Low power consumption and low power DC-DC boost converter

Abstract

The invention relates to a DC-DC boost converter capable of receiving an input voltage (Vin) and delivering an output voltage (Vout) greater than said input voltage (Vin). The DC-DC boost converter comprises: - a conversion module (11) capable of converting the input voltage (Vin) into an output voltage (Vout) according to a control signal (Scon); - a control system (12) capable of transmitting said control signal (Scon) to the conversion module (11). Said control signal (Scon) is obtained from a modulated pulse signal (Smod) capable of taking, depending on the output voltage (Vout), either a periodic form of variable frequency (Simp) or a constant form (0). The variable frequency is determined by the input voltage (Vin) and the output voltage (Vout). Figure 2 (for the abstract)

Description

Title of the invention: Low-power, low-consumption DC-DC boost converter technical field

[0001] The present invention relates to a DC-DC voltage converter. More particularly, the present invention relates to a chopper-type voltage converter for low-consumption, low-power applications. Prior Art

[0002] It is known to use a DC-DC voltage converter to transfer energy between a source (cell, battery, solar panel, etc.) and a receiver (resistive load, motor, battery to be recharged, lighting).

[0003] There are two versions of this type of DC-DC converter, namely the step-down DC-DC converter, called a "Buck converter," and the step-up DC-DC converter, called a "Boost converter." A "Buck converter" provides an output voltage lower than the input voltage. Conversely, a "Boost converter" provides an output voltage higher than the input voltage.

[0004] The DC-DC boost converter is used in numerous applications not only related to transportation, such as, for example, in voltage control between the battery and the motor of electric or hybrid vehicles. The DC-DC boost converter is also used in renewable energy, more specifically in inverters that transfer energy from solar panels to the electricity grid, to storage batteries, to portable devices, or other objects belonging to a network of connected objects (IoT for "Internet of Things").

[0005] The DC-DC boost converter allows the output voltage of several energy sources, for example a battery and a supercapacitor, to be adapted in order to couple them together.

[0006] It also allows for the management of energy flows between the source and the receiver and protects them against short circuits, in the same way as a battery. The DC-DC charger continuously monitors the voltage in order to decide when to start a new charging phase.

[0007] At equal power, a DC-DC boost converter improves the efficiency of the electrical conversion chain by increasing the voltage and decreasing the current, as well as Joule effect losses. It thus allows a battery to reach a high voltage at its terminals, while limiting the number of cells used, thus limiting the size, weight and cost of such a battery.

[0008] Energy recovery conversion solutions exist, particularly for connected devices. However, these are limited by the low output voltage and low efficiency at low output power levels. They also require the use of complex, specialized components, such as specific integrated circuits, which are subject to obsolescence risks.

[0009] There is therefore a need to provide a DC-DC boost converter solution capable of generating an output voltage high enough to be usable with a wide input voltage range, while offering high efficiency in a low power range. Summary of the invention

[0010] The invention relates to a DC-DC boost converter, capable of receiving an input voltage and delivering an output voltage higher than said input voltage. The DC-DC boost converter comprises a conversion module, capable of converting the input voltage into an output voltage according to a control signal, and a control system, capable of transmitting said control signal to the conversion module. Said control signal is obtained from a modulated pulse signal capable of taking, depending on the output voltage, either a periodic form of variable frequency or a constant form. The variable frequency is determined by the input and output voltages.

[0011] The control signal regulation acts as a feedback loop, the topology of which is designed to allow the DC-DC boost converter to adapt to different output load conditions, and therefore to the energy requirements of the device, and to provide a stable and reliable voltage. The low power consumption of this DC-DC converter has the economic advantage of improving its energy efficiency, reliability, and durability—that is, the lifespan of the electronic circuit components—while reducing operating and maintenance costs.

[0012] The DC-DC converter thus adapts to variations in the power of the energy source, such that a decrease in input power causes a decrease in input voltage. This, in turn, leads to a drop in the variable frequency of the control signal, until this frequency becomes sufficiently low to slow down the variations in input voltage. This attenuates the average current that the DC-DC converter draws from the source.

[0013] In one embodiment, the control system includes a control module, said control module being adapted to generate the control signal as a function of the modulated pulse signal.

[0014] In one embodiment, the control module comprises a plurality of transistors or a plurality of comparators.

[0015] In one embodiment, the control system includes a servo module, said servo module being capable of forming the constant part of the modulated pulse signal, if the output voltage is greater than a certain voltage threshold.

