SPSB081 datasheet(38/137 Pages) STMICROELECTRONICS

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3.19

Constant current mode

For the OUT1, OUT2, OUT3, and OUT4 high-side drivers, it is available the CCM (constant current mode)

feature, which is conceived to provide a constant current to the related output. The CCM feature is configurable

via SPI, by setting the OUTx_CCM_EN bit (x = 1, 2, 3, 4) in CR20; these bits can be set only if the related driver

is in OFF state and when the CCM is enabled, the overcurrent and short circuit detection of the related output is

switched OFF while its open load detection is always ON.

The CCM is automatically disabled after an expiration time tCCMTIMEOUT.

The allowed sequences are:

•

Set OUTx_CCM_EN bit, then turn ON the related driver by SPI (the other configurations of the OUTx_y

in CR5 are ignored): driver starts in CCM for tCCMTIMEOUT, then it switches to ON mode and the

OUTx_CCM_EN bit is automatically cleared;

•

If OUTx_CCM_EN = 1, after driver has been started in ON, PWM, timer modes then CCM bit is ignored;

•

If OUTx_CCM_EN bit is cleared by the microcontroller before timeout, then the driver is switched to ON

mode.

The short-circuit and overcurrent detection are enabled in ON, PWM, timer and DIR modes, but not in constant

current mode. The default value for the OUTx_CCM_EN bit is 0, that is, the CCM is disabled by default.

Figure 24. Constant current mode

SPSB081

Constant current mode

DS14048 - Rev 3

page 38/137

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