Self-excited charge pump system with inductive coupling

Abstract

A self-excited inductive charge pump system with inductive coupling converts a low voltage of several tens of millivolts (mV) into a useful voltage (i.e., greater than 1.2 V) using an ultra-low power supply of several microwatts to several tens of microwatts. Energy from an energy source is transmitted to a DC power receiver via a DC power supply and a self-excited DC / DC converter. At the input, the DC power supply has a self-excited power generator connected to an output rectifier. The self-excited power generator has a first capacitor between the input connections. The lower connection of the first capacitor is connected to system ground, and the upper connection is connected to the primary and secondary windings of a transformer. The output connection of the secondary winding of the transformer is connected to the output connection of the self-excited power generator via a fourth capacitor. Meanwhile, the output connection of the primary winding of the transformer is connected to system ground via an N-JFET transistor and also to system ground via an N-MOSFET transistor.

Description

[Technical Field]

[0001] The subject of the present invention is a self-excited charge pump system with inductive coupling designed to convert voltages as low as tens of millivolts to useful voltages (i.e., above 1.2 volts) using an ultra-low power supply, on the order of a few microwatts to a few tens of microwatts. [Background technology]

[0002] A self-excited charge pump circuit known from Chinese Patent Application No. CN108667287 includes a power amplifier circuit for providing stable power, an up-conversion circuit for processing an input signal, and a down-conversion circuit for processing the input signal. According to this invention, the charge pump can achieve self-excitation without the need for external inductive components. The absence of inductive components overcomes problems associated with inductor-based power supplies and minimizes electromagnetic interference. The circuit not only boasts high efficiency, simple circuit structure, small footprint, and low power consumption, but also operates efficiently under low-voltage conditions.

[0003] A self-excited charge pump circuit known from Chinese patent application number CN103607116 is composed of a switching unit and a control unit. The switching unit is appropriately connected to a node in the auxiliary unit and is responsible for controlling the charging and discharging of the auxiliary unit. The control unit is used to control the switching unit and perform the required on / off operation based on the voltage fed back from the output connection. The clock controller required in conventional charge pump circuits is omitted, loop compensation is not required, and the number of external components can be minimized. EMI noise of specific frequency components generated during the operation of the external clock controller is reduced, optimizing the circuit design. The limited electromagnetic interference makes the self-excited charge pump circuit suitable for noise-sensitive medical equipment, overcoming the drawbacks of the prior art. Summary of the Invention [Problem to be solved by the invention]

[0004] Low-power energy sources have very low "cold-start" voltages, on the order of tens to hundreds of millivolts. As a result, standard circuits generally cannot start and operate at these voltages. This limitation hinders the effective use of energy harvesting in microelectronics and low-voltage systems with miniaturized and integrated energy harvesters. Examples of such applications include microphotovoltaic panels, the use of low-voltage thermocouples, vibration energy, and especially radio wave energy. [Means for solving the problem]

[0005] The key feature of the system according to the present invention is that energy from an energy source is transmitted to a DC receiver via a DC power supply and a self-excited DC / DC converter. At the input, the DC power supply includes a self-excited generator connected to an output rectifier. The self-excited generator has a first capacitor between its input terminals. The lower terminal of the first capacitor is connected to system ground, while the upper terminal of the first capacitor is connected to a primary winding and a secondary winding of a transformer. The output terminal of the secondary winding of the transformer is connected to the output terminal of the self-excited generator via a fourth capacitor. Meanwhile, the output terminal of the primary winding of the transformer is connected to system ground via an N-JFET transistor and also to system ground via an N-MOSFET transistor. The gate of the N-JFET transistor is connected to the fourth capacitor via a second capacitor and a first resistor connected in parallel. The gate of the N-MOSFET transistor is connected to the fourth capacitor via a third capacitor. The third capacitor is also connected to the junction connecting the secondary winding of the transformer and the fourth capacitor.

[0006] The output rectifier has a second diode between the input connections, which is connected to the output connection of the output rectifier via the first diode. Furthermore, a fifth capacitor and a Zener diode are connected in parallel with the first and second diodes between the output connections of the output rectifier. Advantageously, the first and second diodes are Schottky diodes.

