Patent ID: 6181118
Filing Date: 2001-01-30
Classification: G05F

Abstract:
A control circuit for controlling a semi-conductor switch in response to an input signal for selectively enabling and disabling the switch and for selectively operating the switch for outputting an output voltage at two respective selectable voltage levels from a single level voltage source when the switch is enabled, the control circuit comprising:a control terminal operable in any one of at least three states in response to the input signal,an output terminal for applying a control signal to a gating input of the semi-conductor switch to enable the switch and to select the output voltage therefrom in response to the state of the control terminal,a ground terminal for connecting the circuit to ground,a power supply terminal at which the circuit is connectable to a power supply voltage,a feedback terminal at which feedback may be received from the output voltage from the semi-conductor switch,a decoder which determines the state of the control terminal, the decoder having an enable output and a select output, and being responsive to the state of the control terminal for outputting an enable signal and a voltage select signal, respectively,a regulating means for outputting the control signal to the output terminal, the regulating means being responsive to the enable signal from the decoding means for outputting the control signal for enabling the semi-conductor switch, and being responsive to the voltage select signal from the decoding means for setting the level of the control signal at one of two levels for selecting the voltage level from the semi-conductor switch in response to the state of the control terminal, and the regulating means being responsive to the feedback signal on the feed back terminal for regulating the control signal at one of the two levels for operating the semi-conductor switch to output a regulated voltage at the corresponding one of the two selectable voltage levels.