TRENCH-GATE SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

Abstract

An inductor-less power converter for converting an input voltage at an input terminal to an output voltage at an output terminal is provided, with a conversion ratio between the input and output voltage. The converter can be an inductor-less power converter which is configured for Direct Current, DC, to DC, DC-DC conversion of an input voltage to an output voltage. The input voltage is provided at an input terminal pair whereas the output voltage is provided at an output terminal pair. The ratio between the input voltage and the output voltage defines the conversion ratio, which may be either larger than one or smaller than one, meaning that the voltage may be stepped-up or stepped-down and thus increased or lowered.

Claims

1. An inductor-less power converter for converting an input voltage at an input terminal to an output voltage at an output terminal, with a conversion ratio between the input and output voltage, the power converter comprising a plurality of cascaded capacitor stages, each capacitor stage comprising a flying capacitor connected in parallel over an input terminal pair and an output terminal pair of the capacitor stage; wherein between each cascaded stage a switching block is provided, the switching block comprising an input terminal pair and an output terminal pair and switching configured to connect the input terminals with one of the output terminals of the switching blocks, to connect one of a top or bottom plate of a capacitor of a respective capacitor stage with a top plate or bottom plate of a capacitor of a respective subsequent cascaded capacitor stage; and wherein the power converter further comprises a control unit arranged to operate the switching of each switching block according to a selected conversion ratio setting of a list of predefined conversion ratio settings each representing a different conversion ratio and comprising a connecting state of each of the switching blocks, wherein the predefined conversion ratio settings are defined so that a steady state voltage of each flying capacitor is equal between each conversion ratio setting, to switch between the conversion ratio settings in a lossless manner.

2. The inductor-less power converter according to claim 1, wherein the converter comprises four cascaded capacitor stages.

3. The inductor-less power converter according to claim 1, wherein the converter comprises five switching blocks.

4. The inductor-less power converter according to claim 1, wherein the control unit comprises a memory unit for storing the list of predefined conversion ratio settings, and wherein the list of predefined conversion ratio setting is a sub-selection of all conversion ratio settings possible.

5. The inductor-less power converter according to claim 1, wherein the converter is arranged for a Direct Current (DC) input voltage.

6. The inductor-less power converter according to claim 1, wherein the converter is arranged to convert an input voltage to an output voltage in a power range between 10 μWatts and 100 mWatts.

7. The inductor-less power converter according to claim 1, wherein the converter is arranged to power at least one module or device selected from the group consisting of: a sensor module, a IoT device, a USB device, and a Bluetooth module.

8. The inductor-less power converter according to claim 1, wherein the converter further comprises a multiple output voltage rail comprising a plurality outputs, each having a different output voltage level, wherein each output comprises a output capacitor connected in parallel over the output, as well as switching outputs configured to connect the voltage rail to the respective output.

9. The inductor-less power converter according to claim 1, wherein the converter is arranged to convert an input voltage to an output voltage in a power range between 50 μWatts and 50 mWatts.

10. The inductor-less power converter according to claim 1, wherein the converter further comprises multiple input voltage rails comprising a plurality of inputs, each having a different input voltage level, wherein each input comprises an input capacitor connected in parallel over the input, as well as switching inputs configured to connect the voltage rail to the respective input.

11. The inductor-less power converter according to claim 2, wherein the converter comprises five switching blocks.

12. The inductor-less power converter according to claim 2, wherein the control unit comprises a memory unit for storing the list of predefined conversion ratio settings, and wherein the list of predefined conversion ratio setting is a sub-selection of all conversion ratio settings possible.

13. The inductor-less power converter according to claim 2, wherein the converter is arranged for a Direct Current (DC) input voltage.

14. The inductor-less power converter according to claim 8, wherein each switching output is activated in a sequential manner for sequentially charging each of the output capacitors.

15. The inductor-less power converter according to claim 10, wherein each switching input is activated in a sequential manner for sequentially charging each of the input capacitors.

16. An energy harvester arrangement comprising: an energy harvesting module for harvesting ambient energy, selected from the group consisting of: solar energy, thermal energy, motion energy and radio frequency energy, and providing the harvested energy as an input voltage to the energy harvester arrangement; and an inductor-less power converter according to claim 1.

