Voltage conversion circuit and energy storage device

Abstract

The application relates to a voltage conversion circuit and an energy storage device, which comprise a first control module, a second control module, a temperature sensing element, an energy storage element and a logic module. The resistance of the temperature sensing element is positively correlated with the temperature parameter of the voltage conversion circuit. The first control module is used for turning on a charging path of an input power supply, the temperature sensing element and the energy storage element in a conducting state. The second control module is used for controlling the first control module to disconnect the charging path and turn on a discharging path between the second control module and the energy storage element when the charging voltage of the energy storage element reaches a first preset voltage, so that the energy storage element discharges through the discharging path, and a triangular wave voltage signal of a first end of the temperature sensing element is obtained based on the charging and discharging process of the energy storage element. The logic module is used for converting the triangular wave voltage signal into a PWM signal. The temperature stability can be improved by adopting the voltage conversion circuit.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a voltage conversion circuit and an energy storage device. Background Technology

[0002] In the field of circuits, driver chips or microcontroller units (MCUs) are typically used to generate pulse width modulation (PWM) signals to drive switching transistors, such as generating PWM signals to drive buck or boost voltage conversion switching transistors. However, driver chips or microcontrollers are too expensive.

[0003] Furthermore, when the PWM signal driving the switching transistor uses a fixed frequency, high ambient temperatures can hinder heat dissipation from the switching transistor, easily leading to circuit failure and low stability. Therefore, providing a voltage conversion circuit with higher stability has become a pressing technical problem to be solved in this field. Summary of the Invention

[0004] Therefore, it is necessary to provide a voltage conversion circuit and energy storage device with high stability to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a voltage conversion circuit, including a first control module, a second control module, a temperature sensing element, an energy storage element, and a logic module; the first control module is used to connect an input power supply and a first terminal of the temperature sensing element, the second terminal of the temperature sensing element is connected to the first terminal of the energy storage element and the second control module respectively, the second control module is connected to the first control module, and the second control module is also grounded; the logic module is connected to the first terminal of the temperature sensing element and the input power supply respectively; wherein, the resistance value of the temperature sensing element is positively correlated with the temperature parameter of the voltage conversion circuit.

[0006] The first control module is used to connect the charging path from the input power supply and temperature sensing element to the energy storage element when it is in the conducting state.

[0007] The second control module is used to control the first control module to disconnect the charging path and open the discharge path between the second control module and the energy storage element when the charging voltage of the energy storage element reaches the first preset voltage, so that the energy storage element can discharge through the discharge path and obtain the triangular wave voltage signal of the first end of the temperature sensing element based on the charging and discharging process of the energy storage element; the frequency of the triangular wave voltage signal is determined based on the resistance value of the temperature sensing element and the capacity value of the energy storage element.

[0008] The logic module is used to convert the triangular wave voltage signal into a PWM signal.

[0009] In one embodiment, the first control module includes a first transistor, the base of which is connected to the output terminal of the second control module and the input power supply, the collector of which is connected to the input power supply, and the emitter of which is connected to the first terminal of the temperature sensing element and used for grounding. The control terminal of the second control module is connected to the first terminal of the energy storage element. The first transistor is turned on based on the input power supply.

[0010] In one embodiment, the second control module includes a second transistor; the base of the second transistor is connected to the first terminal of the energy storage element, the collector of the second transistor is connected to the first control module, and the emitter of the second transistor and the second terminal of the energy storage element are both grounded.

[0011] When the energy storage element is charged to a first preset voltage, the first preset voltage is used to control the second transistor to be in the on state, so as to control the first control module to disconnect the charging path and make the energy storage element discharge through the discharge path between the second transistor and the energy storage element.

[0012] In one embodiment, the logic module includes a gate unit and a voltage divider unit for connecting to the input power supply. A triangular wave voltage signal is input to the first input terminal of the gate unit, and the second input terminal of the gate unit obtains a voltage divider signal based on the voltage divider unit. The output terminal of the gate unit obtains a PWM signal based on the triangular wave voltage signal and the voltage divider signal.

[0013] In one embodiment, the voltage conversion circuit further includes a totem pole module and a step-down module connected to the input power supply; the control terminal of the totem pole module is connected to the output terminal of the gate unit, and the output terminal of the totem pole module is connected to the switching transistor of the step-down module;

[0014] The totem pole module is used to generate drive signals for driving the switching transistors based on PWM signals.

[0015] A step-down module is used to step down the input power supply.

[0016] In one embodiment, the voltage conversion circuit further includes a sampling element and an overcurrent control module. The sampling element is connected to the output terminal of the buck module, and the overcurrent control module is connected to the sampling element and the second input terminal of the gate unit.

[0017] A sampling element is used to obtain a sampling voltage based on the output voltage at the output terminal of the buck module;

[0018] The overcurrent control module is used to output an overcurrent signal to the second input terminal of the gate unit when the sampled voltage is greater than the second preset voltage;

[0019] A gate unit used to output a low-level signal based on an overcurrent signal.

[0020] In one embodiment, the overcurrent control module includes a third transistor, a first diode, and a fourth transistor; the emitter of the third transistor is connected to a first terminal of the sampling element, the base of the third transistor is connected to a second terminal of the sampling element, the collector of the third transistor is connected to the anode of the first diode, the cathode of the first diode is connected to the base of the fourth transistor, the emitter of the fourth transistor is grounded, and the collector of the fourth transistor is connected to the second input terminal of the gate unit.

