CN-224216774-U - MOS tube current sampling circuit and electronic equipment

Abstract

The utility model discloses a MOS tube current sampling circuit and electronic equipment, and relates to the technical field of MOS tube current sampling, wherein the circuit comprises a grid voltage adjusting circuit, a mirror image MOS tube and a first resistor; the first end of the grid voltage adjusting circuit is connected with the grid of the main MOS tube, the second end of the grid voltage adjusting circuit is connected with the grid of the mirror image MOS tube, the source electrode of the mirror image MOS tube and the source electrode of the main MOS tube are connected with source electrode voltage, the drain electrode of the mirror image MOS tube is connected with the first end of the first resistor, and the second end of the first resistor and the drain electrode of the main MOS tube are connected with drain electrode voltage. Therefore, the grid voltage of the main MOS tube and the grid voltage of the mirror image MOS tube are changed through the grid voltage adjusting circuit to adjust the mirror image proportion, so that the mirror image proportion is adjusted in a high-precision and wide-range mode by using one mirror image MOS tube, and the economy is good.

Inventors

• YAN XIANWEI
• ZHAO ZHENG
• CUI KEYU

Assignees

• 杭州瑞盟科技股份有限公司

Dates

Publication Date

20260508

Application Date

20250507

Claims (10)

1. 1. The MOS tube current sampling circuit is characterized by comprising a grid voltage adjusting circuit, a mirror image MOS tube and a first resistor; The first end of the grid voltage adjusting circuit is connected with the grid of the main MOS tube, the second end of the grid voltage adjusting circuit is connected with the grid of the mirror image MOS tube, and the grid voltage adjusting circuit is used for outputting the adjustable grid voltage of the main MOS tube and the adjustable grid voltage of the mirror image MOS tube; The source electrode of the mirror image MOS tube and the source electrode of the main MOS tube are connected with source voltage, and the drain electrode of the mirror image MOS tube is connected with the first end of the first resistor; and the second end of the first resistor and the drain electrode of the main MOS tube are connected to drain voltage.
2. 2. The MOS transistor current sampling circuit of claim 1, wherein the gate voltage adjustment circuit comprises a first current source, a second current source, a third current source, a fourth current source, and a second resistor; The negative electrode of the first current source and the negative electrode of the third current source are connected with power supply voltage, and the common end of the positive electrode of the first current source, the negative electrode of the second current source and the first end of the second resistor is used as the first end of the grid voltage adjusting circuit to be connected with the grid of the main MOS tube; The positive electrode of the third current source, the negative electrode of the fourth current source and the second end common end of the second resistor are used as the second end of the grid voltage adjusting circuit to be connected with the grid of the mirror image MOS tube; the positive electrode of the second current source and the positive electrode of the fourth current source are grounded.
3. 3. The MOS transistor current sampling circuit of claim 2, wherein the second resistor is a resistance-adjustable resistor, and/or the first current source, the second current source, the third current source, and the fourth current source are adjustable current sources.
4. 4. The MOS transistor current sampling circuit of claim 3, wherein the resistance-adjustable resistor comprises N parallel resistor branches; each of the resistor branches includes a series connection of a sub-resistor and a switch.
5. 5. The MOS transistor current sampling circuit of claim 3, wherein the adjustable current source comprises N parallel current source branches; each current source branch comprises a sub-current source and a switch connected in series.
6. 6. The MOS transistor current sampling circuit of claim 1, wherein the main MOS transistor and the mirror MOS transistor are both NMOS transistors or both PMOS transistors.
7. 7. The MOS transistor current sampling circuit of claim 1, further comprising an amplifier, an AD converter, and a processor; The input end of the amplifier is connected with the first resistor and is used for amplifying the voltage at two ends of the first resistor to obtain amplified voltage; The input end of the AD converter is connected with the output end of the amplifier, the output end of the AD converter is connected with the processor, and the AD converter is used for converting the amplified voltage from analog quantity to digital quantity; The processor is used for processing the amplified digital voltage to obtain the current of the main MOS tube.
8. 8. The MOS transistor current sampling circuit of claim 7, further comprising a filter module, a first end of the filter module being connected to the output of the amplifier, a second end of the filter module being connected to the input of the AD converter for filtering the amplified voltage.
9. 9. The MOS transistor current sampling circuit of any one of claims 1 to 8, further comprising a temperature sensor disposed around the mirrored MOS transistor for acquiring an ambient temperature of the mirrored MOS transistor so that a processor corrects a current of the main MOS transistor based on a voltage across the first resistor by the ambient temperature.
10. 10. An electronic device, comprising a main MOS transistor, and further comprising a MOS transistor current sampling circuit according to any one of claims 1 to 9.

