L6228PD datasheet(17/26 Pages) STMICROELECTRONICS

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L6228

Figure 20 shows the Overcurrent Detection operation. The Disable Time tDISABLE before recovering normal oper-

ation can be easily programmed by means of the accurate thresholds of the logic inputs. It is affected whether by

CEN and REN values and its magnitude is reported in Figure 21. The Delay Time tDELAY before turning off the

bridge when an overcurrent has been detected depends only by CEN value. Its magnitude is reported in Figure 22.

CEN is also used for providing immunity to pin EN against fast transient noises. Therefore the value of CEN

should be chosen as big as possible according to the maximum tolerable Delay Time and the REN value should

be chosen according to the desired Disable Time.

The resistor REN should be chosen in the range from 2.2KΩ to 180KΩ. Recommended values for REN and CEN

are respectively 100K

Ω and 5.6nF that allow obtaining 200µs Disable Time.

Figure 20. Overcurrent Protection Waveforms

ISOVER

IOUT

Vth(ON)

Vth(OFF)

VEN(LOW)

VDD

tOCD(ON)

tD(ON)EN

tEN(FALL)

tEN(RISE)

tDISABLE

tDELAY

tOCD(OFF)

tD(OFF)EN

VEN

BRIDGE

OFF

OCD

OFF

D02IN1400

L6228PD 数据表(PDF) 17 Page - STMicroelectronics