CN216696436U - High-voltage small current detection circuit - Google Patents
High-voltage small current detection circuit Download PDFInfo
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- CN216696436U CN216696436U CN202122616110.9U CN202122616110U CN216696436U CN 216696436 U CN216696436 U CN 216696436U CN 202122616110 U CN202122616110 U CN 202122616110U CN 216696436 U CN216696436 U CN 216696436U
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Abstract
The utility model discloses a high-voltage small-current detection circuit which comprises an amplifying unit, a current detection unit, a first interference loop, a second interference loop and a load, wherein the load is respectively and electrically connected with the first interference loop and the second interference loop, the input end of the current detection unit is respectively and electrically connected with the first interference loop and the second interference loop, the output end of the current detection unit outputs detection current to the amplifying unit, the amplifying unit amplifies the detection current and then outputs the detection current to an external main control board, a DEV high-voltage power supply is connected in parallel in the first interference loop, and a TAR high-voltage power supply is connected in parallel in the second interference loop. The circuit structure of the utility model is simple and reliable, and can prevent stray interference current from passing through the detection circuit, thereby improving the stability of output voltage and the accuracy of current detection, reducing the area of the auxiliary circuit and the PCB, and reducing the production and design cost of the circuit.
Description
Technical Field
The utility model relates to the field of printer circuits, in particular to a high-voltage low-current detection circuit.
Background
At present, the laser printer power usually all needs the logic circuit to detect the undercurrent signal, under multichannel negative high voltage output (DEV, TAR), there are other stray undercurrent signal interference to the logic detection undercurrent signal circuit, make detection output voltage have great error, need add auxiliary circuit and eliminate stray interference signal, auxiliary circuit can increase the design difficulty of circuit board, the area of PCB board has been increaseed, material cost and manufacturing cost also will rise by a wide margin simultaneously.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the defects in the prior art, and provides a high-voltage small current detection circuit which is simple and reliable in circuit structure, can prevent stray interference current from passing through the detection circuit, improves the stability of output voltage and the accuracy of current detection, reduces the areas of an auxiliary circuit and a PCB (printed circuit board), and reduces the production and design cost of the circuit.
The purpose of the utility model is realized by the following technical scheme:
a high voltage low current detection circuit comprising: the load is respectively electrically connected with the first interference loop and the second interference loop, the input end of the current detection unit is respectively electrically connected with the first interference loop and the second interference loop, the output end of the current detection unit outputs the detection current to the amplification unit, the amplification unit amplifies the detection current and then outputs the detection current to an external main control board, a DEV high-voltage power supply is connected in parallel in the first interference loop, and a TAR high-voltage power supply is connected in parallel in the second interference loop.
Preferably, the current detection unit includes an operational amplifier U2A, a resistor R6, and a current sampling resistor R5, the current sampling resistor R5 is configured to sample a current of the load, two ends of the current sampling resistor R5 are electrically connected to pins 1 and 2 of the operational amplifier U2A, one end of the resistor R6 is connected to a first input voltage, the other end of the resistor R6 is electrically connected to pin 3 of the operational amplifier U2A, pin 2 of the operational amplifier U2A is further electrically connected to the first interference loop and the second interference loop, and pin 1 of the operational amplifier U2A is further electrically connected to an input end of the amplification unit.
Preferably, the first input voltage is + 5V.
Preferably, the amplifying unit includes an operational amplifier U1A, a resistor R1, a resistor R2, and a resistor R3, a pin 2 of the operational amplifier U1A is electrically connected to the output end of the current detection unit, a pin 3 of the operational amplifier U1A is electrically connected to the resistor R2 and the resistor R3, the other end of the resistor R2 is connected to a second input voltage, two ends of the resistor R1 are electrically connected to a pin 1 and a pin 2 of the operational amplifier U1A, and a pin 1 of the operational amplifier U1A is configured to output a current amplifying signal to an external main control board.
