JP2004135414A - Charge pump for flash memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge pump of a flash memory for maintaining normal operation by preventing a breakdown of a capacitor and a transistor. <P>SOLUTION: This charge pump consists of a conductive circuit, first, second and third charging elements. The conductive circuit includes first, second and third output terminals and a plurality of conductive elements. One of the plurality of conductive elements comprises positive and negative terminals connected to the first and the second output terminals. In another plurality of conductive elements, the positive and the negative terminals are connected to the second and the third output terminals. The charging elements comprise both ends, one end of the first charging element is connected to the first output terminal, one end of the second charging element is connected to the second output element, one end of the third charging element is connected to te third output terminal, and the other end of the third charging element is connected to the first output terminal and substantially forms a short-circuit with the first output terminal. After an electric charge is stored in the first charging element, the voltage of one end which is connected to the first output terminal of the third charging element is made substantially different from that of the one end which is not connected to the first output terminal of the first charging element. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a charge pump for a flash memory, and more particularly, to a charge pump in which capacitors are connected in series to prevent breakdown of an oxide layer of the capacitors.
[0002]
[Prior art]
In various types of storage media, a flash memory is a storage medium that is currently most regarded as important in the electronics industry because it can access reading and writing by applying electrons. Flash memory stores digital data using a plurality of metal oxide semiconductors having floating gates. The floating gate is formed in an oxide layer of a metal oxide semiconductor, and when data is written to a flash memory, electrons are tunneled through the oxide layer and stored in the floating gate, thereby achieving a non-volatile data storage purpose. That is, the flash memory is accessed by applying electrons, and does not require a mechanical operation unlike a hard disk, for example. Therefore, the flash memory has features such as small volume and high speed operation.
[0003]
However, a flash memory requires a considerably high drive voltage whether it is used for tunneling an oxide layer to electrons for writing data and injecting it into a floating gate, or for moving electrons from the floating gate to erase data. And a tunnel effect that drives electrons for the first time is obtained. Usually, such a driving voltage is higher than a bias for driving a general digital logic circuit. Therefore, the flash memory must generate a high drive voltage by a charge pump circuit using a special circuit. Generally, a bias for driving a logic circuit in a flash memory is about 3 V or lower. However, the voltage for driving and tunneling the electrons reaches 10 V or higher. Therefore, a charge pump for generating a high drive voltage has a special structure.
[0004]
FIG. 1 shows a circuit of a charge pump 10 of a conventional flash memory. The charge pump 10 includes a conductive circuit 12 and a plurality of capacitors serving as charging elements. In FIG. 1, when four capacitors Cp1 to Cp4 are disclosed, a load effect is simulated, and a capacitor CLp serving as an equivalent load element is included. The conductive circuit 12 is provided with five n-type metal oxide semiconductor transistors T1 to T5 in accordance with the five capacitors Cp1 to Cp4 and CLp. Each transistor is connected in the form of a diode and becomes a conductive element. The drain of each transistor is connected to the gate and becomes a positive terminal, and the source becomes the negative terminal and becomes the output terminal of the conductive circuit 12. That is, the conductive circuit 12 has five output terminals, that is, the notes Np1 to Np5. Each output is connected to one end of a capacitor as disclosed in FIG.
The other ends of the capacitors Cp1 and Cp3 are connected to a clock CK +, and the capacitors Cp2 and Cp4 are connected to another clock CK-. In addition, the drain of the transistor T1 is connected to a DC power source for bias, and the bias is performed with the voltage Vdd. The node Np5 becomes a load output terminal, and is connected to one end of the capacitor CLp, and the other end of the capacitor CLp is connected to the ground terminal. Further, the voltage Vp0 across the capacitor CLp is the drive voltage provided by the charge pump 10.
[0005]
A transistor serving as a conductive element is connected between each output terminal of the conductive circuit 12, and a predetermined correspondence relationship occurs between each output terminal. For example, when the voltage at the node Np1 is higher than the voltage at the node Np2 and the voltage difference between the nodes Np1 and Np2 exceeds the threshold voltage Vt of the transistor T2, the transistor T2 is turned on. The current is turned on, and current flows from node Np1 to Np2. Conversely, if the voltage difference between node Np1 and node Np2 does not exceed the threshold voltage, or if the voltage at node Np2 is greater than the voltage at node Np1, transistor T2 does not conduct and current flows from node T2 to node T1. Not flowing. That is, when the voltages of the nodes Np1, Np2, Np3, and Np4 become higher than the voltages of Np2, Np3, Np4, and Np5, respectively, and the respective voltage differences exceed the width of the threshold voltage Vt, the respective transistors T2 that are turned on. , T3, T4, T5, a current is provided to nodes Np2, Np3, Np4, Np5. Conversely, the nodes Np2, Np3, Np4, and Np5 cannot cause current to flow back to the nodes Np1, Np2, Np3, and Np4 via the reverse-biased transistors T2, T3, T4, and T5.
[0006]
The clock CK + and the clock CK- are high-frequency clocks that are mutually contradictory. That is, when the voltage of the clock CK + is at a high level, the voltage of the clock CK- is at a low level. When the voltage of the clock CK + is low, the voltage of the clock CK- is high. Usually, the high level voltage of these two clocks is the power supply voltage Vdd, and the low level is the voltage of the ground terminal (that is, the voltage is 0).
[0007]
FIG. 2 is described below in combination with FIG. FIG. 2 is a table showing a temporal change of a voltage at a node when the charge pump 10 is driven. The vertical axis in FIG. 2 represents time, and the voltages of the nodes Np1 to Np5 are disclosed in columns 14A to 14E, respectively. Also, “H” and “L” indicate whether the level state of the clocks CK + and CK− is high (that is, the voltage Vdd) or low (voltage 0). A period in which the voltages of the two clocks change once between a high level and a low level is defined as a period T. Before the time point tp0, no charge is stored in each capacitor. At the time point tp0, the clock CK- rises in voltage to a high level “H” and acts on the capacitors Cp2 and Cp4 at the moment when the voltage rises, and simultaneously raises the voltage across the capacitors Cp2 and Cp4 to the voltage Vdd. I do. Therefore, the voltages at the nodes Np2 and Np4 instantaneously rise to the voltage Vdd. Further, the clock CK + becomes the low level “L”, and the voltage at both ends of the capacitors Cp1 and Cp3 does not change. In this case, the voltage at the drain of the transistor T1 and the voltage at the nodes Np2 and Np4 are higher than the voltages at the nodes Np1, Np3 and Np5, respectively, and the transistors T1, T3 and T5 become conductive, and the nodes Np1, Np3 and Np3, respectively. And Np5, a current is provided to the capacitors Cp1, Cp3, and CLp to be charged, the charge in the capacitors increases, and the voltages of the nodes Np1, Np3, and Np5 increase the width of the voltage dV. The charge pump 10 instantaneously raises the voltage across both capacitors in synchronization with the level fluctuation of the clocks CK + and CK-. Further, by using the conductive circuit 12, the charge is accumulated by the voltage difference between the respective output terminals. Therefore, the frequencies of the clocks CK + and CK- become considerably high, and the period of the change between the high and low levels is shortened. For the first time, a voltage difference can be instantaneously generated by frequently using the level fluctuation. In other words, the time during which the clock CK- maintains the high level between the time points tp0 and tp1 is short. For this reason, the capacitors Cp1, Cp3, and CLp must be charged with a charge corresponding to the voltage dV (usually, the voltage dV is much lower than the voltage Vdd and the threshold voltage Vt) in a small width.
