A low-power bootstrap isolation driving circuit based on single-pole double-throw analog switch

Abstract

The application discloses a low-power bootstrap isolation driving circuit based on single-pole double-throw analog switches, comprising a driving circuit and a main circuit, the driving circuit adopts two pairs of single-pole double-throw analog switches, the main circuit is used for verifying the driving performance of the driving circuit, and the main circuit supplies power for the driving circuit, thereby solving the problems of high loss and the need for isolation power supply of a traditional isolation chip. Moreover, the application has the advantages of simple structure, low loss, small size and the need for no isolation power supply, and can adapt to the isolation driving demand in low-voltage energy collection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronics, in particular to a low-power bootstrap isolation driving circuit based on single-pole double-throw analog switch. BACKGROUND

[0002] With the continuous development of the Internet of Things technology, people's demand for self-powered wireless communication systems and sensors is increasing. The traditional power supply method of wireless communication systems and sensors is to use chemical batteries, but chemical batteries have various disadvantages: they are not environmentally friendly, pose pollution and explosion risks, cannot provide long-term power supply, and due to the limitations of the application environment, battery replacement and maintenance often involve high cost and high difficulty; the size of chemical batteries is relatively large, which does not facilitate the further miniaturization of such devices. Energy harvesting technology has the advantages of economy, environmental protection, sustainability, etc., and is widely studied as an alternative to traditional batteries. Vibration energy, as a ubiquitous energy in the environment, is widely distributed and not limited by natural conditions such as weather, making vibration energy harvesting technology have good application prospects. Energy management circuits play an extremely important role in energy harvesting systems as they are responsible for rectification and voltage regulation. Efficient energy management circuits often use power transistors to achieve power conversion, which inevitably involves isolation driving in practical applications. However, commercially available isolation driving chips have high loss, large size, and require an isolated power supply, which is not suitable for vibration energy harvesting applications. In the field of low-voltage energy harvesting, the requirements for isolation driving are different from traditional isolation driving, with a focus on low loss, small size, and no need for additional power supply, while the requirement for isolation is very low.

[0003] Therefore, there is a need for a low-power bootstrap isolation driving circuit based on single-pole double-throw analog switches. SUMMARY

[0004] The embodiments of the present application provide a low-power bootstrap isolation driving circuit based on single-pole double-throw analog switches to at least solve the technical problems of high loss and the need for an isolated power supply of traditional isolation chips in related technologies.

[0005] According to an aspect of the embodiments of the present application, a low-power bootstrap isolation driving circuit based on single-pole double-throw analog switches is provided, which includes:

[0006] The driving circuit includes two pairs of single-pole double-throw analog switches, and the main circuit is used to verify the driving performance of the driving circuit and supply power to the driving circuit.

[0007] Optionally, the driving circuit includes a first pair of single-pole double-throw analog switches SPDT1, a second pair of single-pole double-throw analog switches SPDT2, a first capacitor C s and a first diode Digd ;

[0008] The normally closed node NC1 of the first pair of single-pole double-throw analog switches SPDT1 is connected to ground, and the normally open node NO1 of the first pair of single-pole double-throw analog switches SPDT1 is connected to the main circuit. The common node A and the first capacitor C of the first pair of single-pole double-throw analog switches SPDT1 are connected to the main circuit. s First diode D igd Power supply V DD And connect to the ground in sequence;

[0009] The normally closed node NC2 of the second pair of analog switches SPDT2 is connected to the main circuit, and the normally open node NO2 of the second pair of analog switches SPDT2 is connected to the first diode D. igd The first connected diode D igd One end of the first pair of analog switches is connected, and the common node of the second pair of analog switches SPDT2 is connected to the main circuit.

[0010] Optionally, the main circuit employs an electromagnetic vibration energy harvesting device.

[0011] Optionally, the main circuit employs a dual Boost AC-DC converter.

