CN-121978383-A - High-voltage side current detection circuit and system based on potential translation

CN121978383ACN 121978383 ACN121978383 ACN 121978383ACN-121978383-A

Abstract

The invention relates to the technical field of electronic measurement, in particular to a high-voltage side current detection circuit and a system based on potential translation, which can utilize a current mirror to translate high common-mode voltage born by two ends of a sampling resistor into a safe low common-mode voltage domain without distortion, so that a subsequent signal extraction and amplification module does not need to bear the high common-mode voltage directly, thereby breaking through the withstand voltage limit of a traditional special detection chip, realizing the withstand capability of hundreds of volts or even higher common-mode voltage only by selecting an external resistor with proper withstand voltage level, avoiding adopting a special current detection and amplification chip with high manufacturing cost, and remarkably reducing the circuit cost. In addition, because the influence of transistor parameter drift in the current mirror of the potential translation module appears in a common mode form in a differential signal path, the influence can be effectively restrained by a signal extraction and amplification module with a follow-up high common mode restraining ratio, and therefore the high withstand voltage is realized, and meanwhile, the detection precision and the temperature stability of the whole system are ensured.

Inventors

XU YOULIAN
LI GANNIAN
YANG XIN
HU CHANGYUAN
Ruan Yongquan

Assignees

上海军陶科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260209

Claims (10)