[0021] A sampling voltage greater than the second preset voltage is used to control the third transistor to turn on, which in turn controls the fourth transistor to turn on. The turned-on fourth transistor is used to output an overcurrent signal to the second input terminal of the gate unit.

[0022] In one embodiment, the voltage divider unit includes a first resistor and a second resistor;

[0023] The first end of the first resistor is connected to the input power supply, and the second end of the first resistor is connected to the second input terminal of the gate unit.

[0024] The first terminal of the second resistor and the collector of the fourth transistor are both connected to the second input terminal of the gate cell, and the second terminal of the second resistor is grounded.

[0025] In one embodiment, the voltage conversion circuit further includes a voltage regulator module, the input terminal of which is connected to an input power supply, and the output terminal of which is connected to a first control module and a gate unit; the voltage regulator module is used to provide a reference voltage to the first control module and the gate unit based on the input power supply.

[0026] In one embodiment, the voltage regulator module includes a fifth transistor and a sixth transistor. The collector and base of the fifth transistor are both connected to the input power supply. The emitter of the fifth transistor is connected to the base of the sixth transistor. The collector of the sixth transistor is connected to the input power supply. The emitter of the sixth transistor is connected to the first control module and the gate unit.

[0027] In one embodiment, the voltage regulator module further includes a seventh transistor and a Zener diode; the collector of the seventh transistor is connected to the base of the fifth transistor, the base of the seventh transistor is connected to the emitter of the sixth transistor, the emitter of the seventh transistor is connected to the negative terminal of the Zener diode, and the positive terminal of the Zener diode is grounded.

[0028] Secondly, this application also provides an energy storage device, which includes the voltage conversion circuit of any of the above.

[0029] The aforementioned voltage conversion circuit and energy storage device include a first control module, a second control module, a temperature sensing element, an energy storage element, and a logic module. The first control module connects the input power supply and the first terminal of the temperature sensing element. The second terminal of the temperature sensing element is connected to both the first terminal of the energy storage element and the second control module. The second control module is connected to the first control module and is also grounded. The logic module is connected to the first terminal of the temperature sensing element and the input power supply. Since the first control module, when in a conducting state, can conduct the charging path from the input power supply and the temperature sensing element to the energy storage element, the input power supply can charge the energy storage element through the temperature sensing element. Furthermore, since the second control module can, when the charging voltage of the energy storage element reaches a first preset voltage, control the first control module to disconnect the charging path and conduct the discharge path between the second control module and the energy storage element, allowing the energy storage element to discharge through the discharge path, a triangular wave voltage signal at the first terminal of the temperature sensing element is obtained based on the charging and discharging process of the energy storage element. Furthermore, since the frequency of the triangular wave voltage signal is determined based on the resistance of the temperature sensing element and the capacity of the energy storage element, and the resistance of the temperature sensing element is positively correlated with the temperature parameter of the voltage conversion circuit, the frequency of the triangular wave voltage signal can be controlled based on the temperature parameter of the voltage conversion circuit. Even further, the logic module can efficiently and accurately determine the corresponding PWM signal from the triangular wave voltage signal. When this PWM signal is used to drive the switching transistor of the voltage conversion circuit, it facilitates heat dissipation of the switching transistor, resulting in better circuit stability and reliability. Moreover, it eliminates the need for an MCU, thus reducing cost. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of a voltage conversion circuit in one embodiment;

[0032] Figure 2 This is a schematic diagram of another voltage conversion circuit in one embodiment;

[0033] Figure 3 This is a schematic diagram of an energy storage device in one embodiment. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0035] Figure 1 This is a schematic diagram of the structure of a voltage conversion circuit in one embodiment, such as... Figure 1 As shown, the voltage conversion circuit 200 includes a first control module 201, a second control module 202, a temperature sensing element 203, an energy storage element 204, and a logic module 205.

[0036] The first control module 201 is used to connect the input power supply 100 and the first end of the temperature sensing element 203. The second end of the temperature sensing element 203 is connected to the first end of the energy storage element 204 and the second control module 202, respectively. The second control module 202 is connected to the first control module 201 and is also grounded. The logic module 205 is connected to the first end of the temperature sensing element 203 and the input power supply 100, respectively.

[0037] In this embodiment, the input power supply 100 can be any form of current source or voltage source. The resistance of the temperature sensing element 203 is positively correlated with the temperature parameter at which the voltage conversion circuit 200 is located. That is, the higher the temperature parameter at which the voltage conversion circuit 200 is located, the greater the resistance of the temperature sensing element 203. Exemplarily, the temperature sensing element 203 includes, but is not limited to, a thermistor. The energy storage element 204 is a component capable of storing and releasing electrical energy, and includes, but is not limited to, a battery or a capacitor.

[0038] The first control module 201, when in a conducting state, is used to connect the charging path from the input power supply 100, the temperature sensing element 203 to the energy storage element 204. In other words, when the first control module 201 is in a conducting state, the charging path from the input power supply 100, the first control module 201, the temperature sensing element 203 to the energy storage element 204 is connected, thereby enabling the input power supply 100 to charge the energy storage element 204 through the temperature sensing element 203.

