To eliminate the possibility of false detection, the TPS23882B uses a TI proprietary 4-point detection method to determine the signature resistance of the PD device. A false detection of a valid 25-kΩ signature can occur with 2-point detection type PSEs in noisy environments or if the load is highly capacitive.

Detection 1 and Detection 2 are merged into a single detection function which is repeated. Detection 1 applies I1 (160 μA) to a channel, waits approximately 60 ms, then measures the channel voltage (V1) with the integrating ADC. Detection 2 then applies I2 (270 μA) to the channel, waits another approximately 60 ms, then measures the channel voltage again (V2). The process is then repeated a second time to capture a third (V3) and fourth (V4) channel voltage measurements. Multiple comparisons and calculations are performed on all four measurement point combinations to eliminate the effects of a nonlinear or hysteretic PD signature. The resulting channel signature is then sorted into the appropriate category.