Datasheet

15
Atmel MSL3086/MSL3088 Datasheet
8-String 60mA LED Drivers with Integrated Boost Controller and Phase Shifted Dimming
8.11 Internal Supervisory and LDO
The MSL3086/88 have a Power-On-Reset circuit that monitors VIN and allows operation when VIN exceeds 4.25V. The MSL3086/88
have built-in LDOs that generate 2.5V to power the logic and oscillator sections. An integrated supervisor ensures that the LDO and
internal oscillator are stable before enabling the boost controller. The boost controller goes through a soft-start before the LED drivers are
enabled.
8.12 Internal Oscillator
The MSL3086/88 include a 20MHz internal oscillator that is divided down to drive the boost controller, and the LED PWM engine. The
oscillator is factory trimmed. Contact the factory if required to change the 20MHz default oscillator frequency, available frequencies fall
between 16MHz and 24MHz
8.13 Over Temperature Shutdown
The MSL3086/88 include automatic over-temperature shutdown. When the die temperature exceeds 135°C, the device turns off, as if EN
is pulled low, and is held off until the die temperature drops below 120°C, at which time it turns back on. While MSL3086/88 is in over-
temperature shutdown the onboard regulators are off, register values reset and the serial interface is disabled.
8.14 Power Saving Modes
The MSL3086/88 have 3 primary power save modes available through the I
2
C compatible serial interface. See the
MSL3040/50/60/80/86/87/88/89 Programming Guide for information.
8.15 I
2
C Serial Interface and Driver Control
The I
2
C serial interface allows control of PWM dimming, fault monitoring, and various other control functions. For a detailed explanation
of interface operation see the “MSL3040/50/60/80/86/87/88/89 Programming Guide”.