Low voltage solution for zener voltage reference
AssigneeSTMicroelectronics International N.V.
InventorsSandro Rossi, Andrea Gambero, Lorenzo Rosati
Life of this patent
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Abstract
A voltage reference circuit includes: a Zener diode and a synchronization circuit coupled to a cathode of the Zener diode. The synchronization circuit includes a first circuit and a second circuit, where each of the first circuit and second circuit includes: a current source coupled between a supply voltage node and a first node; a first switch coupled between the first node and a reference voltage node; a first capacitor coupled between the first node and a second node; a second switch coupled between the second node and the supply voltage node; and a third switch coupled between the second node and the cathode of the Zener diode.
Claims20
A voltage reference circuit comprising:
- a Zener diode;
- and
- a synchronization circuit coupled to a cathode of the Zener diode, wherein the synchronization circuit comprises a first circuit and a second circuit, wherein each of the first circuit and second circuit comprises:
- a current source coupled between a supply voltage node and a first node;
- a first switch coupled between the first node and a reference voltage node;
- a first capacitor coupled between the first node and a second node;
- a second switch coupled between the second node and the supply voltage node;
- and
- a third switch coupled between the second node and the cathode of the Zener diode.
A voltage reference circuit comprising:
- a synchronization circuit, wherein the synchronization circuit comprises a plurality of sub-circuits, wherein each of the sub-circuits comprises:
- a current source coupled between a supply voltage node and a first node;
- a first switch coupled between the first node and a reference voltage node;
- a capacitor coupled between the first node and a second node;
- a second switch coupled between the second node and the supply voltage node;
- and
- a third switch coupled between the second node and an output terminal of the synchronization circuit;
- and
- a Zener diode coupled between the output terminal of the synchronization circuit and the reference voltage node.
A method of operating a voltage reference circuit comprising a synchronization circuit and a Zener diode coupled to an output terminal of the synchronization circuit, wherein the synchronization circuit comprises a plurality of sub-circuits, wherein the method comprises:
- setting the plurality of sub-circuits in a first operating mode for a first duration of time, wherein each of the sub-circuits comprises:
- a current source coupled between a supply voltage and a first node;
- a first switch coupled between the first node and a reference voltage;
- a capacitor coupled between the first node and a second node;
- a second switch coupled between the second node and the supply voltage;
- and
- a third switch coupled between the second node and the output terminal of the synchronization circuit, wherein setting the plurality of sub-circuits in the first operating mode comprises, for each of the plurality of sub-circuits, closing the first switch and the second switch and opening the third switch;
- and
- after the first duration of time elapses, switching each of the plurality of sub-circuits between the first operating mode and a second operating mode alternately, wherein each of the plurality of sub-circuits is set in the second operating mode by opening the first switch and the second switch and closing the third switch.
Dependencies are inferred from the claim text.