TPIC44L01, TPIC44L02, TPIC44L03

4CHANNEL SERIAL AND PARALLEL LOW SIDE PREFET DRIVER

16

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

The TPIC44L01 and TPIC44L02 monitor the battery voltage to prevent the power FETs from being turned on

in the event that the battery voltage is too low. When the battery voltage is below 4.8 V, then GATE0–GATE3

may not provide sufficient gate voltage to the power FETs to minimize the on-resistance that could result in a

thermal stress on the FET. The output goes back to normal operation after the undervoltage condition has been

corrected. An under-battery voltage fault is flagged to the controller through FLT. The under-battery voltage fault

is not reported in the serial fault word. When an under-battery voltage condition occurs, the device reports the

battery fault but disables fault reporting for open- and shorted-load conditions. When the fault condition is

removed before the CS signal transitions low, the fault condition is not captured in the serial fault register. The

fault flag resets on a high-to-low transition of CS provided no other faults are present in the device. Figure 17

illustrates the operation of the under-battery voltage detection circuit.

_

+

VBAT

4.8 V

4.8 V

5 V

12 V

VBAT

GATE0–GATE3

Output Disable

U1

Figure 17