[0016] The control module is thus capable of replacing the periodic, variable-frequency shape of the pulsed signal with a constant value, for example, a zero value. It is therefore possible to control the maximum voltage that the output voltage can reach.

[0017] In one embodiment, the servo module is capable of receiving and processing the pulsed signal to achieve synchronous servo control.

[0018] This allows the control signal to be synchronized with the pulse signal.

[0019] In one embodiment, the control module includes a first Mosfet transistor or a comparator.

[0020] In one embodiment, the control system includes a power generation module, said power generation module being capable of generating the pulse signal as a function of a timing signal, said pulse signal becoming the modulated pulse signal as soon as the power generation module is connected to the servo module.

[0021] In one embodiment, the pulses of the pulsed signal have a predetermined duration.

[0022] In one embodiment, the control system includes a clock module, said clock module being capable of receiving the input voltage and the output voltage to generate the timing signal.

[0023] In one embodiment, the clock module includes at the output a buffer transistor or a logic gate.

[0024] In one embodiment, the conversion module includes a coil for storing magnetic energy, a capacitor for storing electrical energy and means for transferring all or part of the magnetic energy of the coil into electrical energy of the capacitor, said transfer means including a Mosfet transistor and a switching diode.

[0025] In one embodiment, the switching diode is a Schottky diode.

[0026] In one embodiment, the conversion module is a boost converter.

[0027] In one embodiment, the range of powers applied to said converter is between 1 mW and several hundred kW.

[0028] The invention therefore makes it easy to broaden the applicable power range. Description of the figures

[0029] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0030] Fig. 1 illustrates the functional diagram of a DC-DC voltage boost converter according to the invention;

[0031] [Fig.2] illustrates in more detail the DC-DC converter of [Fig.1];

[0032] Figure 3 illustrates a diagram of a clock module belonging to the converter DC-DC of the [Fig.2];

[0033] Fig. 4 illustrates a diagram of a power generation module belonging to the DC-DC converter of Fig. 2;

[0034] Fig. 5 illustrates a diagram of a control module belonging to the DC-DC converter of Fig. 2;

[0035] Fig. 6 illustrates a diagram of a servo module belonging to the DC-DC converter of Fig. 2;

[0036] [Fig.7] illustrates a diagram of a conversion module belonging to the DC-DC converter of [Fig.2];

[0037] Figure [8] illustrates the different functional blocks of the conversion module of Figure [7];

[0038] Figure 9 illustrates a variant of the DC-DC voltage boost converter according to another embodiment of the invention.

[0039] Fig. 10 illustrates a variant of the power generator module;

[0040] Fig. 11 illustrates a variant of the control module;

[0041] Fig. 12 illustrates a variant of the servo module.

[0042] Figure 1 illustrates the functional diagram of a DC-DC step-up converter. Voltage 1. This converter 1 is placed between a source 2 and a load 3. The source 2 is suitable for providing an input voltage Vin to the DC-DC converter. The load 3 is suitable for receiving the output voltage Vout generated by the DC-DC step-up converter 1.

[0043] [Fig.2] illustrates in more detail the DC-DC converter of [Fig.1].

[0044] This DC-DC converter comprises:

[0045] - a conversion module 11;

[0046] - a control system 12.

[0047] The conversion module 11 is capable of converting the input voltage into the output voltage delivered by said DC-DC converter. This conversion is modulated by a control signal Sco n, delivered by the control system 12. The conversion module 11 thus converts the energy from the source 2 into a higher voltage (between 12 and 13 volts) to power the load 3. It also allows the input voltage value to be increased to supply the load with the desired output voltage value.

[0048] The control system 12 is capable of transmitting a control signal Scon to the conversion module 11, to adapt the conversion characteristics of this module 11. This control signal Scon is regulated according to a value Vout of the output voltage of the conversion module 11.

[0049] More specifically, the control system 12 comprises:

[0050] - a clock module 121;

[0051] - a power generation module 122;

[0052] - a control module 123;

[0053] - a servo module 124.

[0054] The clock module 121 is adapted to generate a periodic signal, called the Scad timing signal, for timing the power generation module 122. This Scad timing signal has a variable timing frequency. This variable timing frequency is a function of the input voltage Vin and the output voltage Vout. The Scad timing signal is transmitted to the power generation module 122. Note that the clock module 121 has its own independent power supply.