[0008]
At time point tp1, clock CK + goes high and clock CK- goes low. In this case, the clock CK + synchronously raises the voltage across the capacitors Cp1 and Cp3 with the width of the voltage Vdd, and instantaneously raises the voltages of the nodes Np1 and Np3 to Vdd + dv. (The voltage dV is a voltage corresponding to the electric charge of the capacitors Cp1 and Cp3 during the period from the time tp0 to the time tp1.) Further, the clock CK- acts on Cp2 and Cp4 to synchronize the voltages at both ends. And lowers the voltage Vdd before the time tp1 by the width of the voltage Vdd to be 0 voltage. In this case, the voltages of the nodes Np1 and Np3 become higher than the voltages of the nodes Np2 and Np4, respectively, the transistors T2 and T4 become conductive, and the nodes Np2 and Np4 obtain charging currents flowing through the capacitors Cp2 and Cp4, respectively, to perform charging. Is In this case, the voltage of node Np4 becomes higher than the voltage of node Np5, and the voltage difference does not exceed the width of threshold voltage Vt. Therefore, the transistor T5 is not turned on, and the capacitor CLp connected to the node Np5 is not charged.
[0009]
At time t2b, charges corresponding to the voltage dV are injected into the capacitors Cp2 and Cp4, respectively. One end of the capacitors Cp2 and Cp4 connected to the clock CK- is at a low level (0 voltage), and further, the charge is stored in the capacitors and a voltage is generated, so that the voltages of the nodes Np2 and Np4 slightly increase. The voltage becomes dV. At the time point tp2, the clock CK + changes to the low level again, and the clock CK- rises again to the high level. The clock CK + acts on the capacitors Cp1 and Cp3, synchronously lowers the voltage between both ends by the width of the voltage Vdd, and lowers the voltage of the nodes Np1 and Np3 until the voltage returns to the voltage dV at the time point tp1. In comparison, the clock CK- synchronously raises the voltage across the capacitors Cp2 and Cp4 by the width of the voltage Vdd, and together with the voltage dV corresponding to the charge stored between the time tp1 and the time tp2 of the capacitors Cp2 and Cp4. , The voltages of the nodes Np2 and Np4 are increased to Vdd + dV. In this case, the voltages of the nodes Np1, Np3, and Np5 decrease again, and the voltages of the nodes Np2, Np4 increase again, so that the transistors T1, T3, and T5 are turned on again, and the capacitors Cp1, Cp3, and CLp are set to the voltage. only the width of dV
Charged. That is, the voltage corresponding to the charge stored in the capacitors Cp1, Cp3, and CLp together with the charge injected during the period from the time tp0 to the time tp1 increases to a voltage of 2 dV.
[0010]
As the clocks CK + and CK- constantly change, the respective capacitors in the charge pump 10 also have a voltage difference between each output terminal of the conductive circuit 12 and the corresponding output terminal lower than the threshold voltage Vt. Until the charge is constantly accumulated. For example, at time tp3, charges corresponding to the voltage Vdd-Vt have already been injected into the capacitors Cp1, Cp3, and CLp. At time tp4, the voltage difference between both ends of the transistor T1 no longer exceeds the threshold voltage Vt, and the capacitor Cp1 is not charged. In this case, the charge in the capacitor Cp1 reaches a stable state. Therefore, the voltage corresponding to the stable saturation charge in the capacitor Cp1 is Vdd-Vt. However, at time tp4, the voltage of the node Np2 rises under the action of the high level of the clock CK-, becomes higher than the voltage of the node Np3, and the voltage difference exceeds the threshold voltage Vt. Therefore, the transistor T3 is turned on, and charges Cp3 by flowing current.
[0011]
Similarly, the transistor T5 is turned on, and the capacitor CLp is continuously charged. At time tp5, the voltage corresponding to the charge stored in the capacitor Cp2 has already reached 2Vdd-2Vt. That is, even if the voltage of the node Np1 rises to the voltage 2Vdd-Vt by the action of the clock CK +, the voltage difference between the nodes Np1 and NP2 does not exceed the threshold voltage Vt, and the charge stored in the capacitor Cp2 is stable. The saturation state is reached, and it does not increase continuously. Similarly, the charges stored in the capacitors Cp3 and Cp4 are also in a stable and saturated state in order.
[0012]
When the time point tp6 is reached, the charge of each capacitor becomes a stable saturated state, and the clock CK- acts on the nodes Np2 and Np4 to increase the voltage, provided that the voltage difference between the nodes Np3 and Np5 is a threshold. The voltage does not exceed and the capacitors Cp3 and CLp are not charged. Similarly, when reaching the time point tp7, the clock CK + acts on the nodes Np1 and Np3 to increase the voltage, but the difference between the voltages of the two nodes Np2 and Np4 respectively becomes the threshold voltage Vt. As a result, the transistors T2 and T4 no longer charge the capacitors CP2 and Cp4 depending on the energized state. In summary, when the stored charge reaches a stable saturation state, the voltage corresponding to the charge stored in the capacitors Cp1, Cp2, Cp3, and CP4 is Vdd-Vt, 2 (Vdd, respectively). −Vt), 3 (Vdd−Vt), and 4 (Vdd−Vt). In the equivalent load capacitor CLp, the charge is accumulated up to the voltage 5 (Vdd−Vt), and becomes the output voltage provided by the charge pump 10. Normally, the voltage 5 (Vdd-Vt) is higher than the biased voltage Vdd. If the output voltage is to be increased, a capacitor serving as a charging element and a transistor corresponding to the capacitor are further provided in the charging circuit.
