Power supply circuit and metering device

Abstract

A power supply circuit 100 is provided, comprising: a power converter 120 having a first input node 122 and a first output node 124, operable to receive an input voltage at the first input node 122 and generate an output voltage at the first output node 124 that is higher than the input voltage level; a battery 110 having a second output node 112, wherein the second output node 112 is electrically connected to the first input node 122; an output terminal 160; and a P-channel transistor 130 including a first electrode, a second electrode, and a gate electrode, wherein the first electrode is electrically connected to the second output node 112, and the second electrode is electrically connected to the first input node 124. Output terminal 160 is electrically connected; a first unidirectional conductive device 150 is electrically connected between the first output node 124 and the output terminal 160, wherein the first unidirectional conductive device 150 includes a first anode and a first cathode, and the first anode is electrically connected to the first output node, and the first cathode is electrically connected to the output terminal; and a second unidirectional conductive device 170 is electrically connected between the first output node 124 and the gate electrode of the P-channel transistor 130, wherein the second unidirectional conductive device 170 includes a second anode and a second cathode, and the second anode is electrically coupled to the first output node 124, and the second cathode is electrically coupled to the gate electrode.

Description

Technical Field

[0001] This disclosure relates to a power supply circuit and a metering device including the circuit. More specifically (but not limited thereto), this disclosure relates to a power supply circuit including a battery with an OR gate P-channel transistor and a feedback output network that prevents reverse driving of the battery through the OR gate P-channel transistor. Background Technology

[0002] Figure 1 A known power supply circuit 100' is schematically shown, which supplies power to a load through its output terminal 160'. Output terminal 160' is driven by performing an OR operation between the outputs of battery 110' and power converter 120'. Power converter 120' converts the output voltage of battery 110' to a different, higher voltage level. The OR function is implemented by a P-channel metal-oxide-semiconductor field-effect transistor (P-MOSFET) 130' connected between the output of battery 110' and output terminal 160', and a diode 150' connected between the output of power converter 120' and output terminal 160'. The gate of P-MOSFET 130' is driven by a control circuit 140', which is powered by battery 110'. Power supply circuit 100' is able to adapt to fluctuations in battery input voltage and temperature changes, thereby maintaining a constant and stable output voltage.

[0003] The use of a P-MOSFET 130' instead of a conventional diode is to minimize battery voltage drop. This design is particularly advantageous when the power converter 120' is off and battery current flows through the P-MOSFET 130', which has extremely low DC resistance. Despite the numerous advantages of the power supply circuit 100', reverse drive current can sometimes occur when the battery voltage is sufficiently low. More specifically, the output of the power converter 120' minus the forward voltage drop of the diode 150' is higher than the gate voltage of the P-MOSFET 130' by a factor of Vthreshold. GS(th) When this happens, P-MOSFET 130' will turn on instead of turning off. As a result, a large current will flow backward into the anode of battery 110'. If battery 110' is a primary lithium battery, reversing the flow is essentially equivalent to charging it. This poses a significant danger because, unlike rechargeable batteries, primary lithium batteries are not designed for charging. If this occurs, gas will be generated inside battery 110', causing its internal pressure to rise. This could lead to battery 110' venting, and in the worst case, even an explosion.

[0004] Known solutions to this problem include: (i) preventing the battery voltage from dropping to a level sufficient to trigger a reverse drive current; and (ii) using a battery with a higher V. GS(th) A P-MOSFET of a certain value is used so that the voltage at its source is not exceeded by the output voltage of the power converter 120'. The disadvantage of scheme (i) is that it wastes available battery energy. While scheme (ii) is feasible, it is not ideal because it has a higher Vi when the battery voltage drops. GS(th) The P-type MOSFET will exhibit a higher channel DC resistance, thus negating the purpose of using a P-type MOSFET instead of a diode to implement the OR logic function. Furthermore, it has a high V... GS(th) P-type MOSFETs cannot be perfectly controlled during production, and V GS(th) It also changes with temperature.

