Current sensing circuit, voltage conversion circuit, and electronic device
By combining sensing modules and digital modules, the problem of low integration in acquiring full-cycle inductor current information in voltage conversion circuits is solved, and high-integration inductor current acquisition is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2026-03-10
AI Technical Summary
Existing technologies require additional external components, such as series capacitors and resistors, to obtain full-cycle inductor current information in voltage conversion circuits, resulting in low integration density.
By combining a sensing module and a digital module, the sensing module obtains the sensing voltage through the switching node voltage during the freewheeling phase of the voltage conversion circuit, while the digital module performs digital-to-analog conversion and calculation to obtain the inductor current of the voltage conversion circuit throughout the entire cycle, thus avoiding the need to add external resistors and capacitors.
It achieves highly integrated acquisition of the inductor current throughout the voltage conversion circuit cycle without the need to add external resistors and capacitors.
Smart Images
Figure CN121643399A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of inductance current sampling of voltage conversion circuit, and particularly relates to a current sensing circuit, a voltage conversion circuit and an electronic device. BACKGROUND
[0002] When the voltage conversion circuit is working, the prior art can only obtain the inductance current by sampling the current of the freewheeling tube or the current of the high-end tube, and the inductance current is used for current loop feedback of the voltage conversion circuit. If the inductance current information of the full cycle of the voltage conversion circuit is to be obtained, additional external devices need to be added, for example, a series capacitor resistor is used in parallel to the inductance to detect the inductance current, which results in low integration of the voltage conversion circuit as a whole. SUMMARY
[0003] In order to solve the above problems, the present application provides a current sensing circuit, a voltage conversion circuit and an electronic device, which aims to solve the above problems.
[0004] To solve the above technical problems, one technical scheme adopted by the present application is to provide a current sensing circuit, which is used for sampling the inductance current of a voltage conversion circuit, and the current sensing circuit comprises a sensing module and a digital module. The sensing module is connected to a switching node of the voltage conversion circuit, and is configured to obtain a sensing voltage based on a switching node voltage at the switching node in a freewheeling phase of the voltage conversion circuit, wherein the sensing voltage is related to the inductance current. The digital module is connected to the sensing module, and is configured to perform digital-to-analog conversion and calculation processing on the sensing voltage to obtain the inductance current of the full cycle of the voltage conversion circuit.
[0005] The sensing module comprises a first current mirror unit and a second current mirror unit. The first current mirror unit comprises a first path and a second path. The first path is coupled between a power supply voltage and a ground voltage in a charging phase of the voltage conversion circuit, and is coupled between the power supply voltage and a switching node voltage in a freewheeling phase of the voltage conversion circuit. The second path is coupled between the power supply voltage and the ground voltage, and the current of the second path is a preset multiple of the current of the first path. The second current mirror unit comprises a third path and a fourth path. The third path is connected to an intermediate node on the second path, and is coupled between the power supply voltage and the ground voltage in the charging phase of the voltage conversion circuit, and is coupled between the power supply voltage and the switching node voltage in the freewheeling phase of the voltage conversion circuit. The fourth path is coupled between the power supply voltage and the switching node voltage, and the current of the fourth path mirrors the current of the third path. The fourth path comprises an output node to output the sensing voltage as an output end of the sensing module.
[0006] The sensing module further includes a bias current generation module coupled between the power supply voltage and the ground voltage and connected with the first path and the second path respectively, for providing bias voltage to the first path and the second path to turn on the first path and the second path.
[0007] The first path includes a first transistor, a second transistor, a third transistor and a fourth transistor. The first path of the first transistor is connected with the power supply voltage, and the control end of the first transistor is connected with the bias current generation module. The first path of the second transistor is coupled with the second path of the first transistor and the control end of the second transistor. The second path of the second transistor is connected with the first path of the third transistor and the first path of the fourth transistor respectively, the second path of the third transistor is grounded, and the second path of the fourth transistor is connected with the switch node. The control end of the third transistor receives a first control signal, and the control end of the fourth transistor receives a second control signal. The first control signal is used to control the third transistor to turn on in the charging phase of the voltage conversion circuit and to turn off in the freewheeling phase of the voltage conversion circuit. The second control signal is used to control the fourth transistor to turn off in the charging phase of the voltage conversion circuit and to turn on in the freewheeling phase of the voltage conversion circuit.
[0008] The second path includes a fifth transistor, a sixth transistor and a seventh transistor. The first path of the fifth transistor is connected with the power supply voltage, and the control end of the fifth transistor is connected with the bias current generation module. The second path of the fifth transistor is connected with the first path of the sixth transistor, and the connection between the second path of the fifth transistor and the first path of the sixth transistor is connected with the third path as an intermediate node of the second path. The control end of the sixth transistor is connected with the first path of the second transistor, the second path of the sixth transistor is connected with the first path of the seventh transistor, the second path of the seventh transistor is grounded, and the control end of the seventh transistor receives a preset voltage. The size of the fifth transistor is a preset multiple of the size of the first transistor, and the size of the sixth transistor is the same as the size of the second transistor.
[0009] The third path includes an eighth transistor, a ninth transistor, a third transistor, and a fourth transistor. The first terminal of the eighth transistor is connected to the power supply voltage. The second terminal of the eighth transistor is coupled to the control terminal of the eighth transistor and the first terminal of the ninth transistor. The control terminal of the ninth transistor is connected to the intermediate node of the second path. The second terminal of the ninth transistor is connected to the first terminal of the third transistor and the first terminal of the fourth transistor, respectively. The fourth path includes a tenth transistor and a resistor. The first terminal of the tenth transistor is connected to the power supply voltage. The control terminal of the tenth transistor is connected to the second terminal of the eighth transistor. The second terminal of the tenth transistor is connected to the first terminal of the resistor. The second terminal of the resistor is grounded. The connection between the second terminal of the tenth transistor and the first terminal of the resistor serves as the output terminal of the sensing module, outputting the sensing voltage.
[0010] The current sensing circuit also includes a current sampling voltage generation module, which is connected to the sensing module and the digital module respectively. It is configured to sample the sensing voltage to obtain the current sampling voltage of the voltage conversion circuit for the entire cycle, and send the current sampling voltage to the digital module to obtain the inductor current of the voltage conversion circuit for the entire cycle.
[0011] The current sampling voltage generation module includes a first switch, a second switch, a third switch, a first capacitor, and a second capacitor. The first terminal of the first switch is connected to the output terminal of the sensing module, and the second terminal of the first switch serves as the output terminal of the current sampling voltage generation module. The first terminal of the second switch is connected to the output terminal of the sensing module, and the second terminal of the second switch is connected to the first terminal of the first capacitor and the first terminal of the third switch. The second terminal of the third switch and the first terminal of the second capacitor are connected to the second terminal of the first switch, and the second terminals of the first and second capacitors are grounded. During the freewheeling phase of the voltage conversion circuit, the first switch is turned on, the third switch is turned off, the second switch is turned on for the first half of the freewheeling phase, and the second switch is turned off for the remaining phases of the freewheeling phase. During the charging phase of the voltage conversion circuit, the first and second switches are turned off, and the third switch is turned on.
[0012] The current sampling voltage generation module also includes a buffer. The first input terminal of the buffer is connected to the second terminal of the second switch and the first terminal of the first capacitor. The output terminal of the buffer is connected to the first terminal of the third switch. The second input terminal of the buffer is connected to the output terminal of the buffer.
[0013] The digital module includes a digital-to-analog conversion sampling module and a calculation module. The digital-to-analog conversion sampling module is connected to the current sampling voltage generation module and is used to perform digital-to-analog conversion and sampling of the current sampling voltage. The calculation module is connected to the digital-to-analog conversion sampling module and is used to calculate the inductor current for the entire cycle based on the digital-to-analog conversion and the sampled current sampling voltage.
[0014] To solve the above-mentioned technical problems, another technical solution adopted in this application is to provide a voltage conversion circuit, which includes the current sensing circuit of any one of the above-mentioned components.
[0015] To solve the above-mentioned technical problems, another technical solution adopted in this application is to provide an electronic device that includes the voltage conversion circuit described above.
[0016] Unlike existing technologies, the current sensing circuit of this application includes a sensing module and a digital module. The sensing module is connected to the switching node of the voltage conversion circuit and is configured to acquire a sensing voltage based on the switching node voltage at the switching node during the freewheeling phase of the voltage conversion circuit. The sensing voltage is related to the inductor current. The digital module is connected to the sensing module and is configured to perform digital-to-analog conversion and calculation on the sensing voltage to obtain the inductor current for the entire cycle of the voltage conversion circuit. Through this method, the current sensing circuit of this application can indirectly obtain the inductor current for the entire cycle by acquiring the sensing voltage during the freewheeling phase of the voltage conversion circuit, without the need for external resistors and capacitors, resulting in high integration. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:
[0018] Figure 1 This is a schematic diagram of the structure of the first embodiment of the current sensing circuit of this application;
[0019] Figure 2 This is a schematic diagram of the structure of the second embodiment of the current sensing circuit of this application;
[0020] Figure 3 This is a schematic diagram of the structure of the third embodiment of the current sensing circuit of this application;
[0021] Figure 4 This is a schematic diagram of the structure of the fourth embodiment of the current sensing circuit of this application;
[0022] Figure 5 This is a timing control waveform diagram of an embodiment of the current sampling voltage generation module;
[0023] Figure 6 This is a schematic diagram of the structure of an embodiment of the voltage conversion circuit of this application;
[0024] Figure 7 This is a schematic diagram of the structure of an embodiment of the electronic device of this application. Detailed Implementation
[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0026] In this document, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0027] When a voltage conversion circuit is operating, current technology can only obtain the inductor current by sampling the current of a fixed freewheeling diode or high-side transistor, and use this information for the current loop feedback of the voltage conversion circuit. To obtain the inductor current information for the entire cycle of the voltage conversion circuit, additional external components are required, such as using a series capacitor and resistor connected in parallel across the inductor to detect the inductor current. This results in a lower overall integration of the voltage conversion circuit.
