Positive/negative high voltage charge pump system
First Claim
1. A high voltage charge pump operable from low voltage Vdd and electronically reconfigurable to output from an output port a positive high voltage VPp in a positive mode, or a negative high voltage VPn in a negative mode, comprising:
- a semiconductor substrate;
a charge pump circuit, fabricated on said substrate, having an anode node and a cathode node and including a number (N) of series-coupled charge pump stages, each of said stages including a MOS transistor and being AC-coupled to receive one of two non-overlapping phase pulse train signals of amplitude E1, where E1≦
Vdd, such that adjacent said stages receive different ones of said phase pulse train signals;
said pump stages multiplying the AC-coupled E1 amplitude pulse train signals to create a larger magnitude potential therefrom; and
a switching mechanism, fabricated on said substrate, coupled to said charge pump circuit;
wherein when said charge pump circuit is to operate in said positive mode, said switching mechanism couples a source of said Vdd to said anode node, couples said cathode node to said output port to deliver said VPp, and couples a substrate node of each said MOS transistor to a first potential;
said larger magnitude potential created by said charge pump circuit having magnitude VPp ; and
wherein when said charge pump circuit is to operate in said negative mode, said switching mechanism couples a negative potential to said cathode node, couples said anode node to said output port to deliver said VPn, and couples a substrate node of each said MOS transistor to a second potential;
said larger magnitude potential created by said charge pump circuit having magnitude VPnp.
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Abstract
A two-phase high voltage generator circuit is electronically reconfigurable to output positive (VPp) or negative (VPn) high voltage, depending upon whether positive or negative mode operation is selected. The circuit includes a plurality of series-connected charge multiplier stages that each comprises a MOS transistor and a charging capacitor. Collectively the stages define an anode node and a cathode node. One of two non-overlapping phase signals is coupled to the free end of each charging capacitor such that adjacent charging capacitors are driven by different phases. First and second two-way multiplexers (MUX1, MUX2) control voltages presented to the anode and cathode nodes, to determine whether circuit operation is positive or negative mode. The MOS devices may be PMOS or NMOS, and preferably Vt-cancellation is provided for each charging stage. A precharge/discharge circuit preferably is coupled to each voltage node including the load capacitor. Further, substrate-well protection is provided such that the MOS devices are less prone to exhibit voltage breakdown or substrate to source/drain current flow.
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Citations
20 Claims
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1. A high voltage charge pump operable from low voltage Vdd and electronically reconfigurable to output from an output port a positive high voltage VPp in a positive mode, or a negative high voltage VPn in a negative mode, comprising:
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a semiconductor substrate; a charge pump circuit, fabricated on said substrate, having an anode node and a cathode node and including a number (N) of series-coupled charge pump stages, each of said stages including a MOS transistor and being AC-coupled to receive one of two non-overlapping phase pulse train signals of amplitude E1, where E1≦
Vdd, such that adjacent said stages receive different ones of said phase pulse train signals;
said pump stages multiplying the AC-coupled E1 amplitude pulse train signals to create a larger magnitude potential therefrom; anda switching mechanism, fabricated on said substrate, coupled to said charge pump circuit; wherein when said charge pump circuit is to operate in said positive mode, said switching mechanism couples a source of said Vdd to said anode node, couples said cathode node to said output port to deliver said VPp, and couples a substrate node of each said MOS transistor to a first potential;
said larger magnitude potential created by said charge pump circuit having magnitude VPp ; andwherein when said charge pump circuit is to operate in said negative mode, said switching mechanism couples a negative potential to said cathode node, couples said anode node to said output port to deliver said VPn, and couples a substrate node of each said MOS transistor to a second potential;
said larger magnitude potential created by said charge pump circuit having magnitude VPnp. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A high voltage charge pump system, fabricated on a semiconductor substrate, operable from low voltage Vdd and electronically reconfigurable to output from an output port a positive high voltage VPp in a positive mode, or a negative high voltage VPn in a negative mode, the system comprising:
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a charge pump circuit, fabricated on said substrate, having an anode node and a cathode node and including a plurality of series-coupled solid-state charge pump MOS transistors AC-coupled to receive one of two pulse train signals of amplitude E1≦
Vdd and to output a larger magnitude potential therefrom;a switch mechanism, fabricated on said substrate, coupled to said charge pump transistors; a bias circuit, fabricated on said substrate, coupled to said solid-state charge pump transistors so as to vary at least one of a substrate bias voltage and a well bias voltage thereof as a function of positive mode or negative mode operation of said system; wherein when said system is to operate in said positive mode, said switch mechanism couples a source of said Vdd to said anode node, and couples said cathode node to said output port to deliver said VPp ;
said larger magnitude potential created by said charge pump circuit having a magnitude of said VPp ; andwherein when said system is to operate in said negative mode, said switch mechanism couples a negative potential to said cathode node, and couples said anode node to said output port to deliver said VPn, said larger magnitude potential created by said charge pump circuit having a magnitude of said VPn. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of multiplying a low voltage Vdd in an electronically reconfigurable system whose output port provides a positive high voltage VPp in positive mode, or a negative high voltage VPn in negative mode, the method comprising the following steps:
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providing a charge pump having an anode node and a cathode node and receiving AC-coupled pulse train signals of amplitude E1≦
Vdd and multiplving said pulse train signals to create a larger magnitude potential therefrom;
said charge pump including a plurality of series-coupled pump stages, each of said stages including a MOS transistor;coupling a switchably reconfigurable switching mechanism to said charge pump such that; when said charge pump is to operate in said positive mode, said switching mechanism coupling a source of said Vdd to said anode node, and coupling said cathode node to said output port to deliver said VPp ;
said larger magnitude potential created by said charge pump having magnitude VPp ; andwhen said pump is to operate in said negative mode, said switching mechanism coupling a negative potential to said cathode node, and coupling said anode node to said output port to deliver said VPn ;
said larger magnitude potential created by said charge pump having magnitude VPnp ; andcoupling a substrate or well node of each said MOS transistor to a first potential when said pump operates in said positive mode, and coupling said substrate or well node of each said MOS transistor to a second potential when said pump operates in said negative mode. - View Dependent Claims (20)
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Specification