Patent ID: 8587974

Claim:
A method of operating a bridge power supply circuit comprising at least two switch members connected in series between two rails and operated alternatingly to provide a pulse width modulated output signal at a junction between the two transistors for providing an alternating output voltage to a load, the method comprising: providing a control signal (U control ) for the alternating output voltage, whereby the control signal is an alternating signal; calculating timing signals (T 1 , T 2 ) based on said control signal for activation of the switch members for providing said alternating output voltage at an output of the circuit; measuring a voltage drop over at least one of the switch members in a time window when it is conducting; and adding said measured voltage drop to said control signal before calculating said timing signals in said calculation step for calculating said timing signals, whereby the sum of said voltage drop and said control signal is used for compensating for the voltage drop over the switch members by influencing upon the calculated timing signals in dependence of the sum of said control signal and said measured voltage drop.