[0005] One of the objectives of this invention is to provide an improved power supply circuit to solve the problem of reverse battery drive. Summary of the Invention

[0006] According to a first aspect of this disclosure, a power supply circuit is provided, comprising: a power converter having a first input node and a first output node, wherein the power converter is operatively capable of receiving an input voltage at the first input node and generating an output voltage at the first output node that is higher than the input voltage level; a battery having a second output node, wherein the second output node is electrically connected to the first input node; an output terminal; a P-channel transistor including a first electrode, a second electrode, and a gate, wherein the first electrode is electrically connected to the second output node and the second electrode is electrically connected to the output terminal; a first unidirectional conductive device electrically connected between the first output node and the output terminal, wherein the first unidirectional conductive device includes a first anode and a first cathode, and the first anode is electrically coupled to the first output node and the first cathode is electrically coupled to the output terminal; and a second unidirectional conductive device electrically connected between the first output node and the gate electrode of the P-channel transistor, wherein the second unidirectional conductive device includes a second anode and a second cathode, and the second anode is electrically coupled to the first output node and the second cathode is electrically coupled to the gate electrode.

[0007] Advantageously, the second unidirectional conductor forms an output feedback network that establishes an electrical connection between the power converter output voltage at the first output node and the gate electrode of the P-channel transistor. With the help of the second unidirectional conductor, the voltage at the gate electrode of the P-channel transistor can be controlled to be slightly less than or equal to the voltage at the output terminal, thereby ensuring that the threshold voltage of the P-channel transistor is not exceeded, thus keeping the P-channel transistor in the off state. Therefore, regardless of the battery voltage level, no reverse drive current flows into the battery through the P-channel transistor. Thus, using the second unidirectional conductor provides a low-cost and fairly simple solution that prevents potentially dangerous reverse drive current from flowing into the battery and extends battery life by allowing the battery output voltage to drop to extremely low levels.

[0008] It should be understood that when the voltage level of the first / second anode is higher than the voltage level of the first / second cathode (i.e., when forward biased), the first / second unidirectional conductive device allows current to pass through; while when the voltage level of the first / second anode is lower than the voltage level of the first / second cathode (i.e., when reverse biased), it blocks current from passing through.

[0009] Furthermore, it should be understood that this unidirectional conductive device primarily conducts current in one direction, thus exhibiting asymmetrical conductivity. Under normal operating conditions (excluding reverse breakdown), the unidirectional conductive device has lower resistance in one direction and higher resistance in the other.

[0010] The term "electrically coupled" includes the presence of one or more intermediate elements for signal transmission between electrically coupled elements.

[0011] It should also be understood that the gate electrode controls the current flow between the first electrode and the second electrode.

[0012] The forward voltage drop of the first unidirectional conductive device may be greater than or equal to the forward voltage drop of the second unidirectional conductive device.

[0013] The type of the first unidirectional conductive device can be the same as the type of the second unidirectional conductive device.

[0014] In other words, the first and second unidirectional conductive devices can be made of the same material and / or have the same structure. Alternatively, the first and second unidirectional conductive devices can be different types of electronic devices.

[0015] At least one of the first and second unidirectional conductive devices may include a diode.

[0016] At least one of the first and second unidirectional conductive devices may include a Schottky diode.

[0017] At least one of the first and second unidirectional conductive devices may include a circuit configured to operate like a diode.

[0018] The power supply circuit may also include a third unidirectional conductive device electrically connected between the first and second electrodes of the P-channel transistor. This third unidirectional conductive device may include a third anode and a third cathode. The third anode may be electrically coupled to the second output node, and the third cathode may be electrically coupled to the output terminal.

[0019] The third unidirectional conductive device may include a diode.

[0020] The P-channel transistor can be a P-channel metal-oxide-semiconductor field-effect transistor.

[0021] This power converter may include a DC-DC converter.

[0022] This power converter may include a switch-mode DC-DC converter.

[0023] The switch-mode DC-DC converter can be a switch-mode DC-DC boost converter or a switch-mode DC-DC buck-boost converter.

[0024] The power supply circuit may also include a control circuit configured to control the voltage at the gate electrode of the P-channel transistor. This control circuit may be powered by a battery.

[0025] The control circuit can also be configured to generate an enable signal that allows the power converter to operate.

[0026] The power supply circuit may further include a resistor electrically connected to the second unidirectional conductive device and connected in series between the first output node and the gate electrode of the P-channel transistor.

[0027] This resistor can be configured to limit the current flowing through the control circuit.

[0028] The battery may include a primary lithium battery.

[0029] The battery may include at least one of lithium thiosulfate battery and lithium manganese dioxide battery.

