Preliminary Datasheet TLE6288 R

Vp2

Page 5

13.01.2003

Current Regulator : Peak current control with fixed off-time

Hold only : When the channel is turned on externally (SPI or parallel input) the current rises to the pro-

grammed hold current level. Then the channel is internally turned off and a timer is started for a con-

stant off-time (e.g. 200µs). After this time the channel is internally turned on again until the hold current

level is reached again and so on. This regulation workes automatically until the channel is turned of

externally.

Peak and hold mode with minimum peak time: When the channel is turned on the current rises to the

programmed peak current level. Then the channel is internally turned off, the current regulator changes

to hold current values and a timer is started for a constant off-time. After this time the channel is inter-

nally turned on again until the hold current value is reached and then again turned off for the fixed off

time. This regulation workes automatically until the channel is turned of externally.

Peak and hold mode with programmed peak time: When the channel is turned on the current rises to

the programmed peak current level. Then the channel is internally turned off and a timer is started for a

constant off-time. After this time the channel is internally turned on again until the peak current value is

reached and then again turned off. This works until the programmed peak time is over. Then the cur-

rent regulator changes to hold current values and workes as described under "hold only".

Peak Current, Peak Time, Hold Current and fixed Off-Time can be set via SPI.

To avoid regulation disturbances by current transients during switching (e.g. caused by ESD capacitors

at the outputs) the current regulator has a "leading edge blanking" of typical 20µs in all three regulation

modes. After turning on the DMOS (internally or externally) the current regulation circuit is deactivated

for the first 20µs. This guarantees that switching of the DMOS itself or charging of small capacitors at

the output (e.g. ESD) is not disturbing the current regulation.

Simplified functional block diagram: