6

General description

The STEC01 is an integrated low-side 12 mΩ N-channel power MOSFET used to protect applications where a big

amount of current flows from the battery to an actuator such as the heater inside an e-cigarette. The maximum

on-time can be configured for the actuator with a range from 5 s to 20480 s. Once the set time expires, the

actuator is disconnected from the GND path.

The device monitors the PWM activity and as soon as a rising edge is detected it exits the idle mode, turns the N-

channel power MOSFET on to connect the actuator to the GND path and starts the setting on-time timer (T1). As

soon as a falling edge on PWM is detected, a 285 ms timer (T2) is started and, if within such time no further PWM

activity is recognized, the N-channel MOSFET is turned off and the device enters idle mode till a new PWM signal

is detected (Figure 6. T1 vs RTPF- prescaler x1). Depending on the user's application, the device works with a

continuous or pulsed PWM signal.

If, for any reason, the PWM duration is longer than the value set for timer T1, a fault event is detected, the N-

channel MOSFET is turned off and a fault signal is generated. In order to exit fault mode, a stable low voltage

level on the PWM pin is required. Once the PWM goes low, T2 starts counting about 250 ms to make sure the

fault has been removed and as soon as it expires, the T3 timer is started. Timer T3 sets the cooling window

during which any new activity on the PWM pin is ignored and the internal N-channel power MOSFET is kept OFF

(T3 can be programmed to 69 s, 345 s or 1380 s). Once T3 expires, a new power cycle can be started by a valid

PWM signal.

The STEC01 is able to manage a continuous current up to 7 A through the internal power MOSFET. A higher

current can be supported by using an external N-channel power MOSFET driven through GDRV pin.

A rising edge on the HW_RESET input pin generates a 57 ms pulse on the RESET_FAULT pin that can be

detected by a dedicated MCU GPIO. This function can be used to notify the connection of an external power

source (e.g. USB).

6.1

T1 timer settings

selected. It allows the user to set T1 from 5 s to 20 s as reported in Figure 5. Timer configuration truth table.

0

5

10

15

20

25

50

100

150

200

250

300

350

400

450

For a longer setting time, please refer to the example below:

STEC01

General description

DS13063 - Rev 2

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