[0039] The first control module 201 may include at least one switching element, which can be turned on by the input power supply 100. The switching element includes, but is not limited to, an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), a physical switch, and a relay.

[0040] During the charging process of the energy storage element 204, the voltage across the energy storage element 204, i.e., the charging voltage of the energy storage element 204, will also increase. Furthermore, the second control module 202 is used to control the first control module 201 to disconnect the charging path and open the discharge path between the second control module 202 and the energy storage element 204 when the charging voltage of the energy storage element 204 reaches a first preset voltage.

[0041] The first preset voltage can be set according to requirements and is not limited here. For example, the first control module 201 may also include at least one switching element, and the switching elements in the first control module 201 and the second control module 202 are complementary in conduction. When the charging voltage of the energy storage element 204 reaches the first preset voltage, the switching element in the second control module 202 is in a conducting state, and the switching element in the first control module 201 is turned off. Consequently, the charging path is disconnected, while the discharging path between the second control module 202 and the energy storage element 204 is connected.

[0042] With the charging path disconnected and the discharging path open, the energy storage element 204 can discharge through the discharging path. Thus, based on the charging and discharging process of the energy storage element 204, a triangular wave voltage signal can be obtained at the first terminal of the temperature sensing element 203. A triangular wave voltage signal refers to a voltage signal whose waveform periodically approximates or exhibits a triangular shape. It can be understood that during the charging process of the energy storage element 204, the voltage signal at the first terminal of the temperature sensing element 203 will gradually increase, and during the discharging process of the energy storage element 204, the voltage signal at the second terminal of the temperature sensing element 203 will gradually decrease.

[0043] The frequency of the triangular wave voltage signal is determined based on the resistance of the temperature sensing element 203 and the capacity of the energy storage element 204. For example, the capacity of the energy storage element 204 may include its capacitance value. Optionally, the frequency of the triangular wave voltage signal is determined based on the reciprocal of the product between the resistance of the temperature sensing element 203 and the capacity of the energy storage element 204. For example, the frequency of the triangular wave voltage signal is f = 1 / (C2*RT1), where C2 represents the capacity of the energy storage element 204 and RT1 represents the resistance of the temperature sensing element 203.

[0044] Furthermore, the logic module 205 is used to convert the triangular wave voltage signal into a PWM signal. For example, the logic module 205 can output a high-level signal when the triangular wave voltage signal is within a preset range, and output a low-level signal when the triangular wave voltage signal is not within the preset range, to obtain the corresponding PWM signal.

[0045] The voltage conversion circuit 200 includes a first control module 201, a second control module 202, a temperature sensing element 203, an energy storage element 204, and a logic module 205. The first control module 201 connects the input power supply 100 and the first terminal of the temperature sensing element 203. The second terminal of the temperature sensing element 203 is connected to the first terminal of the energy storage element 204 and the second control module 202. The second control module 202 is connected to the first control module 201 and is also grounded. The logic module 205 is connected to the first terminal of the temperature sensing element 203 and the input power supply 100. Since the first control module 201, when in a conducting state, can conduct the charging path from the input power supply 100 and the temperature sensing element 203 to the energy storage element 204, the input power supply 100 can charge the energy storage element 204 through the temperature sensing element 203. Furthermore, since the second control module 202 can control the first control module 201 to disconnect the charging path and open the discharge path between the second control module 202 and the energy storage element 204 when the charging voltage of the energy storage element 204 reaches the first preset voltage, allowing the energy storage element 204 to discharge through the discharge path, a triangular wave voltage signal at the first end of the temperature sensing element 203 is obtained based on the charging and discharging process of the energy storage element 204. Further, since the frequency of the triangular wave voltage signal is determined based on the resistance value of the temperature sensing element 203 and the capacity value of the energy storage element 204, and the resistance value of the temperature sensing element 203 is positively correlated with the temperature parameter of the voltage conversion circuit 200, the frequency of the triangular wave voltage signal can be controlled based on the temperature parameter of the voltage conversion circuit 200. Even further, the logic module 205 can efficiently and accurately determine the corresponding PWM signal from the triangular wave voltage signal. Thus, the frequency of the PWM signal can also be determined based on the temperature parameter change of the voltage conversion circuit 200, resulting in good stability and reliability. Moreover, it eliminates the need for an MCU, reducing costs.

[0046] Figure 2 This is a schematic diagram of the structure of another voltage conversion circuit in one embodiment, such as... Figure 2 As shown, in an exemplary embodiment, optionally, the first control module 201 includes a first transistor Q8.

[0047] In this configuration, the base of the first transistor Q8 is connected to the output terminal of the second control module 202 and the input power supply 100, the collector of the first transistor Q8 is connected to the input power supply 100, the emitter of the first transistor Q8 is connected to the first terminal of the temperature sensing element 203 and is used for grounding, and the control terminal of the second control module 202 is connected to the first terminal of the energy storage element 204; the first transistor Q8 is turned on based on the input power supply 100.

[0048] Please continue to refer to this. Figure 2 Input power 100 (i.e.) Figure 2When the input power supply (VIN) is powered on, the base of the first transistor Q8 is pulled high, and the first transistor Q8 will be in a conducting state. Then, the input power supply 100 charges the energy storage element 204 through the first transistor Q8 and the temperature sensing element 203.