[0028] To address the aforementioned problems, this application first proposes a current sensing circuit, please refer to [link to relevant documentation]. Figure 1 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the current sensing circuit of this application. The current sensing circuit 100 of this embodiment is used to sample the inductor current of the voltage conversion circuit, such as... Figure 1 As shown, the current sensing circuit 100 includes a sensing module 10 and a digital module 20.
[0029] The sensing module 10 is connected to the switching node of the voltage conversion circuit. The sensing module 10 is configured to obtain a sensing voltage based on the switching node voltage VSW at the switching node during the freewheeling phase of the voltage conversion circuit. The sensing voltage is related to the inductor current. The digital module 20 is connected to the sensing module 10 and is configured to perform digital-to-analog conversion and calculation on the sensing voltage to obtain the inductor current of the voltage conversion circuit throughout the entire cycle.
[0030] In this embodiment, the sensing module 10 operates during the freewheeling phase of the voltage conversion circuit, specifically during the period when the freewheeling diode of the voltage conversion module is on. During this period, the sensing module 10 acquires the inductor current of the voltage conversion circuit, and when the inductor current changes, its output sensing voltage also changes. At this time, the digital module 20 can perform digital-to-analog conversion and calculation based on the preset mapping relationship between the sensing voltage and the inductor current, thereby acquiring the inductor current of the voltage conversion circuit throughout its entire cycle. The structure and working principle of the sensing module 10 are described below and will not be detailed here.
[0031] Unlike existing technologies, the current sensing circuit 100 of this application includes a sensing module 10 and a digital module 20. The sensing module 10 is connected to the switching node of the voltage conversion circuit and is configured to obtain a sensing voltage based on the switching node voltage VSW at the switching node during the freewheeling phase of the voltage conversion circuit. The sensing voltage is related to the inductor current. The digital module 20 is connected to the sensing module 10 and is configured to perform digital-to-analog conversion and calculation on the sensing voltage to obtain the inductor current for the entire cycle of the voltage conversion circuit. Through this method, the current sensing circuit 100 of this application can indirectly obtain the inductor current for the entire cycle by obtaining the sensing voltage during the freewheeling phase of the voltage conversion circuit, without the need for external resistors and capacitors, resulting in high integration.
[0032] Optionally, please refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of the second embodiment of the current sensing circuit of this application. Figure 2 As shown, the sensing module 10 in this embodiment includes a first current mirror unit 11 and a second current mirror unit 12.
[0033] The first current mirror unit 11 includes a first path and a second path. During the charging phase of the voltage conversion circuit, the first path is coupled between the power supply voltage VCC and the ground voltage. During the freewheeling phase of the voltage conversion circuit, the first path is coupled between the power supply voltage VCC and the switching node voltage VSW. The second path is coupled between the power supply voltage VCC and the ground voltage. The current I2 of the second path mirrors the current I1 of the first path, and the current of the second path is a preset multiple m of the current of the first path.
[0034] The second current mirror unit 12 includes a third path and a fourth path. The third path is connected to the intermediate node on the second path. During the charging phase of the voltage conversion circuit, the third path is coupled between the power supply voltage VCC and the ground voltage. During the freewheeling phase of the voltage conversion circuit, the third path is coupled between the power supply voltage VCC and the switching node voltage VSW. The fourth path is coupled between the power supply voltage VCC and the switching node voltage VSW. The current Isense of the fourth path mirrors the current Is of the third path. The fourth path includes an output node to output the sensing voltage VS as the output terminal of the sensing module 10.
[0035] In this embodiment, the first current mirror unit 11 can be configured as a proportional current mirror unit, and the second current mirror unit 12 can be configured as a mirror current mirror unit. During the charging phase of the voltage conversion circuit (i.e., during the high-side transistor turn-on period of the voltage conversion circuit), the current I2 through the second path is a preset multiple m of the current I1 through the first path, and the current Isense through the fourth path is equal to the current Is through the third path. In this embodiment, the preset multiple m can be set to 2. In other embodiments, the preset multiple m can also be set to other values greater than 1, which is not limited here.
