Power supply voltage selection circuit, chip and charging device

Abstract

The present disclosure provides a power supply voltage selection circuit, a chip and a charging device. The power supply voltage selection circuit includes a first power supply, a second power supply, a circuit output terminal, a first zener diode, a second zener diode, a first diode, a first switching device, a second switching device and a third switching device. The first power supply is connected to the first diode and the first switching device. The first zener diode is connected to the second switching device, the first diode, the first switching device and the circuit output terminal. The first diode is connected to the second switching device. The second zener diode is connected to the second switching device, the circuit output terminal, the first switching device and the third switching device. The first switching device is connected to the third switching device. The second power supply is connected to the second switching device and the third switching device. The third switching device is grounded. When the voltage difference between the first power supply and the second power supply is greater than a preset voltage value, the second zener diode is broken down, realizing the performance of smooth power supply switching, high voltage resistance and no mutual leakage.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic circuits, and particularly to a power supply voltage selection circuit, a chip, and a charging device. Background Art

[0002] Lithium-ion batteries are widely used in modern electronic devices. Therefore, there is a high demand for developing charging chips that can effectively and safely charge lithium-ion batteries. USB power has become the standard power interface for many portable devices. Therefore, it is very important to design a charging chip that is compatible with the USB power specification.

[0003] In a high-voltage linear charging chip, the main objective of the high-voltage selector circuit is to select and provide the power required by the internal circuit of the chip, usually to select the higher value of the voltages from the input power supply (such as an external power adapter) and the battery terminal. This power selector circuit must be able to safely accept and process high voltages while maintaining the stable operation of the internal circuit of the chip. It must also achieve smooth power switching to avoid voltage fluctuations during power switching from causing instability or damage to the internal circuit of the chip. It also needs to be able to monitor the voltages of the input power supply and the battery terminal and compare their values to determine which power supply should be selected. Additionally, if the battery is used for power supply, the power selector circuit also needs to include a battery protection function to prevent the battery from over-discharging or being damaged otherwise.

[0004] However, in some cases, especially when the voltage is higher than a certain value, there is mutual leakage between the input power supply and the battery terminal in the existing high-voltage selector, resulting in energy waste and potential battery damage. Summary of the Invention

[0005] The technical problem to be solved by the present disclosure is to overcome the defect that there is mutual leakage between the input power supply and the battery terminal in the existing high-voltage selector, resulting in energy waste and potential battery damage. The purpose is to provide a high-voltage selection circuit without mutual leakage to avoid battery damage and energy waste, and specifically provides a power supply voltage selection circuit, a chip, and a charging device.

[0006] The present disclosure solves the above technical problem through the following technical solutions:

[0007] According to a first aspect of the present disclosure, there is provided a power supply voltage selection circuit, the power supply voltage selection circuit including a first power supply, a second power supply, a circuit output terminal, a first voltage regulator diode, a second voltage regulator diode, a first diode, a first switching device, a second switching device, and a third switching device;

[0008] The output terminal of the first power supply is respectively connected to the positive electrode of the first diode and the drain of the first switching device;

[0009] The positive electrode of the first voltage stabilizing diode is respectively connected to the gate of the second switching device and the negative electrode of the first diode;

[0010] The negative electrode of the first diode is connected to the gate of the second switching device;

[0011] The negative electrode of the first voltage stabilizing diode is respectively connected to the source and body terminal of the first switching device and the circuit output terminal;

[0012] The negative electrode of the second voltage stabilizing diode is respectively connected to the source and body terminal of the second switching device and the circuit output terminal;

[0013] The circuit output terminal is respectively connected to the source and body terminal of the first switching device and the source and body terminal of the second switching device;

[0014] The positive electrode of the second voltage stabilizing diode is respectively connected to the gate of the first switching device and the source and body terminal of the third switching device;

[0015] The gate of the first switching device is connected to the source and body terminal of the third switching device;

[0016] The output terminal of the second power supply is respectively connected to the drain of the second switching device and the gate of the third switching device;

[0017] The drain of the third switching device is grounded;

[0018] When the voltage difference between the first power supply and the second power supply is greater than a preset voltage value, the second voltage stabilizing diode is broken down.

[0019] Preferably, the power supply voltage selection circuit further includes a first resistor;

[0020] The first end of the first resistor is connected to the negative electrode of the first diode, and the second end of the first resistor is connected to the positive electrode of the first voltage stabilizing diode and the gate of the second switching device.

