Datasheet - STEC01 - Ground path safety switch with programmable timers
Document overview
- Manufacturer or author: STMICROELECTRONICS
- PDF pages: 22
Technical content
Datasheet sections
- 1 Block diagram
- 2 Pin configuration
- 3 Typical application diagram
- 4 Maximum ratings
- 5 Electrical characteristics
- 6 General description
- 6.1 T1 timer settings
- 6.2 Timer expiration: normal mode
- 6.3 T1 timer expiration: fault mode
- 6.4 HW_RESET functionality
- 7 Typical performance characteristics
- 8 Package information
Features
- Input voltage range from 2.2 to 5 V
- 12 mΩ typ. N-channel FET R DS(on)
- 7 A continuous current capability
- PWM control signal from 4 Hz to 5 kHz, with 30% to 100% duty cycle
- 30 µA battery supply current
- 2 programmable timers: T1, T3
- 1 fixed timer T2
- Input undervoltage lockout
- VFQFPN 3x3x0.9 16L, 0.5 mm pitch package
Applications
- Electronic cigarettes
- Timing/reset circuitry
- Ground path protection circuitry
Description
The STEC01 is an integrated programmable 12 mΩ power switch managed by the timer based circuitry. The device has 3 timers designed to interrupt the ground path of a power application after a maximum on-time and inhibits the restart of the platform during a cooling window. The maximum on-time can be set from few seconds to hundreds of seconds, while the cooling window can be programmed to 69, 345 and 1380 seconds. 3 multi-level input pins, combined with a programmable oscillator and a fixed oscillator, are used to set the timing. An input continuous or pulsed signal applied to the PWM pin starts the internal logic and counters. In case of a normal operation, as soon as the activity on the PWM pin stops, the device automatically enters idle mode, waiting for a new valid PWM signal to be applied. If the device detects a fault condition, a reset pulse is generated and the safety MOSFET is turned off and managed according to a predefined state machine. The STEC01 has a continuous current capability up to 7 A through the internal power MOSFET. A higher current can be supported by using an external power transistor driven through GDRV pin. A rising edge on the HW_RESET input pin generates a 57 ms pulse on the RESET_FAULT pin. This function can be used to notify the connection of an external power source (e.g. USB). Product status link STEC01 Product summary Order code STEC01PUR Package VFQFPN 3x3x0.9 16L Ground path safety switch with programmable timers STEC01 Datasheet DS13063 - Rev 2 - October 2020 For further information contact your local STMicroelectronics sales office.
1 Block diagram
Figure 1. Block diagram
2 Pin configuration
Figure 2. Pin configuration Table 1. Pin configuration
3 Typical application diagram
Figure 3. Typical application diagram, Iload up to 7 A Figure 4. Typical application diagram, Iload > 7 A, external MOSFET
4 Maximum ratings
Table 2. Absolute maximum ratings Table 3. Thermal data
5 Electrical characteristics
TA = 25 °C, VBAT = 3.7 V, CBAT = 1 μF, T1P1=T1P2=GND, RTPF = 100 kΩ, T3P = GND, unless otherwise specified. Table 4. Electrical characteristics
Electrical characteristics
Symbol Parameter Test conditions Min. Typ. Max. Unit VPT Programming threshold pins VIH, input logic high Applies to T1P1, T1P2, T3P V1.9 IPT Programming input pins leakage current Applies to T1P1, T1P2, T3P. VPT=5 V 1 µA Timer accuracy T1P1,T1P2=GND, RTPF =91 kΩ 4 5 6 sT2 0.250 0.285 0.330 T3 T3P=GND 60 69 80 OTP Overtemperature protection PWR OFF 160 OTP_HYST OTP hysteresis PWR ON 20 1. Guaranteed by design. Figure 5. Timer configuration truth table
0 Floating
1 Floating
Note: See Section 6.1 T1 timer settings for more details.
6 General description
actuator is disconnected from the GND path. continuous or pulsed PWM signal. current can be supported by using an external N-channel power MOSFET driven through GDRV pin.
6.1 T1 timer settings
Figure 6. T1 vs RTPF- prescaler x1 reports the typical T1 curve vs setting resistor RTPF when the prescaler x1 is selected. It allows the user to set T1 from 5 s to 20 s as reported in Figure 5. Timer configuration truth table. Figure 6. T1 vs RTPF- prescaler x1
6.2 Timer expiration: normal mode
Figure 7. Normal power cycle shows a typical power cycle not triggering a fault condition. In this example a PWM and the external gate drive pin is activated. As soon as a falling edge of the PWM signal is detected, T2 is started. waiting for a new cycle to start. Figure 7. Normal power cycle
6.3 T1 timer expiration: fault mode
Figure 8. T1 expiration, fault mode shows an example of platform failure triggering the protection function of the IC. In this case, the power control unit keeps generating the power PWM signal for a time longer than expected. activates the GDRV output as soon as a rising edge on PWM is detected (a). making the device enter fault mode (b). and the power MOSFETs (both internal or external if used) are kept off to let the application cool down. After T3 expires, the device enters again idle mode and is ready for a new cycle. Figure 8. T1 expiration, fault mode
6.4 HW_RESET functionality
Figure 9. HW_RESET input functionality monitoring, during USB disconnection, in case of voltage bouncing, a reset might be generated.
7 Typical performance characteristics
Figure 10. RDS(on) vs VBAT, room temperature Figure 11. RDS(on) vs VBAT@-40 °C Figure 12. RDS(on) vs VBAT@-85 °C Figure 13. Reset pulse width: VBAT=3.7 V Figure 14. PWM VIH_MIN: VBAT=3.7 V Figure 15. PWM VIL_MAX: VBAT=3.7 V
8 Package information
In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com. ECOPACK is an ST trademark. STEC01
Package information
DS13063 - Rev 2 page 14/22
Figure 22. VFQFPN 3x3x0.9 package outline
Table 5. VFQFPN 3x3x0.9 mechanical data exceed 0,15 mm. Package outline exclusive of metal burr dimensions.
Figure 23. VFQFPN 3x3x0.9 recommended footprint
Revision history
Table 6. Document revision history 14-Jan-2020 1 Initial release.