ZHCSIA0A May 2018 – November 2018 TAS3251
PRODUCTION DATA.
If a fault situation occurs while in operation, the device acts accordingly to the fault being a global or a channel fault. A global fault is a chip-wide fault situation and causes all PWM activity of the device to be shut down, and will assert FAULT low. A global fault is a latching fault and clearing FAULT and restarting operation requires resetting the device by toggling RESET. Deasserting RESET should never be allowed with excessive system temperature, so it is advised to monitor RESET by a system microcontroller and only allow releasing RESET (RESET high) if the CLIP_OTW signal is cleared (high). A channel fault results in shutdown of the PWM activity of the affected channel(s). Note that asserting RESET low forces the FAULT signal high, independent of faults being present.
Fault/Event | Fault/Event Description | Global or Channel | Reporting Method | Latched/Self Clearing | Action needed to Clear | Output FETs |
---|---|---|---|---|---|---|
PVDD_X UVP | Voltage Fault | Global | FAULT pin | Self Clearing | Increase affected supply voltage | HI-Z |
VDD UVP | ||||||
AVDD UVP | ||||||
POR (DVDD UVP) | Power On Reset | Global | FAULT pin | Self Clearing | Allow DVDD to rise | HI-Z |
BST_X UVP | Voltage Fault | Channel (Half Bridge) | None | Self Clearing | Allow BST cap to recharge (lowside ON, VDD 12V) | HighSide off |
OTW | Thermal Warning | Global | OTW pin | Self Clearing | Cool below OTW threshold | Normal operation |
OTE | Thermal Shutdown | Global | FAULT pin | Latched | Toggle RESET | HI-Z |
OLP (CB3C>1.7ms) | OC Shutdown | Channel | FAULT pin | Latched | Toggle RESET | HI-Z |
Latched OC (47kΩ<ROC_ADJ<68kΩ) | OC Shutdown | Channel | FAULT pin | Latched | Toggle RESET | HI-Z |
CB3C (22kΩ<ROC_ADJ<30kΩ) | OC Limiting | Channel | None | Self Clearing | Reduce signal level or remove short | Flip state, cycle by cycle at fs/3 |
Stuck at Fault(1) | No OSC_IO activity in Slave Mode | Global | None | Self Clearing | Resume OSC_IO activity | HI-Z |