ZHCSFO3D November 2016 – August 2021 LM5170-Q1
PRODUCTION DATA
The LM5170-Q1 includes a circuit to detect a MOSFET switch short-circuit failure during start-up. If a MOSFET drain and source are found shorted, the LM5170-Q1 pulls down the nFAULT pin to flag the fault, and the controller remains in an OFF state. This feature prevents the LM5170-Q1 from starting with a short-circuit-failed MOSFET, thereby preventing catastrophic failures.
The LM5170-Q1 also integrates a control circuit to control the circuit breaker. As shown in Figure 8-15, the circuit breaker consists of a pair of back-to-back MOSFETs. When the breaker is off, the current path between the HV-Port and LV-Port is cut-off so as to prevent possible catastrophic failures.
The failure detection function must be deactivated if the circuit breaker is not present, or if the circuit breaker FETs are not controlled by the LM5170-Q1.