[0055] The pulse generation module 122 is adapted to generate a Simp pulse signal based on the Scad timing signal, transmitted by the clock module 121. More specifically, the Simp pulse signal comprises a plurality of voltage pulses of a determined duration. The constant duration of these pulses makes it possible to limit the maximum power delivered by the conversion module 11. This Simp pulse signal is called a PPb signal (for "Push-Pull base"). The Simp pulse signal becomes the Smod modulated pulse signal when the power generation module 122 is connected to the control module 124. The Smod modulated pulse signal is capable of taking either a periodic form of variable frequency (Simp pulse signal) or a constant form, which here has a value of zero 0. The Smod modulated pulse signal is transmitted to the control module 123.Note that the power generation module 122 has its own independent power supply.

[0056] The control module 123 is adapted to generate the control signal Scon as a function of the modulated pulse signal Smod. More specifically, the control signal Scon is a signal resulting from the current amplification of the modulated pulse signal Smod. The control signal Scon is used to drive a switch in the IL conversion module. To this end, the control module 123 ensures a short modulated pulse signal Smod, whose rapid transitions limit switching losses in the IL conversion module. It should be noted that the control module 123 has its own independent power supply.

[0057] The control module 124 is adapted to regulate the output voltage values. To this end, this module 124 is capable of grounding the output of the power generation module 122 when the output voltage Vout reaches a maximum value. The modulated pulse signal Smod then takes the value zero 0. It should be noted that the control module 124 has its own independent power supply.

[0058] The clock module 121, the power generation module 122, the control module 123, and the servo module 124 form a control chain for the conversion module 11. The conversion module 11, thus servo-controlled, can adapt to variations in the power of the energy source, such that a decrease in input power causes a decrease in the input voltage Vin. This decrease in the input voltage Vin, in turn, causes the clocking frequency of the clock signal Scad to drop until it becomes low enough to slow down the variations in the input voltage Vin. The chain reaction thus described makes it possible to attenuate the average current that the conversion module 11 draws from the source. The input voltage Vin can then stabilize at a value above a certain critical threshold, below which the conversion module 11 ceases to operate.The servo-controlled conversion module 11 allows its power to be drawn from the source, progressively so as not to weaken it, until finally transferring, over a certain period, more energy than in the case of a conventional DC-DC converter, without risking a shutdown of the conversion module 11 for low power levels.

[0059] The DC-DC converter, the subject of the invention, is optimized in terms of efficiency, i.e., energy efficiency, to operate at very low power levels (1.18 mW), but also at higher power levels, such as 30 mW and up to 100 mW. It therefore allows for a wide range of input voltages and achieves high efficiency with the lowest possible power, while maintaining a stable output voltage. Furthermore, the efficiency of the DC-DC converter, already very high at low power levels, increases with increasing power.

[0060] Figures 3 to 7 detail the different elements constituting the DC-DC converter of figures 1 and 2.

[0061] More specifically, [Fig.3] schematically illustrates the electrical circuit forming the clock module 121. This electrical circuit comprises the following components:

[0062] - a first resistance RI, a second resistance R2, a third resistance R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The values ​​of resistors R1 to R7 can be different and are between 1 MΩ and 5 MΩ. In one particular embodiment: the first resistor R1, the second resistor R2, and the seventh resistor R7 have identical values; the third resistor R3 and the fourth resistor R4 have identical values. The values ​​of resistors R1 to R7 are selected such that R6 <R5<(R3, R4)<(R1, R2, R7) ;

[0063] - a first transistor Q1, a second transistor Q2 and a third transistor Q3. Transistors Q1, Q2, and Q3 are NPN bipolar transistors. Each transistor consists of a base, a collector, and an emitter (the branch with the arrow). Note that the emitters of transistors Q1, Q2, and Q3 are connected to ground;

[0064] - a first capacitor Cl, a second capacitor C2 and a third capacitor C3. The values ​​of capacitors C1, C2, and C3 can be different and range from 100 pF to 180 pF. In one particular embodiment, the first capacitor C1 and the second capacitor C2 have identical values. The values ​​of capacitors C1 through C3 are selected such that C3 < (C1, C2).

[0065] The clock module 121 is, here, powered by the input voltage Vin and the output voltage Vout, and also uses the input voltage Vin as an input signal.