Preferably, the amplifying unit further includes a resistor R4, and two ends of the resistor R4 are electrically connected to the pin 2 of the operational amplifier U1A and the output end of the current detecting unit, respectively.
Preferably, the second input voltage is + 5V.
Preferably, the load includes a load resistor R15, one end of the load resistor R15 is electrically connected to the first interference loop and the second interference loop, respectively, and the other end of the load resistor R15 is grounded.
Preferably, the first interference loop includes a resistor R10, a resistor R12, and an input power source V6, a first end of the resistor R12 is electrically connected to the resistor R10, a second end of the resistor R12 is electrically connected to the DEV high-voltage power source, the load, and a positive electrode of the input power source V6, and a negative electrode of the input power source V6 is electrically connected to the output end of the current detection unit and an end of the resistor R10 away from the resistor R12.
Preferably, the second interference loop includes a resistor R11, a resistor R13, and an input power source V5, a first end of the resistor R13 is electrically connected to the resistor R11, a second end of the resistor R13 is electrically connected to the TAR high-voltage power source and a positive electrode of the input power source V5, respectively, and a negative electrode of the input power source V5 is electrically connected to an output end of the current detection unit and an end of the resistor R11 away from the resistor R13, respectively.
Compared with the prior art, the utility model has the following advantages and beneficial effects:
1. the high-voltage small current detection circuit is simple and reliable in circuit structure by arranging the amplifying unit, the current detection unit, the first interference loop, the second interference loop and the load, stray interference current can not pass through the detection circuit, the stability of output voltage and the accuracy of current detection are improved, the areas of an auxiliary circuit and a PCB are reduced, and the production and design cost of the circuit is reduced.
2. The utility model can avoid sampling the current in the interference loop by canceling the auxiliary circuit, and does not need to subsequently eliminate the current in the interference loop, thereby directly sampling the total current of the load, improving the sampling precision, and canceling the auxiliary circuit, so that the circuit is simpler and more reliable and has lower cost.
Drawings
FIG. 1 is a functional block diagram of a high voltage low current detection circuit according to an embodiment of the present invention;
fig. 2 is a circuit diagram of the high-voltage low-current detection circuit shown in fig. 1.
Detailed Description
To facilitate an understanding of the utility model, the utility model will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
The laser printer power supply usually needs a logic circuit to detect a small current signal, under the condition of multi-path negative high voltage output, other useless small current signals interfere the logic detection small current signal circuit, so that the detection output voltage has a larger error, an auxiliary circuit of an inverse proportion amplifier is needed to be added to eliminate the useless interference current signal, and a detection resistor in the inverse proportion amplifier detects the current of an interference loop and a load. Therefore, after detection, the current in the interference loop needs to be removed, and since the auxiliary circuit does not completely filter the useless interference current, the detection current at the rear-stage end is inaccurate, so that the output Vsense voltage is unstable, the area of the PCB board is increased by the auxiliary circuit, the design difficulty of the circuit board is increased, and the material cost and the manufacturing cost are greatly increased.
In one embodiment, referring to fig. 1, a high-voltage low-current detection circuit includes: the current detection circuit comprises an amplifying unit 100, a current detection unit 200, a first interference loop 300, a second interference loop 400 and a load 500, wherein the load is respectively electrically connected with the first interference loop and the second interference loop, the input end of the current detection unit is respectively electrically connected with the first interference loop and the second interference loop, the output end of the current detection unit outputs detection current to the amplifying unit, the amplifying unit amplifies the detection current and outputs the amplified detection current to an external main control board, a DEV high-voltage power supply is connected in parallel in the first interference loop, and a TAR high-voltage power supply is connected in parallel in the second interference loop. In the present embodiment, the load includes two loads, such as load 1 and load 2 in the figure, and load 1 is connected to the first interference loop, and load 2 is connected to the second interference loop.
