Load pump type of voltage generator circuit
AssigneeSGS-Thomson Microelectronics S.A.
InventorEmilio Miguel Yero
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Abstract
Disclosed is a load pump type of voltage generator circuit designed to produce several levels of voltage higher than a supply voltage of the circuit. The circuit comprises two cascades of elementary pumping cells. Each cell is controlled by at least one driving signal. To make the two cascades work together, it is planned to modify the driving signal or one of the driving signals assigned to the last cell of the first cascade in such a way that the first cascade delivers a voltage equal to the sum of the voltages delivered by the two cascades. In a particular embodiment, the two cascades comprise the same number of cells and can work in parallel. Application to the field of non-volatile memories for the production of read and write voltages.
Claims13
In an electronic circuit comprising a terminal for receiving a suppy voltage, a voltage generator device for providing at least one voltage at a level higher than the supply voltage of the circuit, said voltage generator circuit comprising:
- an output stage;
- first and second cascades of pumping cells, wherein the pumping cells in each cascade are series-connected, said first and second cascades respectively delivering a first level of voltage and a second level of voltage higher than the supply voltage of the circuit, and wherein each of the pumping cells is controlled by at least one driving signal, and each pumping cell comprising a signal input, at least one driving input for receiving at least one driving signal and a signal output;
- and
- a conversion circuit to convert the driving signal or signals assigned to the last cell of the first cascade and to deliver, in its place, a converted driving signal whose amplitude is equal to the second level of voltage so that the first cascade delivers a third level of voltage equal to the sum of the first and second levels of voltage.
In an electronic circuit designed to operate at a supply voltage, a voltage generator circuit for producing several levels of voltage higher than the supply voltage of the electronic circuit, said voltage generator circuit comprising:
- an output stage and a plurality of pumping cells each controlled by at least one clock signal called a driving signal, each cell comprising a signal input, one driving input per driving signal to receive the driving signal or signals and one signal output,
- first and second cascades of pumping cells, in which said pumping cells being series-connected, said first and second cascades respectively delivering a first level of voltage and a second level of voltage higher than the supply voltage of the circuit,
- a driving signal generation unit for the generation, from the driving signal or from one of the driving signals assigned to the last cell of the first and second cascades, said driving signal having pulses with a duration T, of a first driving signal whose pulses have a duration T1 and a second driving signal whose pulses have a duration T2, the leading edge of the first driving signal and the trailing edge of the second driving signal corresponding to the leading edge and to the trailing edge of said driving signal and the periods T1 and T2 meeting the condition T=T1+T2,
- a first conversion circuit to convert said driving signal into a first converted driving signal having the same form as said first driving signal and having its amplitude pulses equal to the second level of voltage, and
- a second conversion circuit for converting said second driving signal into a second converted driving signal having the same form as said second driving signal and having its amplitude pulses equal to the first level of voltage.
Dependencies are inferred from the claim text.