VNF9D5F datasheet(66/108 Pages) STMICROELECTRONICS

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Capacitive charging mode (CCM)

The capacitive charging mode (CCM) is an operative condition, available in both fail-safe and normal device

states, with channels configured in bulb mode. The procedure to enter CCM is described below:

•

Device in fail-safe mode:

–

If MCUext = 1, after 5 consecutive rising edges on DI0 and/or DI1 pins within 400 μs, the

corresponding channels will enter CCM, according to DIx OTP configuration.

–

If MCUext = 0, after 5 consecutive rising edges on DI1 pin within 400 μs, according to OTP mapping,

relevant channels shall enter CCM.

•

Device in normal mode:

–

Set the CAPCRx bit in the SOCR register to enter CCM.

The parameters related to CCM are reported in Table 67.

During CCM, the following behaviors are applied:

•

Harness protection is disabled.

•

Latch-off delay time after TSD (tD_RESTART) is disabled.

The CCM is automatically aborted after tCCM_DIS in both fail-safe and normal states. In normal mode the CCM

can be aborted also through an SPI communication, setting the EXIT_CAPCRx bit in the SOCR register,

whenever within the tCCM_DIS time frame.

The capacitive charging mode charges capacitors with a burst of ICCM pulses, provided that the total impedance

is low enough to reach ICCM when charging the capacitor. If ICCM is not reached, the capacitor is charged with a

single continuous charging pulse.

When a channel is set in capacitive charging mode and the output stage is turned on, an autorestart procedure is

started. If the ESR of the connected capacitor and the total output line impedance is low enough to let the channel

reach its ICCM value, the channel will turn off after the differential thermal threshold of ∆TPLIM_CCM has been

reached and autonomously turned on again after the differential thermal hysteresis goes below

∆TPLIM_CCM_HYST threshold. In this operating mode a smooth capacitor charging with low, moderate RMS

current is enabled allowing to disable the I²t wire harness protection IP in this channel operating mode. Thanks to

the lower values of ∆TPLIM_CCM and ICCM compared to normal operating mode, capacitor charging mode is

compatible with capacitors up to CMAX even in high ambient temperature conditions.

VNF9D5F

Capacitive charging mode (CCM)

DS13946 - Rev 8

page 66/108

VNF9D5F Datasheet(PDF) 66 Page - STMicroelectronics