9.3.1.6 Fault Event – Timing Diagrams

Figure 42 shows the immediate current limit switch off behavior of Versions A,B,E. The diagram also illustrates the retry behavior. As shown, the switch will remain latched off until the LATCH pin is low.

Figure 42. Current Limit – Version A,B,E - Latched Behavior

Figure 43 shows the immediate current limit switch off behavior of versions A,B,E. In this example, LATCH is tied to GND; hence, the switch will retry after the fault is cleared and t_RETRY has expired.

Figure 43. Current Limit – Version A,B,E - LATCH = 0

Figure 44 shows the active current limiting behavior of versions C,D. In versions C,D, the switch will not shutdown until either the energy limit or the thermal shutdown is reached.

Figure 44. Current Limit – Version C,D - Latched Behavior

Figure 45 shows the active current limiting behavior of versions C,D. The switch will not shutdown until either thermal shutdown or energy limit is tripped. In this example, LATCH is tied to GND.

Figure 45. Current Limit – Version C,D - LATCH = 0

When the switch retries after a shutdown event, the SNS fault indication will remain until V_OUT has risen to V_BB – 1.8 V. Once V_OUT has risen, the SNS fault indication is reset and current sensing is available. ST fault indication is reset as soon as the switch is re-enabled (does not wait for V_OUT to rise). If there is a short-to-ground and V_OUT is not able to rise, the SNS fault indication will remain indefinitely. The following diagram illustrates auto-retry behavior and provides a zoomed-in view of the fault indication during retry.

Figure 46. Fault Indication During Retry