ZHCSLM4B August 2020 – May 2024 LP8864S-Q1
PRODUCTION DATA
FAULT NAME | STATUS BIT | CONDITION | TRIGGER FAULT INTERRUPT | ENTER FAULT RECOVERY | ACTION |
---|---|---|---|---|---|
VIN undervoltage | VINUVLO_STATUS | UVLO voltage falls below 0.787V. | Yes | Yes | Device goes to standby and then attempts to restart once the input voltage rises above threshold. |
VIN overvoltage | VINOVP_STATUS | VIN voltage rises above 43V. | Yes | Yes | Device goes to standby and waits until input voltage falls below threshold before restarting. |
VDD undervoltage | VDDUVLO_STATUS | VDD level falls below VDDUVLO threshold. | Yes | No | Device restarts once VDD level rises above VDDUVLO threshold. |
VIN overcurrent | VINOCP_STATUS | Voltage across RISENSE exceeds 220mV. | Yes | Yes | Device goes to Fault Recovery and then attempts to restart 100ms after fault occurs. |
Charge pump fault | CP_STATUS | Charge pump voltage level is abnormal. | Yes | Yes | Device goes to Fault Recovery and then attempts to restart 100ms after fault occurs. |
Charge pump components missing | CPCAP_STATUS | Charge pump is missing components. | Yes | No | Charge pump is disabled. Charge pump fault will be reported. Device tries to keep normal operation. |
Boost sync clock invalid fault | BSTSYNC_STATUS | Device is enabled while a valid external SYNC clock is running. Then SYNC stops or changes to frequency < 75kHz. | Yes | No | Defaults to internal clock frequency selected by BST_FSET resistor. If BST_SYNC input is held high then spread spectrum is enabled. If BST_SYNC input is held low then spread spectrum is disabled. |
CRC error | CRCERR_STATUS | Factory default configuration for registers, options and trim bits are not correctly loaded from memory. | Yes | No | Device functions normally, if possible. |
Boost OVP low | BSTOVPLOW_STATUS | FB pin voltage rises above VFB_OVPL level. | No | No | Boost stops switching until boost voltage level falls. The device remains in normal mode with LED drivers operational. |
Boost OVP high | BSTOVPH_STATUS | FB pin voltage rises above VFB_OVPH level or DISCHARGE pin voltage rises above VBST_OVPH. | Yes | Yes | Device goes to Fault Recovery and waits until output voltage falls below threshold before restarting. |
Boost overcurrent | BSTOCP_STATUS | FB pin voltages falls below VUVP level for 110ms. | Yes | Yes | Device goes to Fault Recovery and then attempts to start 100ms after fault occurs. |
LEDSET detection fault | LEDSET_STATUS | LEDSET resistor missing or invalid. | No | No | Defaults to 4-channel / 150mA configuration. |
MODE detection fault | MODESEL_STATUS | MODE resistor missing or invalid. | No | No | Defaults to phase-shift PWM mode, I2C address is 0x3A. |
FSET detection fault | FSET_STATUS | BST_FSET or PWM_FSET resistor are missing or an invalid value. | No | No | Device keeps operating at 400-kHz switching frequency for boost converter and 305Hz for PWM dimming frequency. |
ISET resistor fault | ISET_STATUS | ISET pin voltage is pulled down to below 1V due to ISET pin resistor shorted to GND | Yes | No | LED_CURRENT[11:0] is written to 0x3FF. Total LED current limited to 70mA. |
Thermal shutdown | TSD_STATUS | Junction temperature rises above TSD threshold. | Yes | Yes | Device goes to standby and then attempts to restart once die temperature falls below threshold. |
Open LED string | LED_STATUS OPEN_LED | Headroom voltage on one or more channels is below minimum level and boost has adapted to maximum level. | Yes | No | Faulted LED string is disabled and removed from adaptive boost control loop. String is re-enabled next power cycle. |
LED internal short | LED_STATUS_SHORT_LED | Headroom voltage on one or more channels is above the SHORTED_LED_THRESHOLD for > 5ms while the headroom of at least one channel is still below this threshold. | Yes | No | Faulted LED string is disabled and removed from adaptive boost control loop. String is re-enabled next power cycle. |
LED short to GND | LED_STATUS_GND_LED |
During PL FET SOFT START, voltage of one or more used LED output is below VHEADROOM when small test current is injected. In BOOST_SU and Normal Stage, voltage of one or more used LED output is below VSHORTGND.and keeps still when the corresponding channel is off and small test current is injected. |
Yes | Yes | Device goes to Fault Recovery and then attempts to restart 100 ms after fault occurs. |
Invalid LED string detected | INVSTRING_STATUS | Configured unused LED output is detected not short to GND. | Yes | No | Device functions normally, if possible. |
I2C timeout | I2C_ERROR_STATUS | Device receives I2C command without STOP signal for 500ms. | Yes | No | Device functions normally and waits for the next I2C command. |