[0030] According to a second aspect of this disclosure, a metering device is provided, which includes a power supply circuit according to a first aspect of this disclosure.

[0031] The metering device can be configured to measure the amount of at least one of gas and water.

[0032] The metering device may also include a wireless communication unit powered by a power supply circuit.

[0033] In other words, the voltage input terminal of the wireless communication unit is electrically connected to the output terminal of the power supply circuit.

[0034] The wireless communication unit may include a modem.

[0035] According to a third aspect of this disclosure, a method for assembling a power supply circuit is provided, the power supply circuit including a power converter, a battery, an output terminal, a P-channel transistor, and first and second unidirectional conductive devices, wherein: the power converter has a first input node and a first output node, and is capable of receiving an input voltage through the first input node and generating an output voltage at the first output node with a voltage level higher than the input voltage; the battery has a second output node; and the P-channel transistor includes a first electrode, a second electrode, and a gate electrode, the method comprising: electrically connecting the first input node of the power converter to the second output node of the battery; and electrically connecting the first unidirectional conductive device to the first output node of the power converter. Between the node and the output terminal, wherein the first unidirectional conductive device includes a first anode and a first cathode, and electrically connecting the first unidirectional conductive device includes electrically connecting the first anode to the first output node and electrically connecting the first cathode to the output terminal; electrically connecting the first electrode of the P-channel transistor to the second output node and electrically connecting the second electrode of the P-channel transistor to the output terminal; and electrically connecting the second unidirectional conductive device between the first output node and the gate electrode of the P-channel transistor; wherein the second unidirectional conductive device includes a second anode and a second cathode, and electrically connecting the second unidirectional conductive device includes electrically coupling the second anode to the first output node and electrically coupling the second cathode to the gate electrode.

[0036] Furthermore, it should be understood that the terms “first,” “second,” and “third” are used in this disclosure only to label the relevant elements (“unidirectional conductive device,” “output node,” etc.) for ease of description, and do not imply any limitation on the order, position, or total number of the relevant elements.

[0037] Where appropriate, any optional features relating to one aspect of this disclosure may be applied to another aspect of this disclosure. Attached Figure Description

[0038] To provide a more complete understanding of this disclosure, several embodiments of this disclosure will now be described by way of example with reference to the accompanying drawings, wherein:

[0039] Figure 1 It is a schematic block diagram of an existing power supply circuit;

[0040] Figure 2 This is a schematic block diagram of a power supply circuit according to one aspect of this disclosure;

[0041] Figure 3 This is a schematic circuit diagram of a power supply circuit according to one aspect of this disclosure;

[0042] Figure 4 schematically shown Figure 3 The simulated waveform of the power supply circuit shown;

[0043] Figure 5 It does not include Figure 2 or Figure 3 A schematic circuit diagram of the comparator power supply circuit for the feedback output network shown.

[0044] Figure 6 schematically shown Figure 5 The simulated waveforms of the power supply circuit shown;

[0045] Figure 7 This is a schematic block diagram of a metering device according to one aspect of this disclosure;

[0046] Figure 8 The processing steps of a power circuit assembly method according to one aspect of this disclosure are illustrated schematically.

[0047] In each drawing, the same parts are indicated by the same reference number.

[0048] It should be understood that the accompanying drawings are for illustrative purposes only and are not drawn to scale. Detailed Implementation

[0049] Figure 2 A power supply circuit 100 according to one aspect of this disclosure is schematically shown. This power supply circuit 100 is used to supply power to an external load (not in...). Figure 2 (as shown in the figure) Powered by, and includes an output terminal 160 for electrical connection to a load.

[0050] The power supply circuit 100 includes a power converter 120 having a first input node 122 and a first output node 124, and a battery 110 having a second output node 112. The second output node 112 is electrically connected to the first input node 122 such that the input voltage received by the power converter 120 at the first input node 122 is substantially the same as the output voltage of the battery 110. The power converter 120 generates an output voltage at the first output node 124, which is higher than the input voltage received at the first input node 122. In one example, the power converter 120 is a DC-DC converter, such as a switch-mode DC-DC converter. More specifically, the power converter 120 may be a switch-mode DC-DC boost converter or a switch-mode DC-DC buck-boost converter. It should be understood that the power converter 120 may take any suitable form. For simplicity, Figure 2 The grounding point is not shown, and it should be understood that nodes 112, 122, 124 and output terminal 160 are all ungrounded (e.g., positive) voltage nodes.

[0051] The power supply circuit 100 also includes a P-channel transistor 130 having a source electrode, a drain electrode, and a gate electrode. In one example, the P-channel transistor 130 is a P-type MOSFET. However, it should be understood that other types of P-channel transistors, such as insulated-gate field-effect transistors (IGFETs) or metal-insulator-semiconductor field-effect transistors (MISFETs), may also be used. Figure 2 As shown, the drain electrode of the P-channel transistor 130 is electrically connected to the second output node 112 of the battery 110, and the source electrode of the P-channel transistor 130 is electrically connected to the output terminal 160. It should be noted that the P-channel transistor 130 may be structurally symmetrical; therefore, its source and drain electrodes are determined by the voltage applied to them and are structurally indistinguishable from each other. The source and drain electrodes can be referred to as the "first electrode" and the "second electrode," respectively, and vice versa. The voltage difference between the gate electrode and the source electrode controls the on / off state of the P-channel transistor 130. Therefore, it can be said that the voltage applied to the gate electrode controls the current flow between the first and second electrodes. A control circuit 140 is used to drive the gate electrode. The control circuit 140 is powered by the battery 110. Specifically, the voltage input terminal of the control circuit 140 is electrically connected to the second output node 112 of the battery 110. The voltage on the gate electrode may be equal to or slightly lower than the output voltage of the battery 110 at the second output node 112.

[0052] Diode 150 is electrically connected between the first output node 124 and the output terminal 160. Specifically, the anode of diode 150 is electrically connected to the first output node 124, and the cathode of diode 150 is electrically connected to the output terminal 160. In one example, diode 150 is a Schottky diode with a forward voltage drop (e.g., 0.35V) lower than that of a PN junction-based diode (e.g., 0.7V). As used in this disclosure, "diode" can be referred to as a "unidirectional conducting device" that allows current to flow (i.e., forward bias) when the voltage level at the anode is higher than that at the cathode, and blocks current flow (i.e., reverse bias) when the voltage level at the anode is lower than that at the cathode. The unidirectional conduction characteristic of diode 150 prevents the battery voltage from driving the output of power converter 120 in reverse. It should be noted that diode 150 can be replaced by other types of unidirectional conducting devices, including integrated ideal diodes (e.g., the LM66100 manufactured by Texas Instruments®), or MOSFETs that are diode-connected by shorting the gate and drain. An integrated ideal diode is a circuit that operates similarly to a diode. Generally speaking, any device that, under normal operating conditions (excluding reverse breakdown), can be controlled to have low resistance in one direction and high resistance in the other can be considered a unidirectional conducting device and can be used to replace diode 150. The anode and cathode of such a unidirectional conducting device can be easily determined based on the voltage polarity in the low resistance direction.

[0053] P-channel transistor 130 and diode 150 together form an OR gate circuit, which performs an OR operation on the output signals of battery 110 and power converter 120, and outputs the signal to output terminal 160. Control circuit 140 can also be called an OR gate controller. When power converter 120 is off, P-channel transistor 130 remains on, so the voltage at output terminal 160 is equal to the output voltage of battery 110 at the second output node 112 minus the on-state voltage drop between the source and drain of P-channel transistor 130. When power converter 120 is on, the output voltage generated by power converter 120 is higher than the output voltage of battery 110. At this time, the voltage at output terminal 160 is equal to the output voltage of power converter 120 at the first output node 124 minus the forward voltage drop across diode 150.

[0054] The power supply circuit 100 also includes an output feedback network 175 to prevent reverse drive current from flowing into the battery 110 when the power converter 120 is turned on and the battery voltage is low. (See reference...) Figure 2The output feedback network 175 includes a resistor 180 and a diode 170 connected in series. The output feedback network 175 samples the output voltage of the power converter 120 at the first output node 124 and connects this output voltage to node 182 between the control circuit 140 and the gate of the P-channel transistor 130. The anode of the diode 170 is electrically connected to the first output node 124 of the power converter 120, while the cathode of the diode 170 is electrically coupled to node 182 through the resistor 180. Of course, those skilled in the art should understand that the relative positions of the diode 170 and the resistor 180 can be interchanged, such that the cathode of the diode 170 is directly connected to node 182, and the resistor 180 is directly connected to the first output node 124.