Description

MOS tube current sampling circuit and electronic equipment Technical Field The utility model relates to the technical field of MOS tube current sampling, in particular to a MOS tube current sampling circuit and electronic equipment. Background The MOS tube is a switching device commonly used in power supply products, the MOS is an abbreviation of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, metal-Oxide semiconductor field effect transistor), and sampling of current flowing in the MOS tube is a precondition for completing closed-loop control and reliability design of the power supply products. The conventional MOS tube current sampling method comprises a first method of adopting a first resistor to be connected in series with the MOS tube and obtaining the current of the MOS tube through the voltage of the first resistor, wherein the first MOS tube current sampling circuit is shown in fig. 1, a second method of adopting a main MOS tube to be connected in parallel with a mirror image MOS tube, adopting the first resistor to be connected in series with the mirror image MOS tube and obtaining the current of the main MOS tube through detecting the current of the mirror image MOS tube, and a second MOS tube current sampling circuit is shown in fig. 2. However, in the first current sampling method, the first resistor can pass a large current to cause the power loss to be increased, and in the second current sampling method, the power loss is small, but the detection accuracy is affected by the proportion of the electric images. Because the MOS tubes have process deviation, the mirror image proportion needs to be repaired and adjusted, in the prior art, by arranging a plurality of mirror image MOS tubes, the mirror image MOS tubes are respectively connected with a plurality of switch tubes in series in a one-to-one correspondence manner, and the switch tubes are respectively opened, so that different current mirror image proportions can be set, and a second MOS tube current sampling circuit with a repair and adjustment circuit is shown in FIG. 3. However, by using the trimming mode of the current mirror proportion, trimming precision is limited by the minimum channel width and the minimum channel length of the MOS tube, and trimming range is limited by the layout area of the mirror MOS tube. The larger the trimming range is, the more mirror image MOS transistors are needed, the larger the layout area of the mirror image MOS transistors is, and the economy is poor. Disclosure of utility model The utility model aims to provide a MOS tube current sampling circuit and electronic equipment, which can change the grid voltage of a main MOS tube and the grid voltage of a mirror image MOS tube through a grid voltage adjusting circuit so as to adjust the mirror image proportion, thereby realizing high-precision and wide-range trimming of the mirror image proportion by using one mirror image MOS tube and having good economy. The utility model discloses a MOS tube current sampling circuit, which comprises a grid voltage adjusting circuit, a mirror image MOS tube and a first resistor, wherein the grid voltage adjusting circuit is connected with the mirror image MOS tube; The first end of the grid voltage adjusting circuit is connected with the grid of the main MOS tube, the second end of the grid voltage adjusting circuit is connected with the grid of the mirror image MOS tube, and the grid voltage adjusting circuit is used for outputting the adjustable grid voltage of the main MOS tube and the adjustable grid voltage of the mirror image MOS tube; The source electrode of the mirror image MOS tube and the source electrode of the main MOS tube are connected with source voltage, and the drain electrode of the mirror image MOS tube is connected with the first end of the first resistor; and the second end of the first resistor and the drain electrode of the main MOS tube are connected to drain voltage. Optionally, the gate voltage adjustment circuit includes a first current source, a second current source, a third current source, a fourth current source, and a second resistor; The negative electrode of the first current source and the negative electrode of the third current source are connected with power supply voltage, and the common end of the positive electrode of the first current source, the negative electrode of the second current source and the first end of the second resistor is used as the first end of the grid voltage adjusting circuit to be connected with the grid of the main MOS tube; The positive electrode of the third current source, the negative electrode of the fourth current source and the second end common end of the second resistor are used as the second end of the grid voltage adjusting circuit to be connected with the grid of the mirror image MOS tube; the positive electrode of the second current source and the positive electrode of the fourth current source are grounded. Optionally, the second