[0049] In the above embodiment, under the action of the input power supply 100, the first transistor Q8 can be in a conducting state efficiently and stably. In this way, the charging path from the input power supply 100, the temperature sensing element 203 to the energy storage element 204 can be turned on in time, so that the input power supply 100 can charge the energy storage element 204 through the temperature sensing element 203.

[0050] Please continue to refer to this. Figure 2 In one exemplary embodiment, optionally, the second control module 202 includes a second transistor Q9. The base of the second transistor Q9 is connected to the first terminal of the energy storage element 204, the collector of the second transistor Q9 is connected to the first control module 201, and both the emitter of the second transistor Q9 and the second terminal of the energy storage element 204 are grounded, i.e., the grounded terminal. Figure 2 GND-VCC in.

[0051] In this embodiment, when the energy storage element 204 is charged to the first preset voltage, the first preset voltage can control the second transistor Q9 to be in the on state, so as to control the first control module 201 to disconnect the charging path and make the energy storage element 204 discharge through the discharge path between the second transistor Q9 and the energy storage element 204.

[0052] In one embodiment, the first preset voltage is equal to the base voltage of the second transistor Q9 when it is in the on state. For example... Figure 2 As shown, when the charging voltage of the energy storage element 204 reaches the first preset voltage, the base of the second transistor Q9 is pulled high, and the second transistor Q9 is in the conducting state. Consequently, the base and emitter of the first transistor Q8 are short-circuited, and the first transistor Q8 is in the cut-off state. In this way, the energy storage element 204 will discharge through the discharge path of the second transistor Q9.

[0053] Furthermore, when the charging voltage of the energy storage element 204 is less than the first preset voltage, the second transistor Q9 will be in the off state. While the second transistor Q9 is in the off state, the first transistor Q8 will remain in the on state, thus connecting the charging path and disconnecting the discharging path. In other words, the input power supply 100 can charge the energy storage element 204 through the temperature sensing element 203. When the charging voltage of the energy storage element 204 reaches the first preset voltage, the energy storage element 204 will continue to discharge through the discharging path, and this process repeats.

[0054] During the repeated charging and discharging process described above, the triangular wave voltage signal at the first terminal of the temperature sensing element 203 can be determined. Let the voltage at the first terminal of the temperature sensing element 203 be denoted as... Figure 2 Since the process of obtaining the triangular wave voltage signal V1 is related to the charging and discharging process of the energy storage element 204 and the temperature sensing element 203, the frequency of the triangular wave voltage signal can be determined based on the resistance value of the temperature sensing element 203 and the capacity value of the energy storage element 204.

[0055] In the above embodiments, since the second transistor Q9 can be turned on by the first preset voltage when the energy storage element 204 is charged to the first preset voltage, and the first control module 201 can be turned off to disconnect the charging path, the energy storage element 204 can be discharged through the discharge path between the second control module 202 and the energy storage element 204. Based on this, the triangular wave voltage signal of the first end of the temperature sensing element 203 can be obtained through the charging and discharging process of the energy storage element 204.

[0056] Please continue to refer to this. Figure 2 In one exemplary embodiment, the logic module 205 may optionally include a gate unit 2051 and a voltage divider unit 2052 for connecting to the input power supply 100. Optionally, the gate unit 2051 may include, but is not limited to, an AND gate unit 2051. The voltage divider unit 2052 may be implemented using any form of voltage divider circuit, such as a resistor divider circuit.

[0057] The triangular wave voltage signal is input to the first input terminal of gate unit 2051, and the second input terminal of gate unit 2051 obtains a voltage divider signal based on voltage divider unit 2052. The output terminal of gate unit 2051 obtains a PWM signal based on the triangular wave voltage signal and the voltage divider signal.

[0058] Optionally, gate unit 2051 can output based on a comparison between the triangular wave voltage signal and the voltage divider signal. For example, if the triangular wave voltage signal is greater than the voltage divider signal, gate unit 2051 outputs a high-level signal; if the triangular wave voltage signal is less than or equal to the voltage divider signal, gate unit 2051 outputs a low-level signal. Of course, in some embodiments, gate unit 2051 can also output a high-level signal when the triangular wave voltage signal is less than or equal to the voltage divider signal, and a low-level signal when the triangular wave voltage signal is greater than the voltage divider signal.

[0059] In the above embodiments, since the output of the gate unit 2051 can obtain the PWM signal based on the triangular wave voltage signal and the voltage divider signal, the triangular wave voltage signal can be efficiently and accurately converted into the PWM signal through the gate unit 2051.

[0060] Please continue to refer to this. Figure 2In one exemplary embodiment, the voltage conversion circuit 200 may optionally include a totem pole module 206 and a step-down module 207 connected to the input power supply 100.

[0061] The step-down module 207 includes, but is not limited to, a BUCK step-down circuit. The control terminal of the totem pole module 206 is connected to the output terminal of the gate unit 2051, meaning that the control terminal of the totem pole module 206 can receive the PWM signal output by the gate unit 2051.

[0062] Furthermore, the output of the totem pole module 206 is connected to the switching transistor Q3 of the buck module 207. In this way, the totem pole module 206 can generate a drive signal for the switching transistor Q3 based on the PWM signal. For example, when the PWM signal is high, it drives the switching transistor Q3 to be in the on state; when the PWM signal is low, it drives the switching transistor Q3 to be in the off state.