[0021] Preferably, the power supply voltage selection circuit further includes a second resistor;

[0022] The first end of the second resistor is connected to the gate of the first switching device and the positive electrode of the second voltage stabilizing diode, and the second end of the second resistor is connected to the source and body terminal of the third switching device.

[0023] Preferably, the power supply voltage selection circuit further includes a second diode and a fourth switching device;

[0024] The negative electrode of the second diode is respectively connected to the gate of the first switching device, the positive electrode of the second voltage stabilizing diode, the source electrode and the body terminal of the third switching device;

[0025] The positive electrode of the second diode is respectively connected to the output terminal of the second power supply and the gate of the third switching device;

[0026] The source electrode and the body terminal of the fourth switching device are connected to the negative electrode of the first diode, the positive electrode of the first voltage stabilizing diode, and the gate of the second switching device;

[0027] The gate of the fourth switching device is connected to the positive electrode of the first diode and the output terminal of the first power supply;

[0028] The drain of the fourth switching device is grounded;

[0029] When the voltage difference between the second power supply and the first power supply is greater than a preset voltage value, the first voltage stabilizing diode is broken down.

[0030] Preferably, when the power supply voltage selection circuit includes a first resistor,

[0031] The first end of the first resistor is connected to the source electrode and the body terminal of the fourth switching device.

[0032] Preferably, when the power supply voltage selection circuit includes a second resistor;

[0033] The second end of the second resistor is connected to the negative electrode of the second diode.

[0034] Preferably, the first switching device is a MOS transistor (metal oxide semiconductor field effect transistor);

[0035] And / or,

[0036] The first diode is a high-voltage diode.

[0037] Preferably, both the first switching device and the second switching device are MOS transistors;

[0038] And / or,

[0039] Both the first diode and the second diode are high-voltage diodes.

[0040] According to a second aspect of the present disclosure, there is provided a chip, and the chip includes the power supply voltage selection circuit according to the first aspect of the present disclosure.

[0041] According to a third aspect of the present disclosure, there is provided a charging device, and the charging device includes the chip according to the second aspect of the present disclosure.

[0042] The positive and progressive effects of the present disclosure are as follows: By adding a first diode and a third switching device to the power supply voltage selection circuit, the current path is changed, preventing direct leakage of the first power supply to the second power supply, so that it will not have an undesirable impact on the second power supply, thereby protecting the battery and related circuits, achieving smooth power supply switching, high voltage resistance, and no mutual leakage performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is the first circuit diagram of a conventional high-voltage selection circuit;

[0044] Figure 2 is the second circuit diagram of a conventional high-voltage selection circuit;

[0045] Figure 3 is the first circuit diagram of the power supply voltage selection circuit according to Embodiment 1 of the present disclosure;

[0046] Figure 4 is the second circuit diagram of the power supply voltage selection circuit according to Embodiment 1 of the present disclosure;

[0047] Figure 5 is the third circuit diagram of the power supply voltage selection circuit according to Embodiment 1 of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The present disclosure will be further described below by way of embodiments, but the present disclosure is not limited to the scope of the described embodiments.

[0049] The existing conventional high-voltage selection circuit, such as Figure 1 shown, this circuit involves the connection between VCC (the power supply voltage of the circuit) and BAT (lithium battery or other battery). In this case, if VCC has a relatively high voltage (high-voltage input source), it may reach BAT through a direct leakage path, which may cause damage to the battery.

[0050] For example, in some cases, as Figure 2 shown, when the VCC voltage is higher than 30V, the current may pass through R1 → D1 → D2 (reverse breakdown) → R2 → leak to BAT (see Figure 2 the arrowed curve current flow direction in). This does not meet the requirements of practical applications, because in the case of high voltage, current should not be allowed to pass directly through this path.

[0051] Similarly, if the BAT voltage is higher than a certain threshold, there may be leakage of BAT to VCC. This is also an undesirable situation, because it may cause energy waste and potential battery damage.

[0052] In view of this, the present disclosure provides a power supply voltage selection circuit, a chip, and a charging device to solve the problem that there is mutual leakage between the input power supply and the battery terminal in a high-voltage selector, resulting in energy waste and potential battery damage.

