JAJSNM6F November 2004 – January 2022 TPS2384
PRODUCTION DATA
PMM Legacy function is used to detect PDs that are non compliant. Legacy detection uses a current source (typically 3.5 mA) as a test current while the A/D measures the average voltage for approximately 18 ms. The waveform shown in Figure 8-14 is the Legacy function charging a 10-μF capacitor. The capacitance charges to a value that is no greater than 20 V below the P port voltage. As the capacitor is charging the A/D is accumulating counts in the voltage A/D register. Figure 8-15 shows the relationship between port capacitance and the number of counts. A user can characterize non-compliant PD's signatures and use the Legacy function to recognize these devices.