[0066] The various components of the clock module 121 are connected to each other via a plurality of nodes:

[0067] - a first node ni is at the intersection between the output voltage line Vout and the third resistance R3;

[0068] - a second node n2 is at the intersection between the third resistance R3, the first capacitor Cl and the collector of the first transistor Ql;

[0069] - a third node n3 is at the intersection between the input signal Vin, the first resistance RI and the second resistance R2;

[0070] - a fourth node n4 is at the intersection between the first capacitor Cl the first resistor RI and the base of the second transistor Q2;

[0071] - a fifth node n5 is at the intersection between the base of the first transistor Q1, the second resistor R2 and second capacitor C2;

[0072] - a sixth node n6 is at the intersection between the output voltage line Vout and the fourth resistance R4;

[0073] - a seventh node n7 is at the intersection between the collector of the second transistor Q2, the second capacitor C2, the fourth resistor R4 and the fifth resistor R5;

[0074] - an eighth node n8 is at the intersection between the fifth resistor R5, the third capacitor C3 and sixth resistor R6;

[0075] - a ninth node n9 is at the intersection between the third capacitor C3, the sixth resistor R6 and the base of the third transistor Q3;

[0076] - a tenth node nlO is at the intersection between the output voltage line Vout and the seventh resistance R7;

[0077] - an eleventh node ni 1 is at the intersection between the seventh resistance R7, the collector of the third transistor Q3 and the output of the clock module 121. At this output, the clock module 121 delivers the Scad timing signal.

[0078] The first transistor Q1, the second transistor Q2, and resistors R1 to R4 form an astable subcircuit. The third transistor Q3, the third capacitor C3, and resistors R5 to R7 form an impedance-matching or buffer subcircuit. Thanks to this impedance-matching subcircuit, it is possible to use the Scad timing signal without disturbing the astable subcircuit.

[0079] The use of the output voltage Vout allows the clock module 121 to remain active even if the input voltage Vin is low. The values ​​of this output voltage Vout are between 12 and 13 V.

[0080] Using the input voltage Vin on resistors RI and R2 allows the frequency of the clocking signal Scad to be varied, which optimizes the total consumption of the DC-DC converter 1. By varying the input voltage Vin on these resistors RI and R2, it is possible to modify the frequency of the clock module 121.

[0081] Figure 4 schematically illustrates the electrical circuit forming the power generation module 122. This electrical circuit comprises:

[0082] - an eighth resistor R8, a ninth resistor R9, a tenth resistor RIO. In a particular embodiment: the values ​​of resistors R8-R10 are identical and have a value which corresponds, here, to the value of resistors RI and R2 of clock module 121;

[0083] - a fourth transistor Q4, a fifth transistor Q5. Transistors Q4 and Q5 These are NPN type bipolar transistors. The emitters of transistors Q4 and Q5 are connected to ground;

[0084] - a fourth Cpl capacitor. In a particular embodiment: the value the value of this capacitor Cpl is much lower than the value of the capacitors Cl, C2, C3 of the clock module 121.

[0085] The various components of the power generation module 122 are connected to each other via a plurality of nodes:

[0086] - a twelfth node nl2 is at the intersection between the output voltage line Vout and the eighth resistance R8;

[0087] - a thirteenth node nl3 is at the intersection between the eighth resistance R8, the collector of the fourth transistor Q4 and the fourth capacitor Cpl.

[0088] - a fourteenth node nl4 is at the intersection between the output of the clock module 121 and the base of the fourth transistor Q4. This node is thus adapted to receive the Scad timing signal;

[0089] - a fifteenth node nl5 is at the intersection between the output voltage line Vout and the ninth resistance R9;

[0090] - a sixteenth node nl6 is at the intersection between the fourth capacitor Cpl, The ninth resistor R9 and the base of the fifth transistor Q5. This sixteenth node nl6 is adapted to receive pulses ("pumps"), formed by the fourth capacitor Cpl. The duration of the pulses is determined by the values ​​of Cpl, R8 and R9.

[0091] - a seventeenth node nl7 is at the intersection between the output voltage line Vout and the tenth resistance RIO;

[0092] - an eighteenth node nl8 is at the intersection between the tenth resistance RIO, the collector of the fifth transistor Q5 and the output of the power generation module 122. At this output, the power generation module 122 delivers the pulse signal Simp, which becomes the modulated pulse signal Smod by the connection of the servo module 124.

[0093] It will be noted that the Simp pulse signal, or the Smod modulated pulse signal, is generated by the generation module 122 at each falling edge of the Scad timing signal.