[0013]
The conventional charge pump 10 disclosed in FIG. 1 has the following disadvantages. First, in the capacitors Cp1 to Cp4 serving as respective charging elements in the charging circuit 10, the charge in a stable state that must be stored in each capacitor increases one after another, and when reaching Cp4, it corresponds to the charge stored in Cp4. The voltage has already reached 4 (Vdd-Vt). If the charge pump 10 is further provided with another charging element, more charge is injected into the capacitor as the charge pump 10 approaches the load output terminal, and the saturated charge in the stable state increases. As those skilled in the art are familiar with, charge is generated by the oxide layer separating both conductive layers. The greater the charge stored in the capacitor, the greater the voltage difference between the two conductive layers, and if the voltage difference exceeds a certain level, breakdown of the oxide layer occurs and the insulating action of the oxide layer is impaired. The charge pump 10 cannot operate correctly.
[0014]
Further, the conventional charge pump 10 uses the n-type metal oxide semiconductor transistors T1 to T5 as conductive elements. As those skilled in the art are familiar, an n-type metal oxide semiconductor is generally formed on a shared p-type substrate. That is, the p-type substrate is a body shared by the respective n-type metal oxide semiconductor transistors, and the normal body is connected to the ground terminal. As disclosed in FIG. 1, the bases of the transistors T1 to T5 are connected to the ground terminal via the same p-type body. In such a structure, the threshold voltages of the respective transistors T1 to T5 are different from each other in order to generate a body effect, which causes difficulty in circuit design and operation. Furthermore, it has a serious drawback that the breakdown of the transistor is easily caused. Taking the transistor T5 closest to the load output end as an example, the maximum value of the voltage of the source of the transistor T5 (connected to the node Np5) reaches the voltage 5 (Vdd-Vt). (See FIG. 2) The maximum value of the voltage of the drain of the transistor T5 (connected to the node Np4) reaches 5Vdd-4Vt. However, the body of the transistor T5 relatively maintains the zero voltage of the ground. For this reason, in the transistor T5, the voltage difference between the source and the body and between the drain and the body becomes excessive, so that the transistor T5 is broken down and damaged. When such a phenomenon occurs, the conventional charge pump 10 cannot operate normally.
[0015]
[Problems to be solved by the invention]
An object of the present invention is to provide a charge pump for a flash memory that can effectively prevent breakdown of a capacitor and a transistor and maintain normal operation of the capacitor.
[0016]
[Means for Solving the Problems]
The inventor of the present invention has conducted intensive studies in view of the drawbacks of the prior art, and as a result, has formed a charge pump with a conductive circuit and first, second, and third charging elements. A first, a second, and a third output terminal and a plurality of conductive elements, each of the plurality of conductive elements has a positive terminal and a negative terminal, and a voltage of each positive terminal is smaller than that of the negative terminal. When the voltage difference exceeds a predetermined value, the conductive element provides a current through the negative terminal, and when the voltage at the negative terminal is higher than the voltage at the positive terminal, the conductive element Prevents current from flowing from the minus end to the plus end. One end of the conductive element has a plus end and a minus end connected to the first output end and the second output end, respectively, and the other end of the conductive element has a plus end and a negative end respectively connected to the second output end. And a third output terminal, wherein the first charging element has both ends, and stores a charge corresponding to the current after receiving a current at one end, and corresponds to the stored charge from between both ends. The corresponding voltage varies depending on the difference in the amount of charge to be output and stored. Further, one end of the first charging element is connected to the first output terminal, one end of the second charging element is connected to the second output terminal, and one end of the third charging element is connected to the third output terminal. Connected to an output end, the other end of the third charging element connected to the first output end to form a substantially short circuit with the first output end, and stored a charge in the first charging element. Then, a problem is caused by the structure in which the voltage at one end of the first output terminal connected to the third charging element is substantially different from the voltage at one end of the first charging element not connected to one end of the first output terminal. The present invention has been completed based on such knowledge, with a focus on the point that can be solved.
[0017]
Hereinafter, the present invention will be described specifically.
[0018]
A charge pump according to claim 1, comprising: a conductive circuit; and first, second, and third charging elements.
The conductive circuit includes first, second, and third output terminals and a plurality of conductive elements,
The plurality of conductive elements each have a positive terminal and a negative terminal, and when the voltage of each positive terminal is higher than the negative terminal and exceeds a predetermined value, the conductive element is connected via the negative terminal. Providing a current, wherein when the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end;
One of the conductive elements has a positive terminal and a negative terminal connected to the first output terminal and the second output terminal, respectively.
The other end of the conductive element has a positive terminal and a negative terminal connected to the second output terminal and the third output terminal, respectively.
The first, second, and third charging elements each have both ends, and after receiving a current at one end, store a charge corresponding to the current and a voltage corresponding to the stored charge from between the both ends. And the corresponding voltage also differs depending on the difference in the amount of charge stored.
One end of the first charging device is connected to the first output terminal, one end of the second charging device is connected to the second output terminal, and one end of the third charging device is connected to the third output terminal. And the other end of the third charging element is connected to the first output to form a substantially short circuit with the first output;
After storing the charge in the first charging element, the voltage at one end connected to the first output terminal of the third charging element is substantially equal to the voltage at one end not connected to the first output terminal of the first charging element. To be different.
[0019]
In the charge pump according to the second aspect, each of the conductive elements in the first aspect is a diode.
[0020]
The charge pump according to claim 3, wherein each of the conductive elements according to claim 1 is a transistor, the transistor including a gate, a source, and a drain, and the source is a positive terminal of the conductive element. The gate is connected to the drain and becomes a negative end of the conductive element.
[0021]
According to a fourth aspect of the present invention, the transistor according to the third aspect is a p-type metal oxide film transistor.
[0022]
In a charge pump according to a fifth aspect, each of the first, second and third charging elements in the first aspect is a capacitor.
[0023]
According to a sixth aspect of the present invention, in the charge pump, the capacitor is connected to the transistor.
[0024]
The charge pump according to claim 7, wherein the conductive circuit according to claim 1 further includes a load output end connected to the load element by an external connection method, and the conductive element of the conductive circuit is connected to the third output end. A plus end and a minus end respectively connected to the load output end, one end of the load element is connected to the load output end, the other end is connected to the ground end, and a current is applied to one end of the load element. When input, the charge corresponding to the current is stored in the load element, and an output voltage is output between both ends of the load element.