1. The high-voltage side current detection circuit based on potential translation is characterized by comprising a sampling resistor, a potential translation module and a signal extraction and amplification module, wherein: the sampling resistor is arranged on the high-voltage side between the external power supply and the external load; The potential translation module is used for potential translation of sampling voltages at two ends of the sampling resistor to a second input end and a first input end of the signal extraction and amplification module through a current mirror principle; The signal extraction and amplification module is used for extracting and amplifying potential signals received by the second input end and the first input end, so as to obtain output voltage, and detecting current according to the output voltage.
2. The high-side current detection circuit based on potential shifting of claim 1, wherein the potential shifting module comprises a first resistor, a second resistor, a third resistor, a first NPN transistor, a second NPN transistor, and a third NPN transistor, wherein: the first end of the first resistor is electrically connected with the load end of the sampling resistor, and the second end of the first resistor is electrically connected with the collector electrode of the first NPN transistor; the first end of the second resistor is electrically connected with the load end of the sampling resistor, and the second end of the second resistor is electrically connected with the collector electrode of the second NPN transistor; the first end of the third resistor is electrically connected with the power supply end of the sampling resistor, and the second end of the third resistor is electrically connected with the collector electrode of the third NPN transistor; The collector of the first NPN transistor is electrically connected with the base of the first NPN transistor, and the emitter of the first NPN transistor is grounded; The collector of the second NPN transistor is electrically connected with the second input end of the signal extraction and amplification module, the base of the second NPN transistor is electrically connected with the base of the first NPN transistor, and the emitter of the second NPN transistor is grounded; The collector of the third NPN transistor is electrically connected with the first input end of the signal extraction and amplification module, the base of the third NPN transistor is electrically connected with the base of the first NPN transistor, and the emitter of the third NPN transistor is grounded.
3. The high-side current detection circuit of claim 1, wherein the potential shift module comprises a first resistor, a second resistor, a third resistor, a first NMOS transistor, a second NMOS transistor, and a third NMOS transistor, wherein: the first end of the first resistor is electrically connected with the load end of the sampling resistor, and the second end of the first resistor is electrically connected with the drain electrode of the first NMOS transistor; the first end of the second resistor is electrically connected with the load end of the sampling resistor, and the second end of the second resistor is electrically connected with the drain electrode of the second NMOS transistor; the first end of the third resistor is electrically connected with the power supply end of the sampling resistor, and the second end of the third resistor is electrically connected with the drain electrode of the third NMOS transistor; the drain electrode of the first NMOS transistor is electrically connected with the grid electrode of the first NMOS transistor, and the source electrode of the first NMOS transistor is grounded; the drain electrode of the second NMOS transistor is electrically connected with the second input end of the signal extraction and amplification module, the grid electrode of the second NMOS transistor is electrically connected with the grid electrode of the first NMOS transistor, and the source electrode of the second NMOS transistor is grounded; The drain electrode of the third NMOS transistor is electrically connected with the first input end of the signal extraction and amplification module, the grid electrode of the third NMOS transistor is electrically connected with the grid electrode of the first NMOS transistor, and the emitter electrode of the third NMOS transistor is grounded.
4. The high-side current detection circuit based on potential shifting according to claim 1, wherein the signal extraction and amplification module comprises a first operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor, wherein: The first end of the fourth resistor is used as a second input end of the signal extraction and amplification module, and the second end of the fourth resistor is electrically connected with the inverting input end of the first operational amplifier; the first end of the fifth resistor is electrically connected with the inverting input end of the first operational amplifier, and the second end of the fifth resistor is electrically connected with the output end of the first operational amplifier; The first end of the sixth resistor is used as a first input end of the signal extraction and amplification module, and the second end of the sixth resistor is electrically connected with the non-inverting input end of the first operational amplifier; the first end of the seventh resistor is electrically connected with the non-inverting input end of the first operational amplifier, and the second end of the seventh resistor is grounded; The output end of the first operational amplifier is used for outputting the output voltage.
5. The high-side current detection circuit according to claim 1, wherein the signal extraction and amplification module comprises a second operational amplifier, a third operational amplifier, a fourth operational amplifier, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor, wherein: the non-inverting input end of the second operational amplifier is used as a second input end of the signal extraction and amplification module, and the inverting input end of the second operational amplifier is electrically connected with the first end of the fourteenth resistor; The non-inverting input end of the third operational amplifier is used as a first input end of the signal extraction and amplification module, and the inverting input end of the third operational amplifier is electrically connected with the second end of the fourteenth resistor; The twelfth resistor is connected in parallel with the inverting input end and the output end of the second operational amplifier, and the thirteenth resistor is connected in parallel with the inverting input end and the output end of the third operational amplifier; The first end of the eighth resistor is electrically connected with the output end of the second operational amplifier, and the second end of the eighth resistor is electrically connected with the inverting input end of the fourth operational amplifier; The first end of the ninth resistor is electrically connected with the inverting input end of the fourth operational amplifier, and the second end of the ninth resistor is electrically connected with the output end of the fourth operational amplifier; the first end of the tenth resistor is electrically connected with the output end of the third operational amplifier, and the second end of the tenth resistor is electrically connected with the non-inverting input end of the fourth operational amplifier; The first end of the eleventh resistor is electrically connected with the non-inverting input end of the fourth operational amplifier, and the second end of the eleventh resistor is grounded; The output end of the fourth operational amplifier is used for outputting the output voltage.