[0007] The self-excited DC / DC converter is preferably connected to the self-excited power generator via a voltage limiting circuit having a transistor connected to the output rectifier.

[0008] The voltage limiting circuit on the transistor is preferably a low-pass AC filter or a high-pass AC filter. Advantageously, at least one thermocouple is present as the DC power source. Advantageously, at least one semiconductor Peltier element is present as the DC power source. Advantageously, at least one solar cell is present as the DC power source.

[0009] Preferably, at least one radio frequency energy recovery circuit is present as a DC power source, the radio frequency energy recovery circuit having an antenna at its input connected via an antenna impedance matching circuit to a rectifier, the rectifier serving as a DC power source for the recovered radio frequency energy.

[0010] The rectifier is preferably a half-wave or full-wave rectifier.

[0011] The self-excited inductive charge pump circuit features extremely low start-up energy for energy harvesting converters from radio waves, solar cells, Peltier elements, and thermocouples. The converter's start-up power is 3 μW at 50 mV, requiring no additional power from an external battery. The minimum power of the converter circuit after startup is at least 1 μW. The converter circuit is based on an N-MOSFET transistor, a transformer, four capacitors, one resistor, one Zener diode, and one double Schottky diode, with one J-FET transistor as the converter driver, resulting in a cost-effective converter. Despite the converter's relatively low complexity, the circuit exhibits high efficiency, reaching 63%, at a power of less than 20 μW. [Brief explanation of the drawings]

[0012] In exemplary embodiments, the present subject matter is illustrated in the following drawings:

[0013] [Figure 1] FIG. 1 is a diagram showing a self-excited inductive charge pump circuit. [Figure 2] FIG. 1 illustrates a self-excited inductive charge pump circuit with a voltage limiting circuit. [Figure 3] FIG. 1 illustrates a DC power source in the form of a thermocouple. [Figure 4] 1 illustrates a DC power source in the form of a solar cell. [Figure 5] 1 shows a radio frequency energy recovery circuit. [Figure 6] FIG. [Figure 7] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] <First Example> The self-excited inductive charge pump circuit comprises an energy source ES. Energy from the energy source ES is transmitted to a DC receiving part DC via a DC power supply DCS and a self-excited DC / DC converter SEI. At the input, the DC power supply DCS includes a self-excited generator SEG connected to an output rectifier OR.

[0015] The self-excited generator SEG incorporates a first capacitor C1 between its input connections. The lower connection of the first capacitor C1 is connected to system ground, while the upper connection of the first capacitor C1 is connected to both the primary and secondary windings of the transformer Tr. The output connection of the secondary winding of the transformer Tr is connected to the output connection of the self-excited generator SEG via a fourth capacitor C4. Furthermore, the output connection of the primary winding of the transformer Tr is connected to system ground via an N-JFET transistor Q1 and an N-MOSFET transistor Q2.

[0016] The gate of N-JFET transistor Q1 is connected to a fourth capacitor C4 via a second capacitor C2 and a first resistor R1 connected in parallel. The gate of N-MOSFET transistor Q2 is connected to a fourth capacitor C4 via a third capacitor C3. The third capacitor C3 is connected to the junction of the secondary winding of transformer Tr and the fourth capacitor C4.

[0017] Between the input connections of the output rectifier OR, a second diode D2 is connected to the output connection of the output rectifier OR via the first diode D1. Furthermore, between the output connections of the output rectifier OR, a fifth capacitor C5 and a Zener diode DZ are connected in parallel with the first and second diodes.

[0018] In this example, the DC power source DCS is a thermocouple T, and the energy source ES generates heat. The self-excited inductive charge pump circuit utilizes an energy source in the form of a temperature difference created at the thermocouple junction. This temperature difference creates a potential difference and a flow of DC current. This DC current is input to a unique converter. This converter converts the 20-60 mV voltage to a 2.5 V voltage useful for powering low-power electronics or charging supercapacitors or batteries.

[0019] <Second Example> The self-excited inductive charge pump circuit is configured similarly to the first embodiment, but differs from the first embodiment in that the self-excited DC / DC converter SEI has a self-excited power generating unit SEG connected to the output rectifier OR via a transistor-based voltage limiting circuit OVP. Furthermore, the transistor-based voltage limiting circuit OVP is a high-pass AC filter.

