Power supply switching circuit of encoder

Abstract

The utility model discloses an encoder power supply switching circuit, which comprises a first switching circuit, a second switching circuit and a power supply output end, and is characterized in that the first switching circuit is arranged between an encoder power supply and the power supply output end, the first switching circuit comprises a first Nmos transistor and a third Pmos transistor, the third Pmos transistor is connected between the encoder power supply and the power supply output end, and the second Nmos transistor is connected between the second Nmos transistor and the third Pmos transistor. The grid electrode of the third Pmos tube is grounded through the first Nmos tube, the grid electrode of the first Nmos tube is connected with an encoder power supply, and the grid electrode of the third Pmos tube is also connected with the power supply output end; and the second switch circuit is arranged between the encoder battery and the power supply output end, the second switch circuit comprises a first Pmos tube, and a grid electrode of the first Pmos tube is connected with the encoder power supply. The power supply switching circuit has the advantages that automatic switching of the power supply of the encoder is realized, the problem of power supply voltage drop is solved, and the power supply switching circuit has smaller voltage drop.

Description

Technical Field

[0001] This application relates to the field of encoder technology, and in particular to an encoder power switching circuit. Background Technology

[0002] Currently, encoders are becoming increasingly important in the field of servo systems, and electronic multi-turn encoders based on the magnetic switch principle are an important type of encoder. This type of electronic multi-turn encoder mainly has two power supply methods: when the driver is powered, the electronic multi-turn section is powered by the driver's power supply side; when the driver is powered off, the electronic multi-turn section is powered by an external battery.

[0003] Currently, the main power switching methods used are, such as Figure 1 As shown, the switching between power and battery is accomplished using two diodes. However, this switching method has the following problems:

[0004] 1. Voltage drop problem: Whether it is the power supply on the driver side or the battery side, there is a voltage drop problem after passing through the diode. In actual use, such voltage drop loss often leads to insufficient input voltage supply.

[0005] 2. Reverse current issue: Most batteries cannot accept direct current flow. For safety reasons, it is not recommended to use this method for automatic switching between batteries and power sources. Summary of the Invention

[0006] This application provides an encoder power switching circuit, which has the advantages of realizing automatic switching of encoder power supply, solving the power supply voltage drop problem, and the power switching circuit has a smaller voltage drop.

[0007] The above-mentioned objective of this application is achieved through the following technical solution: an encoder power switching circuit, comprising a first switching circuit, a second switching circuit, and a power output terminal, wherein:

[0008] The first switching circuit is set between the encoder power supply and the power output terminal. The first switching circuit includes a first N-MOSFET and a third P-MOSFET. The third P-MOSFET is connected between the encoder power supply and the power output terminal. The gate of the third P-MOSFET is grounded through the first N-MOSFET. The gate of the first N-MOSFET is connected to the encoder power supply. The gate of the third P-MOSFET is also connected to the power output terminal.

[0009] The second switching circuit is located between the encoder battery and the power output terminal. The second switching circuit includes a first PMOS transistor. The encoder battery is connected to the drain of the first PMOS transistor, the power output terminal is connected to the source of the first PMOS transistor, and the gate of the first PMOS transistor is connected to the encoder power supply.

[0010] When the encoder is powered on, the first switch circuit is turned on and the second switch circuit is turned off; when the encoder is powered off, the first switch circuit is turned off and the second switch circuit is turned on.

[0011] Furthermore, in the first switching circuit, the gate of the third PMOS transistor is connected to the power output terminal through a first resistor.

[0012] Furthermore, the gate of the first PMOS transistor is connected to a resistor R7, and the other end of the resistor R7 is grounded.

[0013] In summary, the beneficial effects of this application are: by combining MOSFETs, the voltage drop problem caused by diode switching can be solved, the operating voltage of the load end can be increased when the encoder power supply and encoder battery are powered, and zero voltage drop can be achieved when the encoder power supply and encoder battery are powered. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an existing coded power switching method;

[0015] Figure 2 This is a schematic diagram of the circuit principle of an embodiment of this application. Detailed Implementation

[0016] The specific embodiments of this application are described in detail below with reference to the accompanying drawings.