[0036] Optionally, based on the above embodiments, such as Figure 2 As shown, the first path includes a first transistor PM1, a second transistor NM0, a third transistor NS0, and a fourth transistor NS1. The first path terminal of the first transistor PM1 is connected to the power supply voltage VCC, and the control terminal of the first transistor PM1 is connected to the bias current generation module 13. The first path terminal of the second transistor NM0 is coupled to the second path terminal of the first transistor PM1 and the control terminal of the second transistor NM0. The second path terminal of the second transistor NM0 is connected to the first path terminal of the third transistor NS0 and the first path terminal of the fourth transistor NS1, respectively. The second path terminal of the third transistor NS0 is grounded, and the second path terminal of the fourth transistor NS1 is connected to a switching node. The control terminal of the third transistor NS0 receives a first control signal, and the control terminal of the fourth transistor NS1 receives a second control signal. The first control signal is used to control the third transistor NS0 to turn on during the charging phase of the voltage conversion circuit and to control the third transistor NS0 to turn off during the freewheeling phase of the voltage conversion circuit. The second control signal is used to control the fourth transistor NS1 to turn off during the charging phase of the voltage conversion circuit and to control the fourth transistor NS1 to turn on during the freewheeling phase of the voltage conversion circuit.
[0037] In this embodiment, the first control signal can be directly set as the control signal of the high-side transistor of the voltage conversion circuit, and the second control signal can be directly set as the control signal of the freewheeling transistor of the voltage conversion circuit.
[0038] Optionally, based on the above embodiments, such asFigure 2 As shown, the second path includes a fifth transistor PM2, a sixth transistor NM1, and a seventh transistor NS2; the first terminal of the fifth transistor PM2 is connected to the power supply voltage VCC, and the control terminal of the fifth transistor PM2 is connected to the bias current generating module 13; the second terminal of the fifth transistor PM2 is connected to the first terminal of the sixth transistor NM1, and the connection between the second terminal of the fifth transistor PM2 and the first terminal of the sixth transistor NM1 serves as an intermediate node of the second path and connects to the third path; the control terminal of the sixth transistor NM1 is connected to the first terminal of the second transistor NM0, the second terminal of the sixth transistor NM1 is connected to the first terminal of the seventh transistor NS2, the second terminal of the seventh transistor NS2 is grounded, and the control terminal of the seventh transistor NS2 receives a preset voltage; wherein, the size of the fifth transistor PM2 is a preset multiple of the size of the first transistor; the sixth transistor NM1 and the second transistor NM0 have the same size.
[0039] Optionally, based on the above embodiments, such as Figure 2 As shown, the third path includes an eighth transistor PM3, a ninth transistor NM2, a third transistor NS0, and a fourth transistor NS1; the first path terminal of the eighth transistor PM3 is connected to the power supply voltage VCC, the second path terminal of the eighth transistor PM3 is coupled to the control terminal of the eighth transistor PM3 and the first path terminal of the ninth transistor NM2, the control terminal of the ninth transistor NM2 is connected to the intermediate node of the second path, and the second path terminal of the ninth transistor NM2 is connected to the first path terminal of the third transistor NS0 and the first path terminal of the fourth transistor NS1, respectively.
[0040] The fourth path includes the tenth transistor PM4 and a resistor R. The first terminal of the tenth transistor PM4 is connected to the power supply voltage VCC. The control terminal of the tenth transistor PM4 is connected to the second terminal of the eighth transistor PM3. The second terminal of the tenth transistor PM4 is connected to the first terminal of the resistor R. The second terminal of the resistor R is grounded. The connection between the second terminal of the tenth transistor PM4 and the first terminal of the resistor R serves as the output terminal of the sensing module 10, which outputs the sensing voltage VS.
[0041] like Figure 1 and Figure 2 As shown, based on the above embodiments, the working principle of the sensing module 10 in this embodiment is as follows:
[0042] During the freewheeling phase of the voltage conversion circuit, i.e., when the freewheeling transistor of the voltage conversion circuit is on, the fourth transistor NS1 receives the second control signal and turns on, while the third transistor NS0 receives the first control signal and turns off. The first path is coupled between the power supply voltage VCC and the switching node voltage VSW. At this time, due to the conduction of the freewheeling transistor of the voltage conversion circuit, the switching node voltage VSW is as shown in formula (1):
[0043] VSW = -IL*R ds(NML) (1)
[0044] Where IL represents the inductor current of the voltage conversion circuit, and R ds(NML) This represents the equivalent resistance of the voltage conversion circuit when the freewheeling diode is turned on.