6. The utility model provides a high-voltage side current detection system based on potential translation, its characterized in that includes power, load and a high-voltage side current detection circuit based on potential translation, high-voltage side current detection circuit based on potential translation includes sampling resistor, potential translation module and signal extraction amplification module, wherein: The sampling resistor is arranged on the high-voltage side between the power supply and the load; The potential translation module is used for potential translation of sampling voltages at two ends of the sampling resistor to a second input end and a first input end of the signal extraction and amplification module through a current mirror principle; The signal extraction and amplification module is used for extracting and amplifying potential signals received by the second input end and the first input end, so as to obtain output voltage, and detecting current according to the output voltage.
7. The high-side current detection system based on potential shifting of claim 6, wherein the potential shifting module comprises a first resistor, a second resistor, a third resistor, a first NPN transistor, a second NPN transistor, and a third NPN transistor, wherein: the first end of the first resistor is electrically connected with the load end of the sampling resistor, and the second end of the first resistor is electrically connected with the collector electrode of the first NPN transistor; the first end of the second resistor is electrically connected with the load end of the sampling resistor, and the second end of the second resistor is electrically connected with the collector electrode of the second NPN transistor; the first end of the third resistor is electrically connected with the power supply end of the sampling resistor, and the second end of the third resistor is electrically connected with the collector electrode of the third NPN transistor; The collector of the first NPN transistor is electrically connected with the base of the first NPN transistor, and the emitter of the first NPN transistor is grounded; The collector of the second NPN transistor is electrically connected with the second input end of the signal extraction and amplification module, the base of the second NPN transistor is electrically connected with the base of the first NPN transistor, and the emitter of the second NPN transistor is grounded; The collector of the third NPN transistor is electrically connected with the first input end of the signal extraction and amplification module, the base of the third NPN transistor is electrically connected with the base of the first NPN transistor, and the emitter of the third NPN transistor is grounded.
8. The high-side current detection system of claim 6, wherein the potential shifting module comprises a first resistor, a second resistor, a third resistor, a first NMOS transistor, a second NMOS transistor, and a third NMOS transistor, wherein: the first end of the first resistor is electrically connected with the load end of the sampling resistor, and the second end of the first resistor is electrically connected with the drain electrode of the first NMOS transistor; the first end of the second resistor is electrically connected with the load end of the sampling resistor, and the second end of the second resistor is electrically connected with the drain electrode of the second NMOS transistor; the first end of the third resistor is electrically connected with the power supply end of the sampling resistor, and the second end of the third resistor is electrically connected with the drain electrode of the third NMOS transistor; the drain electrode of the first NMOS transistor is electrically connected with the grid electrode of the first NMOS transistor, and the source electrode of the first NMOS transistor is grounded; the drain electrode of the second NMOS transistor is electrically connected with the second input end of the signal extraction and amplification module, the grid electrode of the second NMOS transistor is electrically connected with the grid electrode of the first NMOS transistor, and the source electrode of the second NMOS transistor is grounded; The drain electrode of the third NMOS transistor is electrically connected with the first input end of the signal extraction and amplification module, the grid electrode of the third NMOS transistor is electrically connected with the grid electrode of the first NMOS transistor, and the emitter electrode of the third NMOS transistor is grounded.
9. The high-side current detection system based on potential translation of claim 1, wherein the signal extraction and amplification module comprises a first operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor, wherein: The first end of the fourth resistor is used as a second input end of the signal extraction and amplification module, and the second end of the fourth resistor is electrically connected with the inverting input end of the first operational amplifier; the first end of the fifth resistor is electrically connected with the inverting input end of the first operational amplifier, and the second end of the fifth resistor is electrically connected with the output end of the first operational amplifier; The first end of the sixth resistor is used as a first input end of the signal extraction and amplification module, and the second end of the sixth resistor is electrically connected with the non-inverting input end of the first operational amplifier; the first end of the seventh resistor is electrically connected with the non-inverting input end of the first operational amplifier, and the second end of the seventh resistor is grounded; The output end of the first operational amplifier is used for outputting the output voltage.
10. The high-side current detection system according to claim 1, wherein the signal extraction and amplification module comprises a second operational amplifier, a third operational amplifier, a fourth operational amplifier, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor, wherein: the non-inverting input end of the second operational amplifier is used as a second input end of the signal extraction and amplification module, and the inverting input end of the second operational amplifier is electrically connected with the first end of the fourteenth resistor; The non-inverting input end of the third operational amplifier is used as a first input end of the signal extraction and amplification module, and the inverting input end of the third operational amplifier is electrically connected with the second end of the fourteenth resistor; The twelfth resistor is connected in parallel with the inverting input end and the output end of the second operational amplifier, and the thirteenth resistor is connected in parallel with the inverting input end and the output end of the third operational amplifier; The first end of the eighth resistor is electrically connected with the output end of the second operational amplifier, and the second end of the eighth resistor is electrically connected with the inverting input end of the fourth operational amplifier; The first end of the ninth resistor is electrically connected with the inverting input end of the fourth operational amplifier, and the second end of the ninth resistor is electrically connected with the output end of the fourth operational amplifier; the first end of the tenth resistor is electrically connected with the output end of the third operational amplifier, and the second end of the tenth resistor is electrically connected with the non-inverting input end of the fourth operational amplifier; The first end of the eleventh resistor is electrically connected with the non-inverting input end of the fourth operational amplifier, and the second end of the eleventh resistor is grounded; The output end of the fourth operational amplifier is used for outputting the output voltage.