By canceling the auxiliary circuit, useless interference current is eliminated without adding an inverting proportional amplifier circuit, and the load current to be detected detects the current of an actual load through a current detection unit, so that the stability of logic output voltage is guaranteed, the circuit is simple, the cost is low, and the detection precision of the output voltage is higher. So, through setting up amplifying unit, current detection unit, first interference return circuit, second interference return circuit and load, circuit structure is simple reliable, can make stray interference current can not pass through detection circuitry, has improved output voltage's stability and current detection's precision, reduces auxiliary circuit and PCB area, has reduced circuit production and design cost.
It should be noted that, according to the technical scheme in the application, on one hand, an original auxiliary circuit is eliminated, so that the steps of removing superposed interference current in current detection can be reduced, and the current calculation process is simplified; on the other hand, after redesigning, the interference current is only connected in parallel at two ends of the high-voltage power supply, and the current does not flow through the detection circuit and does not flow into the operational amplifier, so that the interference on the current detection can be further reduced, and the accuracy on the current detection is improved.
Referring to fig. 2, the current detection unit includes an operational amplifier U2A, a resistor R6, and a current sampling resistor R5, the current sampling resistor R5 is configured to sample a current of the load, two ends of the current sampling resistor R5 are respectively electrically connected to pins 1 and 2 of the operational amplifier U2A, one end of the resistor R6 is connected to a first input voltage, the other end of the resistor R6 is electrically connected to pin 3 of the operational amplifier U2A, pin 2 of the operational amplifier U2A is further electrically connected to the first interference loop and the second interference loop, and pin 1 of the operational amplifier U2A is further electrically connected to an input end of the amplification unit. In this embodiment, the first input voltage is + 5V. In this way, by providing the current sampling resistor R5, the current of the load can be sampled, and the sampling accuracy can be improved.
Referring to fig. 2, the amplifying unit includes an operational amplifier U1A, a resistor R1, a resistor R2, and a resistor R3, wherein a pin 2 of the operational amplifier U1A is electrically connected to an output end of the current detecting unit, a pin 3 of the operational amplifier U1A is electrically connected to the resistor R2 and the resistor R3, the other end of the resistor R2 is connected to a second input voltage, two ends of the resistor R1 are electrically connected to a pin 1 and a pin 2 of the operational amplifier U1A, and a pin 1 of the operational amplifier U1A is configured to output a current amplifying signal to an external main control board. In this embodiment, the second input voltage is + 5V. The amplifying unit further comprises a resistor R4, and two ends of the resistor R4 are electrically connected with the pin 2 of the operational amplifier U1A and the output end of the current detection unit respectively. Thus, by arranging the operational amplifier U1A, the detected current can be amplified and then output to the main control board, where the amplified current signal is output.
The load includes a load resistor R15, one end of the load resistor R15 is electrically connected to the first interference loop and the second interference loop, respectively, and the other end of the load resistor R15 is grounded. Therefore, the current detection unit can be convenient to detect.
Referring to fig. 2, the first interference loop includes a resistor R10, a resistor R12, and an input power source V6, a first end of the resistor R12 is electrically connected to the resistor R10, a second end of the resistor R12 is electrically connected to the DEV high-voltage power source, the load, and a positive electrode of the input power source V6, and a negative electrode of the input power source V6 is electrically connected to an output end of the current detection unit and an end of the resistor R10 away from the resistor R12. Therefore, the resistor R10, the resistor R12 and the input power supply V6 can form a loop, so that the current detection unit can be prevented from detecting.
Referring to fig. 2, the second interference loop includes a resistor R11, a resistor R13, and an input power source V5, a first end of the resistor R13 is electrically connected to the resistor R11, a second end of the resistor R13 is electrically connected to the positive electrodes of the TAR high voltage power source and the input power source V5, and a negative electrode of the input power source V5 is electrically connected to the output end of the current detection unit and an end of the resistor R11 away from the resistor R13. Similarly, the resistor R11, the resistor R13 and the input power supply V5 can form a loop, so that the current detection unit can be prevented from detecting.