[0045] During the conduction of the freewheeling diode in the voltage conversion circuit, the fourth transistor NS1 in the first path is turned on, and the third transistor NS0 is turned off. At this time, the operational amplifier composed of the second transistor NM0, the sixth transistor NM1, and the ninth transistor NM2 will make the node voltage V1 at the drain of the second transistor NM0 equal to the node voltage V2 at the drain of the sixth transistor NM1. At this time, the current Is flowing through the ninth transistor NM2 is as shown in formula (2):
[0046] Is=(V1-VSW) / R ds(NS1) -I1=(V2-VSW) / R ds(NS1) -I1(0) (2)
[0047] Where Is represents the current flowing through the ninth transistor NM2 (third path); V1 is the node voltage at the drain of the second transistor NM0; V2 is the node voltage at the drain of the sixth transistor NM1; VSW represents the switching node voltage; R ds(NS1) I1 represents the equivalent resistance of the fourth transistor NS1; I1 represents the current flowing through the second transistor NM0.
[0048] The node voltage V2 at the drain of the sixth transistor NM1 is shown in equation (3):
[0049] V2=I2*R ds(NS2) (3)
[0050] Where I2 represents the current flowing through the sixth transistor NM1; R ds(NS2) This is represented as the equivalent resistance of the seventh transistor NS2.
[0051] In this embodiment, the current I2 flowing through the second path in the first current mirror unit 11 is twice the current I1 flowing through the first path, and the current Is flowing through the third path in the second current mirror unit 12 is equal to the current Isense flowing through the fourth path. In this embodiment, the current I2 flowing through the sixth transistor NM1 is twice the current I1 flowing through the second transistor NM0, and the current Isense flowing through the fourth path is equal to the current Is flowing through the third path, i.e., I2 = 2I1, Isense = Is. Furthermore, the equivalent resistance of the third transistor NS0, the fourth transistor NS1, and the seventh transistor NS2 are all equal. The equivalent resistance of the freewheeling diode in the voltage conversion circuit when it is turned on is N times the equivalent resistance of the fourth transistor NS1, i.e., Rds. (NS0) =R ds(NS1) =R ds(NS2) N = R ds(NML) / R ds(NS1) .
[0052] At this time, as Figure 2 As shown, based on the above inferences and formulas (1) to (3), the calculation formula between the sensed voltage VS and the inductor current IL can be obtained, as shown in formula (4):
[0053] VS = Isense * R0 = Is * R0
[0054] =((I2*R) ds(NS2) -VSW) / R ds(NS1) –I1)*R0
[0055] =(I2*Rds (NS1) +IL*Rds(NML)) / Rds (NS1) –I1
[0056] =N*IL*R0+(I2-I1)*R0=N*IL*R0+I1*R0 (4)
[0057] Where VS represents the sensing voltage VS, Isense represents the current flowing through the fourth path, R0 represents the resistance value of the resistor R on the fourth path, and Is represents the current flowing through the ninth transistor NM2 (the third path). It can be seen from formula (4) that during the conduction period of the freewheeling tube in the voltage conversion circuit, the sensing module 10 can obtain a sensing voltage VS that is proportional to the inductor current IL.
[0058] Optionally, such as Figure 2As shown, in this embodiment, the sensing module 10 further includes a bias current generating module 13. The bias current generating module 13 is coupled between the power supply voltage VCC and the ground voltage, and is connected to the first path and the second path respectively, for providing bias voltage to the first path and the second path to conduct the first path and the second path.
[0059] In this embodiment, the bias current generating module 13 includes an eleventh transistor PM0. The first path terminal of the eleventh transistor PM0 is connected to the power supply voltage VCC. The second path terminal of the eleventh transistor PM0 is coupled to the control terminal of the eleventh transistor PM0, the control terminal of the first transistor PM1, and the control terminal of the fifth transistor PM2, and is used to provide bias voltage to the first transistor PM1 and the fifth transistor PM2 to conduct the first path and the second path.
[0060] In other embodiments, the bias current generating module 13 may also be configured with other circuit structures, as long as they meet the above functions, and no restrictions are imposed here.
[0061] Optionally, please refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of the third embodiment of the current sensing circuit of this application. Figure 3 As shown, the current sensing circuit 100 of this embodiment includes a sensing module 10, a current sampling voltage generation module 30, and a digital module 20 connected together.
[0062] The current sampling voltage generation module 30 is connected to the sensing module 10 and the digital module 20 respectively. It is configured to sample the sensing voltage VS to obtain the current sampling voltage VSENSE of the voltage conversion circuit for the whole cycle, and send the current sampling voltage VSENSE to the digital module 20 to obtain the inductor current IL of the voltage conversion circuit for the whole cycle.
