DEPLOYMENT CIRCUIT FOR A PYROTECHNIC DEVICE, CORRESPONDING INTEGRATED CIRCUIT, VEHICLE AND METHOD

A deployment circuit (20) for a pyrotechnic device (101) is disclosed. The deployment circuit (20) comprises a first terminal (122a) and a second terminal (122b) configured to be connected to the pyrotechnic device (101). A driver circuit (200) comprises at least one electronic switch (2002a) configured to selectively connect the first terminal (122a) and the second terminal (122b) to a supply voltage (VIN) in response to determining that a deployment control signal (DEP_CMD) is asserted. A current limiter (2000a) limits the current (IPYRO) provided via the first terminal (122a) and the second terminal (122b) to a maximum value (IMAX). A control circuit (202) drives the driver circuit (200) as a function of a fire request signal (REQ).Specifically, when the fire request signal (REQ) is de-asserted, the control circuit determines (1004) whether a first value (MR) indicative of a resistance (RPYRO) between the first terminal (122a) and the second terminal (122b) is between a first threshold and a second threshold. In response to determining that the first value (MR) is not between the first threshold and the second threshold, the control circuit signal (1016) an error.Conversely, when the fire request signal (REQ) is asserted, the control circuit starts (1006) a deployment cycle by asserting the deployment control signal (DEP_CMD), and stops (1010) the deployment cycle after a given time-period (tDC) by de-asserting the deployment control signal (DEP_CMD). The control circuit monitors (1008) during the deployment cycle a value (CNT) indicative of the time (tDEPLOY) where the current (IPYRO) provided via the first terminal (122a) and the second terminal (122b) is greater than a current threshold (ITH). Moreover, once the deployment cycle has been stopped, the control circuit obtains (1012) a second value (MR) indicative of the resistance (RPYRO) between the first terminal (122a) and the second terminal (122b), and determines (1014) whether the monitored value (CNT) indicates that the time (tDEPLOY) is greater than a time threshold (tTH) and whether the second value (MR) is greater than a third threshold. Specifically, when both conditions are satisfied, the control circuit signals (1020) a correct deployment of the pyrotechnic device (101).