The above embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (9)
1. A high voltage low current detection circuit, comprising: the load is respectively electrically connected with the first interference loop and the second interference loop, the input end of the current detection unit is respectively electrically connected with the first interference loop and the second interference loop, the output end of the current detection unit outputs the detection current to the amplification unit, the amplification unit amplifies the detection current and then outputs the detection current to an external main control board, a DEV high-voltage power supply is connected in parallel in the first interference loop, and a TAR high-voltage power supply is connected in parallel in the second interference loop.
2. The high-voltage small-current detection circuit according to claim 1, wherein the current detection unit includes an operational amplifier U2A, a resistor R6, and a current sampling resistor R5, the current sampling resistor R5 is used for sampling current of the load, two ends of the current sampling resistor R5 are electrically connected to pin 1 and pin 2 of the operational amplifier U2A, one end of the resistor R6 is connected to a first input voltage, the other end of the resistor R6 is electrically connected to pin 3 of the operational amplifier U2A, pin 2 of the operational amplifier U2A is further electrically connected to the first interference loop and the second interference loop, and pin 1 of the operational amplifier U2A is further electrically connected to the input end of the amplification unit.
3. The high-voltage low-current detection circuit according to claim 2, wherein the first input voltage is + 5V.
4. The high-voltage small-current detection circuit according to claim 1, wherein the amplifying unit comprises an operational amplifier U1A, a resistor R1, a resistor R2 and a resistor R3, wherein a pin 2 of the operational amplifier U1A is electrically connected with an output end of the current detection unit, a pin 3 of the operational amplifier U1A is electrically connected with the resistor R2 and the resistor R3 respectively, the other end of the resistor R2 is connected to a second input voltage, two ends of the resistor R1 are electrically connected with a pin 1 and a pin 2 of the operational amplifier U1A respectively, and a pin 1 of the operational amplifier U1A is used for outputting a current amplifying signal to an external main control board.
5. The high-voltage small-current detection circuit according to claim 4, wherein the amplifying unit further comprises a resistor R4, and two ends of the resistor R4 are electrically connected to the 2 pins of the operational amplifier U1A and the output end of the current detection unit, respectively.
6. The high-voltage low-current detection circuit according to claim 4, wherein the second input voltage is + 5V.
7. The high-voltage small-current detection circuit according to claim 1, wherein the load comprises a load resistor R15, one end of the load resistor R15 is electrically connected to the first interference loop and the second interference loop, respectively, and the other end of the load resistor R15 is grounded.
8. The high-voltage low-current detection circuit according to claim 1, wherein the first interference loop comprises a resistor R10, a resistor R12 and an input power source V6, a first end of the resistor R12 is electrically connected to the resistor R10, a second end of the resistor R12 is electrically connected to the DEV high-voltage power source, the load and a positive electrode of the input power source V6, respectively, and a negative electrode of the input power source V6 is electrically connected to the output terminal of the current detection unit and an end of the resistor R10 away from the resistor R12, respectively.
9. The high-voltage low-current detection circuit according to claim 8, wherein the second interference loop comprises a resistor R11, a resistor R13 and an input power source V5, a first end of the resistor R13 is electrically connected to the resistor R11, a second end of the resistor R13 is electrically connected to the positive electrodes of the TAR high-voltage power source and the input power source V5, respectively, and a negative electrode of the input power source V5 is electrically connected to the output terminal of the current detection unit and an end of the resistor R11 away from the resistor R13, respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122616110.9U CN216696436U (en) | 2021-10-26 | 2021-10-26 | High-voltage small current detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122616110.9U CN216696436U (en) | 2021-10-26 | 2021-10-26 | High-voltage small current detection circuit |
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| Publication Number | Publication Date |
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| CN216696436U true CN216696436U (en) | 2022-06-07 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202122616110.9U Active CN216696436U (en) | 2021-10-26 | 2021-10-26 | High-voltage small current detection circuit |
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| CN (1) | CN216696436U (en) |
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2021
- 2021-10-26 CN CN202122616110.9U patent/CN216696436U/en active Active
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