[0063] like Figure 2 As shown, in one embodiment, the totem pole module 206 may include transistors Q2 and Q5. The buck module 207 includes a switch Q3, an inductor L1, a freewheeling diode D1, and a capacitor C3. When the gate unit 2051 outputs a high-level signal, transistor Q2 is in the on state, transistor Q5 is in the off state, the switch Q3 in the buck module 207 is in the on state, and the inductor L1 is charged. When the gate unit 2051 outputs a low-level signal, transistor Q5 is in the on state, transistor Q2 is in the off state, the switch Q3 in the buck module 207 is in the off state, and the inductor L1 is discharged.

[0064] The step-down module 207 is used to step down the input power supply 100. In other words, the step-down module 207 can perform step-down processing on the input power supply 100 to obtain the corresponding stepped-down voltage.

[0065] In the above embodiments, since the totem pole module 206 generates a drive signal for driving the switch Q3 based on the PWM signal, and the buck module 207 is used to step down the input power supply 100, a buck circuit with adjustable switching frequency can be realized based on the PWM signal. Furthermore, the switching frequency of the buck circuit changes with the temperature parameter, thereby improving stability and reliability.

[0066] Please continue to refer to this. Figure 2In one exemplary embodiment, optionally, the voltage conversion circuit 200 further includes a sampling element 208 and an overcurrent control module 209. The sampling element 208 is a component capable of sampling electrical parameters, including but not limited to a sampling resistor Rm. The sampling element 208 is connected to the output terminal of the buck module 207, and the overcurrent control module 209 is connected to the sampling element 208 and the second input terminal of the gate unit 2051.

[0067] Furthermore, the sampling element 208 is used to obtain a sampling voltage based on the output voltage of the buck module 207. It can be understood that the sampling voltage is positively correlated with the output voltage of the buck module 207.

[0068] The overcurrent control module 209 is used to output an overcurrent signal to the second input terminal of the gate unit 2051 when the sampled voltage is greater than a second preset voltage. The second preset voltage can be set according to actual needs, and this embodiment is not limited thereto. For example, the overcurrent control module 209 can be implemented by a comparator or the like. The overcurrent signal can also be a low-level signal.

[0069] Furthermore, gate unit 2051 is used to output a low-level signal based on the overcurrent signal. That is, when the sampled voltage is less than or equal to the second preset voltage, the overcurrent control module 209 does not output an overcurrent signal, and the output of gate unit 2051 follows the triangular wave voltage signal of its first input. When the sampled voltage is greater than the second preset voltage, the overcurrent control module 209 outputs an overcurrent signal, and the output of gate unit 2051 follows the overcurrent signal of its second input.

[0070] In the above embodiment, the output voltage of the step-down module 207 can be obtained through the sampling element 208. Through the overcurrent control module 209, when the sampling voltage is greater than the second preset voltage, that is, when an overcurrent is about to occur or has already occurred, an overcurrent signal can be output to the second input terminal of the gate unit 2051, so that the gate unit 2051 can output a low-level signal based on the overcurrent signal to realize the overcurrent protection function.

[0071] Please continue to refer to this. Figure 2 In one exemplary embodiment, optionally, the overcurrent control module 209 includes a third transistor Q6, a first diode D2, and a fourth transistor Q7.

[0072] In this configuration, the emitter of the third transistor Q6 is connected to the first terminal of the sampling element 208, the base of the third transistor Q6 is connected to the second terminal of the sampling element 208, the collector of the third transistor Q6 is connected to the anode of the first diode D2, the cathode of the first diode D2 is connected to the base of the fourth transistor Q7, the emitter of the fourth transistor Q7 is grounded, and the collector of the fourth transistor Q7 is connected to the second input terminal of the gate unit 2051.

[0073] Furthermore, a sampling voltage greater than the second preset voltage is used to control the third transistor Q6 to turn on, thereby controlling the fourth transistor Q7 to turn on. The turned-on fourth transistor Q7 is used to output an overcurrent signal to the second input terminal of the gate unit 2051. That is, if the buck module 207 has an overcurrent risk, the sampling voltage obtained by the sampling element 208 will be greater than the second preset voltage. The second preset voltage will pull up the base of the third transistor Q6, causing the second transistor Q9 to turn on. When the second transistor Q9 is turned on, the fourth transistor Q7 will also turn on. Thus, the fourth transistor Q7, which is in the turned-on state, can output an overcurrent signal to the second input terminal of the gate unit 2051.

[0074] In the above embodiment, since the sampling voltage of the second preset voltage is used to control the third transistor Q6 to turn on in order to control the fourth transistor Q7 to turn on, the turned-on fourth transistor Q7 can output an overcurrent signal to the second input terminal of the gate unit 2051, so that when the sampling voltage is greater than the second preset voltage, the output terminal of the gate unit 2051 follows the overcurrent signal to achieve overcurrent protection.

[0075] Please continue to refer to this. Figure 2 In one exemplary embodiment, optionally, the voltage divider unit 2052 includes a first resistor R15 and a second resistor R13.

[0076] The first end of the first resistor R15 is connected to the input power supply 100, and the second end of the first resistor R15 is connected to the second input terminal of the gate unit 2051. The first resistor R15 is used to ensure that when the overcurrent control module 209 does not output an overcurrent signal, the second input terminal of the gate unit 2051 can receive a high-level signal, so that when the sampling voltage is greater than the second preset voltage, the output terminal of the gate unit 2051 follows the triangular wave voltage signal of its first input terminal.