[0025]
According to a charge pump described in claim 8, in the conductive circuit in claim 7, the positive terminal of the conductive element is connected to the second output terminal, and the negative terminal of the conductive element is connected to the load output terminal.
[0026]
A charge pump according to a ninth aspect is the charge pump according to the seventh aspect, further comprising a second conductive circuit, and fourth, fifth, and sixth charge elements.
The second conductive circuit includes a fourth output terminal, a fifth output terminal, a sixth output terminal, a second load terminal, and a plurality of conductive elements,
Each of the plurality of conductive elements has a positive terminal and a negative terminal, and when the voltage of the positive terminal of the conductive element becomes higher than the voltage of the negative terminal and exceeds a predetermined value, the conductive element becomes the negative terminal. Supply current through the
When the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end,
One of the conductive elements has a plus end and a minus end connected to the fourth output end and the fifth output end, respectively.
The other end of the conductive element has a positive terminal and a negative terminal connected to the fifth output terminal and the sixth output terminal, respectively.
The other end of the conductive element has a positive terminal and a negative terminal connected to the sixth output terminal and the second load terminal, respectively.
The fourth, fifth, and sixth charging elements each have both ends, and when a current is input to one end, store the charge corresponding to the current, and apply a voltage corresponding to the stored charge from between both ends. And the corresponding voltage also differs depending on the difference in the amount of charge stored.
One end of the fourth charging element is connected to the fourth output terminal, one end of the fifth charging element is connected to the fifth output terminal, and one end of the sixth charging element is connected to the sixth output terminal. And the second load end is connected to the load output end.
[0027]
According to a tenth aspect of the present invention, in the charge pump according to the ninth aspect, the sixth charging element is connected to the fourth output terminal without being connected to one end of the sixth output terminal.
[0028]
A charge pump according to claim 11, comprising: a conductive circuit; and a first charging element and a second charging element.
The conductive circuit includes a first output terminal, a second output terminal, a load output terminal, and a plurality of conductive elements;
The load output terminal is connected to a load element, the load element stores a charge corresponding to the current when a current is input to the load output terminal, and the load output terminal outputs an output voltage,
The plurality of conductive elements each have a positive terminal and a negative terminal, and when the voltage of each positive terminal is higher than the negative terminal and exceeds a predetermined value, the conductive element is connected via the negative terminal. Providing a current, wherein when the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end;
One of the conductive elements has a positive terminal and a negative terminal connected to the first output terminal and the second output terminal, respectively.
The other end of the conductive element has a plus end and a minus end connected to the second output end and the load output end, respectively.
The other end of the conductive element has a plus end and a minus end connected to the first output end and the load output end, respectively.
The first and second charging elements each have both ends, and when one end receives a current, store the charge corresponding to the current and output a voltage corresponding to the stored charge from between both ends. The voltage corresponding to the difference in the amount of stored charge is also different, and one end of the first charging device is connected to the first output terminal, and one end of the second charging device is connected to the second output terminal. I do.
[0029]
According to a twelfth aspect of the present invention, in the charge pump according to the twelfth aspect, the conductive circuit according to the twelfth aspect further includes a third output terminal, and the conductive circuit further includes a third output terminal having a positive terminal and a negative terminal connected to the third output terminal. Terminal and the first output terminal,
The charge pump further includes a third charging element. The third charging element has both ends. When a current is input to one end of the third charging element, a charge corresponding to the current is stored. And outputs a voltage corresponding to the stored charge, so that the voltage corresponding to the difference in the amount of stored charge is also different,
One end of the third charging element is connected to the third output terminal, and one end of the second charging element not connected to the second output terminal is connected to the third output terminal.
[0030]
The charge pocharge according to claim 13 further includes the second conductive circuit according to claim 11, and fourth and fifth charge elements,
The second conductive circuit includes a fourth output terminal, a fifth output terminal, a second load terminal, and a plurality of conductive elements,
Each of the plurality of conductive elements has a positive terminal and a negative terminal, and when the voltage at the positive terminal of the conductive element becomes higher than the voltage at the negative terminal and exceeds a predetermined value, the conductive element becomes the negative terminal. Provide current through the
When the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end,
One of the conductive elements has a positive terminal and a negative terminal connected to the fourth output terminal and the fifth output terminal, respectively.
The other end of the conductive element has a plus end and a minus end connected to the fifth output end and the load end, respectively.
The fourth and fifth charging elements each have both ends, and when a current is input to one end of the charging element, store the charge corresponding to the current, and apply a voltage corresponding to the stored charge from between the both ends. And the corresponding voltage also differs depending on the difference in the amount of charge stored.
One end of the fourth charging device is connected to the fourth output terminal, one end of the fifth charging device is connected to the fifth output terminal, and the second load terminal is connected to the load output terminal. I do.
[0031]
In the charge pump according to claim 14, the second conductive circuit according to claim 13 is configured such that the other end of the plurality of conductive elements further has a plus terminal connected to the fourth output terminal and a minus terminal connected to the second output terminal. Connect to load end.
[0032]
According to a charge pump described in claim 15, the second conductive circuit in claim 13 further has a sixth output terminal, and the second conductive circuit has one positive terminal and one negative terminal of the conductive element, respectively. Connected to the sixth output terminal and the fourth output terminal,
The charge pump further includes a sixth charging element having both ends. When a current is input to one end of the sixth charging element, a charge corresponding to the current is stored, and the stored charge is stored between the both ends. And output a voltage corresponding to the difference in the amount of charge to be stored, so that the corresponding voltage also differs,
One end of the sixth charging device is connected to the sixth output terminal, and one end of the fifth charging device not connected to the fifth output terminal is connected to the sixth output terminal.
[0033]
In a charge pump according to a sixteenth aspect, each of the conductive circuits according to the eleventh aspect is a diode.
[0034]
According to a charge pump described in claim 17, the diode in claim 16 is formed by connecting a p-type metal oxide semiconductor.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge pump for a flash memory, and more particularly, to a charge pump for connecting a capacitor in series and preventing a breakdown of an oxide layer of the capacitor, comprising a conductive circuit, first, second, and third charging elements. And is configured.
[0036]
In order to describe the structure and features of such a charge pump in detail, a specific embodiment will be described below with reference to the drawings.
