| 摘要 |
A method for operating protection circuitry for a power switch ( 1 ) uses first and second timing windows which are started in response to the power switch ( 1 ) being turned on. The second timing window is greater than the first timing window. During the first timing window, the method prevents operation of first protection circuitry ( 8 ) and during the second timing window the method prevent operation of second protection circuitry ( 10 ). At the end of the first timing window, but before the end of the second timing window, the method allows operation of the first protection circuitry ( 8 ), and at the end of the second timing window, the method allows operation of the second protection circuitry ( 10 ) whilst preferably preventing operation of the first protection circuitry ( 8 ). In an embodiment, the first protection circuitry ( 8 ) provides latched short winding protection for the power switch ( 1 ), and the second protection circuitry provides non-latched over current protection for the power switch ( 1 ). Apparatus for implementing the method generates blanking signals which control the operation of the first and second protection circuitry.
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