[0055] The voltage at the gate of the P-channel transistor 130 (i.e., the voltage at node 182) is determined by the output voltage of the power converter 120, the output feedback network 175, and the control circuit 140. For example, the control circuit 140 may include a current sinking path from the gate electrode to ground; since the gate of the P-channel transistor 130 is insulated, the current flowing through this sinking path will be substantially equal to the current flowing through the output feedback network 175. Therefore, the voltage at the gate electrode will be equal to the output voltage of the power converter 120 minus the forward voltage drop of the diode 170 and the voltage drop across the resistor 180. In other words, the current sinking path of the control circuit 140 and the total resistance of the resistor 180 form a voltage divider and affect the voltage at node 182. In this sense, node 182 can be considered a "voltage summing node." The resistor 180 limits the maximum current absorbed in the current sinking path of the control circuit 140. Therefore, the specific value of the resistor 180 can be appropriately selected based on the current sinking capability of the control circuit 140. In some applications, resistor 180 can be completely omitted from the output feedback network 175.

[0056] Therefore, the output feedback network 175 controls the gate voltage of the P-channel transistor 130 to be slightly less than or equal to the voltage at the output terminal 160 (i.e., the source voltage of the P-channel transistor 130). Thus, the voltage difference between the source and gate electrodes of the P-channel transistor 130 is insufficient to overcome the transistor's threshold voltage V. GS(th) The P-channel transistor 130 remains off. As a result, no reverse drive current flows into the battery 110 regardless of its voltage level. The use of the output feedback network 175 provides a low-cost and fairly simple solution to prevent potentially dangerous reverse drive current from flowing into the battery 110. Furthermore, the output feedback network 175 maximizes battery capacity utilization and thus extends the battery 110's lifespan by allowing the battery 110's output voltage to drop to extremely low levels.

[0057] Similar to diode 150, diode 170 can be replaced by other types of unidirectional conducting devices. For ease of description, diode 150 can be referred to as the "first unidirectional conducting device," and diode 170 can be referred to as the "second unidirectional conducting device." Preferably, the forward voltage drop of the first unidirectional conducting device 150 is greater than or equal to the forward voltage drop of the second unidirectional conducting device 170. The larger the forward voltage drop of the first unidirectional conducting device 150, the lower the source voltage of the P-channel transistor 130 will be. Therefore, the voltage difference between the source and gate of the P-channel transistor 130 can overcome the threshold voltage V. GS(th) The less likely it is that the first and second unidirectional conductive devices 150 and 170 are of the same type (e.g., both Schottky diodes) or different types of devices (e.g., device 150 is a PN junction-based diode, while device 170 is a Schottky diode or an integrated ideal diode). If the first and second unidirectional conductive devices 150 and 170 are diodes, the forward voltage drop can also be referred to as the forward threshold voltage or knee voltage.

[0058] Although Figure 2 Not shown, but power supply circuit 100 may include additional circuitry for generating an enable signal to allow power converter 120 to operate. Alternatively, control circuitry 140 may also generate the enable signal.

[0059] In the power supply circuit 100, the battery 110 can be a primary lithium battery, such as a lithium thiochloride primary battery or a lithium manganese dioxide primary battery. Reverse driving a primary lithium battery can damage the battery and pose serious safety risks. Using an output feedback network 175 in the primary lithium battery can significantly reduce these risks and extend the battery's lifespan.

[0060] The power supply circuit 100 also includes a diode 190 connected in parallel with the P-channel transistor 130. Specifically, the anode of the diode 190 is electrically connected to the second output node 112 and the drain of the P-channel transistor 130, and the cathode of the diode 190 is electrically connected to the output terminal 160 and the source of the P-channel transistor 130. The diode 190 is very useful during the initial power-on phase of the power supply circuit 100 because it enables the power supply circuit 100 to quickly output a stable voltage at the output terminal 160 (this voltage is equal to the output voltage of the battery 110 minus the forward voltage drop of the diode 190). This occurs before the control circuit 140 turns on the P-channel transistor 130, and / or before the power converter 120 is enabled or enters a stable operating mode. This early voltage output by the power supply circuit 100 through the diode 190 can be useful for certain loads that require a fast response time from the power supply circuit 100. Once the control circuit 140 turns on the P-channel transistor 130, the P-channel transistor 130 pulls the voltage level of the output terminal 160 high, causing the diode 190 to turn off. The diode 190 can be appropriately selected based on the magnitude of the initial current flowing from the battery 110 through the diode 190 to the output terminal 160. The rated current of the diode 190 is preferably greater than the magnitude of the initial current. In one example, the diode 190 is a Schottky diode. Similar to diodes 150 and 170, the diode 190 can be replaced by other types of unidirectional conductive devices. For ease of description, the diode 190 can be referred to as a "third unidirectional conductive device." This third unidirectional conductive device 190 can be of the same type as or different from the first and second unidirectional conductive devices 150 and 170. It should be noted that the diode 190 is optional and can be omitted.