[0094] Figure 5 schematically illustrates the electrical circuit forming the control module 123. This electrical circuit comprises the following components:

[0095] - a sixth transistor Q6 and a seventh transistor Q7. The sixth transistor Q6 is an NPN bipolar transistor. The seventh transistor, Q7, is a PNP bipolar transistor. The collector of the sixth transistor, Q6, is connected to the output voltage line Vout, and the collector of the seventh transistor, Q7, is connected to ground. The sixth transistor, Q6, and the seventh transistor, Q7, are complementary and form a push-pull configuration.

[0096] The various components of the control module 123 are connected to each other via a plurality of nodes:

[0097] - a nineteenth node nl9 is at the intersection between the base of the sixth transistor Q6 and the base of the seventh transistor Q7. This nineteenth node n 19 is adapted to receive the Smod modulated pulse signal, coming from the power generation module 122;

[0098] - a twentieth node n20 is at the intersection between the emitter of the sixth transistor Q6 is the emitter of the seventh transistor Q7 and the output of the driver module 123. At this output, the driver module 123 delivers the control signal Scon. This control signal Scon is identical to the modulated pulse signal Smod, but its impedance is matched. Alternatively, the control signal Scon is an amplified signal of the modulated pulse signal Smod.

[0099] Figure 6 schematically illustrates the electrical circuit forming the control module 124. This electrical circuit comprises the following components:

[0100] - an eleventh resistor RI 1, a twelfth resistor R12, a thirteenth resistor Rfbl, a fourteenth resistance Rfb2. The values ​​of the resistances Rll, R12, Rfbl, Rfb2 can be different and are between 520kΩ and 5MΩ. In a particular embodiment: the resistance Rfbl is much larger than the resistance Rfb2. These two resistances form a voltage divider. The resistance Rfbl is, here, equal to the resistances Rll and R12;

[0101] - an eighth transistor Q8, a ninth transistor Q9. Transistors Q8, Q9 are Here are NPN bipolar transistors. Each transistor comprises a base, a collector, and an emitter (the branch with the arrow). Note from the outset that the emitters of the various transistors Q8 and Q9 are connected to ground;

[0102] - a first MOSFET Ml transistor (for "Metal-oxide-semiconductor field-effect") MOSFET (Motor-Oxygen Field-Effect Transistor) is a type of field-effect transistor. It modulates the current flowing through it using a signal applied to its gate. It also has a drain and a source (the branch with the arrow). The transistor M1 shown here is of the N-type.

[0103] The various components of the servo module 124 are connected to each other via a plurality of nodes:

[0104] - a twenty-first node n21 is at the intersection between the tension line Vout and the thirteenth resistance Rfbl;

[0105] - a twenty-second node n22 is at the intersection between the thirteenth resistance Rfbl, the fourteenth resistor Rfb2 and the gate of the MOSFET transistor ML

[0106] - a twenty-third node n23 is at the intersection between the eleventh resistance RI 1, the drain of the Mosfet transistor Ml and the base of the transistor Q8;

[0107] - a twenty-fourth node n24 is at the intersection between the tension line Vout, the eleventh resistance RI 1, the twelfth resistance R12;

[0108] - a twenty-fifth node n25 is at the intersection between the twelfth resistance R12, The collector of transistor Q8 and the base of transistor Q9. Note that the collector of transistor Q9 delivers the control signal Scon. This control signal Scon is either the pulsed signal Simp or a constant value such as zero.

[0109] The electrical circuit of the 124 control module is thus divided into two parts. A first part allows the detection of the output voltage level Vout, thanks to the voltage divider, formed by the thirteenth resistor Rfbl and the fourteenth resistor Rfb2, associated with the first Mosfet transistor Ml and the eleventh resistor RI 1. A second part, consisting of the twelfth resistor R12, the eighth transistor Q8 and the ninth transistor Q9, allows the inhibition of pulsed signals by short-circuiting the pulsed signal Simp.

[0110] The pulse train is interrupted by the control module 124 as soon as the output voltage Vout exceeds, for example, 13 V, and then resumes once this output voltage Vout falls below this value. The power consumption of this control module 124 does not depend on the input voltage Vin, nor on the pulse frequency, but only on the output voltage Vout.

[0111] Figure 7 schematically illustrates the electrical circuit forming the conversion module 11. This electrical circuit comprises the following components:

[0112] - a fifth capacitor Cin and a sixth capacitor Cout. These capacitors Cin, Cout. are suitable for storing energy;

[0113] - a second MOSFET M2 transistor. This transistor has a gate, a drain and a source (branch with the arrow). The gate is here adapted to receive the control signal Scon. Depending on the voltage values ​​of this control signal, the gate of the MOSFET transistor M2 controls its switching on or off. The switching on and off of the MOSFET transistor M2 is determined by an intrinsic threshold value of its gate Vgsth. If the voltage of the control signal Scon is greater than the threshold value Vgsth, then the MOSFET transistor M2 forms a closed switch between the drain and the source. Conversely, if the voltage of the control signal Scon is less than the threshold value Vgsth, then the MOSFET transistor M2 forms an open switch between the drain and the source;

[0114] - a coil L. The coil L is capable of storing energy as soon as the second Mosfet transistor M2. When the Mosfet transistor M2 is opened, an overvoltage is established across the terminals of the coil L;

[0115] - a diode D. This diode D is adapted to take a conducting state and a non-conducting state. Conductive. In the conducting state, diode D corresponds to a closed switch, and in the non-conductive state, diode D corresponds to an open switch. The transition from the non-conductive to the conducting state is linked to the overvoltage present at the of the coil L. Such an overvoltage makes the diode D conductive. Diode D is, for example, a Schottky switching diode.

[0116] The various components of the conversion module 11 are connected to each other via a plurality of nodes:

[0117] - a twenty-sixth node n26 is at the intersection between the input signal Vin, the fifth capacitor Cin and coil L;

[0118] - a twenty-seventh node n27 is at the intersection between the coil L, the drain of the second Mosfet transistor M2 and diode D;

[0119] - a twenty-eighth node n28 is at the intersection between diode D, the sixth capacitor Cout and the output of the conversion module 1L At this output, the conversion module 11 delivers the output voltage Vout, which powers an external equipment or load, of equivalent resistance Rout.

[0120] Fig. 8 illustrates different functional blocks of the conversion module 11 of Fig. 7.

[0121] The power supply 2, which powers the conversion module, is a DC voltage type. The inductive subcircuit, equivalent to an RL circuit, including the coil L, is connected in series with this power supply 2. The switch T, which is periodically made conductive in a programmatic manner, is the second MOSFET transistor M2. The current flowing through it is always positive. The switching of MOSFET transistor M2 is controlled by turning it off and turning it on. The power supply 2 is never permanently open because the switch D, which is the conducting diode, acts as a discharge check valve. The conversion module 11 can operate with both passive loads (resistors) and active loads (batteries).However, in order to use a DC-DC boost converter circuit, as is the case here with conversion module 11, the output load system 3 must be of the DC voltage type. The voltage ripples thus generated are smoothed at the output of diode D through a parallel capacitive subcircuit, equivalent to RC, including the sixth capacitor Cout.

[0122] The power supply 2 is adapted to generate an electric current in the coil L when the second MOSFET transistor M2 is saturated (switch T closed). As the electric current passes through the coil, it establishes a magnetic field, the strength of which depends on the current intensity and the number of turns in the coil. The magnetic field strength reaches its maximum value when the coil is fully charged. The coil L thus stores energy in its magnetic field.

[0123] When the second MOSFET M2 abruptly cuts off (switch T opens), that is, when the control signal voltage Scon suddenly falls below the gate threshold value Vgsth of the second MOSFET M2, the magnetic field in the coil L collapses almost instantaneously, inducing a back electromotive force, which generates a charging current in the sixth capacitor Cout. The potential difference across the terminals of the sixth capacitor Cout indicates that it is storing energy in its electric field. Once the coil L is completely discharged, all the magnetic energy has been converted into electrical energy in the sixth capacitor Cout, and into thermal energy by Joule heating.

[0124] The conversion module 11 is also referred to here as a boost converter. It efficiently converts the electricity it receives, obtaining higher potential differences than those supplied by the energy source, without the need for a transformer or additional electrical accumulators.

[0125] Based on the various modules 121, 122, 123, 124, 11, the overall operation of the DC-DC step-up converter can be summarized as follows:

[0126] The clock module 121 generates a reference clock through the astable multivibrator circuit, consisting of the first transistor Q1, the second transistor Q2, and then the impedance matching (buffer) circuit, consisting of the third transistor Q3 and the third capacitor C3. The clock signal Scad is reshaped by the fourth transistor Q4, the fifth transistor Q5, and the fourth capacitor Cpl to form the modulated pulse signal Smod. This modulated pulse signal Smod is current-matched by the driver module 123 using a push-pull configuration consisting of the sixth transistor Q6 and the seventh transistor Q7. The resulting control signal Scon is sent to the gate of the second MOSFET transistor M2 of the conversion module 11.

