SAE) automotive standard for a tail light, using one light source for all three
functions. This example is similar to many applications currently in use today with LEDs. The applications
that exist on the market are using resistor or linear voltage drop regulators, and it will be easy to compare
the superior result from this application example with existing products.
Conventional switch regulator IC’s do not typically result in circuits that are suitable for use in noise
sensitive environments like an automobile. Many competitive, switched Buck topology regulators on the
market cannot meet the typical EMC requirements, but MLX10803 and MLX10801 contain features that
make it possible to design to an acceptable, low noise level. This document will show to achieve the
lowest noise level of CISPR25, class 5.
An engineer who follows the strategies described in this application note should be able you to make
good, low noise LED drivers for automotive applications, with good protection at a low cost. Many
applications do not need CISPR25 at the highest class 5. You can select to implement the appropriate
parts of the design that suit your situation. For more detailed help and information please contact your
closest Melexis representative or distributor.
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