[0020] This circuit utilizes the temperature difference that occurs at the junctions of five thermocouples T. This temperature difference generates a potential difference and a flow of direct current. This current is input to a self-excited DC / DC converter SEI. The self-excited DC / DC converter SEI converts the voltage from 120 to 250 mV to a voltage of 3.7 V, which is useful for powering low-power electronic circuits or charging supercapacitors or batteries. In this example, the thermocouples T are connected in series, and the first diode D1 and the second diode D2 are Schottky diodes.

[0021] <Third Example> The self-excited inductive charge pump circuit is configured similarly to the second embodiment, but differs in that it utilizes the temperature difference generated at the junctions of eight thermocouples T connected in parallel. In this circuit, a supercapacitor or battery is charged with a power in the range of approximately 100 μW to 3 mW.

[0022] <Fourth Example> The self-excited induction charge pump circuit is configured similarly to the first to third embodiments, except that the thermocouple T is replaced with a semiconductor Peltier element. The supercapacitor or battery is charged with a power in the range of approximately 10 μW to 1 mW.

[0023] <Fifth Example> The self-excited inductive charge pump circuit is configured similarly to the first embodiment, except that the DC power source DCS is a solar cell PV, and the energy source ES emits light. When exposed to light, the solar cell PV generates a DC current. This DC current is input to a self-excited DC / DC converter SEI. The voltage of 120 to 350 mV is converted to a voltage of 3.3 V, which is useful for powering low-power electronic circuits or charging supercapacitors or batteries.

[0024] <Sixth Example> The self-excited inductive charge pump circuit is similar to the first and fifth embodiments, except that four solar cells PV connected in series form a DC power source DCS, and the energy source ES emits light. Furthermore, the self-excited DC / DC converter SEI has a self-excited power generating section SEG connected to the output rectifier OR via a transistor-based voltage limiting circuit OVP. The transistor-based voltage limiting circuit OVP acts as a low-pass AC filter. This circuit uses one solar cell PV as its energy source. When exposed to light, the solar cell PV generates DC current. This DC current is input to the self-excited DC / DC converter SEI. The self-excited DC / DC converter SEI converts a voltage between 400 mV and 1.2 V to a 5 V voltage, which is useful for powering low-power electronic circuits and charging supercapacitors.

[0025] <Seventh Example> The self-excited inductive charge pump circuit is configured in the same way as in the sixth embodiment, except that nine solar cells PV connected in parallel form a DC power supply DCS, and the energy source ES emits light.

[0026] <Eighth Example> The self-excited inductive charge pump circuit is configured similarly to the first embodiment, except that the DC power source DCS is a radio frequency energy recovery circuit and the energy source ES emits radio frequency energy. This circuit includes an antenna ANT connected to an RC rectifier via an impedance matching circuit IM having an input impedance Z. The RC rectifier functions as a DC power source for the recovered radio frequency energy. The RC rectifier is a single-diode rectifier. This circuit utilizes radio waves having frequencies ranging from 27 MHz to 60 GHz.

[0027] The circuit requires an additional radio waves harvesting circuit to absorb the energy or radio waves. The radio waves harvesting circuit consists of an antenna ANT tuned to the frequency of the radio frequency energy source, an impedance matching circuit IM, and an RC rectifier that converts the radio frequency current to direct current. The rectified current is input to a self-excited DC / DC converter SEI. The self-excited DC / DC converter SEI converts a voltage of 20mV to 140mV to a voltage of 2.5V, which is useful for powering low-power electronic circuits or charging supercapacitors or batteries.

[0028] <Ninth Example> The self-excited inductive charge pump circuit is configured similarly to the first and eighth embodiments, except that the rectifier RC is a full-wave rectifier. Furthermore, the self-excited DC / DC converter SEI has a self-excited power generating unit SEG connected to the output rectifier OR via a transistor-based voltage limiting circuit OVP. The transistor-based voltage limiting circuit OVP is a high-pass AC filter. In this example, three radio frequency energy recovery circuits are provided. The self-excited inductive charge pump circuit utilizes energy from radio waves with frequencies ranging from 27 MHz to 60 GHz.