[0077] The first terminal of the second resistor R13 and the collector of the fourth transistor Q7 are both connected to the second input terminal of the gate unit 2051, and the second terminal of the second resistor R13 is grounded. The first resistor R15 is used to ensure that when the second transistor Q9 is in the on state, the fourth transistor Q7 in the on state can output a low-level overcurrent signal to the second input terminal of the gate unit 2051, so that when the sampling voltage is less than or equal to the second preset voltage, the output terminal of the gate unit 2051 will output a low-level signal following the overcurrent signal.

[0078] In the above embodiment, since the voltage divider unit 2052 includes a first resistor R15 and a second resistor R13, and the first end of the first resistor R15 is connected to the input power supply 100, the second end of the first resistor R15 is connected to the second input terminal of the gate unit 2051, the first end of the second resistor R13 and the collector of the fourth transistor Q7 are both connected to the second input terminal of the gate unit 2051, and the second end of the second resistor R13 is grounded, the reliability of the voltage conversion circuit 200 can be improved by the first resistor R15 and the second resistor R13.

[0079] Please continue to refer to this. Figure 2 In one exemplary embodiment, the voltage conversion circuit 200 may optionally include a voltage regulator module 210. The input terminal of the voltage regulator module 210 is connected to the input power supply 100, and the output terminal of the voltage regulator module 210 is connected to the first control module 201 and the gate unit 2051.

[0080] Furthermore, the voltage regulator module 210 is used to provide a reference voltage to the first control module 201 and the gate unit 2051 based on the input power supply 100. That is, the voltage regulator module 210 is used to convert the injected power supply into a reference voltage within a preset voltage range. The reference voltage is expressed as... Figure 2 VCC in the example. The voltage regulator module 210 may include, but is not limited to, a linear regulator.

[0081] In the above embodiments, the input power supply 100 can be converted into a reference voltage through the voltage regulator module 210, and a more stable and reliable reference voltage can be provided for the first control module 201 and the gate unit 2051.

[0082] Please continue to refer to this. Figure 2 In one exemplary embodiment, optionally, the voltage regulator module 210 includes a fifth transistor Q10 and a sixth transistor Q1. The collector and base of the fifth transistor Q10 are both connected to the input power supply 100, the emitter of the fifth transistor Q10 is connected to the base of the sixth transistor Q1, the collector of the sixth transistor Q1 is connected to the input power supply 100, and the emitter of the sixth transistor Q1 is connected to the first control module 201 and the gate unit 2051.

[0083] In this embodiment, after the input power supply 100 is powered on, the fifth transistor Q10 is in a conducting state, which also causes the sixth transistor Q1 to be in a conducting state, providing a reference voltage for the first control module 201 and the gate unit 2051. Thus, under the action of the reference voltage, the first control module 201 conducts the charging path from the input power supply 100, the temperature sensing element 203 to the energy storage element 204, and the gate unit 2051 obtains a PWM signal based on the triangular wave voltage signal and the voltage divider signal.

[0084] In the above embodiment, since the collector and base of the fifth transistor Q10 are both connected to the input power supply 100, the emitter of the fifth transistor Q10 is connected to the base of the sixth transistor Q1, the collector of the sixth transistor Q1 is connected to the input power supply 100, and the emitter of the sixth transistor Q1 is connected to the first control module 201 and the gate unit 2051, a reference voltage can be stably provided to the first control module 201 and the gate unit 2051 through the fifth transistor Q10 and the sixth transistor Q1.

[0085] Please continue to refer to this. Figure 2 In one exemplary embodiment, optionally, the voltage regulator module 210 further includes a seventh transistor Q4 and a Zener diode DZ1. The collector of the seventh transistor Q4 is connected to the base of the fifth transistor Q10, the base of the seventh transistor Q4 is connected to the emitter of the sixth transistor Q1, the emitter of the seventh transistor Q4 is connected to the negative terminal of the Zener diode DZ1, and the positive terminal of the Zener diode DZ1 is grounded.

[0086] In this embodiment, the voltage conversion circuit 200 may further include resistors R7 and R12. Resistor R7 is connected to the input power supply 100 and the base of the seventh transistor Q4, respectively; one end of resistor R12 is connected to the base of the seventh transistor Q4, and the other end of resistor R12 is grounded.

[0087] Resistors R7 and R12 are sampling resistors for the VCC voltage, used to control the magnitude of the reference voltage VCC. In one embodiment, the reference voltage VCC = (VDZ1 + Vd1) / ((R7 + R12) * R12). Where VDZ1 is the regulated voltage after the Zener diode DZ1 breaks down, Vd1 is the on-state voltage drop of the seventh transistor Q4, R7 represents the resistance value of resistor R7, and R12 represents the resistance value of resistor R12.

[0088] For example, assume the base voltage of the seventh transistor Q4 is 3.3V + 0.7V = 4 volts (V). According to the above formula, when the voltage across resistor R12 is greater than 4V, the seventh transistor Q4 is in the on state; when the voltage across resistor R12 is less than 4V, the seventh transistor Q4 is in the off state. After stabilization, the base voltage of the seventh transistor Q4 is kept stable at 4V, thus keeping the reference voltage VCC constant.

