Patent ID: 7692474

Claim:
A control circuit for a high-side semiconductor switch for switching a positive supply voltage, said high-side semiconductor switch being connected between said supply voltage and a floating switching point, said control circuit comprising: a circuit portion for providing a drive voltage for said high-side semiconductor switch; a driver circuit portion for driving said high-side semiconductor switch on basis of said drive voltage, said circuit portion for providing said drive voltage and said driver circuit portion operating in relation to said floating switching point; an input circuit portion for receiving a control signal related to ground; and a level shift circuit portion that is connected between said input circuit portion and said driver circuit portion and configured to transform said control signal related to ground into a floating voltage level for said driver circuit portion; wherein said level shift circuit portion comprises a degeneratively coupled control semiconductor switch and is coupled to a negative feedback circuit portion, said negative feedback circuit portion comprising a holding transistor, a first negative feedback resistor, and a second negative feedback resistor, and said negative feedback circuit portion configured such that during a switch-off operation of said high-side semiconductor switch, said holding transistor blocks conduction and said first and said second negative feedback resistors generate a relatively large current negative feedback and during a stationary OFF state of said high-side semiconductor switch, said holding transistor is switched on and said first and said second negative feedback resistors generate a low current negative feedback, and wherein said first and said second negative feedback resistor are connected in series and said holding transistor is connected in parallel to said second negative feedback resistor.