DS749A1

17

CS4412

4.5

Device Protection and Error Reporting

The CS4412 has built-in protection circuitry for over-current, under-voltage, and thermal warning/overload

conditions. The levels of the over-current error, thermal error, and VP under-voltage trip points are listed

in the PWM Power Output Characteristics table on page 6. Automatic shut-down will occur whenever any

of these preset thresholds are crossed.

Each error and warning pin implements an active-low open-drain driver and requires an external pull-up

for proper operation.

4.5.1

Over-current Protection

Over-current errors are reported on the ERROCx/y pins. For example, an over-current error on OUT1 is

reported by the ERROC1/2 pin. The power output of the channel which is reporting the over-current con-

dition will be set to high-impedance until the error condition has been removed and the RSTx/y signal for

that channel has been toggled from low to high.

4.5.2

Thermal Warning, Thermal Error, and Under-Voltage Error

Table 7 shows the behavior of the TWR and ERRUVTE pins. When the junction temperature exceeds the

junction thermal warning trip point, the TWR pin will be set low. If the junction temperature continues to

increase beyond the junction thermal error trip point, the ERRUVTE pin will be set low. If the voltage on

VP falls below the VP under-voltage error trip point, ERRUVTE will be set low.

When the thermal error or VP under-voltage trip point is crossed, all power outputs will be set to high-

impedance until the error condition has been removed and the RSTx/y signals have been toggled from

low to high.

ERROCx/y

Reported Condition

0

Over-current error on channel x or channel y.

1

Operating current of channel x and y within allowable limits.

Table 6. Over-current Error Conditions

TWR

ERRUVTE

Reported Condition

0

0

Thermal warning and thermal error and/or under-voltage error.

0

1

Thermal warning only.

1

0

Under-voltage error.

1

1

Junction temperature and VP voltage within normal limits.

Table 7. Thermal and Under-Voltage Error Conditions