L9663 datasheet(21/104 Pages) STMICROELECTRONICS

21 / 104 page

DocID028693 Rev 1

21/104

L9663

Power supply

103

If an overcurrent condition on PSIx is detected, the current limitation is active and after a

filter time tfilt a fault bit is set and the interface is shut off. In order to switch on again, the

interface must be first switched off by SPI and then switched on, as for over temperature.

The channels’ switch off by overcurrent can be disabled if the corresponding bits

STG_MASK for every channel are set in the SPI registers.

During start up, a configurable blanking time is implemented (128 μs/5 ms/10 ms, see

BLANKING_SEL bits in SPI register); during this time current limitation is active, even

though the interface will not shut off for overcurrent, thermal shutdown is always active, the

PSI5 receiver is disabled, and some fault flags are masked (short to battery, under voltage,

leakage to ground).

The quiescent current is monitored for minimum and maximum value, depending on the

range selected by SPI (CH1_CR1, QC_SEL bits). In failure case the corresponding bit in the

diagnostic register is set (SR2).

The voltage at PSIx is compared with VAS to monitor short to battery condition: if an over

voltage occurs PSIx is disconnected from VAS and the corresponding bit in diagnostic

(OLx in SR2) after a transient time.

Figure 10. Block diagram Transceiver 1

L9663 数据表(PDF) 21 Page - STMicroelectronics