[0012] Optionally, the dual Boost AC-DC converter includes: an inductor L, a first power transistor M1, a second power transistor M2, a second diode D1, a third diode D2, a second capacitor C1, a third capacitor C2, a fourth capacitor C3, and a load R;

[0013] The sources and gates of the first power transistor M1 and the second power transistor M2 are connected to each other. The source of the first power transistor M1 is connected to the normally closed node NC2 of the second pair of analog switches SPDT2, and the gate of the first power transistor M1 is connected to the common node of the second pair of analog switches SPDT2. The drain, inductor L, and AC power supply V of the first power transistor M1 are connected. EH The drain of the second power transistor M2 is connected in sequence. The drain of the first power transistor M1, the third capacitor C2, the fourth capacitor C3, the third diode D2, and the drain of the first power transistor M1 are connected in sequence. The drain of the second power transistor M2 is connected between the fourth capacitor C3 and the third diode D2. The ends of the connected fourth capacitor C3 and the third diode D2 are connected in parallel with the second capacitor C1. The ends of the second capacitor C1 are connected in parallel with the load R. One end of the load R is grounded.

[0014] Optionally, the source and gate of the first power transistor M1 and the second power transistor M2 are connected to each other to form a bidirectional power switch S1, which is used to ensure bidirectional current flow and bidirectional blocking.

[0015] Optionally, during the positive half-cycle of the input voltage of the main circuit, when M1 and M2 are turned on, the current in inductor L rises from zero; when M1 and M2 are turned off, the second diode D1 is turned on to charge the output second capacitor C1 and the third capacitor C2.

[0016] Optionally, the principle of the negative half-cycle of the input voltage of the main circuit is the same as that of the positive half-cycle of the input voltage of the main circuit.

[0017] Optionally, the main circuit operates in BCM mode.

[0018] Compared with existing technologies, the present invention has the following advantages:

[0019] The low-power bootstrap isolation drive circuit based on single-pole double-throw analog switches provided by this invention includes a drive circuit and a main circuit. The drive circuit uses two pairs of single-pole double-throw analog switches, and the main circuit is used to verify the drive performance of the drive circuit and supplies power to the drive circuit, thereby solving the problems of high loss and the need for isolated power supply in traditional isolation chips. Furthermore, this invention has a simple structure, low loss, small size, and does not require an isolated power supply, making it suitable for the isolation drive requirements in low-voltage energy harvesting. Attached Figure Description

[0020] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a low-power bootstrap isolation drive circuit based on a single-pole double-throw analog switch according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of key waveforms for bootstrap isolation drive according to an embodiment of the present invention;

[0023] Figure 3 This is a measured waveform diagram of the isolated drive signal according to an embodiment of the present invention;

[0024] Figure 4 This is a measured waveform diagram of the switching transistor and main circuit signals according to an embodiment of the present invention. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] Example 1

[0029] like Figure 1 This is a schematic diagram of a low-power bootstrap isolation drive circuit based on a single-pole double-throw analog switch according to an embodiment of the present invention, as shown below. Figure 1 As shown, the low-power bootstrap isolation drive circuit includes a drive circuit and a main circuit. The drive circuit uses two pairs of single-pole double-throw analog switches. The main circuit is used to verify the drive performance of the drive circuit and supplies power to the drive circuit.

[0030] Continue to refer to Figure 1 The driving circuit includes: a first pair of single-pole double-throw analog switches SPDT1, a second pair of single-pole double-throw analog switches SPDT2, and a first capacitor C. s and the first diode D igd ;

[0031] The normally closed node NC1 of the first pair of single-pole double-throw analog switches SPDT1 is connected to ground, and the normally open node NO1 of the first pair of single-pole double-throw analog switches SPDT1 is connected to the source (M1 or M2) of the power switch transistor in the main circuit. The common node A of the first pair of single-pole double-throw analog switches SPDT1 and the first capacitor C s First diode D igd Power supply V DD Connect to ground in sequence, power supply V DD DC voltage is provided through the main circuit; specifically, the first capacitor C... s The positive terminal of the first diode D igdThe negative terminal of the first diode D is connected. igd The positive terminal is connected to the power supply V. DD The positive terminal is connected, and the power supply V DD The negative terminal is connected to ground; the first pair of single-pole double-throw analog switches SPDT1 and the first capacitor C s First diode D igd Power supply V DD Loop1 is formed;

[0032] The normally closed node NC2 of the second pair of analog switches SPDT2 is connected to the source of the power switch (M1 or M2) in the main circuit, and the normally open node NO2 of the second pair of analog switches SPDT2 is connected to the first diode D. igd The first connected diode D igd One end of the first pair of analog switches SPDT2 is connected to the second pair of analog switches SPDT2, and the common node of the second pair of analog switches SPDT2 is connected to the gate of the power transistor (M1 or M2) of the main circuit; the second pair of analog switches SPDT2 and the first capacitor C s The first pair of single-pole double-throw analog switches SPDT1 and bidirectional power switches S1 form Loop 2.

