Negative-voltage charge pump power circuit realized by low-voltage MOS (metal-oxide-semiconductor) pipe solely

Abstract

The invention discloses a negative-voltage charge pump power circuit realized by low-voltage transistor solely, comprising a P-type field effect transistor, four N-type field effect transistors and two capacitors, wherein a grid of each transistor is connected with a level shift module. A source electrode of the P-type field effect transistor is connected with a substrate and then connected with a power inlet end, and a drain electrode is connected with a drain electrode of a first N-type field effect transistor. A source electrode of the first N-type field effect transistor is in short-circuit connection with the substrate to a ground potential. Drain electrodes of a second and a third N-type field effect transistors are connected to the ground potential, and the source electrodes are connected with respective substrates and then connected to a drain electrode of a fourth N-type field effect transistor. A substrate of the fourth N-type field effect transistor is in short-circuit connection with a source electrode and connected to a voltage outlet end. A first capacitor is connected with the drain electrode of the P-type field effect transistor and the source electrode of the second N-type field effect transistor. A second capacitor is connected with the source electrode of the fourth N-type field effect transistor and the ground potential. The negative-voltage charge pump power circuit of the invention realizes a negative-voltage power supply so as to reduce board area of a charge pump and enrich technical options.

Description

technical field [0001] The invention relates to a negative voltage charge pump power supply circuit realized by only using low-voltage MOS tubes. Background technique [0002] Negative voltage charge pump power supply is widely used in analog chips. It can double the output swing of the chip, improve the dynamic range, and realize special functions such as signal output based on ground potential. The requirements of the pump module include high conversion efficiency and small layout area, etc. A US patent (patent number 6,803,807) proposes a negative voltage charge pump circuit, such as figure 1 As shown, the signal S1 controls the switches EP1 and DP1, and the signal S2 controls the switches EN1 and DP2. When the switches EP1 and DP1 are turned on, C1 is charged to Vin, and when the switches EN1 and DP2 are turned on, the charges of C1 and C2 are redistributed. After several cycles, the output OUT will reach -Vin. This structure can convert the positive input voltage Vin ...

AI Technical Summary

Problems solved by technology

When DP1 or DP2 is turned off, its gate and substrate voltage are 5V, and its drain potential is about -5V, so it is necessary to use a high-voltage PMOS with stronger withstand voltage capability to withstand this gate-drain, substrate-drain 10V voltage difference. On the one hand, the use of high-voltage devices limits the choice of process. On the other hand, due to the influence of the gate oxide unit capacitance and threshold voltage of high-voltage devices, to achieve the same charge pump driving capability, DP1 and DP2 must use larger Layout area

[0004] 2. In the patent, the substrate potentials of DP1 and DP2 are both connected to the most positive potential, Vin, which makes the two PMOSs have serious substrate bias effects and reduces their current drive capability. Therefore, it is necessary to ensure the same charge pump performance , must increase the layout area of ​​DP1, DP2

[0005] 3. In the patent, in order to transmit 0V and -5V (potential of point B), DP1 and DP2 choose depletion-type PMOS. Although this can effectively realize low-voltage transmission, the use of special devices also limits the choice of process

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