Patent ID: 7362082

Claim:
A switch mode power supply for feeding a single ended class D amplifier, said power supply comprising two voltage sources ( 1 , 2 ), the negative side of the first source ( 1 ) being connected to the positive side of the second source ( 2 ) in a common point ( 3 ), characterized by a voltage equalizer circuit including a coil ( 10 ) having a first terminal connected to said common point ( 3 ), a first switch ( 11 ) connected between a second terminal of the coil ( 10 ) and the positive side of the first source ( 1 ), a second switch ( 12 ) connected between said second terminal of the coil ( 1 ) and the negative side of the second source ( 2 ), and control circuitry ( 13 , 14 ) for determining when the voltage (v 1 , v 2 ) of one of the voltage sources ( 1 or 2 ) exceeds a first threshold value (v thresh,ON ), and, in response to such a determination, periodically operate the switch ( 11 or 12 ) associated with said one voltage source ON and OFF, thereby redistributing energy from said one voltage source ( 1 or 2 ) to the other voltage source ( 2 or 1 ).