Datasheet
SLIS056A − FEBRUARY 1995 − REVISED MARCH 1996
10
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443
• HOUSTON, TEXAS 77251−1443
PRINCIPLES OF OPERATION
open-load/short-to-ground sensing
The TPIC2603 checks for open-load and short-to-ground conditions when the output is turned OFF. When the
output turns OFF, a 40-µA current source switches onto the drain. Under normal conditions, the load provides
adequate current to overcome the current source and the drain voltage remains above the open-load detection
threshold. When the output is open, then the current source pulls the drain low and an open-load condition is
flagged. The open-load test is enabled approximately 70 µs after the output turns OFF to allow the drain to
stabilize. Figure 6 illustrates device operation under open-load conditions.
t
(stb)
Glitches
Control
Register
DRAIN
Fault
Register
NORMAL
t
(stb)
OPEN-LOAD
Control
Register
DRAIN
Fault
Register
Figure 6. Open-Load Condition
over-voltage sensing and protection
The TPIC2603 monitors the V
bat
input terminal to protect the device and load from over-battery voltage
conditions. The device disables all of the drain outputs when V
bat
goes above 35 V. An over-battery voltage
hysteresis is provided to prevent the outputs from transiting ON and OFF erratically near the over-voltage
threshold. The device automatically returns to normal operation after the over-voltage condition has been
corrected. Figure 7 illustrates device operation under an over-battery voltage condition.
34 V
35 V
V
bat
(Typ)
All Drains
Fault Bit
Figure 7. Over-Battery Voltage Condition