[0037]
[First Embodiment]
FIG. 3 discloses a circuit of a charge pump 20 according to an embodiment of the present invention. The charge pump 20 includes a conductive circuit 22, capacitors C1 to C4 serving as charging elements, and a capacitor CL serving as a load element, which simulates equivalent loading of the charge pump 20, and a voltage across the capacitor CL is applied to the charge pump. 20 provides the output voltage V0. P-type metal oxide semiconductor transistors M1 to M5 are provided in conductive circuit 22 corresponding to the respective capacitors. Each transistor is connected as a conductive element to form a diode, and has a source as a positive terminal and a drain connected to a gate as a negative terminal. The body may be connected to the drain.
[0038]
When the voltage at the positive terminal of the conductive element formed by each transistor is higher than that at the negative terminal, and the difference exceeds the threshold voltage of each transistor, the transistor is energized and the current becomes minus from the positive terminal. Flows to the edge. Conversely, if the voltage at the positive terminal of the conductive element is higher than the negative terminal, but the difference does not exceed the threshold voltage, the conductive element is not energized.
[0039]
The drain (positive terminal) of the transistor M1 is connected to a DC bias power supply of the voltage Vdd, and the negative terminal of each conductive element is the output terminal of the conductive circuit 22. Therefore, the nodes N1 to N5 in the conductive circuit 22 become output terminals. The nodes N1 to N4 are connected to one ends of the capacitors C1 to C4, respectively, and the node N5 is a load output end and is connected to a load element. The other end of the capacitor C1 is connected to the clock CK +, and the other end of the capacitor C2 is connected to the clock CK-.
[0040]
The difference between the charge pump 20 of the embodiment and the conventional technique is that the other end of the capacitor C3 is connected to the node N1 without being connected to a clock, and the other end of the capacitor C4 is connected to the node N2. The clock CK + and the clock CK− are opposite to each other, like the clock used in the conventional charge pump 10.
[0041]
As in the case where the conventional charge pump 10 is operated, the charge pump 20 according to the present invention also causes the clock CK + and the clock CK- to alternately act on each node, instantaneously change the voltage of the node, and change the conduction of each node. The voltage difference between the positive and negative ends of the element is made higher than the threshold voltage Vt of the transistor which is a conductive element to make the transistor conductive, and further, a current for charging toward the negative end is transmitted to each of the capacitors C1 to C4. And raise the voltage of each node. When the voltage difference between the positive and negative terminals of each conductive element does not exceed the threshold voltage, the conductive element is turned off, and the charging of each capacitor reaches a saturation state.
[0042]
FIG. 4 shows a situation in which the voltages of the respective nodes N1 to N5 change according to the clock after the charge of each capacitor in the charge pump 20 reaches a stable saturated state. According to the drawing, when the clock CK + is a low voltage (represented by the symbol “L”) of 0 voltage and the clock CK− is a high level (represented by the symbol “H”) of the voltage Vdd, the nodes N1 to The voltages of N5 are (Vdd-Vt), (3Vdd-2Vt), (3Vdd-3Vt), (5Vdd-4Vt), and (5Vdd-5Vt), respectively. Conversely, when the clock CK + goes high and the clock CK- goes low, the voltages at the nodes N1 to N5 are (2Vdd-Vt), (2Vdd-2Vt), (4Vdd-3Vt), and (4Vdd-, respectively). 4Vt) and (5Vdd-5Vt). When the charge of each capacitor reaches a stable state, the voltage of each node of the charge pump 20 becomes similar to the voltage of the conventional charge pump 10. However, the charge in the stable state stored in each capacitor in the charge pump 20 in the present invention is greatly reduced, so that breakdown of each capacitor as a charging element can be effectively prevented. The node N3 in the charge pump 20 is further connected to the clock CK + via the capacitors C3 and C1. The voltage at the node N3 is equal to a voltage obtained by adding a voltage level for driving the clock CK + to a voltage across the capacitors C3 and C1. Therefore, even if the voltage of the node N3 rises to the voltage (4Vdd-3Vt), the voltage corresponding to the stable charge stored in the capacitor C3 is actually (2Vdd-2Vt). Similarly, the voltage of the node N4 is obtained by adding a voltage across the capacitor C2 and a level for driving the clock CK- to the capacitor C4. Even if the voltage at the node N4 reaches the highest value (5Vdd-4Vd), the voltage corresponding to the steady state charge stored in the capacitor C4 is only (2Vdd-2Vt). In summary, the voltages for the stable state charges stored in the capacitors C1 to C4 in the charge pump 20 according to the present invention are (Vdd-Vtt), (2Vdd-2Vt), (2Vdd-2Vt), and (2Vdd), respectively. -2Vt).
[0043]
It should be noted here that the capacitor C4 closest to the load output terminal and the voltage corresponding to the maximum stored electric charge are only a little (2Vdd-2Vt). However, in the conventional charge pump 10, the voltages corresponding to the charges in the stable state stored in the capacitors Cp1 to Cp4 are (Vdd-Vt), (2Vdd-2Vt), (3Vdd-3Vt), and (4Vdd), respectively. -4Vt). A comparison of the two shows that the charging element of the charge pump according to the present invention can effectively provide a high output voltage without increasing the stored charge.
[0044]
FIG. 5 discloses a circuit of a charge pump according to the present invention configured by a general connection method. As shown in the figure, the charge pump 20B is provided with transistors M1, M2, M3, etc. connected in the form of K diodes to the conductive circuit 22B to form conductive elements, and the nodes N1 to Nk, which are load output terminals, are connected. N2, N3, etc. are output terminals, and capacitors C1, C2, C3 up to the capacitor CL0, which is a load element, are charging elements. Each capacitor is connected to a corresponding output terminal. For example, the capacitor C1 connected to the capacitor CL0 connected to the load output terminal is connected to the node N1, the capacitor C2 is connected to the node N2, and the k-th capacitor Ck is connected to the node Nk. The other ends of the capacitors C1C2 are connected to clocks CK + and CK-, respectively. However, the other ends of the other k-th capacitors Ck are connected to the node Nk-2. Therefore, the capacitor Ck is actually connected to the nodes Nk and Nk-2. In other words, the k-th node Nk other than the load output terminal is assumed to be an odd number from the capacitors Ck, Ck-2, Ck-4, etc. to the capacitor C1, or if k is an odd number until the capacitor C2. Are connected to the clock CK + or the clock CK− via the clock signal if the number is an even number. Therefore, the clock acts on the node Nk via these capacitors to increase or decrease the voltage, thereby achieving the purpose of accumulating charges one by one.