[0061] Figure 3 Implementation shown Figure 2 The circuit diagram of the power supply circuit 100 shown is shown. Figure 3 Showing Figure 3 The circuit diagram and Figure 2 The correspondence between the block diagrams in the diagram.

[0062] exist Figure 3 In the circuit diagram, the output voltage of battery 110 is 2.7 volts (represented by a voltage source labeled "V_BATT_2V7"). During the initial use of battery 110, its output voltage may be higher (e.g., 3.6V). Figure 3 The circuit diagram is designed to simulate the state where battery 110 is almost fully discharged, a state in which reverse drive current is more likely to occur. A P-type MOSFET T2 (e.g., ON Semiconductor® model NTR4101P) is used to implement P-channel transistor 130. A Schottky diode SD2 (e.g., ON Semiconductor® model MBR160) is used to implement diode 190. The output terminal “Vout” corresponds to… Figure 2 Output terminal 160. Resistor R3 (10kΩ) and capacitor C5 (2.2µF) represent the load 200 powered by output terminal "Vout". A buck-boost DC-DC converter U1 (Texas Instruments® model TPS63082) is used to implement power converter 120, producing an output voltage of approximately 3.8 volts. Schottky diode SD4 is used to implement diode 150. Schottky diode SD1 and resistor R4 (501 Ω) are used to implement output feedback network 175. Both Schottky diodes SD1 and SD4 are based on ON Semiconductor® model MBR160. The gate of P-type MOSFET T2 is driven by the battery voltage via the microcontroller's general purpose input / output (GPIO). Considering that the GPIO output voltage will be slightly lower than the battery voltage, a voltage source labeled "V_EN_2V5" is used to simulate the GPIO output, which has an output voltage of 2.5 volts. Figure 3 In this example, control circuit 140 includes a voltage source "V_EN_2V5", resistors R8, R9, and R1, capacitor C1, and diode D2. Resistor R1 and capacitor C1 form a low-pass filter to control the rise time of the gate voltage, while diode D2 enables the gate capacitor to discharge quickly. In this example, control circuit 140 not only drives the gate of P-type MOSFET T2 but also sends an enable signal to buck-boost converter U2.

[0063] Figure 5 A comparative schematic diagram is shown, which omits the output feedback network 175 (i.e., Schottky diode SD1 and resistor R4), but the rest is exactly the same as in Figure 3.

[0064] Figure 4 Showing Figure 3 SPICE simulation results of the circuit diagram in the image. Figure 6 Showing Figure 5 SPICE simulation results for the circuit diagram. In both cases, the simulation time is 5.5 milliseconds, and ammeter AM1 measures the current flowing from P-type MOSFET T2 to the battery.

[0065] Reference Figure 6 At time t1 (approximately 2.15ms), ammeter AM1 measured a negative reverse drive current of several hundred milliamps. This is because the output voltage of the buck-boost converter U1 has reached a level at this point that is higher than the gate drive voltage (2.5V) of the P-type MOSFET T2 by the sum of the threshold voltage of P-type MOSFET T2 and the forward voltage drop of the Schottky diode SD4. In contrast, at Figure 4In the simulation results, at the same time point t1, the reverse drive current measured by ammeter AM1 is actually zero. This is because the feedback output network (R4 and SD1) prevents the P-type MOSFET T2 from turning on.

[0066] It should be noted that, in Figure 2 block diagram and Figure 3 In a circuit diagram, a direct electrical connection between two components can be modified by adding an additional component (such as a resistor or similar component) that is suitable for transmitting signals between the two components, thereby enabling the two components to be electrically coupled through that additional component.

