Micrel, Inc.

MIC2298

October 2007

9

M9999-101707-B

Figure 7. LED Current vs. DC (on BRT pin)

Should the SS/DIM pin be used for voltage programming

the LED current, note that there will be a small offset due

mismatches between the 30k FB input and the

impedance driving the SS/DIM pin.

Soft Start Functionality

operation (typically 33nF); therefore, if any increases in

capacitor. The approximate total startup time is given by

the larger of: -

SS

SS

C

k

ms

T

⋅

+

=

175

1

Or

6

10

44

/

1

−

⋅

+

=

COMP

SS

C

ms

T

increase startup time from 1.75ms. The soft start

capacitor should be connected from the SS/DIM pin to

ground.