MCT8317A datasheet(61/161 Pages) TI1

61 / 161 page

8.3.19.8 Lock Detection Current Limit (LOCK_ILIMIT)

The lock detection current limit function provides a configurable threshold for limiting the current to prevent

damage to the system. The MCT8317A continuously monitors the output of the current sense amplifier (CSA)

through the ADC. If at any time, the voltage on the output of CSA exceeds LOCK_ILIMIT for a time longer

than tLCK_ILIMIT, a LOCK_ILIMIT event is recognized and action is taken according to LOCK_ILIMIT_MODE. The

threshold is set through LOCK_ILIMIT, the tLCK_ILIMIT is set through LOCK_ILIMIT_DEG. LOCK_ILIMIT_MODE

can be set to four different modes: LOCK_ILIMIT latched shutdown, LOCK_ILIMIT automatic retry, LOCK_ILIMIT

report only and LOCK_ILIMIT disabled.

8.3.19.8.1 LOCK_ILIMIT Latched Shutdown (LOCK_ILIMIT_MODE = 00xxb)

When a LOCK_ILIMIT event happens in this mode, the status of MOSFETs will be configured by

LOCK_ILIMIT_MODE and nFAULT is driven low. Status of MOSFETs during LOCK_ILIMIT:

• LOCK_ILIMIT_MODE = 0000b: All MOSFETs are turned OFF.

• LOCK_ILIMIT_MODE = 0001b: MOSFET which was switching is turned OFF while the one which was

conducting stays ON till inductive energy is completely recirculated.

• LOCK_ILIMIT_MODE = 0010b: All high-side MOSFETs are turned ON.

• LOCK_ILIMIT_MODE = 0011b: All low-side MOSFETs are turned ON.

The CONTROLLER_FAULT and LOCK_ILIMIT bits are set to 1b in the fault status registers. Normal operation

resumes (gate driver operation and the nFAULT pin is released) when the LOCK_ILIMIT condition clears and a

clear fault command is issued through the CLR_FLT bit.

8.3.19.8.2 LOCK_ILIMIT Automatic Recovery (LOCK_ILIMIT_MODE = 01xxb)

When a LOCK_ILIMIT event happens in this mode, the status of MOSFETs will be configured by

LOCK_ILIMIT_MODE and nFAULT is driven low. Status of MOSFETs during LOCK_ILIMIT:

• LOCK_ILIMIT_MODE = 0100b: All MOSFETs are turned OFF.

• LOCK_ILIMIT_MODE = 0101b: MOSFET which was switching is turned OFF while the one which was

conducting stays ON till inductive energy is completely recirculated.

• LOCK_ILIMIT_MODE = 0110b: All high-side MOSFETs are turned ON

• LOCK_ILIMIT_MODE = 0111b: All low-side MOSFETs are turned ON

The CONTROLLER_FAULT and LOCK_ILIMIT bits are set to 1b in the fault status registers. Normal operation

resumes automatically (gate driver operation and the nFAULT pin is released) after the tLCK_RETRY (configured

by LCK_RETRY) time lapses. The CONTROLLER_FAULT and LOCK_ILIMIT bits are reset to 0b after the

tLCK_RETRY period expires.

8.3.19.8.3 LOCK_ILIMIT Report Only (LOCK_ILIMIT_MODE = 1000b)

No protective action is taken when a LOCK_ILIMIT event happens in this mode. The lock detection current limit

event is reported by setting the CONTROLLER_FAULT and LOCK_ILIMIT bits to 1b in the fault status registers.

The gate drivers continue to operate. The external controller manages this condition by acting appropriately.

The reporting clears when the LOCK_ILIMIT condition clears and a clear fault command is issued through the

CLR_FLT bit.

8.3.19.8.4 LOCK_ILIMIT Disabled (LOCK_ILIMIT_MODE = 1xx1b)

No action is taken when a LOCK_ILIMIT event happens in this mode.

8.3.19.9 Over Temperature Warning (OTW)

If the die temperature exceeds the over temperature warning limit (TOTW), all the FETs are

disabled and the nFAULT pin is driven low. In addition, the DRIVER_FAULT and OTW bits in the

GATE_DRIVER_FAULT_STATUS register are set to 1b. Normal operation resumes (driver operation and the

nFAULT pin is released) when the die temperature decreases below the hysteresis point of the over temperature

warning limit (TOTW - TOTW_HYS). The OTW bit stays latched high indicating that a thermal event occurred until a

clear fault command is issued through the CLR_FLT bit. This protection feature cannot be disabled.

www.ti.com

MCT8317A

SLLSFQ2 – JANUARY 2023

Submit Document Feedback

Product Folder Links: MCT8317A

MCT8317A Scheda tecnica(PDF) 61 Page - Texas Instruments

MCT8317A Scheda tecnica(HTML) 61 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Scheda tecnica Scarica

Link URL