Switching power supply and electronic control unit
A switching power supply converts an input voltage to a predetermined output voltage by controlling a switching device. The switching power supply includes a controller and a current detector. The controller controls the switching device. The current detector detects electric current flowing through the switching device. The controller starts a forced-OFF action to forcedly turn OFF the switching device when the current detected by the current detector exceeds a predetermined threshold and then ends the forced-OFF action at a start of a predetermined switching period.
1. A switching power supply for converting an input voltage to a predetermined output voltage by controlling a switching device, the switching power supply comprising:
a controller that controls the switching device;
a current detector that detects electric current flowing through the switching device; and
a voltage detector that detects an output voltage of the switching device, wherein
the controller starts a forced-OFF action to forcedly turn OFF the switching device when the current detected by the current detector exceeds a predetermined threshold and then ends the forced-OFF action at a start of a predetermined switching period, and
the controller ends the forced-OFF action when the voltage detected by the voltage detector decreases below a predetermined lower limit after starting the forced-OFF action.
2. The switching power supply according to claim 1 , wherein,
the controller is implemented as a semiconductor integrated circuit, and
the switching device is located outside the semiconductor integrated circuit.
3. An electronic control unit comprising:
the switching power supply as defined in claim 1 , and
a control processor that operates on power supplied from the switching power supply.
4. The switching power supply according to claim 1 , wherein,
the controller continues the forced-OFF action after repeating the forced-OFF action.
5. The switching power supply according to claim 4 , wherein,
the controller continues the forced-OFF action after repeating the forced-OFF action a predetermined number of times.
6. The switching power supply according to claim 5 , wherein,
the controller has a counter to count a number of times the forced-OFF is executed in total, and
the controller continues the forced-OFF action after the counted number reaches the predetermined number.
7. The switching power supply according to claim 5 , wherein,
the controller has a counter to count a number of times the forced-OFF is executed in a row, and
the controller continues the forced-OFF action after the counted number reaches the predetermined number.
8. The switching power supply according to claim 4 , wherein,
the controller continues the forced-OFF action after repeating the forced-OFF action for a predetermined time.
9. A switching power supply for converting an input voltage to a predetermined output voltage by controlling a switching device, the switching power supply comprising:
a controller that controls the switching device; and
a current detector that detects electric current flowing through the switching device, wherein
the controller starts a forced-OFF action to forcedly turn OFF the switching device when the current detected by the current detector exceeds a predetermined threshold and then ends the forced-OFF action at a start of a predetermined switching period,
the controller continues the forced-OFF action after repeating the forced-OFF action a predetermined number of times,
the controller continues the forced-OFF action after repeating the forced-OFF action for a predetermined time,
the controller has a timer to measure a total execution time for which the forced-OFF is executed in total, and
the controller continues the forced-OFF action after the total execution time reaches the predetermined time.
10. A switching power supply for converting an input voltage to a predetermined output voltage by controlling a switching device, the switching power supply comprising:
a controller that controls the switching device; and
a current detector that detects electric current flowing through the switching device, wherein
the controller starts a forced-OFF action to forcedly turn OFF the switching device when the current detected by the current detector exceeds a predetermined threshold and then ends the forced-OFF action at a start of a predetermined switching period,
the controller continues the forced-OFF action after repeating the forced-OFF action a predetermined number of times,
the controller continues the forced-OFF action after repeating the forced-OFF action for a predetermined time,
the controller has a timer to measure a continuous execution time for which the forced-OFF is executed continuously, and
the controller continues the forced-OFF action after the continuous execution time reaches the predetermined time.