Further, the accumulation of the voltage at each node Nk is obtained by the sum total of the electric charges accumulated by the capacitors as a plurality of charging elements. Therefore, even if the amount of electric charge stored in a single capacitor is not large, a high voltage can be stored at each node, and the load output terminal can store a high output voltage. As the node Nk approaches the load output end, that is, as the k value increases, the node Nk is connected to the clock via a series of a large number of capacitors Ck-2 and Ck-4. Thus, the closer the node Nk is to the load output end, the higher the voltage will be, but the voltage will be shared by more capacitors. In the present invention, no matter how many capacitors are provided as charge elements, the charge element closest to the load output terminal needs only to store a stable state charge corresponding to a slight voltage (2Vdt-2Vt) at the maximum.
However, any of the charging elements in the conventional charge pump is directly connected to the clock. Assuming that the conventional charge pump is provided with L charging elements, the voltage corresponding to the charge stored in the capacitor closest to the load output terminal is L (Vdt-Vt). As in the conventional charge pump 10 disclosed in FIG. 1, as the number of charging elements increases, the amount of charge stored to accumulate voltage at each node must also increase. For this reason, each of the charging elements eventually breaks down very easily.
[0045]
[Second embodiment]
FIG. 6 discloses a second embodiment. The charge pump 30 according to the second embodiment includes four capacitors Cb1 to Cb4 serving as charging elements, and a capacitor CL2 serving as a load element for simulating a load effect. According to the four charging elements, the conductive circuit 32 is provided with p-type metal oxide semiconductor transistors Q1 to Q6 connected in the form of six diodes to form conductive elements. Nodes Nb1 to Nb5 are output terminals, and one ends of Nb1 to Nb4 are connected to one ends of capacitors Cb1 to Cb4, respectively. The node Nb5 is a load output terminal and is connected to the capacitor CL2. These elements are connected by a connection method similar to the charge pump 20. That is, the capacitors Cb1 and Cb2 are connected to the clocks CK + and CK-, respectively, and the capacitors Cb3 and Cb4 are connected to the nodes Nb1 and Nb2, respectively. In the charge pump 30 of the second embodiment, a transistor Q6 serving as a conductive element is connected between a node Nb3 and a node Nb5 at a load output terminal. This point is different from the charge pump 20. This connection feature can increase the charging speed of the capacitor CL2, which is a load element. The charge pump 20 disclosed in FIG. 3 can only charge the capacitor CL loaded only with the transistor M5 in an energized state. However, the charge pump 30 disclosed in FIG. 6 charges the capacitor CL2 loaded by the two transistors Mb5 and Mb6. In the process of charging the capacitors Cb1 to Cb4 and the load capacitor CL2, when the clock CK- goes low, the voltage at the node Nb4 of the transistor Q5 becomes lower than the voltage at the node Nb5. In this case, the transistor Q5 is turned on and cannot transmit the charging current to the capacitor CL2. However, in this case, the clock CK + goes high and acts on the node Nb3 to raise the level, so that the transistor Q6 is turned on and charges CL2.
[0046]
Similarly, when the clock CK- transitions to the high level and the clock CK + transitions to the low level, the voltage of the node Nb3 decreases and the transistor Q6 stops conducting, except that the node Nb4 of the transistor Q5 connects the clock CK-. , The voltage rises, transistor Q5 is turned on, and capacitor CL2 is charged. Therefore, in one cycle in which the high and low levels of the clock transition to each other, whether in the first half or the second half of the cycle, one transistor is energized and loaded until the charge stored in each capacitor reaches a stable saturated state. Is charged.
[0047]
FIG. 7 discloses a circuit of the charge pump 30 disclosed in FIG. 6 when a transistor is actually used as a charging element. In FIG. 6, capacitors Cb1 to Cb4 serving as charging elements are formed by p-type metal oxide semiconductor transistors QC1 to QC4 in FIG. 7, respectively. In the p-type metal oxide semiconductor transistors QC1 to QC4, the gate is used as one end of the capacitor, and the source, drain and body are connected to each other and used as the other end of the capacitor. As described above, each capacitor in the present invention does not need to store a large amount of charge. Therefore, it is suitable for a structure in which a capacitor formed by connecting transistors is used as a charging element.
[0048]
[Third embodiment]
FIG. 8 shows a third embodiment. The charge pump 40 according to the third embodiment includes two conductive circuits 42A and 42B. The conductive circuit 42A uses the transistors K1 to K6 as diode-type conductive elements, and connects the nodes Nb1 to Nb4 to the capacitors Cc1 to Cc4, which are charging elements, as output terminals. The node Nc5 serves as a load output terminal and is connected to a capacitor CL3 for representing a load effect. The voltage across both ends of the capacitor CL3 is the output voltage provided by the charge pump 40. The transistor K6 is provided between the nodes Nc3 and Nc5 similarly to the charge pump disclosed in FIG. With a similar layout, the conductive circuit 42B uses the transistors D1 to D6 as diode-type conductive elements and uses the nodes Nd1 to Nd4 as output terminals to connect to the capacitors Cd1 to Cd4 serving as charging elements. The node Nd5 serves as another load output terminal, and is connected to the capacitor CL3 together with the node Nc5. The other ends of the capacitors Cc3, Cc4, Cd3, Cd4 are connected to nodes Ne1, Ne2, Nd1, Nd2, respectively.
[0049]
It should be noted that the clock CK + controls the two conductive circuits via the capacitors Cc1 and Cd2, respectively, and the clock CK- is electrically connected to the two conductive circuits via the capacitors Cc2 and Cd1. Is a point. The charge pump 40 can further increase the charging speed of the equivalently loaded capacitor CL3. For example, in the process of charging each of the charging elements with a stable saturated charge, when the clock CK + is at a high level and the clock CK− is at a low level, the voltages of the nodes Nc3 and Nd4 increase due to the action of the clock CK +, K6 and D5 are turned on, and simultaneously charge the capacitor CL3 to be loaded.
When the clock CK + is at a low level and the clock CK- is at a high level, the voltages of the nodes Nc4 and Nd3 rise due to the action of the clock CK-, the transistors K5 and D6 are turned on, and the charges of the respective charging elements reach a stable state. Until the capacitor CL3 is charged. Therefore, in the process of charging each charging element and stabilizing the charge, a maximum of two transistors charge the capacitor CL3 regardless of the first half or the second half of one cycle in which the level of the clock transitions.