[0127] The coil L stores energy as soon as the second MOSFET M2 is closed. A voltage surge is established across the coil L when this second MOSFET M2 is opened. This voltage surge is stored in the sixth capacitor Cout when the second MOSFET M2 is closed. Each turn-on-off cycle of this second MOSFET M2 progressively increases the voltage across the sixth capacitor Cout.

[0128] The output voltage Vout is regulated by means of feedback from the control module 124 (first MOSFET transistor M1, eighth transistor Q8, and ninth transistor Q9). The first MOSFET transistor M1 closes when the output voltage Vout exceeds an intrinsic threshold value Vgsth of the gate of transistor ML. The comparator output triggers the opening of the eighth transistor Q8, then The ninth transistor, Q9, is switched off. The saturation of this ninth transistor, Q9, inhibits the pulsed signal Simp destined for the second MOSFET, M2, when the output voltage, Vout, reaches the setpoint value determined by the thirteenth resistor, Rfbl, and the fourteenth resistor, Rfb2. This method of regulating the output voltage, Vout, is called Pulse-Frequency Modulation (PFM) or pulse skipping. This method uses very short pulses of fixed duration to control the conducting state of the second MOSFET, M2. The higher the pulse frequency, the greater the power transmission between the input and output of the conversion module, 11.

[0129] Other variations can be made to the DC-DC converter of the invention.

[0130] Thus, [Fig. 9] illustrates in more detail a variant embodiment of the DC-DC converter 1 of [Fig. 1], in which the control module 124 receives information from the pulse signal Simp. The control module 124 then comprises a plurality of logic gates and comparators (not shown) in place of the first MOSFET transistor M1, the eighth transistor Q8, and the ninth transistor Q9 of [Fig. 6]. These logic gates, combined with the pulse signal Simp, enable synchronous control.

[0131] Fig. 10 illustrates a variant embodiment of the power generation module 122, in which the "buffer" transistors at the output of the clock module are replaced by logic gates.

[0132] This variant embodiment of the power generation module 122 thus comprises:

[0133] - a first logic gate U1. The first logic gate U1 is of type "Gate NO " ;

[0134] - a second logic gate U2. The second logic gate U2 is also of type "Door NO";

[0135] - a seventh capacitor Cpl';

[0136] - a fifteenth resistor R13.

[0137] The first logic gate Ul is adapted to receive the timing signal Scad as input. The fifteenth resistor R13 forms, with the seventh capacitor Cpl', an RC network which determines the width of the power generator 122.

[0138] Fig. 11 illustrates an alternative embodiment of the control module 123, in which the transistors of its push-pull assembly are replaced by a comparator.

[0139] This variant embodiment of the control module 123 thus comprises:

[0140] - a sixteenth resistance R14;

[0141] - a seventeenth R15 resistance;

[0142] - a first comparator H1.

[0143] The first comparator H1 is adapted to receive, at its + (positive) input, the modulated pulse signal Smod, and at its - (negative) input, the output voltage of the voltage divider consisting of R14 and R15. Its - input is raised to a voltage Vout / 2, through the voltage divider of resistors R14 and R15, since R14=R15. Its output is connected to the output voltage line Vout when the voltage of the Smod signal is greater than Vout / 2, and it is grounded when the voltage of the Smod signal is less than Vout / 2.

[0144] Figure 12 illustrates an alternative embodiment of the control module 124, in which the transistors are essentially replaced by a comparator and a Zener diode. This improves accuracy while reducing the number of components. Energy consumption is thus reduced.

[0145] This alternative embodiment of the servo module 124 comprises:

[0146] - a second comparator H2;

[0147] - an eighteenth R16 resistance;

[0148] - a nineteenth R17 resistor;

[0149] - a twentieth resistance RI8;

[0150] - an eighth capacitor C4;

[0151] - the Zener diode DZ.

[0152] The Zener diode DZ is biased through resistor R16. Capacitor C4 filters and stabilizes the voltage, which is the same across the Zener diode DZ and at the + (positive) input of comparator H2. The voltage divider, consisting of resistors R17 and RI8, delivers a voltage to the - (negative) input of comparator H2 equal to a fraction of the output voltage Vout. The output of H2 is connected to the output voltage line Vout when the + input voltage of comparator H2 is greater than this fraction of Vout present at the - input of H2. Conversely, the output of H2 is grounded when the + input voltage of comparator H2 is less than the fraction of Vout present at the - input of H2. Finally, the output voltage of comparator H2 is equal to Vout when the voltage Vout is less than a voltage fixed by DZ, R17 and R18, and is equal to zero otherwise.

