Fault thresholds are set by programming the desired trip threshold into the corresponding fault register. Table 6-1 shows the list of supported fault registers.

An overcurrent threshold is set by programming the Current Over-Limit Threshold register (COL). The value that must be programmed into this register is calculated by dividing the overcurrent limit value by the current LSB size. For this example, the target value for the COL register is 9A ÷ 480μA = 18750d (493Eh).

An overvoltage fault threshold on the bus voltage is set by programming the bus overvoltage limit register (BOVL). In this example the desired overvoltage threshold is 14V. The value that must be programmed into this register is calculated by dividing the target threshold voltage by the bus voltage fault limit LSB value of 3.125mV. For this example, the target value for the BOVL register is 14V ÷ 3.125mV = 4480d (1180h).

When setting the power over-limit value, the LSB size used to calculate the value needed in the limit registers are 256 times greater than the power LSB. This is because the power register is a 24 bits in length while the power fault limit register is 16 bits. The LSB value to use for setting the over-power fault limit is 24.576mW.

Values stored in the alert limit registers are set to the default values after V_S power cycle events and must be reprogrammed each time power is applied.