[0050]
As described above, the charge pump provides a high output voltage in the step of writing or erasing the flash memory. The output voltage is used to generate a tunnel effect as a driving voltage. In actual operation, the charge pump must provide some current drive capability in addition to providing a high output voltage. In other words, the capacitor CL3, which is an equivalent load element, drives a current by losing charge. Once the capacitor CL3 loses charge, the voltage across the two ends drops. In this case, the charge pump 40 charges the capacitor CL3 again. In the charge pump 40, when stable charge in a stable state is stored in each charging element like the charge pumps 20 and 30, the nodes Nc1 to Nc4 and Nd1 to Nd4 reach the maximum voltage. This is similar to the case where the nodes N1 to N4 of the charge pump 20 reach the maximum voltage as disclosed in FIG. When the charge stored in each capacitor reaches a stable saturation state, for example, when the voltage across both ends of the capacitor CL3 drops again to the voltage 5Vdd-6Vt, the charge pump disclosed in FIG. 3 will be disclosed in FIG. Regardless of the charge pump, the transistor M5 or Q5 closest to the load output charges the capacitor CL3 by transitioning the clock CK- to a high level. In other words, in one cycle in which the clock transitions to a high or low level, the charge is not replenished to the capacitor to be loaded in only half of the cycle. However, when the same situation occurs in the charge pump 40 disclosed in FIG. 8, when the clock CK + transitions to the high level (the first half of one cycle), the voltage of the node Nd4 is driven to reach the voltage 5Vdd-4Vt, The transistor CL is turned on to charge the capacitor CL3 to be loaded. When the clock CK + shifts to the low level (the latter half of one cycle), the clock CK- shifts to the high level, and acts on the node Nc4 to increase the voltage to 5Vdd-4Vt, thereby turning on the transistor K5. Then, the capacitor CL3 to be loaded is charged. Thus, in one cycle in which the clock transitions high or low, at least one transistor, whether in the first half or the second half, transmits the charging current, recharges the capacitor CL3, and the speed of the voltage recovery of the capacitor CL3. Enhance.
[0051]
In a conventional charge pump, each conductive element connects an n-type metal oxide semiconductor transistor. Therefore, a body effect may easily occur, and the voltage difference between the electrodes may be excessively large, which may cause damage to the transistor. Excessively, each of the charging elements in the conventional charge pump is directly connected to a clock, so that it stores a large amount of electric charge and accumulates a voltage, and generates a high output voltage, so that a large amount of electric charge is stored. Breakdown of the oxide layer in the capacitor occurs very easily, causing damage. In this case, the conventional charge pump cannot operate. However, the charge pump according to the present invention employs a p-type metal oxide semiconductor transistor. The p-type metal oxide semiconductor transistor has an n-type well as a body. Therefore, the drain of the p-type metal oxide semiconductor transistor can be connected to a high voltage, so that the occurrence of a body effect and the breakdown of the transistor can be prevented. Further, in the present invention, each charging element (that is, a capacitor) in the charge pump is connected in series to store a high voltage. That is, although the amount of charge stored in a single charging element is not large, a high output voltage can be accumulated by combining the respective charging elements in series. Moreover, the normal operation of the charge pump can be ensured without the breakdown of the capacitor as the charging element. The present invention also discloses a different embodiment to provide a technique capable of accelerating charging, generating an output voltage at a high speed, and replenishing a charge lost at a load at a high speed.
[0052]
The above is a preferred embodiment of the present invention, and does not limit the scope of the present invention. Therefore, any modifications or changes that can be made by those skilled in the art, which are made in the spirit of the present invention and which have an equivalent effect on the present invention, fall within the scope of the claims of the present invention. Shall be.
[0053]
【The invention's effect】
The charge pump according to the present invention has an effect of effectively preventing breakdown of a capacitor and a transistor and maintaining normal operation. Further, the charge pump according to the present invention can replenish the loss of charge of the capacitor to be loaded at a high speed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a structure of a conventional charge pump.
FIG. 2 is a table showing a change with time of a voltage of an associated node when the charge pump disclosed in FIG. 1 is operated.
FIG. 3 is an explanatory diagram showing a structure of a charge pump according to the present invention.
FIG. 4 is a table showing voltages of respective nodes in a state where charging of the charge pump disclosed in FIG. 3 is stabilized.
FIG. 5 is an explanatory diagram showing a mode in which the charge pump disclosed in FIG. 3 is applied.
FIG. 6 is an explanatory diagram showing a charge pump structure according to a second embodiment.
FIG. 7 is an explanatory diagram showing a mode in which the charge pump disclosed in FIG. 6 is applied.
FIG. 8 is an explanatory diagram showing a charge pump structure according to a third embodiment.
[Explanation of symbols]
10, 20, 30 charge pump
12, 22, 32 conductive circuit
14A-14E column
CK +, CK- clock
Vdd, dV voltage
T period
tp0 to tp7
Vt threshold voltage
Vp0, V0 output voltage
Cp1 to Cp4, CLp, C1 to C4, Cb1 to Cb4, Cc1 to Cc4, Cd1 to Cd4, CL, CL0, CL2, CL3
Capacitor
Np1 to Np5, N1 to N5, Nb1 to Nb5, Nc1 to Nc5,
Nd1 to Nd5 nodes
T1 to T5, M1 to M5, Q1 to Q6, QC1 to QC4, K1 to K6, D1 to D6 Transistors

Claims (17)

In a charge pump including a conductive circuit and first, second, and third charging elements,
The conductive circuit includes first, second, and third output terminals and a plurality of conductive elements,
The plurality of conductive elements each have a positive terminal and a negative terminal, and when the voltage of each positive terminal is higher than the negative terminal and exceeds a predetermined value, the conductive element is connected via the negative terminal. Providing a current, wherein when the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end;
One of the conductive elements has a positive terminal and a negative terminal connected to the first output terminal and the second output terminal, respectively.
The other end of the conductive element has a positive terminal and a negative terminal connected to the second output terminal and the third output terminal, respectively.
The first, second, and third charging elements each have both ends, and after receiving a current at one end, store a charge corresponding to the current and a voltage corresponding to the stored charge from between the both ends. And the corresponding voltage also differs depending on the difference in the amount of charge stored.