[0053] Embodiment 1

[0054] In a specific embodiment of the present disclosure, a power supply voltage selection circuit is provided. As Figure 3 shown, the power supply voltage selection circuit includes a first power supply V1, a second power supply V2, a circuit output terminal Vmax, a first voltage regulator diode D1, a second voltage regulator diode D2, a first diode D3, a first switching device M1, a second switching device M2, and a third switching device M3;

[0055] The output terminal of the first power supply V1 is respectively connected to the positive electrode of the first diode D3 and the drain (D pole) of the first switching device M1;

[0056] The positive electrode of the first voltage regulator diode D1 is respectively connected to the gate (G pole) of the second switching device M2 and the negative electrode of the first diode D3;

[0057] The negative electrode of the first diode D3 is connected to the gate (G pole) of the second switching device M2;

[0058] The negative electrode of the first voltage regulator diode D1 is respectively connected to the source and body terminal (S / B pole) of the first switching device M1 and the circuit output terminal Vmax;

[0059] The negative electrode of the second voltage regulator diode D2 is respectively connected to the source and body terminal (S / B pole) of the second switching device M2 and the circuit output terminal Vmax;

[0060] The circuit output terminal Vmax is respectively connected to the source and body terminal (S / B pole) of the first switching device M1 and the source and body terminal (S / B pole) of the second switching device M2;

[0061] The positive electrode of the second voltage regulator diode D2 is respectively connected to the gate (G pole) of the first switching device M1 and the source and body terminal (S / B pole) of the third switching device M3;

[0062] The gate (G pole) of the first switching device M1 is connected to the source and body terminal (S / B pole) of the third switching device M3;

[0063] The output terminal of the second power supply V2 is respectively connected to the drain (D pole) of the second switching device M2 and the gate (G pole) of the third switching device M3;

[0064] The drain (D pole) of the third switching device M3 is grounded;

[0065] When the voltage difference between the first power supply V1 and the second power supply V2 is greater than a preset voltage value, the second voltage regulator diode D2 is broken down.

[0066] In a specifically implementable manner, the power supply voltage selection circuit further includes a first resistor R1;

[0067] The first end of the first resistor R1 is connected to the negative electrode of the first diode D3, and the second end of the first resistor R1 is connected to the positive electrode of the first voltage regulator diode D1 and the gate (G pole) of the second switching device M2.

[0068] In a specifically implementable manner, the power supply voltage selection circuit further includes a second resistor R2;

[0069] The first end of the second resistor R2 is connected to the gate (G pole) of the first switching device M1 and the positive electrode of the second voltage regulator diode D2, and the second end of the second resistor R2 is connected to the source and body terminal (S / B pole) of the third switching device M3.

[0070] Wherein, the first power supply V1 can be VCC, then the second power supply V2 can be BAT. When the voltage difference between VCC and BAT is greater than a preset voltage value, the direct leakage between VCC and BAT is shielded by introducing new electronic components - M3 and high-voltage diode D3; or, the first power supply V1 can be BAT, then the second power supply V2 can be VCC. When the voltage difference between BAT and VCC is greater than a preset voltage value, the direct leakage between BAT and VCC is shielded by introducing new electronic components - M3 and high-voltage diode D3.

[0071] The following embodiments are all explained with the first power supply V1 being VCC and the second power supply V2 being BAT. The working principle with the first power supply V1 being BAT and the second power supply V2 being VCC is similar thereto.

[0072] Specifically, when the voltage of VCC is higher than that of BAT, M1 is turned on and M2 is turned off, thereby performing power supply switching to make VMAX equal to VCC, ensuring that the device uses electrical energy from the external power supply (VCC) and does not consume electrical energy from the battery.

[0073] Zener diodes (D1 and D2) These diodes are used for voltage regulation and protection purposes. When an unexpected peak value appears in the VCC or BAT voltage, the Zener diodes limit the gate voltage of M1 and M2 to prevent the voltage of the power supply (VCC or BAT) from exceeding their tolerance (preventing gate breakdown), ensuring that M1 and M2 are not damaged, thereby protecting the switching MOSFETs (M1 and M2).