[0063] In this embodiment, after the sensing module 10 obtains the sensing voltage VS using the method described above, it can then be processed by the current sampling voltage generation module 30 to obtain the current sampling voltage VSENSE for the entire cycle of the voltage conversion circuit. Since the load current equals the average value of the inductor current IL, which equals the inductor current value during half the high-side transistor's charging phase, and equals the inductor current value during half the freewheeling transistor's freewheeling phase, the current sampling voltage generation module 30 can sample the sensing voltage VS at the moment halfway through the freewheeling transistor's freewheeling phase of the voltage conversion circuit. This sampled voltage is used as the current sampling voltage VSENSE during the high-side transistor's conduction period. During the freewheeling transistor's conduction period, the current sampling voltage VSENSE tracks the sensing voltage VS. Therefore, regardless of whether the voltage conversion circuit operates in continuous conduction mode or discontinuous conduction mode, the current sampling voltage VSENSE for the entire cycle can be obtained through the sensing module 10 and the current sampling voltage generation module 30.
[0064] Optionally, such as Figure 3 As shown, the current sampling voltage generation module 30 includes a first switch S0, a second switch S1, a third switch S2, a first capacitor C0, and a second capacitor C1. The first end of the first switch S0 is connected to the output end of the sensing module 10, and the second end of the first switch S0 serves as the output end of the current sampling voltage generation module 30. The first end of the second switch S1 is connected to the output end of the sensing module 10, and the second end of the second switch S1 is connected to the first end of the first capacitor C0 and the first end of the third switch S2. The second end of the third switch S2 and the first end of the second capacitor C1 are connected to the second end of the first switch S0, and the second ends of the first capacitor C0 and the second end of the second capacitor C1 are grounded. During the freewheeling phase of the voltage conversion circuit, the first switch S0 is turned on, the third switch S2 is turned off, the second switch S1 is turned on for the first half of the freewheeling phase, and the second switch S1 is turned off for the remaining phases of the freewheeling phase. During the charging phase of the voltage conversion circuit, the first switch S0 and the second switch S1 are turned off, and the third switch S2 is turned on.
[0065] Alternatively, in other embodiments, please refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of the fourth embodiment of the current sensing circuit of this application. Figure 4 As shown, based on Figure 3 In the embodiment shown, the current sampling voltage generation module 30 further includes a buffer BUF. The first input terminal of the buffer BUF is connected to the second terminal of the second switch S1 and the first terminal of the first capacitor C0. The output terminal of the buffer BUF is connected to the first terminal of the third switch S2. The second input terminal of the buffer BUF is connected to the output terminal of the buffer BUF.
[0066] Compared to Figure 3In this embodiment, the current sampling voltage generation module 30 shown can be enhanced by adding a buffer BUF to improve the sampling capability of the second capacitor C1 to the first capacitor C0, thereby improving the accuracy of the current sampling voltage VSENSE output by the current sampling voltage generation module 30.
[0067] based on Figure 3 and Figure 4 For an example application scenario, please refer to [link / reference]. Figure 5 , Figure 5 This is a timing control waveform diagram of an embodiment of the current sampling voltage generation module. For example... Figure 5 As shown, GH_B is the control signal waveform of the first switch S0, and GH is the control signal waveform of the third switch S2. In this embodiment, the control signal of the first switch S0 can be set as the control signal of the freewheeling diode in the voltage conversion circuit; the control signal of the third switch S2 can be set as the control signal of the high-current diode in the voltage conversion circuit. SAMPLE is the control signal waveform of the second switch S1; VSW is the voltage waveform diagram of the switching node of the voltage conversion circuit; VSENSE is the waveform diagram of the current sampling voltage VSENSE; VS is the waveform diagram of the sensing voltage VS; VSH is the voltage waveform diagram at the connection node between the second terminal of the second switch S1 and the first terminal of the third switch S2; IL is the waveform diagram of the inductor current, where Iavg is the average value of the inductor current IL.
[0068] like Figure 5 As shown, during the freewheeling phase of the voltage conversion circuit, the first switch S0 is on, the third switch S2 is off, and the second switch S1, under the control of SAMPLE, is on for the first half of the freewheeling phase. At this time, the current sampling voltage VSENSE tracks the sensing voltage VS, and the sensing voltage VS charges the first capacitor C0 and the second capacitor C1. In the second half of the freewheeling phase, after the second switch S1 is off, the voltage of the first capacitor C0 is the sensing voltage VS at that moment, halfway through the freewheeling phase. During the charging phase of the voltage conversion circuit, the first switch S0 and the second switch S1 are off, and the third switch S2 is on. At this time, the current sampling voltage VSENSE is maintained by the first capacitor C0 and the second capacitor C1 at the sensing voltage VS at that moment, halfway through the freewheeling phase. The final waveform of the output current sampling voltage VSENSE generated by the current sampling voltage VSENSE is as follows: Figure 5 As shown, after acquiring the current sampling voltage VSENSE for the entire cycle, it can then be sent to the digital module 20 for processing to obtain the inductor current IL for the entire cycle.
