l9958 STMicroelectronics, l9958 Datasheet - Page 21

• Manufacturer Part Number: l9958
• Description: Low Rdson Spi Controlled H-bridge
• Manufacturer: STMicroelectronics

L9958
Figure 16. Open load in on state - Low-side current recirculation
5.2.5
5.2.6
LOW SIDE
RECIRCULATION
OL_ON
PWM
SPI activity
to write OL_ON Bit
FAULT
VOUTx
-0.7V
GND
This disable the turning on of the low-side drivers during current recirculation. The current
flows through the body diode of the low-side MOS for a fixed time. At the end of this fixed
time the Vout voltage is sampled and the possible open load condition detected (see
Figure
Over-temperature
When Twarn is reached, thermal current reduction is activated, and the information is
stored and latched. When Tsd is reached, the “TSD” bit is set and all output transistors are
put in tri-state conditions as long as a reset is applied.
Table 12.
Vs under-voltage shutdown
If the supply-voltage at the V
Vs_uv_off, the outputs are set to tri-state and the error bit "Undervoltage at V
A filtering time "Tuv_Vs" is implemented to avoid unwanted detection due to parasitic
glitches. The information is transferred into the SPI register in a bit called "VS_UV". This bit
is NOT latched. As soon as the voltage rises again above the Vs under-voltage threshold
(hysteresis implemented), the bridge is switched back to normal mode driven by DIR and
PWM. All the settings are kept as before the under-voltage event.
LS MOS
0 (default)
OFF
TSD
16).
1
Diangonsis OFF
LS MOS ON
set
Over-temperature
Tj > TSD
Tj < TSD
S
Doc ID 17269 Rev 1
pins falls below the under-voltage detection threshold
Tuc
Comments
Diangonsis ON
reset
set
OPEN LOAD OCCURRED!
Tuc
Diagnostics and protections
Bridge state
OPEN LOAD DETECTED!
Tri-state-
reset
-
LS MOS
S
OFF
" is set.
FSI
LS MOS
1
0
AC00666
ON
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