LR8
The minimum capacitance required for given boot-up time is
given by the following equation:
IPWM − ILIM
COUT > tBOOT
VHYS
where COUT = Capacitor at LR8 output
tBOOT = Time required for supply to bootstrap
IPWM = Current used by PWM controller
ILIM = LR8 current limit (10mA min)
VHYS = PWM controller UVL hysteresis
Remember that this equation is valid only when PWM current
exceeds the LR8’s current limit.
11/30/01rev.1
1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 744-0100 • FAX: (408) 222-4895
www.supertex.com
11