Open-loop output power supply and electronic device

Abstract

The application provides an open-loop output power supply and electronic equipment, which receives an input voltage through a first end of a first resistor; a cathode of a Zener diode is coupled to a second end of the first resistor; a first end and a second end of a second resistor are coupled to an anode of the Zener diode and receive the input voltage respectively; a control end of an output MOS tube is coupled to the second end of the first resistor and the cathode of the Zener diode, and a first end and a second end of the output MOS tube receive the input voltage and an output voltage of the output power supply respectively. A first end of a low-voltage stabilizing module receives the input voltage, a second end of the low-voltage stabilizing module is coupled to the second end of the first resistor and the cathode of the Zener diode, a third end of the low-voltage stabilizing module is coupled to the second end of the second resistor, and the low-voltage stabilizing module injects a current of a branch in which the second resistor is located into the Zener diode. Therefore, the stability and reliability of the breakdown voltage of the Zener diode are improved, and the stability of the output voltage of the power supply is improved.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to an open-loop output power supply and electronic device. Background Technology

[0002] The open-loop output power supply uses a resistor and a Zener diode connected in series. The output voltage provided by the open-loop output power supply utilizes the reverse breakdown characteristic of the Zener diode, which is more stable than the output voltage provided by the traditional closed-loop power supply circuit.

[0003] However, in actual manufacturing processes, due to fluctuations in the fabrication processes of some Zener diode manufacturers, the reverse breakdown voltage characteristics of Zener diodes are difficult to maintain a high degree of consistency. Especially in operating modes where the input voltage is low, resulting in a smaller reverse breakdown current, the actual breakdown voltage of the Zener diode may drop significantly, deviating from the design target voltage characteristic curve of the Zener diode beyond the safety limit, thus leading to unstable power supply output voltage in the open-loop output power supply. Summary of the Invention

[0004] This invention provides an open-loop output power supply and electronic device that improves the stability and reliability of the Zener diode breakdown voltage, thereby improving the stability of the power supply output voltage.

[0005] According to a first aspect of the present invention, the present invention provides an open-loop output power supply, comprising: A first resistor, the first terminal of which receives the input voltage; A Zener diode, wherein the cathode of the Zener diode is coupled to the second terminal of the first resistor, and the anode of the Zener diode is grounded; A second resistor, the first end of which is coupled to the anode of the Zener diode; A low-voltage regulator module, wherein a first terminal of the low-voltage regulator module receives the input voltage, a second terminal of the low-voltage regulator module is coupled to a second terminal of a first resistor and a cathode of a Zener diode, a second terminal of a second resistor is coupled to a third terminal of the low-voltage regulator module, and the low-voltage regulator module is used to inject the current of the branch containing the second resistor into the Zener diode; An output MOSFET is provided, the control terminal of which is coupled to the second terminal of the first resistor and the cathode of the Zener diode. The first terminal of the output MOSFET receives the input voltage, and the second terminal of the output MOSFET outputs the power supply output voltage.

[0006] Optionally, the low-voltage regulator module includes: A current mirror module, wherein a first terminal of the current mirror module receives the input voltage, a second terminal of the current mirror module is coupled to the cathode of the Zener diode, and a third terminal of the current mirror module is coupled to the first terminal of a second resistor, and the current mirror module is used to copy the current of the branch where the second resistor is located and inject it into the cathode of the Zener diode. The first MOSFET has its first terminal coupled to the third terminal of the current mirror module, its second terminal coupled to the first terminal of the second resistor, and its control terminal coupled to the cathode of the Zener diode and the second terminal of the first resistor.

[0007] Optionally, the current in the branch containing the second resistor is: I = (Vd1 - Vgs) / R2, where I is the current in the branch containing the second resistor, Vd1 is the voltage across the Zener diode, Vgs is the gate-source voltage of the first MOSFET, and R2 is the resistance value of the second resistor.

[0008] Optionally, the power supply output voltage is: V = Vd1 - Vgs, where V is the power supply output voltage.

[0009] Optionally, the current mirror module includes: The second MOSFET has a first terminal that receives the input voltage, a second terminal that is coupled to the second terminal of the first resistor and the cathode of the Zener diode, and a control terminal that is coupled to the first terminal of the first MOSFET. The third MOSFET has a first terminal that receives the input voltage, a second terminal that is coupled to the first terminal of the first MOSFET, and a control terminal that is coupled to the control terminal of the second MOSFET.

[0010] According to a second aspect of the present invention, the present invention also provides an electronic device comprising an open-loop output power supply as described above.