[0029] The circuit requires an additional radio wave recovery circuit to absorb the energy or radio waves. The radio wave recovery circuit consists of an antenna ANT tuned to the frequency of the radio frequency energy source, an antenna impedance matching circuit IM, and an RC rectifier that converts the radio frequency AC current to DC current. The rectified current is input to a self-excited DC / DC converter SEI. The self-excited DC / DC converter SEI converts a voltage of 20mV to 140mV to a voltage of 2.5V, which is useful for powering low-power electronic circuits or charging supercapacitors or batteries.

[0030] The operation of the circuit involves connecting the drain and source of an N-JFET transistor Q1 and an N-MOSFET transistor Q2 between the primary winding of a transformer Tr and ground, which allows the primary winding to be connected to ground, allowing current to flow through the primary winding.

[0031] As the voltage on the primary winding rises, the voltage on the secondary winding of the transformer Tr also begins to rise. However, the secondary winding is wound in the opposite direction to the primary winding. When the primary winding is grounded, a reverse current is induced in the secondary winding, magnifying the voltage by the turns ratio of the secondary winding to the primary winding. The current induced in the secondary winding passes through the second and third capacitors C2 and C3, closing the N-JFET transistor Q1 and the N-MOSFET transistor Q2. Therefore, the magnetically "charged" transformer Tr can only be discharged through the fourth capacitor, whose capacitance is tuned to the operating frequency of the self-excited generator SEG. This transfers more than 90% of the energy stored in the secondary winding to the output rectifier circuit OR, which includes two Schottky diodes D1 and D2. At the same time, some of the charge stored in the secondary windings by capacitors C2 and C3 will enter the bases of N-JFET transistor Q1 and N-MOSFET transistor Q2, reconnecting the primary windings to ground and repeating the self-induction process described above.

[0032] The circuit includes resistor R1, which acts as a charge leak to the gate of N-JFET transistor Q1. N-JFET transistor Q1 saturates and blocks when the energy input from the energy source becomes excessive. The key feature of this circuit is that N-JFET transistor Q1 and N-MOSFET transistor Q2 are connected in parallel via second capacitor C2, resistor R1, and fourth capacitor C4 in a manner similar to known DC converters, but with a difference: N-JFET transistor Q1 acts as the converter's trigger. This configuration requires a minimum voltage of 50 mV to start operation, and a power of 3 μW to start the circuit.

[0033] Once operation begins, the primary role of switching the voltage across the secondary winding is taken over by N-MOSFET transistor Q2. With N-MOSFET transistor Q2, the converter achieves approximately 65% ​​efficiency when driven at 20 μW of power and 30 mV of voltage. The converter's minimum operating thresholds are 1 μW of power and 20 mV of voltage. Without N-JFET transistor Q1, the minimum operating thresholds required for the start of the self-excitation process are 400 mV and approximately 50 μW of power. Furthermore, while the self-excited inductive converter is operating, the voltage across the secondary winding of transformer Tr must be controlled. This control is achieved by implementing an on-transistor voltage limiting circuit (OVP) in the form of an AC filter to prevent the gate voltages of N-JFET transistor Q1 and N-MOSFET transistor Q2 from exceeding acceptable values.

[0034] The self-excited inductive charge pump circuit comprises a direct current power source DCS in the form of a thermocouple T, a Peltier element, a solar cell, or a circuit for harvesting radio frequency energy.

[0035] DC power supplies DCS in the form of thermocouples or Peltier elements are particularly useful in wireless seismic or strain gauge sensors that operate to detect collapses or deformations that indicate hazards in mines, and wireless explosive gas sensors that operate to detect concentrations of dangerous gases in mines.

[0036] A direct current power supply DCS in the form of a solar cell can be incorporated into television remote control devices, wireless thermometers, wireless strain gauge sensors that monitor deformation in structures, electronic price displays in stores, portable location systems such as AirTags®, etc.