[0069] In this way, regardless of whether the voltage conversion circuit operates in continuous conduction mode or discontinuous conduction mode, the current sensing circuit 100 of this embodiment can achieve the full-cycle inductor current IL sampling function without the need to add external capacitors, resistors, R devices and pins. That is, the inductor current IL during the conduction period of the freewheeling tube is sampled as the inductor current IL of the freewheeling phase, and the inductor current IL at the moment when the freewheeling tube is conducting for half the time of the freewheeling phase is sampled as the average value of the inductor current IL of the charging phase, thereby realizing the full-cycle inductor current IL sampling.
[0070] Optionally, based on the above embodiments, the digital module 20 of this embodiment includes a digital-to-analog conversion sampling module and a calculation module; the digital-to-analog conversion sampling module is connected to the current sampling voltage generation module 30 and is used to perform digital-to-analog conversion and sampling on the current sampling voltage VSENSE; the calculation module is connected to the digital-to-analog conversion sampling module and is used to calculate and obtain the inductor current IL of the whole cycle based on the digital-to-analog conversion and the sampled current sampling voltage VSENSE.
[0071] As mentioned above, after obtaining the current sampling voltage VSENSE for the entire cycle, the digital-to-analog conversion sampling module can be used to filter the current sampling voltage VSENSE before performing digital-to-analog conversion and sampling. At this time, the calculation module can subtract I1*R0 from the current sampling voltage VSENSE that has undergone digital-to-analog conversion and sampling based on the formula (4) mentioned above, and multiply by the corresponding current sampling coefficient 1 / (N*R0) to obtain the load current information for the entire cycle.
[0072] Optionally, this application further proposes a voltage conversion circuit, please refer to [link to relevant documentation]. Figure 6 , Figure 6 This is a schematic diagram of the structure of an embodiment of the voltage conversion circuit of this application. Figure 6 As shown, the voltage conversion circuit of this embodiment includes the current sensing circuit 100 of any of the above embodiments.
[0073] Optionally, this application further proposes a voltage conversion circuit, please refer to [link to relevant documentation]. Figure 7 , Figure 7 This is a schematic diagram of the structure of an embodiment of the electronic device of this application. Figure 7 As shown, the voltage conversion circuit of this embodiment includes the current sensing circuit 100 of any of the above embodiments.
[0074] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.
Claims
1. A current sense circuit, characterized by, A current sensing circuit for sensing an inductor current of a voltage conversion circuit, the current sensing circuit comprising: a sensing module connected to a switching node of the voltage conversion circuit, the sensing module configured to obtain a sensing voltage based on a switching node voltage at the switching node during a freewheeling phase of the voltage conversion circuit, wherein the sensing voltage is related to the inductor current; a digital module connected to the sensing module and configured to perform digital-to-analog conversion and calculation processing on the sensing voltage to obtain the inductor current for a full cycle of the voltage conversion circuit.
2. The current sense circuit of claim 1, wherein, The sensing module comprises: a first current mirror unit comprising: a first path coupled between a supply voltage and a ground voltage during a charging phase of the voltage conversion circuit, and coupled between the supply voltage and a switching node voltage during a freewheeling phase of the voltage conversion circuit; a second path coupled between the supply voltage and the ground voltage, the second path having a current proportional to the first path, and the current of the second path being a preset multiple of the current of the first path; a second current mirror unit comprising: a third path connected to an intermediate node of the second path, the third path being coupled between the supply voltage and the ground voltage during the charging phase of the voltage conversion circuit, and being coupled between the supply voltage and the switching node voltage during the freewheeling phase of the voltage conversion circuit; a fourth path coupled between the supply voltage and the switching node voltage, the fourth path mirroring the third path, the fourth path comprising an output node to output the sensing voltage as an output of the sensing module.
3. The current sense circuit of claim 2, wherein, The sensing module further comprises: a bias current generation module coupled between the supply voltage and the ground voltage and connected to the first path and the second path, respectively, for providing a bias voltage to the first path and the second path to turn on the first path and the second path.