[0011] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects: In the open-loop output power supply and electronic device of this invention, the first terminal of the first resistor receives the input voltage; the cathode of the Zener diode is coupled to the second terminal of the first resistor, and the anode of the Zener diode is grounded; the first terminal of the second resistor is coupled to the anode of the Zener diode, and the second terminal of the second resistor receives the input voltage; the control terminal of the output MOSFET is coupled to the second terminal of the first resistor and the cathode of the Zener diode, the first terminal of the output MOSFET receives the input voltage, and the second terminal of the output MOSFET outputs the power supply output voltage. Therefore, an open-loop output power supply with no startup risk is formed. Furthermore, since the first terminal of the low-voltage regulator module receives the input voltage, the second terminal of the low-voltage regulator module is coupled to the second terminal of the first resistor and the cathode of the Zener diode, and the third terminal of the low-voltage regulator module is coupled to the second terminal of the second resistor, the low-voltage regulator module is used to inject the current in the branch containing the second resistor into the Zener diode. Therefore, by controlling the current in the branch containing the second resistor, the breakdown current of the Zener diode is ensured to be greater than a certain current value, improving the stability and reliability of the Zener diode breakdown voltage, thereby improving the stability of the power supply output voltage. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of an open-loop output power supply according to an embodiment of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of an open-loop output power supply according to an embodiment of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the structure of an open-loop output power supply according to an embodiment of the present invention. Figure 3 . Detailed Implementation

[0014] As described in the background section, the present invention aims to solve the technical problem of suppressing the instability of power supply output voltage in open-loop output.

[0015] In view of this, the present invention proposes an open-loop output power supply. The input voltage is received through the first terminal of the first resistor; the cathode of the Zener diode is coupled to the second terminal of the first resistor, and the anode of the Zener diode is grounded; the first terminal of the second resistor is coupled to the anode of the Zener diode, and the second terminal of the second resistor receives the input voltage; the control terminal of the output MOSFET is coupled to the second terminal of the first resistor and the cathode of the Zener diode, the first terminal of the output MOSFET receives the input voltage, and the second terminal of the output MOSFET outputs the power supply output voltage. Therefore, an open-loop output power supply with no startup risk is formed. Furthermore, since the first terminal of the low-voltage regulator module receives the input voltage, the second terminal of the low-voltage regulator module is coupled to the second terminal of the first resistor and the cathode of the Zener diode, and the third terminal of the low-voltage regulator module is coupled to the second terminal of the second resistor, the low-voltage regulator module is used to inject the current in the branch containing the second resistor into the Zener diode. Therefore, by controlling the current in the branch containing the second resistor, the breakdown current of the Zener diode is ensured to be greater than a certain current value, improving the stability and reliability of the Zener diode breakdown voltage, thereby improving the stability of the power supply output voltage.

[0016] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a 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.

[0017] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0018] Please refer to Figure 1 An embodiment of the present invention provides an open-loop output power supply, which may include: a first resistor R1, a Zener diode D1, a second resistor R2, a low-voltage regulator module 100, and an output MOSFET M.

[0019] The first terminal of the first resistor R1 receives the input voltage PVIN.

[0020] The cathode of Zener diode D1 is coupled to the second end of the first resistor R1, and the anode of Zener diode D1 is grounded.

[0021] The first end of the second resistor R2 is coupled to the anode of the Zener diode D1.

[0022] The first terminal of the low-voltage regulator module 100 receives the input voltage PVIN. The second terminal of the low-voltage regulator module 100 is coupled to the second terminal of the first resistor R1 and the cathode of the Zener diode D1. The second terminal of the second resistor R2 is coupled to the third terminal of the low-voltage regulator module 100. The low-voltage regulator module 100 is used to inject the current of the branch where the second resistor R2 is located into the Zener diode D1.

[0023] The control terminal of the output MOSFET M is coupled to the second terminal of the first resistor R1 and the cathode of the Zener diode D1. The first terminal of the output MOSFET M receives the input voltage PVIN, and the second terminal of the output MOSFET M outputs the power supply output voltage LVDD.

[0024] In this embodiment, the output MOS transistor M is a MOS transistor.

[0025] As can be seen, by controlling the current in the branch where the second resistor R2 is located, this invention ensures that the breakdown current of the Zener diode D1 is greater than a certain current value, thereby improving the stability and reliability of the breakdown voltage of the Zener diode D1, and thus improving the stability of the power supply output voltage LVDD.

[0026] For one specific implementation method, please refer to Figure 2 The low-voltage regulator module 100 includes a current mirror module 110 and a first MOSFET.

[0027] The first terminal of the current mirror module 110 receives the input voltage PVIN, and the second terminal of the current mirror module 110 is coupled to the cathode of the Zener diode D1. The current mirror module 110 is used to copy the current of the branch where the second resistor R2 is located and inject it into the cathode of the Zener diode D1.

[0028] The first terminal of the first MOSFET M1 is coupled to the third terminal of the current mirror module 110, the second terminal of the first MOSFET M1 is coupled to the first terminal of the second resistor R2, and the control terminal of the first MOSFET M1 is coupled to the cathode of the Zener diode D1 and the second terminal of the first resistor R1.

[0029] In this embodiment, the first MOS transistor M1 is a MOS transistor.

[0030] In this embodiment, the current in the branch where the second resistor R2 is located is: I=(Vd1-Vgs) / R2, where I is the current in the branch where the second resistor R2 is located, Vd1 is the voltage across Zener diode D1, Vgs is the gate-source voltage of the first MOS transistor M1, and R2 is the resistance value of the second resistor.