17. The energy harvester arrangement according to claim 16, wherein the arrangement further comprises: a maximum power point tracking module, wherein the maximum power point tracking module is operated as the control unit of the inductor-less power converter, to operate switching of each switching block of the power converter according to a maximum power point tracking algorithm selected in accordance with steady state voltage of each flying capacitor to be equal between each conversion ratio setting.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0033] The present disclosure will now be explained by means of a description of an embodiment of an inductor-less power converter in accordance to the first aspect, and an energy harvester arrangement in accordance to the second aspect, in which reference is made to the following figures, in which:

[0034] FIG. 1 shows a schematic overview of an embodiment of an inductor-less power converter in accordance to the first aspect of the present disclosure, wherein the possible connections between the input terminals and output terminals of one of the switching blocks are indicated.

[0035] FIG. 2 shows a schematic overview of the inductor-less power converter of FIG. 1, wherein an embodiment of the switching blocks in one of the switching blocks is indicated.

[0036] FIG. 3 shows an example of the configuration of an inductor-less power converter in accordance to the first aspect of the present disclosure for four different conversion ratios.

[0037] FIG. 4 shows a schematic overview of another embodiment of an inductor-less power converter in accordance to the first aspect of the present disclosure.

[0038] FIG. 5 shows a schematic overview of an embodiment of an energy harvester arrangement in accordance to the second aspect of the present disclosure.

DETAILED DESCRIPTION

[0039] FIGS. 1 and 2 show an inductor-less power converter 1 for converting an input voltage VA at an input terminal of the inductor-less power converter 1 to an output voltage VB at an output terminal of the inductor-less power converter 1. The power converter 1 comprises four cascaded capacitor stages CSn, with n=1-4, wherein each capacitor stage comprising a flying capacitor Cn, connected in parallel over an input terminal pair and an output terminal pair of the capacitor stage CSn.

[0040] Between each cascaded stage CSn a switching block SBm, with m=1−n+1, is provided. Each switching block SBm comprises an input terminal pair and an output terminal pair and switching means for connecting one of the two input terminals with one of the two output terminals of the switching block SBm. For switching block SB2, FIG. 1 shows in more detail the four possible connections between the input terminals and the output terminals of the respective switching block SB2, which is applicable to the other switching block SBm.

[0041] The first switching block SB1 is arranged for connecting either the top plate or the bottom plate of a capacitor C1, connected to the output terminals of the first switching block SB1, with either the input voltage VA of the power converter 1 or to ground. The last switching block SB5 is arranged for connecting either the top plate or the bottom plate of a capacitor C4, connected to the input terminals of the last switching block SB5, with either the output voltage VB of the power converter 1 or to ground.

[0042] Switching block SBm, with m=2-4, are arranged for connecting either the top plate or bottom plate of a capacitor Cm-1, connected to the input terminals of the respective switching block SBm, with either the top plate or bottom plate of a capacitor Cm, connected to the output terminals of the respective switching block SBm.

[0043] A control unit 21 (for clarity not shown in FIGS. 1-3) of the power converter 1 is arranged to operate the switching means of each switching block SBm according to a selected conversion ratio setting of a list of predefined conversion ratio setting. Each predefined conversion ratio setting represents a different conversion ratio between the input voltage VA and output voltage VB, and comprises a connecting state of each of the individual switching blocks SBm. The predefined conversion ratio setting are defined such that a steady state voltage of each flying capacitor Cn is equal between each conversion ratio setting, for switching between the conversion ratio setting in a lossless manner.

[0044] FIG. 2 shows an embodiment of the switching block SBm, wherein the switching block SBm comprises four switching means for connecting each of the input terminals and output terminals of the switching block SBm to a common internal node Vint,m. The switching means, for example transistors, are controlled by the control unit 21 of the power converter 1.

[0045] The control unit 21 comprises a memory unit 23 for storing the list of predefined conversion ratio settings, wherein the list of predefined conversion ratio settings is a sub-selection of all conversion ratio setting possible.

[0046] The voltage of each capacitor, can be added or subtracted from the respective internal node voltage Vint,m to create the following internal node voltage Vint,m+1. For the internal voltages Vint,m the following applies:

