AN1625 STMicroelectronics, AN1625 Datasheet - Page 11

• Manufacturer Part Number: AN1625
• Description: L6235 THREE PHASE BRUSHLESS DC MOTOR DRIVER
• Manufacturer: STMicroelectronics

2.9 Input Logic pins
H1, H2, H3, FWD/REV, BRAKE, ENABLE, are CMOS/TTL compatible logic input pins. The input comparator
has been realized with hysteresis to ensure the required noise immunity. Typical values for turn-on and turn-off
thresholds are V
electro-static discharge), and can be directly connected to the logic outputs of a µC; a series resistor is generally not
recommended, as it could help inducted noise to disturb the inputs. All logic pins enforce a specific behavior and can-
not be left unconnected. If connected to the DIAG pin, EN pin must be driven through a series resistor of 2.2 k min-
imum (for 5 V logic), to allow the voltage at the pin to be pulled below the turn-off threshold (see below).
Figure 10. Logic input pins.
2.10 DIAG pin
DIAG pin is an open-drain output pulled to GND in case of overcurrent or over temperature conditions. Connect-
ing this pin to EN will allow the internal open drain to disable all the power DMOS of the L6235, provided that
the EN pin is driven through a resistor (see Input Logic pins).
A capacitor (C1 in Figure 5 and Figure 11) connected between EN and DIAG pins and GND is also recommend-
ed, to reduce the r.m.s. value of the output current when overcurrent conditions persist (see Over Current Pro-
tection section).
Figure 11. DIAG pin.
TH(ON)
= 1.8 V and V
TH(OFF)
H1 , H2 H3 ,
FWD/REV , BRAKE ,
ENABLE
µC or Logic
Output
= 1.3 V. Pins are ESD protected (see Figure 10) (2kV human-body
R1
C1
Protection
ESD
DIAG
EN
5 V
AN1625 APPLICATION NOTE
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