Zero-voltage-difference dual-power seamless switching circuit

Abstract

The utility model provides a zero-voltage-difference dual-power seamless switching circuit which comprises a first power supply module, a second power supply module, a first switch module, a second switch module, a third switch module, a fourth switch module, a fifth switch module and a sixth switch module. The circuit can realize the automatic switching of two power supplies, almost completely eliminates the voltage difference, has the characteristic of low static loss, is convenient to develop and apply, makes up the defects of the prior art, and has higher practical value.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a zero-voltage-difference dual-power supply seamless switching circuit. Background Art

[0002] At present, with the rapid development of electronic application products, the application demand for power supply equipment is gradually increasing, and the reliability requirements of power supply equipment are gradually improving; for example, in many application scenarios, two or more power supplies may be involved for switching, and the continuity of power supply is also required.

[0003] In the existing power switching scheme, dual power switching is basically achieved through a single MOS tube and a single diode, but when applied, the voltages of the two power supplies are usually different, and there will be a diode voltage difference in between; this method has limitations, it cannot control two power supplies of the same voltage to switch automatically, and the diode voltage difference efficiency is not high. Once an electronic device that requires the input voltages of the two power supplies to be equal and the voltage drop cannot be too large when the same output voltage is required is encountered, the above scheme cannot be effectively applied.

[0004] In summary, the problems existing in the prior art need to be solved urgently. Utility Model Content

[0005] The utility model provides a zero-voltage-difference dual-power supply seamless switching circuit, which is used to solve the defects in the prior art and realize zero-voltage-difference switching power supply.

[0006] The utility model provides a zero-voltage-difference dual-power seamless switching circuit, comprising: a first power supply module, a second power supply module, a first switch module, a second switch module, a third switch module, a fourth switch module, a fifth switch module and a sixth switch module;

[0007] The first power supply module is connected to the input end of the first switch module, the output end of the first switch module and the second power supply module are both connected to the input end of the second switch module, the output end of the second switch module and the second power supply module are both connected to the input end of the third switch module, the output end of the third switch module is connected to the output end of the fourth switch module, the input end of the fourth switch module is connected to the input end of the fifth switch module, the output end of the fifth switch module is connected to the input end of the sixth switch module, the output end of the fifth switch module and the output end of the sixth switch module are both connected to the first power supply module, and the fourth switch module and the sixth switch module are both connected to the output end of the zero-voltage difference dual power supply seamless switching circuit.

[0008] According to a zero-voltage difference dual-power supply seamless switching circuit provided by the utility model, the zero-voltage difference dual-power supply seamless switching circuit also includes a capacitor, the first switch module and the second switch module are both connected to the first end of the capacitor, and the fourth switch module and the sixth switch module are both connected to the second end of the capacitor.

[0009] According to a zero-voltage-difference dual-power seamless switching circuit provided by the utility model, the first switch module, the second switch module and the fifth switch module are all NPN-type triodes.

[0010] According to a zero-voltage-difference dual-power seamless switching circuit provided by the utility model, emitters of the first switch module, the second switch module and the fifth switch module are all grounded.

[0011] According to a zero-voltage-difference dual-power supply seamless switching circuit provided by the utility model, a first resistor is arranged between the base and the emitter of the first switch module.

[0012] According to a zero-voltage-difference dual-power supply seamless switching circuit provided by the utility model, a second resistor is arranged between the base and the emitter of the second switch module.

[0013] According to a zero-voltage-difference dual-power seamless switching circuit provided by the utility model, the third switch module, the fourth switch module and the sixth switch module are all PMOS tubes.

[0014] According to a zero-voltage-difference dual-power supply seamless switching circuit provided by the utility model, the source of the third switch module is connected to the second power supply module.

[0015] According to a zero-voltage-difference dual-power seamless switching circuit provided by the utility model, a third resistor is arranged between the gate and the source of the sixth switch module.

[0016] According to a zero-voltage-difference dual-power seamless switching circuit provided by the utility model, the third switch module, the fourth switch module and the sixth switch module are all provided with parasitic diodes.

[0017] The utility model provides a zero-voltage-difference dual-power supply seamless switching circuit, which can realize automatic switching of two power supplies and almost completely eliminate the voltage difference, has the characteristics of low static loss, is easy to develop and apply, makes up for the shortcomings of the existing technology, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a structural schematic diagram of a zero-voltage-difference dual-power supply seamless switching circuit provided by the utility model;

[0020] Figure 2 It is a specific circuit diagram of the zero-voltage difference dual-power supply seamless switching circuit provided by the utility model. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] At this stage, similar technical solutions mainly include diode parallel switching circuits and MOS tube + diode switching circuits, through which power switching is achieved. The diode parallel switching circuit is simple in design, but due to the voltage difference of the diode, the voltage drop is still too large for the battery, and the smaller the voltage drop, the greater the reverse leakage current, which affects power consumption. The MOS tube + diode switching circuit also has the problem of diode voltage difference.