[00001]$V_{\mathrm{int},1}=\{\begin{array}{c}0\\ V_A\end{array}=w_A.Math.V_A$$V_{\mathrm{int},2}=\{\begin{array}{c}{V}_{\mathrm{int},1}\\ V_{\mathrm{int},1}+V_{C1}=V_{\mathrm{int},1}+w_1.Math.V_{C1}\\ V_{\mathrm{int},1}-V_{C1}\end{array}$$V_{\mathrm{int},3}=\{\begin{array}{c}{V}_{\mathrm{int},2}\\ V_{\mathrm{int},2}+V_{C2}=V_{\mathrm{int},2}+w_2.Math.V_{C2}\\ V_{\mathrm{int},2}-V_{C2}\end{array}$$V_{\mathrm{int},4}=\{\begin{array}{c}{V}_{\mathrm{int},3}\\ V_{\mathrm{int},3}+V_{C3}=V_{\mathrm{int},3}+w_3.Math.V_{C3}\\ V_{\mathrm{int},3}-V_{C3}\end{array}$$\begin{array}{c}{V}_{\mathrm{int},5}=\{\begin{array}{c}{V}_{\mathrm{int},4}\\ V_{\mathrm{int},4}+V_{C4}=V_{\mathrm{int},4}+w_4.Math.V_{C4}\\ V_{\mathrm{int},4}-V_{C4}\end{array}\\ =\{\begin{array}{c}{V}_B\\ 0\end{array}=w_B.Math.V_B\end{array}$

[0047] The weight factors wA, wB and wx, with x=n=1-4, define how the capacitors are connected together. The weight factor wA can either be 0, when the ground terminal is connected to the input terminal of switching block SB1, or 1, when the input voltage VA of the power converter 1 is connected to the input terminal of switching block SB1. The weight factor wB can either be 0, when the ground terminal is connected to the output terminal of switching block SB5, or 1, when the output voltage VB of the power converter 1 is connected to the output terminal of switching block SB5. The capacitor weight factor wx, with x=n, can either be 0, when capacitor Cn is bypassed, −1, when capacitor voltage VCn is subtracted, or 1, when capacitor voltage VCn is added. For the weight factors wA, wB and wx the following applies:

[00002]$w_A=\{\begin{array}{c}1\\ 0\end{array}$$w_B=\{\begin{array}{c}1\\ 0\end{array}$$w_x=\{\begin{array}{c}1\\ 0\\ -1\end{array}$

[0048] The following is assumed: the input voltage VA of the power converter 1 is a fixed voltage, for example provided by a battery or supply rail, the steady state voltages across the capacitors Cn are assumed to be fixed and a fraction of the input voltage VA of the power converter 1, with VCx=VA.Math.kx, and the ratio between the input voltage VA of the power converter 1 and the output voltage VB of the power converter 1 is defined by the conversion ratio VB=VA.Math.M.

[0049] Using the equations for the internal node voltages Vint,m, the following applies:

w.sub.A.Math.V.sub.A+w.sub.1.Math.V.sub.C1+w.sub.2.Math.V.sub.C2+w.sub.3.Math.V.sub.C3+w.sub.4.Math.V.sub.C4=w.sub.B.Math.V.sub.B

[0050] Which can be reduced to:

w.sub.A+w.sub.1.Math.k.sub.1+w.sub.2.Math.k.sub.2+w.sub.3.Math.k.sub.3+w.sub.4.Math.k.sub.4=w.sub.B.Math.M

[0051] The following equation is valid for each of the phases in one conversion ratio:

[00003]$\left[\begin{array}{c}{w}_{A,1}\\ w_{A,2}\\ w_{A,3}\\ w_{A,4}\\ w_{A,5}\end{array}\right]+\left[\begin{array}{cccc}{w}_{1,1}& w_{2,1}& w_{3,1}& w_{4,1}\\ w_{1,2}& w_{2,2}& w_{3,2}& w_{4,2}\\ w_{1,3}& w_{2,3}& w_{3,3}& w_{4,3}\\ w_{1,4}& w_{2,4}& w_{3,4}& w_{4,4}\\ w_{1,5}& w_{2,5}& w_{3,5}& w_{4,5}\end{array}\right].Math.\left[\begin{array}{c}{k}_1\\ k_2\\ k_3\\ k_4\end{array}\right]=\left[\begin{array}{c}{w}_{B,1}\\ w_{B,2}\\ w_{B,3}\\ w_{B,4}\\ w_{B,5}\end{array}\right].Math.M$$\stackrel{.fwdarw.}{w_A}+W.Math.\stackrel{.fwdarw.}{k}=\stackrel{.fwdarw.}{w_B}.Math.M$

[0052] The following example illustrates how multiple conversion ratios M can be made with the same k-vector, wherein the size of k is equal to the number of capacitors n. In this example, the power converter 1 comprises four capacitors Cn, n=1-4 and five switching block SBm, m=1-5. Corresponding equations can be extended accordingly for a power converter 1 comprises more or less capacitors Cn.