[0031] In this embodiment, the current mirror module injects the current of the second resistor R2 into the Zener diode D1.

[0032] In this embodiment, the power supply output voltage LVDD is: V = Vd1 - Vgs, where V is the power supply output voltage LVDD.

[0033] For one specific implementation method, please refer to Figure 3 The current mirror module 110 includes a second MOSFET M2 and a third MOSFET M3.

[0034] The first terminal of the second MOSFET M2 receives the input voltage PVIN. The second terminal of the second MOSFET M2 is coupled to the second terminal of the first resistor R1 and the cathode of the Zener diode D1. The control terminal of the second MOSFET M2 is coupled to the first terminal of the first MOSFET M1.

[0035] The first terminal of the third MOSFET M3 receives the input voltage PVIN, the second terminal of the third MOSFET M3 is coupled to the first terminal of the first MOSFET M1, and the control terminal of the third MOSFET M3 is coupled to the control terminal of the second MOSFET M2.

[0036] In this embodiment, the second MOS transistor M2 is a MOS transistor, and the third MOS transistor M3 is also a MOS transistor.

[0037] In summary, in this embodiment, the first terminal of the first resistor receives the input voltage; the cathode of the Zener diode is coupled to the second terminal of the first resistor, and the anode of the Zener diode is grounded; the first terminal of the second resistor is coupled to the anode of the Zener diode, and the second terminal of the second resistor receives the input voltage; the control terminal of the output MOSFET is coupled to the second terminal of the first resistor and the cathode of the Zener diode, the first terminal of the output MOSFET receives the input voltage, and the second terminal of the output MOSFET outputs the power supply output voltage LVDD. Therefore, an open-loop output power supply with no startup risk is formed. Furthermore, since the first terminal of the low-voltage regulator module receives the input voltage, the second terminal of the low-voltage regulator module is coupled to the second terminal of the first resistor and the cathode of the Zener diode, and the third terminal of the low-voltage regulator module is coupled to the second terminal of the second resistor, the low-voltage regulator module is used to inject the current in the branch containing the second resistor into the Zener diode. Therefore, by controlling the current in the branch containing the second resistor, the breakdown current of the Zener diode is ensured to be greater than a certain current value, improving the stability and reliability of the Zener diode breakdown voltage, thereby improving the stability of the power supply output voltage LVDD.

[0038] Accordingly, the present invention also provides an electronic device, including the open-loop output power supply as described above.

[0039] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An open-loop output power supply, characterized in that, include: A first resistor, the first terminal of which receives the input voltage; A Zener diode, wherein the cathode of the Zener diode is coupled to the second terminal of the first resistor, and the anode of the Zener diode is grounded; A second resistor, the first end of which is coupled to the anode of the Zener diode; A low-voltage regulator module, wherein a first terminal of the low-voltage regulator module receives the input voltage, a second terminal of the low-voltage regulator module is coupled to a second terminal of a first resistor and a cathode of a Zener diode, a second terminal of a second resistor is coupled to a third terminal of the low-voltage regulator module, and the low-voltage regulator module is used to inject the current of the branch containing the second resistor into the Zener diode; An output MOSFET is provided, the control terminal of which is coupled to the second terminal of the first resistor and the cathode of the Zener diode. The first terminal of the output MOSFET receives the input voltage, and the second terminal of the output MOSFET outputs the power supply output voltage.

2. The open-loop output power supply as described in claim 1, characterized in that, The low-voltage regulator module includes: A current mirror module, wherein a first terminal of the current mirror module receives the input voltage, a second terminal of the current mirror module is coupled to the cathode of the Zener diode, and a third terminal of the current mirror module is coupled to the first terminal of a second resistor, and the current mirror module is used to copy the current of the branch where the second resistor is located and inject it into the cathode of the Zener diode. The first MOSFET has its first terminal coupled to the third terminal of the current mirror module, its second terminal coupled to the first terminal of the second resistor, and its control terminal coupled to the cathode of the Zener diode and the second terminal of the first resistor.

3. The open-loop output power supply as described in claim 2, characterized in that, The current in the branch containing the second resistor is: I = (Vd1 - Vgs) / R2, where I is the current in the branch containing the second resistor, Vd1 is the voltage across the Zener diode, Vgs is the gate-source voltage of the first MOS transistor, and R2 is the resistance value of the second resistor.

4. The open-loop output power supply as described in claim 3, characterized in that, The power supply output voltage is: V = Vd1 - Vgs, where V is the power supply output voltage.

5. The open-loop output power supply as described in claim 4, characterized in that, The current mirror module includes: The second MOSFET has a first terminal that receives the input voltage, a second terminal that is coupled to the second terminal of the first resistor and the cathode of the Zener diode, and a control terminal that is coupled to the first terminal of the first MOSFET. The third MOSFET has a first terminal that receives the input voltage, a second terminal that is coupled to the first terminal of the first MOSFET, and a control terminal that is coupled to the control terminal of the second MOSFET.

6. An electronic device, characterized in that, Includes the open-loop output power supply as described in any one of claims 1-5.

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