[0033] As an optional embodiment, the main circuit employs an electromagnetic vibration energy harvesting device.

[0034] Specifically, the main circuit uses dual Boost AC-DC converters.

[0035] Further reference Figure 1 The dual Boost AC-DC converter includes: inductor L, first power transistor M1, second power transistor M2, second diode D1, third diode D2, second capacitor C1, third capacitor C2, fourth capacitor C3, and load R. Since the output voltage of the dual Boost AC-DC converter needs to be used for power supply for converter control, the power transistors need to be controlled by isolated drivers. However, since the circuit itself has a low voltage level and low output power, the isolation driver does not need to pursue high isolation, but needs to achieve high efficiency.

[0036] The sources and gates of the first power transistor M1 and the second power transistor M2 are connected to each other. The source of the first power transistor M1 is connected to the normally closed node NC2 of the second pair of analog switches SPDT2, and the gate of the first power transistor M1 is connected to the common node of the second pair of analog switches SPDT2. The drain, inductor L, and AC power supply V of the first power transistor M1 are connected. EHThe drain of the second power transistor M2 is connected in sequence. The drain of the first power transistor M1, the third capacitor C2, the fourth capacitor C3, the third diode D2, and the drain of the first power transistor M1 are connected in sequence. The drain of the second power transistor M2 is connected between the fourth capacitor C3 and the third diode D2. The ends of the connected fourth capacitor C3 and the third diode D2 are connected in parallel with the second capacitor C1. The ends of the second capacitor C1 are connected in parallel with the load R. One end of the load R is grounded.

[0037] In this circuit, the source and gate of the first power transistor M1 and the second power transistor M2 are connected to each other to form a bidirectional power switch S1. The bidirectional power switch S1 is used to ensure bidirectional current flow and bidirectional blocking.

[0038] The main circuit operates in BCM mode. During the positive half-cycle of the main circuit's input voltage, when M1 and M2 are on, the inductor current L rises from zero; when M1 and M2 are off, the second diode D1 conducts, charging the output second capacitor C1 and the third capacitor C2. The principle of the negative half-cycle of the main circuit's input voltage is the same as that of the positive half-cycle.

[0039] like Figure 2 As shown, Figure 2 This is the bootstrap isolation drive signal waveform of a low-power bootstrap isolation drive circuit based on single-pole double-throw analog switches. The control signal of the main circuit switching transistor is the drive signal of the single-pole double-throw analog switch. When the control signal Q of the main circuit switching transistor is low, the first pair of single-pole double-throw analog switches SPDT1 switches to node NC1, and the second pair of single-pole double-throw analog switches SPDT2 switches to node NC2. The voltage v gs Clamped to 0, power switches M1 and M2 are turned off, and V... DD The first capacitor C is supplied via Loop1. s Charging causes the first capacitor C to... s Voltage V at both ends CS =V DD When Q is high, the first pair of single-pole double-throw analog switches SPDT1 switches to node NO1, the second pair of single-pole double-throw analog switches SPDT2 switches to node NO2, and the first capacitor C... S Loop2 provides drive voltage to power switches M1 and M2, turning them on. When power switches M1 and M2 are turned on, the first capacitor C... s Point A at the lower end is connected to the fourth capacitor C3 via the second power transistor M2, and the first capacitor C... S The potential of point B at the top relative to ground is V. B =V c3 +V DD This potential is higher than the supply voltage V of the analog switch. DD .

[0040] As an optional embodiment, to avoid analog switch latch-up, an over-rail series analog switch, model MAX4852, was selected, which supports the potential at both ends of a single-pole double-throw analog switch exceeding its supply voltage. Its key parameters include: supply voltage (+2 to +5.5V), supply current (1μA), on-resistance (3.5Ω / 7Ω), and injected charge (8pC). First diode D igd Select a Schottky diode of model 1PS79SB30, and the first capacitor C s 100μF. DC power supply V DD It can be provided by the output voltage of the main circuit.

