L99MM70XP datasheet(26/68 Pages) STMICROELECTRONICS

26 / 68 page

Protection and diagnosis

L99MM70XP

26/68

Doc ID 022637 Rev 2

Protection and diagnosis

4.1

Power supply fail

Overvoltage and undervoltage detection on VS (Power1).

4.1.1

Overvoltage

If the supply voltage VS rises above the overvoltage threshold (VSOV) for more than 56 µs

(typ.)

●

The outputs OUT1-9, ECV, ECFD and LIN are switched to high impedance state (load

protection). Electrochrome mode is switched off. If the bit OVUVR is set to 0, the

outputs are re-enabled automatically if the overvoltage condition is removed. If it is set

to 1, then the overvoltage bit has to be cleared to re-enable the outputs. LIN is always

automatically re-enabled.

●

The overvoltage bit is set and can be cleared with a “read and clear” command.

4.1.2

Undervoltage

If the supply voltage VS drops below the under voltage threshold voltage (VSUV) for more

than 56 µs (typ.)

●

The outputs OUT1-9, ECV, ECFD and LIN are switched to high impedance state.

Electrochrome mode is switched off. If the bit OVUVR is set to 0, the outputs are re-

enabled automatically if the under voltage condition is removed. If it is set to 1, then the

under voltage bit has to be cleared to re-enable the outputs. LIN is always automatically

re-enabled.

●

The under voltage bit is set and can be cleared with the “read and clear” command.

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