[0037] The radio frequency energy recovery system includes radio waves in the range of 50 Hz to 100 GHz, an antenna ANT for absorbing (recovering) radio waves in at least one range of radio frequencies, an antenna impedance matching circuit IM, and an RC rectifier. DCS in the form of radio frequency energy harvesting systems can be incorporated into wireless strain gauge sensors that monitor deformation of wind turbine rotor blades, ultra-low power wireless headphones, wall, desk and other low power time control devices, low or ultra-low power IoT devices, small computer wireless peripherals such as low or ultra-low power electronic pens, computer mice, computer keyboards, touchpads and other similar devices, radio frequency tags for locating pallets / crates in warehouses, wireless sensors for industrial ICS / SCADA infrastructure supporting industrial automation and safety, remote control devices for automatic gates, smart door locks including central locking in the automotive industry, shutters, blinds and other home and office automation components, fob-key and smart key systems, control and measurement equipment for large, medium and small scale electrical storage warehouses, personal medical diagnostic equipment where self-excited charge pump circuits are used, anywhere internal batteries / supercapacitors are recharged, and many other applications. [Explanation of symbols]

[0038] ANT antenna C1 First capacitor C2 Second capacitor C3 Third capacitor C4 Fourth capacitor C5 Fifth capacitor D1 First diode D2 Second diode DC direct current receptor DZ Zener diode DCS DC power supply ES Energy Source IM Antenna Impedance Matching Circuit OR output rectifier OVP Voltage limiting circuit for transistors PV solar cell R1 First resistor RC rectifier Q1 N-JFET transistor Q2 N-MOSFET transistor SEI Self-Excited DC / DC Converter SEG self-excited power generation unit T thermocouple Tr transformer Z Input impedance

Claims

1. 1. A self-excited charge pump system with inductive coupling, comprising: Energy from an energy source (ES) is transmitted to a DC power receiving unit (DC) via a DC power supply (DCS) and a self-excited DC / DC converter (SEI); At the input, the DCS has a self-excited generator (SEG) connected to an output rectifier (OR); the self-excited generator (SEG) has a first capacitor (C1) connected between its input connections; a lower connection of the first capacitor (C1) connected to a system ground and an upper connection of the first capacitor (C1) connected to a primary winding and a secondary winding of a transformer (Tr); the output connection of the secondary winding of the transformer (Tr) is connected to the output connection of the self-excited generator (SEG) via a fourth capacitor (C4); The output connection of the primary winding of the transformer (Tr) is connected to the system ground via an N-JFET transistor (Q1) and to the system ground via an N-MOSFET transistor (Q2); The gate of the N-JFET transistor (Q1) is connected to a connection point connecting the secondary winding of the transformer (Tr) and the fourth capacitor (C4) via a second capacitor (C2) and a first resistor (R1) connected in parallel, The gate of the N-MOSFET transistor (Q2) is connected to a connection point connecting the secondary winding of the transformer (Tr) and the fourth capacitor (C4) via a third capacitor (C3); the output rectifier (OR) has a second diode (D2) connected to its input; the second diode (D2) is connected to the output connection of the output rectifier (OR) via the first diode (D1); Furthermore, a fifth capacitor (C5) and a Zener diode (DZ) are connected in parallel with the first diode (D1) and the second diode (D2) between the output connections of the output rectifier (OR), The first diode (D1) and the second diode (D2) are advantageously Schottky diodes; system.

2. 2. The system of claim 1, wherein the self-excited DC / DC converter (SEI) has a self-excited generator (SEG) connected to the output rectifier (OR) via a voltage limiting circuit (OVP) for a transistor.

3. 3. The system of claim 2, wherein the voltage limiting circuit (OVP) for the transistor is a low pass AC filter.

4. 3. The system of claim 2, wherein the voltage limiting circuit (OVP) for the transistor is a high-pass AC filter.

5. The system of claim 1 , wherein the direct current power source (DCS) is at least one thermocouple (T).

6. The system of claim 1 , wherein the direct current power source (DCS) is at least one solid state Peltier element.

7. The system of claim 1 , wherein the direct current power source (DCS) is at least one photovoltaic (PV) source.

8. the direct current power source (DCS) is at least one radio frequency energy recovery system; The radio frequency energy recovery system has at its input an antenna (ANT) connected to a rectifier (RC) via an antenna impedance matching circuit (IM), The rectifier (RC) acts as a DC power source for the recovered radio frequency energy. The system of claim 1 .

9. 8. The system of claim 7, wherein the rectifier (RC) is a half-wave rectifier.

10. 8. The system of claim 7, wherein the rectifier (RC) is a full-wave rectifier.

Images