[0017] Example 1: An encoder power switching circuit includes a first switching circuit, a second switching circuit, and a power output terminal, wherein: the first switching circuit is disposed between the encoder power supply and the power output terminal, and the second switching circuit is disposed between the encoder battery and the power output terminal; when the encoder power supply is on, the first switching circuit is turned on and the second switching circuit is turned off; when the encoder power supply is off, the first switching circuit is turned off and the second switching circuit is turned on.

[0018] It should be noted that in this application, encoder power supply refers to the power provided by the encoder driver, while encoder battery refers to the external battery in the encoder.

[0019] refer to Figure 2 The first switching circuit includes a first NMOS transistor Q6 and a third PMOS transistor Q4. The third PMOS transistor Q4 is connected between the encoder power supply and the power output terminal. The gate of the third PMOS transistor Q4 is grounded through the first NMOS transistor Q6. The gate of the first NMOS transistor Q6 is connected to the encoder power supply, and the gate of the third PMOS transistor Q4 is also connected to the power output terminal. The gate of the third PMOS transistor is connected to the power output terminal through a first resistor R9.

[0020] The second switching circuit includes a first PMOS transistor Q1, whose gate is connected to the encoder power supply. The encoder battery is connected to the drain of the first PMOS transistor Q1, and the power output terminal is connected to the source of the first PMOS transistor Q1. The gate of the first PMOS transistor Q1 is connected to the encoder power supply. A resistor R7 is connected to the gate of the first PMOS transistor, and the other end of the resistor R7 is grounded. The resistor R7 is selected with a large resistance value, such as 10K ohms, to control the voltage of the gate of the first PMOS transistor Q1 to a high voltage state when the encoder power supply is on, thus preventing the first PMOS transistor Q1 from conducting.

[0021] In this scheme, when the encoder power supply is on, the first NMOS transistor Q6 is turned on, the first PMOS transistor Q5 is turned off, and the third PMOS transistor Q4 is turned on. At this time, the encoder power supply P5V achieves zero voltage drop at the load end. When the power supply is turned off, Q6 is turned off, Q4 is turned off, and Q5 is turned on. At this time, the encoder battery BAT achieves zero voltage drop at the load end.

[0022] Furthermore, the first switching circuit also includes a fourth PMOS transistor and / or a fourth diode, wherein the fourth PMOS transistor or the fourth diode is connected in parallel with the third PMOS transistor, and the fourth PMOS transistor and the third PMOS transistor are in opposite directions, and the gates of the fourth PMOS transistor and the third PMOS transistor are connected to each other.

[0023] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of this application, and these all fall within the protection scope of this application.

Claims

1. An encoder power switching circuit, characterized by, It includes a first switching circuit, a second switching circuit, and a power output terminal, wherein: The first switching circuit is set between the encoder power supply and the power output terminal. The first switching circuit includes a first N-MOSFET and a third P-MOSFET. The third P-MOSFET is connected between the encoder power supply and the power output terminal. The gate of the third P-MOSFET is grounded through the first N-MOSFET. The gate of the first N-MOSFET is connected to the encoder power supply. The gate of the third P-MOSFET is also connected to the power output terminal. The second switching circuit is located between the encoder battery and the power output terminal. The second switching circuit includes a first PMOS transistor. The encoder battery is connected to the drain of the first PMOS transistor, the power output terminal is connected to the source of the first PMOS transistor, and the gate of the first PMOS transistor is connected to the encoder power supply. When the encoder is powered on, the first switch circuit is turned on and the second switch circuit is turned off; when the encoder is powered off, the first switch circuit is turned off and the second switch circuit is turned on.

2. The encoder power supply switching circuit of claim 1, wherein, In the first switching circuit, the gate of the third PMOS transistor is connected to the power output terminal through a first resistor.

3. The encoder power supply switching circuit of claim 1, wherein, The gate of the first PMOS transistor is connected to a resistor R7, and the other end of the resistor R7 is grounded.

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