[0153] The invention thus provides improvements through the use of a low operating frequency, minimal consumption and a low input voltage:

[0154] - It can use exclusively passive and discrete components, which limits the risks of obsolescence, just as it can also use integrated circuits, such as logic gates and comparators;

[0155] - It has a power output limitation through the use of time-limited power supplies fixed (constant duty cycle);

[0156] - It uses the "pump skipping" method (also called modulation of the pulse frequency as a function of the load (in French), which optimizes energy consumption at low operating power;

[0157] It uses a low operating frequency at startup, allowing us to increase the input impedance of our converter;

[0158] It uses a variable frequency, which depends on the input voltage, in order to obtain good efficiency without resorting to a complex circuit, such as an MPPT (for "Maximum Power Point Tracker" in English);

[0159] It uses its own output voltage to power its sub-functions (timer, power generator, Mosfet driver, servo);

[0160] It can use a pre-priming system which allows it to avoid the use of a charge pump at start-up, if the input voltage is too low.

Claims

Demands

1. DC-DC boost converter capable of receiving an input voltage (Vin) and delivering an output voltage (Vout) greater than said input voltage (Vin), said DC-DC boost converter comprising: - a conversion module (11) capable of converting the input voltage (Vin) into an output voltage (Vout) as a function of a control signal (Scon); - a control system (12) capable of transmitting said control signal (Scon) to the conversion module (11), said control signal (Scon) being obtained from a modulated pulse signal (Smod) capable of taking, depending on the output voltage (Vout), either a periodic form of variable frequency (Simp) or a constant form (0), characterized in that the variable frequency is timed from the input voltage (Vin) and the output voltage (Vout).

2. DC-DC boost converter according to claim 1, characterized in that the control system (12) comprises a driver module (123), said driver module (123) being adapted to generate the control signal (Scon) as a function of the modulated pulse signal (Smod).

3. DC-DC boost converter according to claim 2, characterized in that the driver module (123) comprises a plurality of transistors (Q6, Q7) or a plurality of comparators.

4. DC-DC boost converter according to claim 2 or claim 3, characterized in that the control system (12) comprises a servo module (124), said servo module being capable of forming the constant part of the modulated pulse signal (Smod) if the output voltage (Vout) is greater than a certain voltage threshold.

5. DC-DC boost converter according to claim 4, characterized in that the control module (124) is capable of receiving and processing the pulsed signal (Simp) to achieve synchronous control.

6. DC-DC boost converter according to claim 4 or claim 5, characterized in that the control module (124) comprises a first Mosfet transistor (M1) or comparator.

7. DC-DC boost converter according to any one of claims 4 to 6, characterized in that the control system (12) comprises a power generation module (122), said power generation module (122) being capable of generating the pulse signal (Simp) as a function of a timing signal (Scad), said pulse signal (Simp) becoming the modulated pulse signal (Smod) as soon as the power generation module (122) is connected to the control module (124).

8. DC-DC boost converter according to claim 7, characterized in that the pulses of the pulse signal (Simp) have a predetermined duration.

9. DC-DC boost converter according to claim 7 or claim 8, characterized in that the control system (12) includes a clock module (121), said clock module (121) being capable of receiving the input voltage (Vin) and the output voltage (Vout) to generate the timing signal (Scad).

10. DC-DC boost converter according to claim 9, characterized in that the clock module (121) includes at output a buffer transistor (Q3) or a logic gate.

11. DC-DC boost converter according to any one of claims 1 to 10, characterized in that the conversion module (11) comprises a coil (L) for storing magnetic energy, a capacitor (Cout) for storing electrical energy and means for transferring all or part of the magnetic energy of the coil (L) into electrical energy of the capacitor (Cout), said transfer means comprising a second Mosfet transistor (M2) and a switching diode (D).

12. DC-DC boost converter according to claim 11, characterized in that the switching diode (D) is a Schottky diode.

13. DC-DC boost converter according to any one of claims 1 to 12, characterized in that the conversion module (11) is a boost chopper.

14. DC-DC boost converter according to any one of claims 1 to 13, characterized in that the range of powers applied to said converter is between 1 mW and several hundred kW.

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