A8510 View Datasheet(PDF) - Allegro MicroSystems
Part Name
Description
MFG CO.
'A8510' PDF : 33 Pages View PDF
A8510
Wide Input Voltage Range, High Efficiency
Fault Tolerant LED Driver
When selecting the external PMOS, check for the following
parameters:
• Drain-source breakdown voltage V(BR)DSS > –40 V
• Gate threshold voltage (make sure it is fully conducting at
VGS = -4 V, and cut-off at –1 V)
• RDS(on): Make sure the on-resistance is rated at VGS = -4.5 V or
similar, not at -10 V; derate it for higher temperature
If the input current level goes above the preset current limit
threshold, the A8510 will shut down in less than 3 μs regardless
of user input (figure 29). This is a latched condition. The Fault
flag is also set to indicate a fault. This feature is meant to prevent
catastrophic failure in the system due to a short of the inductor or
output voltage to GND.
VIN
RSC
Q1 To L1
RADJ
VGATE
VSENSE
VIN
A8510
Figure 28. Typical circuit showing the implementation of the input
disconnect feature.
FAULT
C1
C2 VGATE
IIN
C3
C4 EN/PWM
A8510 shuts down
t
Figure 29. Diagram showing input disconnect current limit wave forms
during fault condition; shows ¯F¯¯A¯U¯¯L¯¯T¯ (ch1, 5 V/div.), VGATE (ch2,
10 V/div.), IIN (ch3, 2 A/div.), and EN/PWM (ch4, 5 V/div.), t = 5 μs/div.
Allegro MicroSystems, Inc.
20
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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