[0074] In this embodiment, as Figure 4As shown, the direct leakage between VCC and BAT is shielded by introducing new electronic components - M3 and high-voltage diode D3. When the voltage of VCC is higher than that of BAT (for example, VCC = 30V, BAT = 4.2V), and the voltage difference between VCC and BAT is greater than the preset voltage value (for example, 6V), M1 (a switch or current controller) is in the open state. At this time, M1 is connected to VCC, and the current flows in sequence through VCC → D3 → R1 → D1 → D2 (reverse breakdown) → R2 → M4 → and finally to ground (GND) (see Figure 4 the arrowed curve current flow in

[0075] ). Through this new leakage path, the current path is changed to bypass BAT, so it will not directly affect BAT, shielding the direct leakage path from VCC to BAT, thereby protecting the battery and related circuits.

[0076] It should be noted that the preset voltage value is determined by the reverse breakdown voltage of D2.

[0077] In an implementable embodiment, as Figure 5 shown, the power supply voltage selection circuit further includes a second diode D4 and a fourth switching device M4;

[0078] The negative electrode of the second diode D4 is respectively connected to the gate (G pole) of the first switching device M1, the positive electrode of the second voltage stabilizing diode D2, the source and body terminal (S / B pole) of the third switching device M3;

[0079] The positive electrode of the second diode D4 is respectively connected to the output terminal of the second power supply V2 and the gate (G pole) of the third switching device M3;

[0080] The source and body terminal (S / B pole) of the fourth switching device M4 is connected to the negative electrode of the first diode D3, the positive electrode of the first voltage stabilizing diode D1, and the gate (G pole) of the second switching device M2;

[0081] The gate (G pole) of the fourth switching device M4 is connected to the positive electrode of the first diode D3 and the output terminal of the first power supply V1;

[0082] The drain (D pole) of the fourth switching device M4 is grounded;

[0083] When the voltage difference between the second power supply V2 and the first power supply V1 is greater than the preset voltage value, the first voltage stabilizing diode D1 is broken down.

[0084] Wherein, when the power supply voltage selection circuit includes the first resistor R1,

[0085] The first end of the first resistor R1 is connected to the source and body terminal of the fourth switching device M4.

[0086] When the power supply voltage selection circuit includes the second resistor R2;

[0087] The second end of the second resistor R2 is connected to the negative electrode of the second diode D4.

[0088] Specifically, by simultaneously introducing new electronic components - M3, M4 and high-voltage diodes D3, D4, the shielding of direct leakage from VCC to BAT and the shielding of direct leakage from BAT to VCC are realized. When the voltage of VCC is higher than that of BAT, the current passes through VCC → D3 → R1 → D1 → D2 (reverse breakdown) → R2 → M4 → and finally to ground (GND) in sequence (the specific current flow direction can be referred to Figure 4 the curve with arrows in). When BAT is higher than a certain threshold, the current passes through BAT → D4 → R2 → D2 → D1 (reverse breakdown) → R1 → M3 → and finally to ground (GND) in sequence. By introducing new leakage paths, the current path is changed, bypassing BAT when VCC is higher than BAT and bypassing VCC when BAT is higher than VCC. Therefore, it will not directly affect BAT, shielding the direct leakage paths from VCC to BAT and from BAT to VCC, thereby protecting the battery and related circuits.

[0089] In an implementable manner, both the third switching device M3 and the fourth switching device M4 are MOS transistors, and both the first diode D3 and the second diode D4 are high-voltage diodes.

[0090] Specifically, the reverse breakdown voltage withstand values of the first diode D3 and the second diode D4 need to be greater than the maximum voltage withstand value required by VCC. For example, it can be 50V. In a specific implementable manner, the first diode D3 and the second diode D4 can be the body diode of a high-voltage MOS transistor (the body diode of the MOS transistor), wherein the reverse breakdown voltage withstand value of the body diode needs to be greater than the maximum voltage withstand value required by VCC.

[0091] In this embodiment, by adding the first diode, the second diode, the third switching device and the fourth switching device in the power supply voltage selection circuit, the current path is changed, preventing direct leakage from VCC to BAT and from BAT to VCC, so that it will not have an undesirable impact on BAT, thereby protecting the battery and related circuits, and realizing the performance of smooth power supply switching, high voltage resistance and no mutual leakage.

[0092] Embodiment 2

[0093] In a specific embodiment of the present disclosure, a chip is provided, and the power supply voltage selection circuit of Embodiment 1 is included on the chip.

[0094] Specifically, the chip serves as an application carrier of the power supply voltage selection circuit of Embodiment 1 to provide a stable voltage or stable current for the backend load.