[0041] The testing of the low-power bootstrap isolation drive circuit based on a single-pole double-throw analog switch of the present invention is described in detail to enable those skilled in the art to better understand the present invention:

[0042] like Figure 3 and Figure 4 As shown, Figure 3 The test waveforms of the prototype under the above parameter conditions are shown. When the Q signal is low, the drive signal v gs Clamped to 0, capacitor C s The voltage at the upper end to ground is V DD –V drop = 3.119V, where V drop This is the diode voltage drop. When the Q signal is high, C... S The potential of the upper end of the capacitor relative to ground is V. C3 +V DD -V drop =5.119V. For example... Figure 4 The figure shows the V of the main circuit switching transistor. gs Signal and inductor current waveforms. The inductor current waveform shows that the GaNHEMT switch (model EPC2040) in the main circuit can be successfully driven at a frequency of 160kHz with a driving loss of 660μW, verifying the feasibility of this invention.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A low power bootstrap isolation driver circuit based on a single pole double throw analog switch, characterized by, The driving circuit comprises two pairs of single-pole double-throw analog switches, and the main circuit is used for verifying the driving performance of the driving circuit and powering the driving circuit; The drive circuit includes a first pair of single-pole double-throw analog switches SPDT 1 , a second pair of single-pole double-throw analog switches SPDT 2 , a first capacitor C s , and a first diode D igd ​ The first pair of single-pole double-throw analog switch SPDT 1 The normally closed node NC 1 Connected with the ground, the first pair of single-pole double-throw analog switch SPDT 1 The normally open node NO 1 Connected with the main circuit, the first pair of single-pole double-throw analog switch SPDT 1 The common node A, the first capacitor C s , The first diode D igd , Power supply V DD And the ground are connected in sequence; second pair of analog switches SPDT 2 normally closed node NC 2 connected to the main circuit, a common node of the second pair of analog switches SPDT 2 normally open node NO 2 connected to a first diode D igd first diode connected to the first diode D igd connected to one end of the second pair of analog switches SPDT 2 a common node of the second pair of analog switches connected to the main circuit The main circuit adopts an electromagnetic vibration energy collection device. The main circuit adopts a double-Boost AC-DC converter. The dual Boost AC-DC converter comprises: an inductor L , a first power transistor M 1 , a second power transistor M 2 , a second diode D 1 , a third diode D 2 , a second capacitor C 1 , a third capacitor C 2 , a fourth capacitor C 3 and a load R； a first power transistor M 1 a second power transistor M 2 the source and the gate of the first power transistor M 1 are connected to each other, respectively, the source of the first power transistor SPDT 2 is connected to a normally closed node of a second pair of analog switches NC 2 , the gate of the first power transistor M 1 is connected to a common node of the second pair of analog switches SPDT 2 , the drain of the first power transistor M 1 is connected to an inductor L , an AC power source V EH , the drain of the second power transistor M 2 in this order, the drain of the first power transistor M 1 is connected to a third capacitor C 2 , a fourth capacitor C 3 , a third diode D 2 in this order, the drain of the first power transistor M 1 is connected to the drain of the second power transistor M 2 , the drain of the second power transistor C 3 is connected to the fourth capacitor D 2 , the third diode C 3 , one end of a second capacitor D 2 is connected to the other end of the fourth capacitor C 1 , the other end of the second capacitor C 1 is connected to a load R , and one end of the load R is grounded.

2. The low power bootstrap isolation driver circuit based on a single pole double throw analog switch of claim 1, wherein, a first power transistor M 1 a second power transistor M 2 the source and the gate of the first and the second power transistor are connected to each other, respectively, to form a bidirectional power switch S1 for securing bidirectional current flow and bidirectional current block.

3. The low power bootstrap isolation driver circuit based on a single pole double throw analog switch of claim 1, wherein, The input voltage positive half cycle of the main circuit is in M 1 And M 2 When the inductor L The current rises from zero; M 1 And M 2 When the second diode D 1 Conducting the output second capacitor C 1 , the third capacitor C 2 Charge.

4. The low power bootstrap isolation driver circuit based on a single pole double throw analog switch of claim 3, wherein, The principle of the input voltage negative half cycle of the main circuit is the same as that of the input voltage positive half cycle of the main circuit.

5. The low power bootstrap isolation driver circuit based on a single pole double throw analog switch of claim 1, wherein, The main circuit works in the BCM mode.

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