SNVS039J June 2000 – April 2015 LM1086
PRODUCTION DATA.
A simple constant current source with protection can be designed by controlling the impedance between the lamp and ground. The LM1086-ADJ shown in Figure 24 makes use of an external TTL or CMOS input to drive the NPN transistor. This pulls the output of the regulator to a few tenths of a volt and puts the part into current limit. Releasing the logic will reduce the current flow across the lamp into the normal operating current thereby protecting the lamp during startup.