[0095] In this embodiment, by adding a first diode and a third switching device in the power supply voltage selection circuit, the current path is changed, preventing direct leakage of VCC to BAT, so that it will not have an undesirable impact on BAT, thereby protecting the battery and related circuits, and realizing the performance of smooth power supply switching, high voltage resistance, and no mutual leakage.

[0096] Embodiment 3

[0097] In a specific embodiment of the present disclosure, a charging device is provided, and the chip of Embodiment 2 is included in the charging device.

[0098] In this embodiment, by adding a first diode and a third switching device in the power supply voltage selection circuit, the current path is changed, preventing direct leakage of VCC to BAT, so that it will not have an undesirable impact on BAT, thereby protecting the battery and related circuits, and realizing the performance of smooth power supply switching, high voltage resistance, and no mutual leakage.

[0099] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only for illustration purposes. The protection scope of the present disclosure is defined by the appended claims. Without departing from the principles and essence of the present disclosure, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A power supply voltage selection circuit, characterized in that, The power supply voltage selection circuit includes a first power supply, a second power supply, a circuit output terminal, a first zener diode, a second zener diode, a first diode, a first switching device, a second switching device, and a third switching device; The output terminal of the first power supply is respectively connected to the positive electrode of the first diode and the drain of the first switching device; The positive electrode of the first zener diode is respectively connected to the gate of the second switching device and the negative electrode of the first diode; The negative electrode of the first diode is connected to the gate of the second switching device; The negative electrode of the first zener diode is respectively connected to the source and body terminal of the first switching device and the circuit output terminal; The negative electrode of the second zener diode is respectively connected to the source and body terminal of the second switching device and the circuit output terminal; The circuit output terminal is respectively connected to the source and body terminal of the first switching device and the source and body terminal of the second switching device; The positive electrode of the second zener diode is respectively connected to the gate of the first switching device and the source and body terminal of the third switching device; The gate of the first switching device is connected to the source and body terminal of the third switching device; The output terminal of the second power supply is respectively connected to the drain of the second switching device and the gate of the third switching device; The drain of the third switching device is grounded; When the voltage difference between the first power supply and the second power supply is greater than a preset voltage value, the second zener diode is broken down, where the voltage of the first power supply is higher than that of the second power supply.

2. The power supply voltage selection circuit according to claim 1, wherein The power supply voltage selection circuit further includes a first resistor; The first end of the first resistor is connected to the negative electrode of the first diode, and the second end of the first resistor is connected to the positive electrode of the first zener diode and the gate of the second switching device.

3. The power supply voltage selection circuit according to claim 1, characterized in that, The power supply voltage selection circuit further includes a second resistor; The first end of the second resistor is connected to the gate of the first switching device and the positive electrode of the second zener diode, and the second end of the second resistor is connected to the source and body terminal of the third switching device.

4. The power supply voltage selection circuit according to any one of claims 1 to 3, characterized in that The power supply voltage selection circuit further includes a second diode and a fourth switching device; The negative electrode of the second diode is respectively connected to the gate of the first switching device, the positive electrode of the second zener diode, and the source and body terminal of the third switching device; The positive electrode of the second diode is respectively connected to the output terminal of the second power supply and the gate of the third switching device; The source and body terminal of the fourth switching device is connected to the negative electrode of the first diode, the positive electrode of the first zener diode, and the gate of the second switching device; The gate of the fourth switching device is connected to the positive electrode of the first diode and the output terminal of the first power supply; The drain of the fourth switching device is grounded; When the voltage difference between the second power supply and the first power supply is greater than a preset voltage value, the first zener diode is broken down.

5. The power supply voltage selection circuit according to claim 4, wherein When the power supply voltage selection circuit includes a first resistor, The first end of the first resistor is connected to the source and body terminal of the fourth switching device.

6. The power supply voltage selection circuit according to claim 4, wherein When the power supply voltage selection circuit includes a second resistor; The second end of the second resistor is connected to the negative electrode of the second diode.

7. The power supply voltage selection circuit according to any one of claims 1 to 3, characterized in that, The first switching device is a MOS transistor; and / or, The first diode is a high-voltage diode.

8. The power supply voltage selection circuit according to claim 4, wherein Both the first switching device and the second switching device are MOS transistors; and / or, Both the first diode and the second diode are high-voltage diodes.

9. A chip, characterized in that, The chip includes the power supply voltage selection circuit according to any one of claims 1 to 8.

10. A charging device, characterized in that, The charging device includes the chip according to claim 9.

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