When CPU is running in turbo mode, the system peak power may exceed available power from adapter and battery together. The adapter current and battery discharge peak current, or system voltage drop is an indication that system power is too high. The charger processor hot function monitors these events, and PROCHOT pulse is asserted if the system power is too high. Once CPU receives PROCHOT pulse from charger, it slows down to reduce system power. The events monitored by the processor hot function include:

• ICRIT: adapter peak current, as 110% of I_LIM2
• INOM: adapter average current (110% of IIN_DPM)
• IDCHG1: battery discharge current level 1
• IDCHG2: battery discharge current level 2. Note that IDCHG2 threshold is always larger than IDCHG1 threshold, determined by IDCHG_TH2 register setting.
• VBUS_VAP: VBUS threshold to trigger PROCHOT in VAP mode
• VSYS: system voltage on VSYS.
• Adapter Removal: upon adapter removal (PROCHOT pin is one time falling edge trigger when VBUS falls below V_{VBUS_CONVENZ} threshold and deglitch time is within 1 μs. If triggered, STAT_ADAPTER_REMOVAL bit will be set to 1b, it will be high until clear through host read or REG_RESET bit. The status bit is level trigger which means if VBUS is still below V_{VBUS_CONVENZ} when status bit gets cleared, then the status bit should be triggered again immediately)
• Battery Removal: upon battery removal (PROCHOT pin is one time falling edge trigger when CELL_BATPRES pin voltage falls below V_{CELL_BATPRES_FALL} and deglitch time is within 1 μs. If triggered STAT_BATTERY_REMOVAL bit will be set to 1b, it will be locked until clear through host read or REG_RESET bit. The status bit is also falling edge trigger which means if CELL_BATPRES pin is still below V_{CELL_BATPRES_FALL} when status bit gets cleared, the status bit will still be cleared to 0b)
• CMPOUT: Independent comparator output (CMPOUT pin HIGH to LOW)
• VINDPM: VBUS lower than 83%/91%/100% of VINDPM setting. The effective threshold PROCHOT_VINDPM is determined by combination of register PROCHOT_VINDPM_80_90 bit and LOWER_PROCHOT_VINDPM bit:
  • PROCHOT_VINDPM=VINDPM register setting: LOWER_PROCHOT_VINDPM=0b;
  • PROCHOT_VINDPM=83% VINDPM register setting: LOWER_PROCHOT_VINDPM=1b;PROCHOT_VINDPM_80_90=0b;
  • PROCHOT_VINDPM=91% VINDPM register setting: LOWER_PROCHOT_VINDPM=1b;PROCHOT_VINDPM_80_90=1b;
• EXIT_VAP: Every time when the charger exits VAP mode.
• THERMAL: If enabled (PP_THERMAL=1b), then when the CMPIN_TR pin voltage is lower than V_{TREG_PP} for 1s/100ms (THERMAL_DEG bit configurable) deglitch time. Then STAT_THERMAL will be latched until clear through host read or REG_RESET bit.

The thresholds of ICRIT, IDCHG1,IDCHG2,VSYS or VINDPM, and the deglitch times of ICRIT, INOM, IDCHG1, IDCHG2, or CMPOUT are programmable. Except for the PROCHOT_EXIT_VAP which is always enabled, the other triggering events can be individually enabled in ProchotOption1[7:0], PP_IDCHG2 and PP_VBUS_VAP. When any enabled event in PROCHOT profile is triggered, PROCHOT is asserted low for a single pulse with minimal width  programmable in PROCHOT_WIDTH register bits. At the end of the single pulse, if the PROCHOT event is still active, the pulse gets extended until the event is removed.

If the PROCHOT pulse extension mode is enabled by setting EN_PROCHOT_EXT= 1b, the PROCHOT pin will be kept as low until host writes PROCHOT_CLEAR= 1b, even if the triggering event has been removed.

If the PROCHOT_VINDPM or PROCHOT_EXIT_VAP is triggered, PROCHOT pin will always stay low until the host clears it, no matter the PROCHOT is in one pulse mode or in extended mode. In order to clear PROCHOT_VINDPM, host needs to write 0 to STAT_VINDPM. In order to clear PROCHOT_EXIT_VAP, host needs to write 0 to STAT_EXIT_VAP.

Figure 7-10 PROCHOT Profile