One end of the first charging device is connected to the first output terminal, one end of the second charging device is connected to the second output terminal, and one end of the third charging device is connected to the third output terminal. And the other end of the third charging element is connected to the first output to form a substantially short circuit with the first output;
After storing the charge in the first charging element, the voltage at one end connected to the first output terminal of the third charging element is substantially equal to the voltage at one end not connected to the first output terminal of the first charging element. A charge pump characterized by being different from the above. The charge pump according to claim 1, wherein each of the conductive elements is a diode. Wherein each of the conductive elements is a transistor, the transistor comprising a gate, a source, and a drain, wherein the source is a positive end of the conductive element, and the gate is connected to the drain to form the conductive element. The charge pump according to claim 1, wherein a negative end of the charge pump is provided. The charge pump according to claim 3, wherein the transistor is a p-type metal oxide film transistor. The charge pump according to claim 1, wherein the first, second, and third charging elements are all capacitors. The charge pump according to claim 5, wherein the capacitor is formed by connecting transistors. The conductive circuit further includes a load output terminal connected to the load element by an external connection method, and the conductive element of the conductive circuit separately includes a positive terminal and a negative terminal connected to the third output terminal and the load output terminal, respectively. And one end of the load element is connected to the load output end, the other end is connected to the ground end, and when a current is input to one end of the load element, the load element corresponds to the current. The charge pump according to claim 1, wherein the charge is stored, and an output voltage is output between both ends of the load element. 8. The charge pump according to claim 7, wherein the conductive circuit has a positive terminal of the conductive element connected to the second output terminal and a negative terminal of the conductive element connected to the load output terminal. The charge pump further includes a second conductive circuit and fourth, fifth, and sixth charging elements.
The second conductive circuit includes a fourth output terminal, a fifth output terminal, a sixth output terminal, a second load terminal, and a plurality of conductive elements,
Each of the plurality of conductive elements has a positive terminal and a negative terminal, and when the voltage of the positive terminal of the conductive element becomes higher than the voltage of the negative terminal and exceeds a predetermined value, the conductive element becomes the negative terminal. Supply current through the
When the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end,
One of the conductive elements has a plus end and a minus end connected to the fourth output end and the fifth output end, respectively.
The other end of the conductive element has a positive terminal and a negative terminal connected to the fifth output terminal and the sixth output terminal, respectively.
The other end of the conductive element has a positive terminal and a negative terminal connected to the sixth output terminal and the second load terminal, respectively.
The fourth, fifth, and sixth charging elements each have both ends, and when a current is input to one end, store the charge corresponding to the current, and apply a voltage corresponding to the stored charge from between both ends. And the corresponding voltage also differs depending on the difference in the amount of charge stored.
One end of the fourth charging element is connected to the fourth output terminal, one end of the fifth charging element is connected to the fifth output terminal, and one end of the sixth charging element is connected to the sixth output terminal. 8. The charge pump according to claim 7, wherein the second load terminal is connected to the load output terminal. The charge pump according to claim 9, wherein the sixth charging element is connected to the fourth output terminal without being connected to one end of the sixth output terminal. In a charge pump including a conductive circuit, a first charging element and a second charging element,
The conductive circuit includes a first output terminal, a second output terminal, a load output terminal, and a plurality of conductive elements;
The load output terminal is connected to a load element, the load element stores a charge corresponding to the current when a current is input to the load output terminal, and the load output terminal outputs an output voltage,
The plurality of conductive elements each have a positive terminal and a negative terminal, and when the voltage of each positive terminal is higher than the negative terminal and exceeds a predetermined value, the conductive element is connected via the negative terminal. Providing a current, wherein when the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end;
One of the conductive elements has a positive terminal and a negative terminal connected to the first output terminal and the second output terminal, respectively.
The other end of the conductive element has a plus end and a minus end connected to the second output end and the load output end, respectively.
The other end of the conductive element has a plus end and a minus end connected to the first output end and the load output end, respectively.
The first and second charging elements each have both ends, and when one end receives a current, store the charge corresponding to the current and output a voltage corresponding to the stored charge from between both ends. The voltage corresponding to the difference in the amount of stored charge is also different, and one end of the first charging device is connected to the first output terminal, and one end of the second charging device is connected to the second output terminal. A charge pump. The conductive circuit further includes a third output terminal, and the conductive circuit further includes a positive terminal and a negative terminal of another conductive element connected to the third output terminal and the first output terminal, respectively.
The charge pump further includes a third charging element. The third charging element has both ends. When a current is input to one end of the third charging element, a charge corresponding to the current is stored. And outputs a voltage corresponding to the stored charge, so that the voltage corresponding to the difference in the amount of stored charge is also different,
The one end of the third charging element is connected to the third output terminal, and the other end of the second charging element that is not connected to the second output terminal is connected to the third output terminal. 12. The charge pump according to item 11. The charge pocharge further includes a second conductive circuit, and fourth and fifth charging elements,
The second conductive circuit includes a fourth output terminal, a fifth output terminal, a second load terminal, and a plurality of conductive elements,
Each of the plurality of conductive elements has a positive terminal and a negative terminal, and when the voltage at the positive terminal of the conductive element becomes higher than the voltage at the negative terminal and exceeds a predetermined value, the conductive element becomes the negative terminal. Provide current through the
When the voltage at the minus end is higher than the voltage at the plus end, the conductive element prevents current from flowing from the minus end to the plus end,
One of the conductive elements has a positive terminal and a negative terminal connected to the fourth output terminal and the fifth output terminal, respectively.
The other end of the conductive element has a plus end and a minus end connected to the fifth output end and the load end, respectively.
The fourth and fifth charging elements each have both ends, and when a current is input to one end of the charging element, store the charge corresponding to the current, and apply a voltage corresponding to the stored charge from between the both ends. And the corresponding voltage also differs depending on the difference in the amount of charge stored.
One end of the fourth charging device is connected to the fourth output terminal, one end of the fifth charging device is connected to the fifth output terminal, and the second load terminal is connected to the load output terminal. The charge pump according to claim 11, wherein: 14. The second conductive circuit according to claim 13, wherein the other end of the plurality of conductive elements further has a plus end connected to the fourth output end, and a minus end connected to the second load end. The charge pump according to 1. The second conductive circuit further has a sixth output terminal, and the second conductive circuit has one positive terminal and one negative terminal of the conductive element connected to the sixth output terminal and the fourth output terminal, respectively. ,
The charge pump further includes a sixth charging element having both ends. When a current is input to one end of the sixth charging element, a charge corresponding to the current is stored, and the stored charge is stored between the both ends. And output a voltage corresponding to the difference in the amount of charge to be stored, so that the corresponding voltage also differs,
The one end of the sixth charging device is connected to the sixth output terminal, and the other end of the fifth charging device not connected to the fifth output terminal is connected to the sixth output terminal. The charge pump according to 1. The charge pump according to claim 11, wherein each of the conductive circuits is a diode. 17. The charge pump according to claim 16, wherein the diode is formed by connecting a p-type metal oxide semiconductor.

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