[0067] Figure 7 A metering device 1000 is shown, comprising a power supply circuit 100 and a wireless communication unit 200 that receives electrical energy from an output terminal 160 of the power supply circuit 100. The wireless communication unit 200 may include a modem. The metering device 1000 can be used to measure the amount of at least one substance (gas or water). The gas may include methane and / or carbon monoxide, although other types of gases may also be included. The wireless communication unit 200 can wirelessly transmit data indicating the amount used to a receiving device located remotely at the metering device 1000. For simplicity, Figure 7 Other components of the metering device 1000 are not shown. The feedback output network 175 allows the use of any P-channel transistor (regardless of its threshold voltage V). GS(th) By maximizing the use of available battery capacity, the metering device 1000's battery life is extended to the maximum extent possible (e.g., at least 15-20 years). It should be understood that the power supply circuit 100 can be used with any type of battery-powered device, including but not limited to the metering device 1000.

[0068] Figure 8 The processing steps of an assembly method for a power supply circuit (e.g., power supply circuit 100) are illustrated schematically. The power supply circuit includes a power converter (e.g., power converter 120), a battery (e.g., battery 110), an output terminal (e.g., output terminal 160), a P-channel transistor (e.g., transistor 130), and first and second unidirectional conductive devices (e.g., diodes 150, 170). The power converter has a first input node (i.e., first input node 122) and a first output node (first output node 124), and is capable of receiving an input voltage through the first input node and generating an output voltage at the first output node that is higher than the input voltage. The battery has a second output node (e.g., second output node 112). The P-channel transistor includes a first electrode (e.g., drain electrode), a second electrode (e.g., source electrode), and a gate electrode.

[0069] In step S1, the first input node of the power converter (e.g., node 122) is electrically connected to the second output node of the battery (e.g., node 112).

[0070] In step S2, a first unidirectional conductive device (e.g., diode 150) is electrically connected between a first output node (e.g., node 124) and an output terminal (e.g., terminal 160) of the power converter. The first unidirectional conductive device includes a first anode and a first cathode. Electrically connecting the first unidirectional conductive device includes electrically coupling the first anode to the first output node and electrically coupling the first cathode to the output terminal.

[0071] In step S3, the first electrode of the P-channel transistor is electrically connected to the second output node (e.g., node 112), and the second electrode of the P-channel transistor is electrically connected to the output terminal (e.g., terminal 160).

[0072] In step S4, a second unidirectional conductive device (e.g., diode 170) is electrically connected between the first output node (e.g., node 124) and the gate electrode of the P-channel transistor. The second unidirectional conductive device includes a second anode and a second cathode. Electrically connecting the second unidirectional conductive device includes electrically coupling the second anode to the first output node (e.g., node 124) and electrically coupling the second cathode to the gate electrode of the P-channel transistor.

[0073] It should be understood that the execution order of the above steps may differ from the order described.

[0074] The terms “having,” “containing,” “including,” “consisting of,” etc., are open-ended; these terms indicate the presence of the stated structure, element, or feature but do not exclude the presence of other elements or features. The definite articles “a,” “an,” and “the” are intended to include both singular and plural forms unless the context explicitly states otherwise.

[0075] Although this disclosure has been described above by way of preferred embodiments, it should be understood that these embodiments are for illustrative purposes only, and the claims are not limited to these embodiments. Modifications and substitutions can be made to this disclosure by those skilled in the art, and such modifications and substitutions are considered to fall within the scope of the appended claims. Every feature disclosed or described in this specification may be incorporated into this disclosure, whether used alone or in combination with any other feature disclosed or described in this specification in any suitable manner.

Claims

1. A power supply circuit, comprising: A power converter having a first input node and a first output node; wherein the power converter is capable of receiving an input voltage at the first input node and generating an output voltage at the first output node that is higher than the input voltage level; A battery having a second output node; wherein the second output node is electrically connected to the first input node; Output terminals; A P-channel transistor includes a first electrode, a second electrode, and a gate electrode; wherein the first electrode is electrically connected to a second output node, and the second electrode is electrically connected to the output terminal; A first unidirectional conductive device is electrically connected between the first output node and the output terminal; wherein the first unidirectional conductive device includes a first anode and a first cathode, and the first anode is electrically coupled to the first output node, and the first cathode is electrically coupled to the output terminal; and A second unidirectional conductive device is electrically connected between the first output node and the gate electrode of the P-channel transistor; wherein the second unidirectional conductive device includes a second anode and a second cathode, and the second anode is electrically coupled to the first output node, and the second cathode is electrically coupled to the gate electrode.

