The internal round robin measurement scheme for the INA4235 is shown in Figure 6-1. For each channel the current, power, and energy registers are calculated from the shunt and bus voltage measurements and are not directly affected by ADC conversion times. Register values are updated for each channel before preceding to the next channel. When averaging is enabled, the registers for each channel updates once the number of averages is complete. Fault conditions are compared immediately after conversions or calculations based on the ADC conversion time and are independent of the number of averages set. Reducing the conversion times result in faster alert responses but at lower effective resolutions due to noise. Longer conversion times slow the alert response but are less sensitive to noise. Channels or measurements that are disabled are skipped in the round robin cycle. The conversion ready flag is set at the end of conversions after the selected number of averages are met.

Figure 6-1 Internal Measurement and Calculation Scheme

Current is calculated from the shunt voltage measurements and the value entered in the corresponding calibration register. Power is calculated based on the previous current calculation and the latest bus voltage measurement. Energy is accumulated by adding the previous power calculation multiplied by the current timebase interval. If the value loaded into the corresponding calibration register is zero, current, power, and energy values are reported as zero also. When the averaging is enabled, register values are updated once the number of averages are met. These calculations are performed in the background and do not add to the overall conversion time.