[0023] In order to solve the problems in the prior art, the utility model proposes a zero-voltage difference dual power supply seamless switching circuit to achieve zero-voltage difference switching power supply. The zero-voltage difference dual power supply seamless switching circuit is described below. Figure 1 , Figure 2 As shown, including but not limited to the following parts:

[0024] A zero-voltage-difference dual-power seamless switching circuit, characterized in that it comprises: a first power supply module, a second power supply module, a first switch module, a second switch module, a third switch module, a fourth switch module, a fifth switch module and a sixth switch module;

[0025] The first power supply module is connected to the input end of the first switch module, the output end of the first switch module and the second power supply module are both connected to the input end of the second switch module, the output end of the second switch module and the second power supply module are both connected to the input end of the third switch module, the output end of the third switch module is connected to the output end of the fourth switch module, the input end of the fourth switch module is connected to the input end of the fifth switch module, the output end of the fifth switch module is connected to the input end of the sixth switch module, the output end of the fifth switch module and the output end of the sixth switch module are both connected to the first power supply module, and the fourth switch module and the sixth switch module are both connected to the output end of the zero-voltage difference dual power supply seamless switching circuit.

[0026] Specifically, the first power supply module VIN is connected to the input end of the first switch module Q1 through the resistor R1 (1 kΩ), the collector of the first switch module Q1 and the second power supply module VCC are both connected to the base of the second switch module Q2 through R3 (1 kΩ), the output end of the second switch module Q2 is connected to the gate of the third switch module Q3 through R5 (10 kΩ), the second power supply module VCC is connected to the gate of the third switch module Q3 through R6 (100 kΩ), the drain of the third switch module Q3 is connected to the drain of the fourth switch module Q4, the drain of the fourth switch module Q4 is connected to the base of the fifth switch module Q5 through R10 (3.3 kΩ), the collector of the fifth switch module Q5 is connected to the gate of the sixth switch module Q6, the collector of the fifth switch module Q5 and the drain Q6 of the sixth switch module are both connected to the first power supply module VIN, and the fourth switch module Q4 and the sixth switch module Q6 are both connected to the output end OUT of the zero-voltage difference dual-power seamless switching circuit.

[0027] As a further optional embodiment, the zero-voltage difference dual-power seamless switching circuit also includes a capacitor, the first switch module and the second switch module are both connected to the first end of the capacitor, and the fourth switch module and the sixth switch module are both connected to the second end of the capacitor.

[0028] Specifically, the emitters of the first switch module Q1 and the second switch module Q2 are connected to the first end of the capacitor C1 (100 μF), and the fourth switch module Q4 and the sixth switch module Q6 are connected to the second end of the capacitor C1 (100 μF).

[0029] As a further optional embodiment, the first switch module, the second switch module and the fifth switch module are all NPN transistors.

[0030] Specifically, the first switch module Q1 , the second switch module Q2 and the fifth switch module Q5 are all NPN transistors.

[0031] As a further optional embodiment, emitters of the first switch module, the second switch module and the fifth switch module are all grounded.

[0032] Specifically, the emitters of the first switch module Q1 , the second switch module Q2 and the fifth switch module Q5 are all connected to GND.

[0033] As a further optional embodiment, a first resistor is arranged between the base and the emitter of the first switch module.

[0034] Specifically, a first resistor R2 (10 kΩ) is provided between the base and the emitter of the first switch module Q1 .

[0035] As a further optional embodiment, a second resistor is arranged between the base and the emitter of the second switch module.

[0036] Specifically, a second resistor R4 (10 kΩ) is provided between the base and the emitter of the second switch module Q2 .

[0037] As a further optional embodiment, the third switch module, the fourth switch module and the sixth switch module are all PMOS tubes.

[0038] Specifically, the third switch module Q3 , the fourth switch module Q4 and the sixth switch module Q6 are all PMOS tubes.

[0039] As a further optional embodiment, the source of the third switch module is connected to the second power supply module.

[0040] As a further optional embodiment, a third resistor is arranged between the gate and the source of the sixth switch module.

[0041] Specifically, a third resistor R8 (10 kΩ) is provided between the gate and the source of the sixth switch module Q6 .

[0042] As a further optional embodiment, the third switch module, the fourth switch module and the sixth switch module are all provided with parasitic diodes.

[0043] Specifically, the third switch module Q3 , the fourth switch module Q4 and the sixth switch module Q6 are all provided with parasitic diodes.