[00004]$\mathrm{For}k=\left[\begin{array}{cccc}\frac{1}{2}& \frac{1}{4}& \frac{1}{6}& \frac{1}{12}\end{array}\right]\&M=\frac{1}{12}:\left[\begin{array}{c}0\\ 0\\ 0\\ 0\\ 1\end{array}\right]+\left[\begin{array}{cccc}0& 0& 0& 1\\ 0& 0& 1& -1\\ 0& 1& -1& 0\\ 1& -1& -1& 0\\ \text{-1}& -1& -1& 0\end{array}\right].Math.\left[\begin{array}{c}{k}_1\\ k_2\\ k_3\\ k_4\end{array}\right]=\left[\begin{array}{c}1\\ 1\\ 1\\ 1\\ 1\end{array}\right].Math.M$$\mathrm{For}k=\left[\begin{array}{cccc}\frac{1}{2}& \frac{1}{4}& \frac{1}{6}& \frac{1}{12}\end{array}\right]\&M=\frac{19}{12}:\left[\begin{array}{c}0\\ 0\\ 1\\ 1\\ 1\end{array}\right]+\left[\begin{array}{cccc}0& 1& -1& -1\\ 1& -1& -1& -1\\ -1& -1& -1& -1\\ 1& 0& 0& 1\\ 1& 0& 1& -1\end{array}\right].Math.\left[\begin{array}{c}{k}_1\\ k_2\\ k_3\\ k_4\end{array}\right]=\left[\begin{array}{c}0\\ 0\\ 0\\ 1\\ 1\end{array}\right].Math.M$

[0053] FIG. 3 illustrates the complete configuration for a power converter 1 with two capacitors Cn, n=1-2 and three switching block SBm, m=1-3, with k=[2/3 1/3] such that VC1=VA.Math.2/3 and VC2=VA.Math.1/3, and four possible conversion ratios M. For which the following applies for the weight matrices:

[00005]$\mathrm{For}M=\frac{1}{3}:\circ \left[\begin{array}{c}0\\ 0\\ 1\end{array}\right]+\left[\begin{array}{cc}0& 1\\ 1& -1\\ -1& 0\end{array}\right]\stackrel{.fwdarw.}{k}=\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right]M$$\mathrm{For}M=\frac{2}{3}:\circ \left[\begin{array}{c}0\\ 1\\ 1\end{array}\right]+\left[\begin{array}{cc}1& 0\\ -1& 1\\ 0& -1\end{array}\right]\stackrel{.fwdarw.}{k}=\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right]M$$\mathrm{For}M=\frac{4}{3}:\circ \left[\begin{array}{c}1\\ 1\\ 1\end{array}\right]+\left[\begin{array}{cc}0& 1\\ 1& -1\\ -1& -1\end{array}\right]\stackrel{.fwdarw.}{k}=\left[\begin{array}{c}1\\ 1\\ 0\end{array}\right]M$$\mathrm{For}M=2:\circ \left[\begin{array}{c}1\\ 1\end{array}\right]+\left[\begin{array}{cc}1& 1\\ -1& -1\end{array}\right]\stackrel{.fwdarw.}{k}=\left[\begin{array}{c}1\\ 0\end{array}\right]M$

[0054] FIG. 4 shows another embodiment of an inductor-less power converter 10 according to first aspect of the present disclosure. The power converter 10 further comprises a multiple output voltage rail 15. The multiple output voltage rail 14 comprises a plurality outputs Output y, with y=1-N, each having a different output voltage level. Each output y comprises an output capacitor Cy, connected in parallel over the output y, and switching output means Sy, for connecting the voltage rail 14 to the respective output y.

[0055] Each switching output means Sy are activated, by the control unit 21, in a sequential manner for sequentially charging each of said output capacitors Cy.

[0056] FIG. 5 shows an embodiment of an energy harvester arrangement 100 in accordance to the second aspect of the present disclosure. The energy harvester arrangement 100 comprises an energy harvester for harvesting ambient energy, preferably one of solar, motion or radio frequency energy. The harvested energy is provided as an input voltage to the inductor-less power converter 1 as described above. The output voltage of the inductor-less power converter 1 is provided to a battery.

[0057] The energy harvester arrangement 100 further comprises a maximum power point tracking, MPPT, module 11, wherein the MPPT module 11 is operated as the control unit 21 of the inductor-less power converter 1. The MPPT module 11 controls the switching means of each switching block SBm of the power converter 1 according to a maximum power point tracking algorithm selected in accordance with steady state voltage of each flying capacitor Cn to be equal between each conversion ratio setting.

[0058] Based on the above description, a skilled person may provide modifications and additions to the method and arrangement disclosed, which modifications and additions are all comprised by the scope of the appended claims.