公开(公告)号：EP3744576A1

公开(公告)日：2020-12-02

申请号：EP20170928.4

申请日：2020-04-22

Applicant: STMicroelectronics S.r.l.

Inventor： RAGONE, Giancarlo ,  POLETTO, Vanni

IPC: B60R21/017

Abstract: A drive circuit (10) for airbag systems, for instance comprises:
- a differential transconductance amplifier (14) having a first input node (146), a second input node (144), an output node (140), the output node (140) coupled to the second input node (144) via a feedback line (142),
- a supply node (101) and a drive node (103) configured to be coupled to the current path through a transistor (PT) with the transistor intermediate the supply node (101) and the drive node (103), the supply node (101) configured to be coupled to a power supply source (VS),
- a control node (102) configured to be coupled to the control electrode of the transistor (PT), the control node (102) coupled to the output node (140) of the differential transconductance amplifier (14),
- a zener diode arrangement (16) having cathode and anode terminals coupled to the supply node (101) and the first input node (146) of the differential transconductance amplifier (14),
- a pull-up component (20, 20') arranged in parallel to the zener diode arrangement (16), and
- an enable switch (18) coupled to the first input node (146) of the differential transconductance amplifier (14), the enable switch (18) referred to ground (GND) and switchable (E) between a conductive state and a non-conductive state with the differential transconductance amplifier (14) providing controlled current discharging/charging of the control node (102) to make the transistor (PT) conductive/non-conductive, respectively.