CURRENT LIMITER CIRCUIT

摘要

The present invention relates to a circuit configuration for detecting and rapidly limiting large current increase based on high current injection at the output terminal (out). In particular, a gate-controlled switching device (PO), controlled by a driver circuit (40) through a low resistive element (RO) and passed through by a current overshoot, will be alternatively driven by the circuit of the present invention while having its control terminal charged by the high injected current. Thus, when large voltage increase generated by a steep front impulse with a positive slope is detected by the capacitor (C) and transmitted to the gate terminal (GateN), the circuit of the present invention bypasses the driver circuit (40) while injecting a significant current peak issued from the transistor (P3) towards the gate terminal (GateP) of the gate-controlled switching device (PO), whereas the capacitor (C) is discharging very slowly through the gate terminal (GateN). The current amplification leading to the injected current peak is made through the use of the current mirror (P4, P3) with a large current mirror ratio and enhanced by the presence of the diodes (DO, Dl). In a quiescent mode or when large voltage decrease generated by a steep front impulse with a negative slope is detected by the capacitor (C) and transmitted to the gate terminal (GateN), the transistor (P4) becomes short-circuited by the current source (C S3) sourcing the current flowing through the diode (Dl), such that the current mirror (P4+P5, P3) is virtually replaced by the current mirror (P5, P3) with a much lower current mirror ratio. As a result, the low current of the sinking current source (CS2) will be sufficient to sink the lower current mirrored by the current mirror (P3, P5) and will then allow the driver circuit (40) to take over the control of the switching device (PO). Finally, this circuit configuration operates unidirectionally while limiting large current increase but not large current decrease through the gate-controlled switching device (PO).