Voltage down converter for multiple voltage levels
First Claim
1. A voltage regulator circuit for converting an external supply voltage from an external voltage source to an internal supply voltage, the voltage regulator circuit comprising:
- a reference voltage generator for converting the external supply voltage to a stable reference voltage;
a tuning circuit for converting the stable reference voltage to the internal supply voltage; and
an output driver circuit for stabilizing the internal supply voltage, wherein the output driver circuit comprises;
a first op-amp having an inverting input terminal connected to an output terminal of the tuning circuit;
a first resistive element connected between a non-inverting input terminal of the first op-amp and a first voltage source; and
a plurality of PMOS power transistors, the drain terminal of each of the plurality of PMOS power transistors being coupled to receive the external supply voltage, the source terminal of each of the plurality of PMOS power transistors being connected to the non-inverting input terminal of the first op-amp, and the gate terminal of each of the plurality of PMOS power transistors being connected to an output terminal of the first op-amp.
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Accused Products
Abstract
A voltage regulator circuit in an integrated circuit (IC) device such as a Complex Programmable Logic Device (CPLD) includes a reference voltage generator, a tuning circuit, and an output driver circuit. The reference voltage generator converts an external supply voltage provided to the IC device into a stable reference voltage. The tuning circuit converts the stable reference voltage into a desired internal supply voltage, such as the reduced voltage required by deep sub-micron transistors. The output driver circuit provides the desired internal supply voltage with sufficient current to properly power the circuits of the IC device. The tuning circuit includes an op-amp and resistive elements configured in a voltage divider configuration in the negative feedback loop of the op-amp. The output of the op-amp can be set to the desired internal supply voltage by properly sizing the resistive elements. By making at least one of the resistive elements adjustable, a variable internal supply voltage can be provided by the voltage regulator circuit.
114 Citations
11 Claims
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1. A voltage regulator circuit for converting an external supply voltage from an external voltage source to an internal supply voltage, the voltage regulator circuit comprising:
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a reference voltage generator for converting the external supply voltage to a stable reference voltage; a tuning circuit for converting the stable reference voltage to the internal supply voltage; and an output driver circuit for stabilizing the internal supply voltage, wherein the output driver circuit comprises; a first op-amp having an inverting input terminal connected to an output terminal of the tuning circuit; a first resistive element connected between a non-inverting input terminal of the first op-amp and a first voltage source; and a plurality of PMOS power transistors, the drain terminal of each of the plurality of PMOS power transistors being coupled to receive the external supply voltage, the source terminal of each of the plurality of PMOS power transistors being connected to the non-inverting input terminal of the first op-amp, and the gate terminal of each of the plurality of PMOS power transistors being connected to an output terminal of the first op-amp. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An integrated circuit comprising:
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a first plurality of I/O circuits; an internal circuit for routing output signals to the first plurality of I/O circuits; a second plurality of circuit power pins for receiving an external supply voltage for the internal circuit; an internal power bus for transmitting an internal supply voltage to the internal circuit; and a first voltage regulator circuit for applying the internal supply voltage to the internal power bus, the first voltage regulator circuit comprising; a first reference voltage generator for converting the external supply voltage to a first stable reference voltage; a first tuning circuit for converting the first stable reference voltage to the internal supply voltage; and an output driver circuit comprising; a first op-amp having an inverting input terminal connected to an output terminal of the first tuning circuit, and a non-inverting input terminal connected to the internal power bus; a first resistive element connected between the non-inverting input terminal of the first op-amp and ground; and a third plurality of PMOS power transistors, the drain terminal of each of the third plurality of PMOS power transistors being coupled to one of the second plurality of circuit power pins, the source terminal of each of the third plurality of PMOS power transistors being connected to the internal power bus, and the gate terminal of each of the third plurality of PMOS power transistors being connected to an output terminal of the first op-amp. - View Dependent Claims (10, 11)
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Specification