a6280ees-t Allegro MicroSystems, Inc., a6280ees-t Datasheet - Page 9

• Manufacturer Part Number: a6280ees-t
• Description: 3-channel Constant-current Led Driver With Programmable Pwm Control
• Manufacturer: Allegro MicroSystems, Inc.

A6280
Undervoltage Lockout
The A6280 includes an internal undervoltage lockout (UVLO)
circuit that disables the driver outputs in the event of the logic
supply voltage dropping below a minimum acceptable level. This
prevents the display of erroneous information, a necessary func-
tion for some critical applications. The shift register will not shift
any data in a UVLO condition. Upon recovery of the logic supply
voltage and on power up, the internal shift register and all latches
will be set to zero.
Ballast Resistors
The voltage on the outputs should be kept in the range 1 to 3 V.
If the voltage goes below 1V, the current will begin to rolloff as
the driver runs out of headroom. At V
dissipation may become a problem, as each output contributes
V
power supply nominal voltage is chosen to keep the output volt-
age in this range. Alternatively, series resistors can be added to
dissipate the extra power and keep the output voltage within the
recommended range.
OUT
× I
LED
of power loss in the output sink driver. Typically the
OUT
above 3 V, the power
3-Channel Constant-Current LED Driver
with
Programmable
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
PWM Control
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