2. The power supply circuit according to claim 1, wherein the forward voltage drop of the first unidirectional conductive device is greater than or equal to the forward voltage drop of the second unidirectional conductive device.

3. The power supply circuit according to claim 1 or 2, wherein the type of the first unidirectional conductive device is the same as the type of the second unidirectional conductive device.

4. The power supply circuit according to any one of the preceding claims, wherein at least one of the first unidirectional conductive element and the second unidirectional conductive device comprises a diode.

5. The power supply circuit according to claim 4, wherein at least one of the first unidirectional conductive element and the second unidirectional conductive device comprises a Schottky diode.

6. The power supply circuit according to any one of the preceding claims, wherein at least one of the first unidirectional conductive element and the second unidirectional conductive device includes a circuit configured to operate like a diode.

7. The power supply circuit according to any one of the preceding claims further includes a third unidirectional conductive device, the third unidirectional conductive device being electrically connected between the first electrode and the second electrode of the P-channel transistor; wherein, The third unidirectional conductive device includes a third anode and a third cathode, wherein the third anode is electrically coupled to the second output node, and the third cathode is electrically coupled to the output terminal.

8. The power supply circuit according to claim 7, wherein the third unidirectional conductive device comprises a diode.

9. The power supply circuit according to any one of the preceding claims, wherein the P-channel transistor is a P-channel metal-oxide-semiconductor field-effect transistor.

10. The power supply circuit according to any one of the preceding claims, wherein the power converter comprises a DC-DC converter.

11. The power supply circuit according to any one of the preceding claims, wherein the power converter comprises a switch-mode DC-DC converter.

12. The power supply circuit according to claim 11, wherein, The switch-mode DC-DC converter is either a switch-mode DC-DC boost converter or a switch-mode DC-DC buck-boost converter.

13. The power supply circuit according to any one of the preceding claims further includes a control circuit configured to control the gate electrode voltage of a P-channel transistor, wherein the control circuit is powered by a battery.

14. The power supply circuit of claim 13, wherein the control circuit is further configured to generate an enable signal that causes the power converter to enter an operating state.

15. The power supply circuit according to any one of the preceding claims, further comprising: A resistor connected in series with the second unidirectional conductive device between the first output node and the gate electrode of the P-channel transistor.

16. The power supply circuit according to claim 15, which is dependent on claim 14, wherein the resistor is configured to limit the current flowing through the control circuit.

17. The power supply circuit according to any one of the preceding claims, wherein the battery comprises a primary lithium battery.

18. The power supply circuit according to any one of the preceding claims, wherein the battery comprises one or more of lithium thiochloride battery and lithium manganese dioxide battery.

19. A metering device comprising a power supply circuit according to any one of the preceding claims.

20. The metering device according to claim 19, wherein the metering device is configured to measure the amount of at least one of gas and water.

21. The measuring device according to claim 19 or 20, further comprising: A wireless communication unit powered by the power supply circuit.

22. The metering device of claim 21, wherein the wireless communication unit comprises a modem.

23. A method for assembling a power supply circuit, the power supply circuit comprising a power converter, a battery, an output terminal, a P-channel transistor, a first unidirectional conductive device, and a second unidirectional conductive device, wherein: The power converter has a first input node and a first output node, and is capable of receiving an input voltage to the first input node and generating an output voltage at the first output node that is higher than the input voltage. The battery has a second output node; The P-channel transistor includes a first electrode, a second electrode, and a gate electrode, and the method includes: The first input node of the power converter is electrically connected to the second output node of the battery; The first unidirectional conductive device is electrically connected between the first output node and the output terminal of the power converter; wherein the first unidirectional conductive device includes a first anode and a first cathode, and the electrical connection of the first unidirectional conductive device includes electrically coupling the first anode to the first output node and electrically coupling the first cathode to the output terminal; Electrically connect the first electrode of the P-channel transistor to the second output node, and electrically connect the second electrode of the P-channel transistor to the output terminal; and The second unidirectional conductive device is electrically connected between the first output node and the gate electrode of the P-channel transistor; wherein the second unidirectional conductive device includes a second anode and a second cathode, and the electrical connection of the second unidirectional conductive device includes electrically coupling the second anode to the first output node and electrically coupling the second cathode to the gate electrode.

Images