[0089] In the above embodiment, since the collector of the seventh transistor Q4 is connected to the base of the fifth transistor Q10, the base of the seventh transistor Q4 is connected to the emitter of the sixth transistor Q1, the emitter of the seventh transistor Q4 is connected to the negative terminal of the Zener diode DZ1, and the positive terminal of the Zener diode DZ1 is grounded, the input power supply 100 can be converted into a reference voltage more stably through the seventh transistor Q4 and the Zener diode DZ1.

[0090] Please continue to refer to this. Figure 2 In one embodiment, the voltage conversion circuit 200 may further include at least one of the following: resistor R1, diode D3, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R8, resistor R9, resistor R10, resistor R11, resistor R14, resistor RL, and capacitor C6.

[0091] To more clearly illustrate the voltage conversion circuit of this application, the following is combined with... Figure 2 The following description is provided. In one embodiment, the temperature sensing element 203 includes a positive temperature coefficient thermistor RT1, which has a resistance of 10 kΩ at room temperature. The energy storage element 204 includes a capacitor C2. The fifth transistor Q10 and the sixth transistor Q1 are in the on state by default. The input power supply VIN passes through resistor R1, the fifth transistor Q10, and the sixth transistor Q1 to obtain the reference voltage VCC.

[0092] Under the influence of the reference voltage VCC, the first transistor Q8 is in the conducting state. The reference voltage VCC passes through the first transistor Q8, resistor R4, and resistor R9 in sequence to reach the ground terminal GNC_VCC. The reference voltage VCC charges C2, and V1 gradually rises.

[0093] V3 is the voltage across resistor R9. Assuming the on-state voltage drop of the second transistor Q9 is Vd2, the base voltage U1 when the second transistor Q9 is on is U1 = V3 + Vd2. Therefore, when the voltage across capacitor C2 reaches U1, the second transistor Q9 is on, short-circuiting the base and emitter of the first transistor Q8, causing the first transistor Q8 to be off. Capacitor C2 discharges through the discharge path of the second transistor Q9 and resistor R9, and V1 drops to 0V.

[0094] When the voltage across capacitor C2 is lower than U1, the second transistor Q9 is off, and the first transistor Q8 resumes conduction. The reference voltage VCC continues to charge C2, and then disconnects when it reaches U1. This cycle repeats, making the switching frequency f of the triangular wave voltage signal V1 equal to 1 / (C2*RT1). When the temperature is too high, the resistance of RT1 increases, f decreases, thereby reducing the switching frequency and lowering the temperature of the switching transistor Q3.

[0095] When the switching transistor Q3 is in the on state, the input power supply VIN passes through the switching transistor Q3, inductor L1, and sampling resistor Rm in sequence to obtain the step-down voltage Vout. When the switching transistor Q3 is in the off state, the step-down voltage is achieved through the freewheeling diode D1.

[0096] Furthermore, gate unit 2051 includes AND gate U2B. Under normal conditions without overcurrent, the third transistor Q6 is not turned on, the I_OCP signal is high, and pin 3 of AND gate U2B outputs a high level. In this case, the output of AND gate U2B follows pin 1 of AND gate U2B. That is, when pin 1 of AND gate U2B is high, pin 3 of AND gate U2B outputs a high level, and when pin 1 of AND gate U2B is low, pin 3 of AND gate U2B outputs a low level.

[0097] When an overcurrent occurs at the output, the third transistor Q6 is turned on, and through the first diode D2 and resistor R14, the fourth transistor Q7 is turned on, pulling I_OCP low. In this case, regardless of whether V1 is a high or low level signal, pin 3 of gate U2B will output a low level signal, thus turning off the switching transistor Q3, preventing the buck module from working, achieving the overcurrent protection function, and ensuring the stability of the system.

[0098] Conventional buck converter circuits in related technologies typically drive MOSFETs by generating PWM signals through a driver chip or CPU. This results in high circuit costs and complex control. Furthermore, conventional buck converter circuits are prone to damage at high temperatures. However, the circuit described in this application, using simple components, can step down the high input voltage VIN to a stable low output voltage Vout, achieving buck conversion. This not only eliminates the need for CPU control and simplifies the circuit structure, but also includes a function to reduce the switching frequency of the MOSFET in case of over-temperature conditions, thus achieving MOSFET heat dissipation. In addition, it can promptly disconnect the output in case of overcurrent, protecting system stability and increasing circuit efficiency and output voltage stability.

[0099] In summary, this application proposes a buck converter circuit with adjustable switching frequency. It eliminates the need for a driver chip or MCU to generate a PWM signal, and can be implemented using transistors, temperature sensors, and other components, resulting in low circuit cost. When the circuit overheats, it automatically adjusts the switching frequency to reduce heat generation from the switching transistors and includes overcurrent protection, improving operational stability.