Description

High-voltage side current detection circuit and system based on potential translation Technical Field The invention relates to the technical field of electronic measurement, in particular to a high-voltage side current detection circuit and system based on potential translation. Background In a power electronic system, accurate detection of load current is a key to realizing accurate control, reliable protection and state monitoring of the system. In many current detection technologies, the high-voltage side current detection scheme in which the sampling resistor is arranged between the positive electrode of the power supply and the load has the advantages of not damaging the ground line path, effectively detecting the open circuit fault of the load and the like, and is widely applied to various industries and the field of consumer electronic circuits. However, in existing high side current detection schemes, the differential signal across the sampling resistor is typically very weak and completely submerged under a common mode voltage that is extremely high relative to the system ground potential. Therefore, how to accurately extract useful differential signals from high common mode voltages becomes a current detection difficulty. The prior art mainly relies on a special high-voltage side current detection amplifier to solve the problems (such as TI INA240 series chips), and the special chips inhibit the influence of high common-mode voltage through an internally integrated precise circuit structure, so that the current is amplified and measured. For the special chip, when facing higher requirements or special application scenes, the chip is limited to a withstand voltage process of a semiconductor device, and the common-mode voltage input range of the chip is generally limited to about 60V to 100V, so that the chip cannot be suitable for application scenes of industrial motor driving, electric automobile driving and the like which need to bear high voltage exceeding 100V. Secondly, in order to realize high Common Mode Rejection Ratio (CMRR) and low offset voltage, the chip manufacturing process often needs to adopt complex processes such as laser trimming and the like, so that the chip manufacturing cost is high, and the overall cost of the current detection system is increased. In addition, the existing special current detection amplifier chip has fixed voltage withstanding index and gain setting, lacks flexibility, and cannot adapt to application requirements of diversified scenes. Therefore, there is an urgent need in the art to develop a high-side current detection scheme that can break through the existing voltage-withstanding limitation, is low in cost, and has excellent performance, so as to solve the defects existing in the prior art. Disclosure of Invention The invention aims to provide a high-voltage side current detection circuit and a high-voltage side current detection system based on potential translation, so as to provide a high-voltage side current detection scheme with high voltage resistance, low cost and excellent performance, and solve the defects in the existing high-voltage side current detection technology. In order to achieve the above object, a first aspect of the present invention provides a high-voltage side current detection circuit based on potential shift, including a sampling resistor, a potential shift module, and a signal extraction and amplification module, wherein: the sampling resistor is arranged on the high-voltage side between the external power supply and the external load; The potential translation module is used for potential translation of sampling voltages at two ends of the sampling resistor to a second input end and a first input end of the signal extraction and amplification module through a current mirror principle; The signal extraction and amplification module is used for extracting and amplifying potential signals received by the second input end and the first input end, so as to obtain output voltage, and detecting current according to the output voltage. According to the high-voltage side current detection circuit based on potential translation, the current mirror is realized through the specific resistor and transistor structure of the potential translation module, and the high common-mode voltage born by two ends of the sampling resistor can be translated to a safe low common-mode voltage domain by using the current mirror without distortion. The design ensures that the subsequent signal extraction and amplification module does not need to directly bear high common-mode voltage, thereby breaking through the withstand voltage limit of the traditional special detection chip, and realizing the withstand capability of hundreds of volts or even higher common-mode voltage only by selecting an external resistor with proper withstand voltage level. Meanwhile, the circuit avoids adopting a special current detection amplifying chip with high manufacturing cost,