4. The current sensing circuit of claim 3, wherein the first path comprises a first transistor, a second transistor, a third transistor, and a fourth transistor, a first path terminal of the first transistor is connected to the supply voltage, a control terminal of the first transistor is connected to the bias current generation module, a first path terminal of the second transistor is coupled to a second path terminal of the first transistor and a control terminal of the second transistor, a second path terminal of the second transistor is connected to a first path terminal of the third transistor and a first path terminal of the fourth transistor, respectively, a second path terminal of the third transistor is connected to the ground, and a second path terminal of the fourth transistor is connected to the switching node. The control end of the third transistor receives a first control signal, and the control end of the fourth transistor receives a second control signal; the first control signal is used to control the third transistor to be turned on during the charging phase of the voltage conversion circuit and to be turned off during the freewheeling phase of the voltage conversion circuit; and the second control signal is used to control the fourth transistor to be turned off during the charging phase of the voltage conversion circuit and to be turned on during the freewheeling phase of the voltage conversion circuit.
5. The current sensing circuit according to claim 4, wherein, the second path comprises a fifth transistor, a sixth transistor and a seventh transistor; the first path end of the fifth transistor is connected with the power supply voltage, and the control end of the fifth transistor is connected with the bias current generation module; the second path end of the fifth transistor is connected with the first path end of the sixth transistor, and the connection between the second path end of the fifth transistor and the first path end of the sixth transistor is connected with the third path as the intermediate node of the second path; the control end of the sixth transistor is connected with the first path end of the second transistor, the second path end of the sixth transistor is connected with the first path end of the seventh transistor, the second path end of the seventh transistor is grounded, and the control end of the seventh transistor receives a preset voltage; wherein the size of the fifth transistor is the preset multiple of the size of the first transistor; and the size of the sixth transistor is the same as the size of the second transistor.
6. The current sensing circuit according to claim 4, wherein, the third path comprises an eighth transistor, a ninth transistor, the third transistor and the fourth transistor; the first path end of the eighth transistor is connected with the power supply voltage, the second path end of the eighth transistor is coupled with the control end of the eighth transistor and the first path end of the ninth transistor, the control end of the ninth transistor is connected with the intermediate node of the second path, and the second path end of the ninth transistor is connected with the first path end of the third transistor and the first path end of the fourth transistor respectively; the fourth path comprises a tenth transistor and a resistor; the first path end of the tenth transistor is connected with the power supply voltage, the control end of the tenth transistor is connected with the second path end of the eighth transistor, and the second path end of the tenth transistor is connected with the first end of the resistor; the second end of the resistor is grounded, and the connection between the second path end of the tenth transistor and the first end of the resistor is the output end of the sensing module for outputting the sensing voltage.
7. The current sense circuit of claim 1, wherein, a current sampling voltage generation module is further included, which is connected with the sensing module and the digital module respectively and is configured to sample the sensing voltage to obtain a voltage sampling voltage of the voltage conversion circuit in a whole cycle and send the voltage sampling voltage to the digital module to obtain the inductor current of the voltage conversion circuit in the whole cycle.
8. The current sense circuit of claim 7, wherein, The current sampling voltage generation module comprises a first switch, a second switch, a third switch, a first capacitor and a second capacitor; a first end of the first switch is connected with an output end of the sensing module, and a second end of the first switch serves as an output end of the current sampling voltage generation module; a first end of the second switch is connected with the output end of the sensing module, a second end of the second switch is connected with a first end of the first capacitor and a first end of the third switch, a second end of the third switch and a first end of the second capacitor are connected with the second end of the first switch, and a second end of the first capacitor and a second end of the second capacitor are grounded; In the freewheeling phase of the voltage conversion circuit, the first switch is turned on, the third switch is turned off, the second switch is turned on in the first half of the freewheeling phase, and the second switch is turned off in the remaining phase of the freewheeling phase; in the charging phase of the voltage conversion circuit, the first switch and the second switch are turned off, and the third switch is turned on.
9. The current sense circuit of claim 8, wherein, The current sampling voltage generation module further comprises a buffer, a first input end of the buffer is connected with the second end of the second switch and the first end of the first capacitor, an output end of the buffer is connected with the first end of the third switch, and a second input end of the buffer is connected with the output end of the buffer.
10. The current sense circuit of claim 7, wherein, The digital module comprises a digital-to-analog conversion sampling module and a calculation module; the digital-to-analog conversion sampling module is connected with the current sampling voltage generation module, and is configured to perform digital-to-analog conversion and sampling on the current sampling voltage; The calculation module is connected with the digital-to-analog conversion sampling module, and is configured to calculate the inductor current in a full cycle based on the current sampling voltage after digital-to-analog conversion and sampling.
11. A voltage conversion circuit, characterized by comprising: The current sensing circuit of the inductor current comprises any one of claims 1-10.
12. An electronic device, comprising: The voltage conversion circuit comprises claim 11.