[0100] Figure 3 This is a schematic diagram of an energy storage device in one embodiment, such as... Figure 3 As shown, this application also provides an energy storage device 300, which includes the voltage conversion circuit 200 of any of the above.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0102] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A voltage conversion circuit, characterized by, The voltage conversion circuit comprises a first control module, a second control module, a temperature sensing element, an energy storage element and a logic module; the first control module is used for connecting an input power supply and a first end of the temperature sensing element, a second end of the temperature sensing element is connected with the first end of the energy storage element and the second control module respectively, the second control module is connected with the first control module, and the second control module is also grounded, and the logic module is connected with the first end of the temperature sensing element and the input power supply respectively; wherein the resistance value of the temperature sensing element is positively correlated with the temperature parameter where the voltage conversion circuit is located. The first control module comprises a first transistor, the base of the first transistor is connected with the output end of the second control module and the input power supply, the collector of the first transistor is connected with the input power supply, the emitter of the first transistor is connected with the first end of the temperature sensing element and is used for grounding, and the control end of the second control module is connected with the first end of the energy storage element; the first transistor is turned on based on the input power supply, and is used for turning on the charging path of the input power supply, the temperature sensing element to the energy storage element in the case of being in the turned-on state; The second control module comprises a second transistor; the base of the second transistor is connected with the first end of the energy storage element, the collector of the second transistor is connected with the first control module, and the emitter of the second transistor and the second end of the energy storage element are both grounded, and are used for controlling the second transistor to be in the turned-on state in the case that the energy storage element is charged to a first preset voltage, so as to control the first control module to disconnect the charging path, and make the energy storage element discharge through the discharge path between the second transistor and the energy storage element, so as to obtain the triangular wave voltage signal of the first end of the temperature sensing element based on the charging and discharging process of the energy storage element; the frequency of the triangular wave voltage signal is determined based on the resistance value of the temperature sensing element and the capacity value of the energy storage element; The logic module is used for converting the triangular wave voltage signal into a PWM signal.

2. The voltage conversion circuit according to claim 1, characterized by, The logic module comprises a gate unit and a voltage division unit used for connecting the input power supply, the triangular wave voltage signal is input into the first input end of the gate unit, the second input end of the gate unit obtains a voltage division signal based on the voltage division unit; the output end of the gate unit obtains the PWM signal based on the triangular wave voltage signal and the voltage division signal.

3. The voltage conversion circuit of claim 2, wherein, The voltage conversion circuit further comprises a totem pole module and a step-down module connected with the input power supply; the control end of the totem pole module is connected with the output end of the gate unit, and the output end of the totem pole module is connected with the switch tube of the step-down module; The totem pole module is used for generating a driving signal for driving the switch tube based on the PWM signal; The step-down module is used for step-down the input power supply.

4. The voltage conversion circuit according to claim 3, characterized by The voltage conversion circuit further comprises a sampling element and an overcurrent control module, the sampling element is connected with the output end of the step-down module, and the overcurrent control module is connected with the sampling element and the second input end of the gate unit; The sampling element is configured to obtain a sampling voltage based on an output voltage of an output terminal of the voltage reduction module. The overcurrent control module is configured to output an overcurrent signal to a second input terminal of the gate unit when the sampling voltage is greater than a second preset voltage. The gate unit is configured to output a low-level signal based on the overcurrent signal.

5. The voltage conversion circuit of claim 4, wherein, The overcurrent control module includes a third transistor, a first diode, and a fourth transistor. The emitter of the third transistor is connected to a first terminal of the sampling element, the base of the third transistor is connected to a second terminal of the sampling element, the collector of the third transistor is connected to the anode of the first diode, the cathode of the first diode is connected to the base of the fourth transistor, the emitter of the fourth transistor is grounded, and the collector of the fourth transistor is connected to the second input terminal of the gate unit. The sampling voltage greater than the second preset voltage is configured to control the third transistor to be turned on to control the fourth transistor to be turned on, and the turned-on fourth transistor is configured to output the overcurrent signal to the second input terminal of the gate unit.

6. The voltage conversion circuit of claim 5, wherein, The voltage division unit includes a first resistor and a second resistor. A first terminal of the first resistor is connected to the input power supply, and a second terminal of the first resistor is connected to the second input terminal of the gate unit. The first terminal of the second resistor and the collector of the fourth transistor are both connected to the second input terminal of the gate unit, and a second terminal of the second resistor is grounded.

7. The voltage conversion circuit of claim 2, wherein, The voltage conversion circuit further includes a voltage stabilizing power supply module. An input terminal of the voltage stabilizing power supply module is connected to the input power supply, and an output terminal of the voltage stabilizing power supply module is connected to the first control module and the gate unit. The voltage stabilizing power supply module is configured to provide a reference voltage to the first control module and the gate unit based on the input power supply.

8. The voltage conversion circuit of claim 7, wherein, The voltage stabilizing power supply module includes a fifth transistor and a sixth transistor. The collector and the base of the fifth transistor are both connected to the input power supply. The emitter of the fifth transistor is connected to the base of the sixth transistor. The collector of the sixth transistor is connected to the input power supply. The emitter of the sixth transistor is connected to the first control module and the gate unit.

9. The voltage conversion circuit of claim 8, wherein, The voltage stabilizing power supply module further includes a seventh transistor and a voltage stabilizing tube. The collector of the seventh transistor is connected to the base of the fifth transistor. The base of the seventh transistor is connected to the emitter of the sixth transistor. The emitter of the seventh transistor is connected to the negative electrode of the voltage stabilizing tube. The positive electrode of the voltage stabilizing tube is grounded.

10. An energy storage device, characterized by, The energy storage device includes the voltage conversion circuit according to any one of claims 1-9.

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