Voltage down converter for high speed memory
View Patent ↗A voltage down converter (VDC) applicable to high-speed memory devices. The VDC includes a steady driver and active driver along with at least one additional transistor. The steady driver and active driver are coupled by a transistor switch during device start-up to provide fast ramp-up to operating voltage and current. After start-up, the steady driver and active drive function to maintain a steady operating voltage and current. An additional transistor is digitally controlled to drive up operating voltage and current upon issuance of an active command representing read, write, and/or refresh of memory. In this manner, the additional transistor provides fast compensation for fluctuations in operating voltage and current brought on by activity in the memory array.
1. A voltage down converter for providing a supply voltage and current to a high-speed memory device, said converter comprising:
a first driver circuit including a first comparator and a steady driver transistor having a large transistor width;
a second driver circuit including a second comparator and an active driver transistor having a small transistor width relative to said steady driver;
a first logic circuit for connecting said first driver circuit and said second driver circuit;
a second logic circuit for providing an active command indicating occurrence of an activity; and
at least one additional transistor for receiving said active command;
wherein said first and second driver circuits provide a substantial portion of said supply voltage and current to said high speed memory device and said at least one additional transistor provides additional supply current in response to said active command.
2. The converter as claimed in claim 1 wherein said first logic circuit connects said first driver circuit and said second driver via a transistor switch.
3. The converter as claimed in claim 2 wherein said transistor switch, in response to an output signal of said first logic circuit, connects a base of said steady driver transistor to a base of said active driver transistor during start-up of said high speed memory device.
4. The converter as claimed in claim 2 wherein said transistor switch, in response to an output signal of said first logic circuit, ties an output of said first comparator together with an output of said second comparator to bases of both said steady driver transistor and said active driver transistor during start-up of said high speed memory device.
5. The converter as claimed in claim 2 wherein said second logic circuit includes a combination logic circuit and a level shifter circuit that provides said active command forming a pulse signal to activate said at least one additional transistor to drive said additional supply voltage and current such that said substantial portion of said supply voltage and current combined with said additional supply voltage and current compensate for operating load losses during said occurrence of said activity.
6. The converter as claimed in claim 5 wherein said activity is selected from the group consisting of reading from memory, writing to memory, and refreshing memory.
7. The converter as claimed in claim 5 further including
a second additional transistor and
a third logic circuit including another combination logic circuit and corresponding level shifter circuit that provides a second active command indicating occurrence of an additional activity, said second active command forming a second pulse signal to activate said second additional transistor to drive further additional supply voltage and current such that said substantial portion of said supply voltage and current combined with both said additional supply voltage and current and said further additional supply voltage and current compensate for said operating load losses during said occurrences of said activity and said additional activity.
8. The converter as claimed in claim 7 wherein said activity is selected from the group consisting of reading from memory and writing to memory.
9. The converter as claimed in claim 8 wherein said additional activity is refreshing memory.