[0044] In combination with the above embodiments, the working principle of the present invention is described as follows:

[0045] When only the first power supply module VIN is powered on, the current passes through R1 to supply power to the base of the first switch module Q1. At this time, the base and collector pins of the first switch module Q1 are at a high level, and this transistor is an NPN transistor, causing the first switch module Q1 to be in a conducting state. Because the first switch module Q1 is in a conducting state, the base and collector of the second switch module Q2 are in a low level state, so the second switch module Q2 is cut off. When the first power supply module VIN is powered, the current flows from the drain to the source through the parasitic diode of the sixth switch module Q6MOS tube and reaches the output end. At this time, the first power supply module VIN flows to the base of the fifth switch module Q5 of the NPN transistor through R10 at the same time, which makes the base and collector pins of the fifth switch module Q5 at a high level. The fifth switch module Q5 is in a conducting state, and the gate of the sixth switch module Q6 is pulled down to GND. At this time, the gate-source voltage of the sixth switch module Q6 is less than 0 and reaches the conduction threshold level, the sixth switch module Q6 is turned on, and then the parasitic diode in the sixth switch module Q6 is turned off, and the first power supply module reaches the output terminal OUT through the sixth switch module Q6. At this time, the gate-source voltage of the Q4MOS tube is almost equal, and the fourth switch module Q4 and the parasitic diode are both turned off, preventing the first power supply module from backflowing to the second power supply module.

[0046] When the first power supply module is not powered on and only the second power supply module is powered on, the base and collector pins of the first NPN transistor switch module Q1 are at a low level, and the first switch module Q1 is turned off. The second power supply module is connected to the base of the second NPN transistor switch module Q2 through R3. At this time, the base and collector pins of the second switch module Q2 are at a high level, the second switch module Q2 is turned on, the gate voltage of the third switch module Q3 is at a low level, the gate-source voltage is less than 0 and reaches the turn-on threshold level, the third switch module Q3 is turned on, and then reaches the output terminal OUT through the parasitic diode of the fourth switch module Q4, and the gate of the fourth switch module Q4 is at a low level at this time, so the gate-source voltage is also less than 0, the fourth switch module Q4 is turned on, its parasitic diode is turned off, and the battery voltage reaches the output terminal OUT.

[0047] When the first power supply module and the second power supply module are powered on at the same time, the first power supply module has the highest priority. Because when the first power supply module is powered on, the gate voltage of the fourth switch module Q4 is at a high level, the gate-source voltage is nearly equal, and the fourth switch module Q4 and the parasitic diode are both cut off. At this time, the second power supply module cannot flow to OUT through the fourth switch module Q4.

[0048] When the two power supplies are switching, there will be a moment when the device is temporarily without power supply. At this time, R10 can speed up the conduction speed of the fifth switch module Q5. At the same time, capacitor C1 has an energy storage function and can supply power to the device at the moment of power switching (the size of the capacitor is determined by the rear load).

[0049] Compared with diodes, the three MOS tubes used in the main power supply path show a significant low voltage difference advantage when fully turned on, with a value of only a few tenths of a volt, close to 0. This is significantly lower than that of diodes, which makes the conduction loss of the circuit extremely low.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A zero-voltage-difference dual-power seamless switching circuit, characterized in that: include: A first power supply module, a second power supply module, a first switch module, a second switch module, a third switch module, a fourth switch module, a fifth switch module and a sixth switch module; The first power supply module is connected to the input end of the first switch module, the output end of the first switch module and the second power supply module are both connected to the input end of the second switch module, the output end of the second switch module and the second power supply module are both connected to the input end of the third switch module, the output end of the third switch module is connected to the output end of the fourth switch module, the input end of the fourth switch module is connected to the input end of the fifth switch module, the output end of the fifth switch module is connected to the input end of the sixth switch module, the output end of the fifth switch module and the output end of the sixth switch module are both connected to the first power supply module, and the fourth switch module and the sixth switch module are both connected to the output end of the zero-voltage difference dual power supply seamless switching circuit.

2. The zero-voltage-difference dual-power seamless switching circuit according to claim 1, characterized in that: The zero-voltage-difference dual-power seamless switching circuit also includes a capacitor, the first switch module and the second switch module are both connected to the first end of the capacitor, and the fourth switch module and the sixth switch module are both connected to the second end of the capacitor.

3. The zero-voltage-difference dual-power seamless switching circuit according to claim 1, characterized in that: The first switch module, the second switch module and the fifth switch module are all NPN transistors.

4. The zero-voltage-difference dual-power seamless switching circuit according to claim 3, characterized in that: The emitters of the first switch module, the second switch module and the fifth switch module are all grounded.

5. The zero-voltage-difference dual-power seamless switching circuit according to claim 4, characterized in that: A first resistor is arranged between the base and the emitter of the first switch module.

6. The zero-voltage-difference dual-power seamless switching circuit according to claim 5, characterized in that: A second resistor is arranged between the base and the emitter of the second switch module.

7. The zero-voltage-difference dual-power seamless switching circuit according to claim 1, characterized in that: The third switch module, the fourth switch module and the sixth switch module are all PMOS tubes.

8. The zero-voltage-difference dual-power seamless switching circuit according to claim 7, characterized in that: A source of the third switch module is connected to the second power supply module.

9. The zero-voltage-difference dual-power seamless switching circuit according to claim 8, characterized in that: A third resistor is arranged between the gate and the source of the sixth switch module.

10. The zero-voltage-difference dual-power seamless switching circuit according to claim 9, characterized in that: The third switch module, the fourth switch module and the sixth switch module are all provided with parasitic diodes.

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