Power supply circuit with a voltage selector
AssigneeSTMicroelectronics S.r.l.
InventorClaude Renous
Life of this patent
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Abstract
A power supply circuit receiving several supply voltages on respective switches, at least one of the switches being a first PMOS transistor connected between one of the supply voltages and a common output terminal, this switch being associated with a second PMOS transistor connected between the gate of the first transistor and a power supply node maintained at the highest of the other supply voltages, with a third NMOS transistor, which is less conductive in the on state than the second transistor, connected between the gate of the first transistor and the ground, and with a fourth PMOS transistor having its source connected to the power supply line of the switch and its drain connected to ground via a current source, and to the gates of the second, third, and fourth transistors.
Claims17
A power supply circuit receiving several supply voltages on respective power supply lines, comprising:
- switches, wherein each of the respective power supply lines is connected to a respective switch, at least one of the switches including:
- a first transistor of a first conductivity type connected between an associated power supply line and a common output terminal;
- a second transistor of the first conductivity type connected between a gate of the first transistor and a power supply node maintained at a highest of the other supply voltages;
- a third transistor of a second conductivity type which is less conductive in an on state than the second transistor, connected between the gate of the first transistor and a reference potential;
- and
- a fourth transistor of the first conductivity type having a source terminal connected to the associated power supply line, and a drain terminal connected to the reference potential via a current source, and to a gate of the second transistor, a gate of the third transistor and a gate of the fourth transistor.
A power supply circuit receiving several supply voltages on respective power supply lines, comprising:
- a number of switches, each power supply line being connected to a respective switch, at least one of the switches including:
- a first transistor connected between a respective power supply line and a common output terminal of the power supply circuit and having a first terminal;
- a second transistor connected between the first terminal of the first transistor and a power supply node maintained at a highest of the other supply voltages and having a second terminal;
- a third transistor connected between the first terminal of the first transistor and a reference potential and having a third terminal;
- and
- a fourth transistor having a fourth terminal, a fifth terminal and a sixth terminal,
- wherein the fourth terminal is connected to the respective power supply line and the fifth terminal is connected to the reference potential via a current source and to the second terminal, the third terminal and the sixth terminal.
Dependencies are inferred from the claim text.