A current detection circuit applicable to a switching circuit using switching
transistors
to supply a prescribed load current to a load, comprises a sample-hold capacitor
for temporarily holding a terminal voltage of the switching transistor that is
turned on, and a switch that is inserted between the switching transistor and sample-hold
capacitor and is controlled to be turned on in synchronization with the ON-timing
of the switching transistor, wherein charged voltage of the sample-hold capacitor
is detected as a detection voltage. An overcurrent detection circuit is constituted
in such a way that the switching transistor is compulsorily turned off when the
detection voltage exceeds reference voltage. The switching circuit may correspond
to a pulse-width modulation (PWM) amplifier using a pair of a PMOS transistor and
an NMOS transistor that are alternately turned on or off.
